Journal of Clinical Lipidology (2014) 8, 206–216
Prevalence of dyslipidemia and associated risk factors in Turkish adults Fahri Bayram, MD, Derya Kocer, MD, Kursat Gundogan, MD, Ahmet Kaya, MD, Ozgur Demir, MD, Ramazan Coskun, MD, Tevfik Sabuncu, MD, Ahmet Karaman, MD, Mustafa Cesur, MD, Manfredi Rizzo, MD, Peter P. Toth, MD, PhD*, Vedia Gedik, MD Faculty of Medicine, Department of Endocrinology and Metabolism, Erciyes University, Kayseri, Turkey (Dr. Bayram); Department of Biochemistry, Kayseri Research and Training Hospital, Kayseri, Turkey (Dr. Kocer); Faculty of Medicine, Department of Intensive Care, Erciyes University, Kayseri, Turkey (Dr. Gundogan, Dr. Coskun); Division of Endocrinology and Metabolism, Department of Internal Medicine, Meram Medical Faculty, Selcuk University, Konya, Turkey (Dr. Kaya); Faculty of Medicine, Department of Endocrinology and Metabolism, Ankara University, Ankara, Turkey (Dr. Demir, Dr. Gedik); Faculty of Medicine, Department of Endocrinology and Metabolism, Harran University, S¸anlıurfa, Turkey (Dr. Sabuncu); Department of Gastroenterology, Kayseri Training and Research Hospital, Kayseri, Turkey (Dr. Karaman); Department of Endocrinology and Metabolic Disease, Ankara Guven Hospital, Ankara, Turkey (Dr. Cesur); BioMedical Department of Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy (Dr. Rizzo); Euro–Mediterranean Institute of Science and Technology, Italy (Dr. Rizzo); Department of Preventative Cardiology, CGH Medical Center, Sterling, IL (Dr. Toth); and University of Illinois College of Medicine, Peoria, IL (Dr. Toth) KEYWORDS: Dyslipidemia; Cholesterol; Low-density lipoprotein; Triglycerides; High-density lipoprotein; Prevalence; Turkey
BACKGROUND AND OBJECTIVES: Dyslipidemia is a modifiable major risk factor for coronary heart disease. The objective of this study was to determine the prevalence of dyslipidemia among Turkish adults and its associations with other cardiovascular risk factors. METHODS: This study included 4309 people ages 20 to 83 years old from 7 provinces of Turkey. People from the city centers, districts, and villages were selected by a stratified sampling method. Weight, height, and waist and hip circumferences were measured. Blood samples were obtained to determine glucose, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG); these parameters were measured with an autoanalyzer. Dyslipidemia was defined according to National Cholesterol Education Program Adult Treatment Panel III diagnostic criteria. RESULTS: Of 4309 subjects, 43% had high TC, 41.5% had low HDL-C, 36.2% had high LDL-C, and 35.7% had high TG. Of these measures, at least 1 lipid abnormality was diagnosed in 78.7% of men and 80.4% of women. The prevalence of high TC, LDL-C, and TG increased with age, with the highest prevalence in the 46-to-65-year-old age group. The mean values (mg/dL) of TC, LDL-C, HDL-C, and TG were 194.2 6 47.7, 117.7 6 41.1, 50.3 6 16.3, and 145.4 6 96.3, respectively. Dyslipidemia was positively associated with age, body mass index, waist circumference, fasting blood glucose, and blood pressure, and negatively associated with altitude.
* Corresponding author. E-mail address: [email protected] Submitted May 16, 2013. Accepted for publication December 26, 2013. 1933-2874/$ - see front matter Ó 2014 National Lipid Association. All rights reserved. http://dx.doi.org/10.1016/j.jacl.2013.12.011
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CONCLUSIONS: The high prevalence of dyslipidemia in Turkey is an important public health problem. Enhanced public health preventive measures should be implemented to better diagnose and comprehensively treat dyslipidemia in Turkey. Ó 2014 National Lipid Association. All rights reserved.
Dyslipidemia is a major independent modifiable risk factor for cardiovascular diseases.1 The prevalence of dyslipidemia is high and increasing in most developed countries as well as in many developing countries as a result of the Westernization of diet, obesity, reduced physical activity, and other adverse lifestyle changes2 Hypertriglyceridemia, low serum high-density lipoprotein cholesterol (HDL-C) concentrations, and elevated low-density lipoprotein cholesterol (LDL-C) are established, defining features of dyslipidemia. Dyslipidemia is highly prevalent worldwide and risk for mixed forms of dyslipidemia is increased by visceral adiposity, metabolic syndrome (MS)/insulin resistance, and diabetes mellitus (DM).3,4 Although the measurement of plasma lipid and lipoprotein levels in different regions of Turkey was examined in previous studies,5–7 the relationship of dyslipidemia with other risk factors such as hypertension (HTN), DM, obesity, and MS has not been previously reported. Several studies have reported a high prevalence of DM, obesity, HTN, and MS in Turkish adults.8–13 In Turkey, the relationship between dyslipidemia and associated risk factors is inadequately defined. It has been shown that the effective treatment of dyslipidemia reduces the rate of cardiovascular morbidity and mortality. Therefore, estimation of the prevalence of dyslipidemia ensures proper planning of health actions for both the primary and secondary prevention of cardiovascular events. In this study, we present the findings of a study that evaluated the prevalence of dyslipidemia and its association with other risk factors that includes 23 provinces from 7 regions of Turkey.
Materials and methods
Giresun, Hatay, Istanbul, Izmir, Kars, Kayseri, Konya, Mersin, Samsun, Sivas, Sanliurfa, Van, Zonguldak) from 7 regions of Turkey (Fig. 1). Approval from the Ministry of Health was obtained and the household identification form data from the Primary Health Care Centers of Provincial Health Directorates, affiliated with the Ministry of Health, was used. The study sample included males and nonpregnant females between 20 and 83 years of age. Populations of city centers, districts, and villages were classified by using the stratified sampling method and then were selected from the household identification form data by a simple random sampling method. According to the 2000 census, population distribution of regions and number of received people are shown in Table 1. The age groups were also classified according to results from the 2000 census as 20 to 25 years, 26 to 30 years, 31 to 35 years, 36 to 40 years, 41 to 45 years, 46 to 50 years, 51 to 55 years, 56 to 60 years, 61 to 65 years, 66 to 70 years, and 70 and older. Descriptive features of the provincial district centers and villages, including gender, demographics, economic, social, and geographical status, were taken into consideration. Information was sent to the regions’ health units (primary health care centers, hospitals, and health houses) about 2 weeks before the study was to be conducted. Although it varies depending on the region, 83% of invited subjects actually participated in this study. The participants were told to fast for 10 to 12 hours before the sampling. Between 7:00 and 10:00 AM, about 100 people were evaluated in health units affiliated with the Ministry of Health. Informed consent was obtained from all participants. Structured questionnaires were completed with faceto-face interviews. The study was performed in accordance with the Declaration of Helsinki.
Study plan and sampling
Study protocol
This study was a cross-sectional survey conducted in Turkey to assess the prevalence of abnormal lipid values among different Turkish populations. The sampling design was based on multistage probability sampling. According to this method, 7 regions of Turkey were taken as stratum (the populations of these 7 regions were obtained from the results of a 2000 national Turkish census). At least 3 provinces were selected from each region by a simple random sampling method. A total of 23 provinces were taken as ‘‘clusters.’’ This study was conducted in these 23 provinces (Ankara, Antalya, Bursa, Canakkale, Denizli, Diyarbakir, Edirne, Erzurum, Eskisehir, Gaziantep,
Medical histories and measurements of participants were obtained by well-trained nurses and specialist physicians. The age and gender of participants were recorded. Personal and family histories of HTN, DM, cardiovascular disease, and other chronic diseases were obtained. Heights and weights of participants were measured. Body mass index (BMI) was calculated by dividing the weight (in kilograms) by the square meters of the height. BMI lower than 19 kg/ m2 was classified as underweight and between 19 and 25 kg/m2 as normal. BMI values between 25 and 29.9 kg/ m2 were considered as overweight and above 30 kg/m2 as obese. Also, waist circumference (WC) of participants
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Figure 1
Seven regions of Turkey.
was measured at the level of the iliac processes and the umbilicus with a tape measure to evaluate abdominal obesity. Systolic blood pressure and diastolic blood pressure were measured twice in the sitting position, with an interval of 15 minutes between the measurements, by means of standard sphygmomanometers of appropriate width, after a rest period of 30 minutes. The normal limit for systolic HTN was 130 mm Hg and for diastolic HTN was 85 mm Hg, consistent with the Third Adult Treatment Panel (ATP III) cut points for blood pressure in the definition of metabolic syndrome. Patients taking antihypertensive medication were classified as hypertensive by definition. Blood samples were centrifuged at room temperature for 10 minutes at 3000 rpm. The extracted sera were stored in ice bags and placed into deep freezers at 270 C on the same day. Glucose, total cholesterol (TC), HDL-C and triglyceride (TG) levels were evaluated by an enzymatic spectrophotometric method with the Kone Lab Auto Analyzer (Thermo Clinical Labsystems Oy Vantaa, Finland). LDL-C was calculated by the Friedewald formula (in those with TG level ,400 mg/dL). DM was diagnosed according to the American Diabetes Association criteria. Accordingly, single fasting blood glucose (FBG) .126 mg/ dL was considered diagnostic of DM. Those with a previous DM diagnosis and the use of oral antidiabetic agents and/or insulin therapy were classified as being diabetic. Impaired fasting glucose was defined as FBG levels between 110 and 126 mg/dL. The diagnosis of MS was made depending on the presence of at least 3 of the Table 1
following parameters, according to ATP III criteria: abdominal obesity (WC .102 cm for males and .88 cm for females), HTN (systolic blood pressure .130 mm Hg and/or diastolic blood pressure .85 mm Hg), hypertriglyceridemia ($150 mg/dL), low HDL-C (,40 mg/dL in males and ,50 mg/dL in females), and elevated FBG ($100 mg/dL). Dyslipidemias were defined according to National Cholesterol Education Program ATP III criteria14 High TC was defined as TC $200 mg/dL and hypertriglyceridemia was defined as serum TG level $150 mg/dL. Low HDL-C was defined as serum HDL-C level ,40 mg/dL in males and ,50 mg/dL in females. High LDL-C was defined as serum LDL-C $130 mg/dL.14 Although we considered using the International Diabetes Federation diagnostic criteria for Mediterranean populations,15 these were not widely applicable because not all of the indigenous populations in Turkey are ‘‘Mediterranean.’’ Therefore, we elected to use the ATP III criteria to make our study more comparable with previous studies performed in other populations, including Asian populations. We defined the coast as elevations between 0 and 300 m, medium altitude as elevations between 300 and 1000 m, and high altitude as elevations above 1000 m.
Statistical analysis Unbalanced sampling selections were made during the multistage sampling process. Because of this unbalanced
Population distribution of regions and number of received people according to the 2000 census
Regions
Turkey-wide population status
Turkey-wide over 20 years Population status (%)
Received by regions Number of people (%)
Weight
Marmara Center Anatolia Aegean Mediterranean Black Sea Southeastern Anatolia Eastern Anatolia Total
17,365,027 11,608,868 8,938,781 8,706,005 8,439,213 6,608,619 6,137,414 67,803,927
13,730,962 8,039,036 5,495,575 5,204,203 4,137,466 4,143,136 3,255,896 44,006,274
820 816 424 674 535 603 437 4309
1.63 0.95 1.33 0.77 0.77 0.68 0.69 —
31 18 13 12 9.5 9.5 7 100
19.0 18.9 9.8 15.6 12.4 14.0 10.1 100
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selection, we calculated post-stratification weights using the results of the 2000 national Turkish census to adjust our data to conform more to the population’s parameters. To make this calculation, we used Statistical Package for the Social Sciences Syntax Editor and wrote syntax codes to calculate post-stratification weights. Weights are given in the last column of Table 1; syntax codes were as follows:
Marmara, 820 (19.0%); Center Anatolia, 816 (18.9%); Aegean, 424 (9.8%); Mediterranean, 674 (15.6%); Black Sea, 535 (12.4%); Southeastern Anatolia, 437 (10:1%); and Eastern Anatolia, 603 (14.0%) (Table 1). The mean age of participants was 47.1 6 14.7 years (20–83); that of males was 49.0 6 14.5 years and of females was 45.5 6 14.7 years. The distribution of age classifications was: 7.4% (n 5 319) between 20 and 25 years, 6.8% (n 5 294) between 26 and 30 years, 10.0% (n 5 433) between 31 and 35 years, 12.0% (n 5 519) between 36 and 40 years, 11.4% (n 5 492) between 41 and 45 years, 11.6% (n 5 498) between 46 and 50 years, 11.3% (n 5 487) between 51 and 55 years, 9.0% (n 5 387) between 56 and 60 years, 7.3% (n 5 314) between 61 and 65 years, 6.3% (n 5 273) between 66 and 70 years, and 6.8% (n 5 293) older than 70 years. Locations of participants were: 40.1% (n 5 1729) living in city centers, 36.9% (n 5 1589) in districts, and 23% (n 5 991) in the villages. Clinical characteristics of the participants are shown in Table 2.
IF (bolge1 5 IF (bolge1 5 IF (bolge1 5 IF (bolge1 5 IF (bolge1 5 IF (bolge1 5 IF (bolge1 5 EXECUTE.
1) 2) 3) 4) 5) 6) 7)
weight weight weight weight weight weight weight
5 5 5 5 5 5 5
0.77. 0.95. 0.68. 1.33. 1.63. 0.77. 0.69.
After this process, we weighted our data based on the recently calculated weights and followed classical statistical procedures using the tests written in the following section. The chi-squared test was used to determine significant differences in proportions among categorical variables. The Student t-test and Mann-Whitney U-test were used to compare differences of continuous variables. The univariate and multiple binary logistic regression models were used to investigate the probability of having dyslipidemia according to sociodemographic variables. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using binary logistic regression for each model. All statistical analyses were calculated with the Statistical Package for the Social Sciences, version 15.0 (Chicago, IL). Two-tailed P values of ,.05 were considered to be statistically significant.
As shown in Table 2, the mean level of TG was higher in men than women (P , .05), whereas the mean levels of TC and HDL-C were higher in women than in men (P , .05). Mean levels of TG, LDL-C, and HDL-C concentrations according to gender and age groups are presented in Table 3. The levels of TC, LDL-C, and TG in both women and men increased with age, with the highest values being observed in the 46-to-60-year-old group.
Prevalence of dyslipidemia and associated factors
Results Demographic features A total of 4309 adults participated in the study (1947 males, 45.2%; 2362 females, 54.8%) from 7 regions: Table 2
Mean plasma lipid levels
Of 4309 subjects, 43% had high TC, 41.5% had low HDL-C, 36.2% had high LDL-C, and 35.7% had high TG. The prevalence of binary and ternary combinations of dyslipidemia components are shown in Figure 2. Of these
Clinical characteristics of participants
Variants
General n 5 4309 x6sd
Age (years) SBP (mm Hg) DBP (mm Hg) BMI (kg/m2) WC (cm) FBG (mg/dL) TC (mg/dL) TG (mg/dL) LDL-C (mg/dL) HDL-C (mg/dL)
47.1 133.5 81.4 28.3 92.6 103.7 194.2 145.4 117.7 50.3
6 6 6 6 6 6 6 6 6 6
14.7 27.2 15.1 5.2 12.9 44.8 47.7 96.3 41.1 16.3
Gender Males n 5 1947 x6sd 49.0 133.0 81.2 27.4 95.6 102.7 191.2 152.7 117.1 46.9
6 6 6 6 6 6 6 6 6 6
14.5 26.6 15.3 4.3 11.9 41.7 47.5 103.2 40.8 15.8
Females n 5 2362 x6sd 45.5 133.9 81.5 29.1 90.2 104.5 196.7 139.4 118.3 53.1
6 6 6 6 6 6 6 6 6 6
14.7 27.7 14.9 5.6* 13.2* 47.2 47.7* 89.7* 41.2 16.2*
BM, body mass index; DBP, diastolic blood pressure; FBG, fasting blood glucose; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; SBP, systolic blood pressure; SD, standard deviation; TC, total cholesterol; TG, triglyceride; WC, waist circumference. *P , .05 significantly different between the males and females.
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Table 3
Mean of TG, LDL-C, and HDL-C concentrations according to gender and age decades
Gender/age Male 21–25 26–30 31–35 36–40 41–45 46–50 51–55 56–60 61–65 66–70 .70 Total Female 21–25 26–30 31–35 36–40 41–45 46–50 51–55 56–60 61–65 66–70 .70 Total Total P (men vs. women)
n
TG (mg/DL) x6sd
109 100 161 207 242 252 230 177 166 129 174 1947
110.9 139.3 155.2 162.6 158.2 164.3 172.9 157.4 140.5 133.1 143.0 152.7
6 6 6 6 6 6 6 6 6 6 6 6
84.9 116.0 117.2 106.4 101.3 100.8 118.4 84.1 92.7 71.7 109.8 103.2
91.1 109.4 113.5 115.2 115.4 122.8 121.8 121.9 118.2 121.9 121.6 117.1
6 6 6 6 6 6 6 6 6 6 6 6
34.1 34.8 38.2 42.4 37.2 42.1 41.8 42.9 39.0 45.2 39.2 40.8
47.2 44.9 46.9 44.9 48.3 46.5 47.7 48.2 45.8 45.4 48.9 46.9
6 6 6 6 6 6 6 6 6 6 6 6
12.8 13.6 17.4 15.1 18.9 15.3 17.7 16.4 14.2 12.3 14.5 15.8
210 194 272 312 250 246 257 210 148 144 119 2362 4309
100.0 6 111.5 6 125.1 6 134.1 6 144.4 6 147.3 6 162.9 6 162.3 6 165.5 6 142.7 6 147.0 6 139.4 6 145.4 6 ,.001
50.8 62.9 72.6 86.2 110.9 81.6 94.2 110.3 113.6 80.1 77.5 89.7 96.3
87.1 99.7 105.3 114.6 116.3 135.6 134.0 129.2 134.4 125.2 129.1 118.3 117.7 .353
6 6 6 6 6 6 6 6 6 6 6 6 6
33.2 35.3 33.7 37.6 35.6 44.8 41.8 38.8 39.4 42.3 40.9 41.2 41.1
55.2 6 53.7 6 51.9 6 52.8 6 52.8 6 55.2 6 51.6 6 52.0 6 49.9 6 45.4 6 53.0 6 53.1 6 50.3 6 ,.001
15.7 16.5 14.1 16.6 16.5 18.3 16.2 15.5 15.3 12.3 14.3 16.2 16.3
LDL-C (mg/DL) x6sd
HDL-C (mg/DL) x6sd
HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; SD, standard deviation; TG, triglyceride.
measures, at least 1 abnormal lipid concentration was recorded in 78.7% in men and 80.4% in women. The prevalence of dyslipidemia components according to gender, age, BMI, and location is shown in Table 4. The prevalence of high TG, high LDL-C, and low HDL-C were 35.7% (33.5% for women and 38.3% for men (P , .05), 36.2% (37.2% for women and 35.0% for men, (P . .05), and 41.5% (46.2% for women and 35.9% for men (P , .05), respectively. The higher prevalence of low HDL-C and high LDL-C/low HDL-C in women compared with men is particularly striking. The prevalence of dyslipidemia components increased with age, with the highest values being observed in the 46-to-65-year-old group, except HDL-C. In addition, the highest prevalence of dyslipidemia components was observed in obese subjects with trends for increasing prevalence of a variety of dyslipidemias as patients go from normal weight to overweight and then becoming obese (elevated TG, elevated LDL-C, low HDL-C, high LDL-C/low HDL-C, high LDL-C/high TG, and high LDL-C/high TG/low HDL-C). The highest prevalence of high LDL-C and low HDL-C were observed in district centers, whereas the prevalence of high TG was greatest in city centers. Table 5 shows the frequency of dyslipidemia components according to regions. The highest prevalence of high LDL-C
and low HDL-C were observed in the Marmara region, whereas the highest prevalence of hypertriglyceridemia occurred in the Mediterranean region. The highest prevalence of binary and ternary combinations of dyslipidemia
Figure 2 The frequency of dyslipidemia components and the prevalence ratio (%). HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TG, triglyceride.
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The prevalence of dyslipidemia components according to gender, age, BMI, and location (%)
Variants Gender Male Female Age groups 21–25 26–30 31–35 36–40 41–45 46–50 51–55 56–60 61–65 66–70 .70 BMI Normal Overweight Obese Location City center District Village
High TG (%)
High LDL-C (%)
Low HDL-C (%)
High LDL-C 1 low HDL-C (%)
High LDL-C 1 high TG (%)
Low HDL-C 1 high TG (%)
High LDL-C 1 low HDL-C 1 high TG (%)
38.3* 33.5
35.0 37.2
35.9 46.2†
8.7 13.6†
12.7† 8.5
8.0 7.5
11.2 14.2
15.4 25.2 31.2 37.2 38.2 41.6 48.3† 41.6 38.5 30.8 30.7
12.5 20.1 22.9 33.6 34.9 47.6† 47.2 43.4 45.1 39.3 45.4
37.0 42.2 43.0 45.9 41.5 40.6 43.5 42.1 44.6* 39.6 32.4
3.9 8.1 10.0 11.7 12.3 14.3 10.6 11.9 14.1 14.9 11.7
4.9 7.1 5.7 9.7 10.0 13.4 15.4 13.0 10.9 9.7 11.0
4.6 6.4 10.0 10.5 9.4 6.2 8.9 8.2 8.0 4.8 3.4
2.6 6.4 10.0 12.3 12.8 15.7 19.5 15.3 17.0 12.3 12.1
21.0 36.8 45.2†
25.6 35.0 45.9†
35.5† 41.6 45.5
8.3 9.9 15.2†
5.8 10.4 14.0
5.2 10.2 8.0
5.7 11.1 22.7
37.9 35.1 32.6
37.5 39.9† 28.3
41.9 46.3† 33.4
10.9 14.3† 7.5
11.1 9.5 10.3
8.3 7.8 6.4
13.1 13.9 10.5
Prevalence of dyslipidemia in Turkish adults
Table 4
BMI, body mass index; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TG, triglyceride. *P , .05. †P , .001.
211
10.6 12.4 22.7 7.1 10.2 11.5 25.5* 9.6 322 Marmara Mediterranean Center Anatolia Aegean Black Sea Eastern Anatolia Southeastern Anatolia General (%) n
HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TG, triglyceride. *P , .001.
39.5* 6.1 18.5 17.6 5.5 4.4 8.4 14.2 476 37.6 43.8* 38.0 32.3 30.8 27.0 33.8 35.7 1537
Regions
63.9* 35.3 32.2 53.1 25.0 17.1 16.9 36.2 2205
52.4* 23.6 45.7 50.9 26.0 37.1 51.6 41.5 1790
17.5 27.2* 17.5 9.2 13.1 6.5 9.0 13.0 434
Low HDLC 1 high TG (%) High LDLC 1 high TG (%) High LDLC 1 low HDL-C (%) Low HDL-C (%) High LDL-C (%) High TG (%)
Dyslipidemia components
The frequency of dyslipidemia components according to regions (%) Table 5
33.5* 10.2 21.2 12.3 6.3 6.1 10.2 16.0 537
Journal of Clinical Lipidology, Vol 8, No 2, April 2014 High LDL-C 1 low HDL-C 1 high TG (%)
212
components were observed in the Marmara region, except for the low HDL-C and high TG combination. The frequencies of HTN, DM, MS, and abdominal obesity in the dyslipidemic population are presented in Table 6. The participants who have 3 components of dyslipidemia had the highest prevalence of abdominal obesity, HTN, hyperglycemia, and MS (63.3%, 69.1%, 19.9%, and 91.8%, respectively). The high prevalence of all forms of dyslipidemia in patients with HTN is striking. Table 7 shows univariate and multivariate analysis of factors associated with dyslipidemia. According to multivariate analysis, age was associated with dyslipidemia. Compared with subjects 18 to 25 years of age, those who were 56 to 60 years of age had a greater prevalence of dyslipidemia (2.93; 95% CI, 1.92–4.47; P , .001). Each unit of increase in BMI is associated with a 1.09-fold increase in the risk of dyslipidemia (95% CI, 1.08–1.12; P , .001). With regard to altitude, compared with subjects living along coastal areas, subjects living in high altitudes had a 0.88-fold decreased prevalence of dyslipidemia (0.88; 95% CI, 0.68–1.00; P 5 .057). Evaluation of location showed that, compared with subjects living in cities, subjects living in district centers had a 1.21-fold increased prevalence of dyslipidemia (95% CI, 0.99–1.46; P 5 .054), and subjects living in villages had a 0.66-fold decreased prevalence of dyslipidemia (95% CI, 0.54–0.80; P , .001). Dyslipidemia was significantly associated with WC. Subjects who have high WC had a 1.31-fold greater prevalence of dyslipidemia (95% CI, 1.06–1.64; P 5 .014). Also, subjects with type 2 diabetes had a 1.59-fold increased prevalence of dyslipidemia (95% CI, 1.22–2.07; P 5 .001), and subjects with HTN had 1.51-fold increased prevalence of dyslipidemia (95% CI, 1.27–1.81; P , .001).
Discussion Dyslipidemia is one of the major risk factors for coronary heart disease besides age, family history, cigarette smoking, hyperglycemia/DM, and HT.16–19 The prevalence of dyslipidemia varies widely according to the ethnic, socioeconomic, and cultural characteristics of distinct population groups.20–24 This study was performed in 7 regions of Turkey to determine the prevalence of dyslipidemia as well as associated risk factors for the first time. In this study of 4309 subjects, 36.2% had elevated LDL-C, 35.7% had elevated TG, and 41.5% had low HDL-C concentrations. Males had significantly greater values of LDL-C and TG, and mean HDL-C levels were lower than for females. More than three quarters (79.6%) had at least 1 abnormal lipid measurement. We determined the prevalence of dyslipidemia as 78.7% in men and 80.4% in women. Onat et al. reported mean TC levels of 192 mg/dL in women and 185 mg/dL in men, with the highest values in the 40- to 49-year-old group in Turkey. The mean TG levels were 126 mg/dL for women and 149 mg/dL for men.7 In the Turkish Heart Study, Mahley and coworkers reported
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213
Frequency of HT, DM, MS, AO in the dyslipidemic population (%)
Dyslipidemia components
AO M .102, F .88 cm
HT $ 130/85 mm Hg
Diabetes and FBG $126 mg/DL
MS (ATP III)
High TG High LDL-C Low HDL-C High LDL-C 1 low HDL-C High LDL-C 1 high TG Low HDL-C 1 high TG High LDL-C 1 high TG 1 low HDL-C
41.7 44.1 29.1 52.9 54.6 47.8 63.3*
55.3 66.4 38.4 65.5 69.1 57.8 70.3*
19.1 8.6 3.4 10.1 21.9 19.9 22.0
43.7 10.9 22.5 48.1 57.8 77.6 91.8*
AO, abdominal obesity; ATP III, Adult Treatment Panel III; DM, diabetes mellitus; FBG, fasting blood glucose; HDL-C, high-density lipoprotein cholesterol; HT, hypertension; LDL-C, low-density lipoprotein cholesterol; MS, metabolic syndrome; TG, triglyceride. *P , .001.
that the mean levels of LDL-C, HDL-C, and TG in Turkey were 118 mg/dL, 38 mg/dL, and 117 mg/dL, respectively.6 In the Turkish Adults Heart Disease and Risk Factors Study (TEKHARF) study from the survey of 1997/1998, Onat Table 7
et al. reported mean LDL-C values of 114.6 mg/dL in men and 122.4 mg/dL in women.25 Erem et al. reported that the mean levels of TC, LDL-C and HDL-C, and TG in Trabzon were 190, 127.5, 50.3, and 137.3 mg/dL,
Univariate and multiple analysis of factors associated with dyslipidemia Univariate analysis
Variables Gender Male Female Age groups 18–25 26–30 31–35 36–40 41–45 46–50 51–55 56–60 61–65 66–70 .70 Each unit of increase in BMI Altitude Coast Medium High Location City center District Village WC (ATP) M # 102, F # 88 cm M .102, F .88 cm Diabetes, FBG ,126 mg/dL $126 mg/dL HT ,130/85 mm Hg $130/85 mm Hg
Multiple analysis OR
95%CI
P
.002 ,.001 ,.001 ,.001 ,.001 ,.001 ,.001 ,.001 ,.001 ,.001 ,.001
1.00 1.25 1.41 1.80 1.63 2.12 2.29 2.93 2.08 1.82 1.77 1.09
0.88–1.78 1.01–1.96 1.29–2.51 1.16–2.28 1.48–3.04 1.57–3.34 1.92–4.47 1.37 -3.15 1.19–2.77 1.19–2.65 1.08–1.12
.211 .042 ,.001 .005 ,.001 ,.001 ,.001 .001 .005 .005 ,.001
0.57–0.85 0.59–0.84
,.001 ,.001
1.00 1.00 0.83
0.81–1.24 0.54–0.80
.960 .057
1.00 1.31 0.68
1.09–1.57 0.56–0.81
.003 ,.001
1.00 1.21 0.66
0.99–1.46 0.54–0.80
.054 ,.001
1.00 3.04
2.56–3.61
,.001
1.00 1.31
1.06–1.64
.014
1.00 2.46
1.92–3.15
,.001
1.00 1.59
1.22–2.07
.001
1.00 2.36
2.02–2.75
,.001
1.00 1.51
1.27–1.81
,.001
OR
95%CI
1.00 1.10
0.95–1.28
1.00 1.72 2.28 3.13 3.08 4.58 5.51 6.76 4.75 3.88 3.42 1.16
1.23–2.40 1.66–3.11 2.29–4.28 2.24–4.23 3.27–6.41 3.87–7.83 4.54–10.06 3.22- 6.98 2.63–5.72 2.36–4.95 1.14–1.18
1.00 0.70 0.71
P
.185
ATP, Adult Treatment Panel; BMI, body mass index; CI, confidence interval; F, female; FBG, fasting blood glucose; HDL-C, high-density lipoprotein cholesterol; HT, hypertension; M, male; LDL-C, low-density lipoprotein cholesterol; OR, odds ratio; WC, waist circumference.
214 respectively.5 We determined that the mean levels of TC, LDL-C, HDL-C, and TG were 194.2, 117.7, 50.3, and 145.4 mg/dL, respectively. Our results are fairly consistent with previous studies.5–7,25 In our study, the most prevalent component of dyslipidemia was decreased HDL-C, with a prevalence of 41.5% (35.9% in men and 46.2% in women, P , .001). The changes in normal values for HDL-C14 make direct comparison between studies problematic. In the Turkish Heart Study in which HDL-C levels were examined in more than 9000 Turkish adults, 53% of men and 26% of women in Turkey had HDL-C ,35 mg/dL.6 The TEKHARF cohort of 2001/2002 revealed that the prevalence of low HDL-C level (,40 mg/dL) was 64% in men and 35.5% in women.25 Erem et al. reported the prevalence of low HDL-C as 21.1% in Trabzon.5 Our results are not in agreement with those of previous studies from Turkey.5,6,25 Importantly, this study was conducted in a larger population that includes all regions and age groups. A study conducted in Turkish migrants living in The Netherlands reported that the prevalence of low HDL-C was 28.7% for men and 39.4% in women.26 Compared with the results of other surveys from other countries in the world, the prevalence of low HDL-C in Turkey is higher than that in Mexico,27 Iran,24 Guadeloupe,28 the United Kingdom,29 and China,22 and lower than in Jordan.30 Genetic predisposition and lifestyle factors that include less physical activity, obesity, cigarette smoking, and the proportion of calories consumed as carbohydrates might be associated with low HDL-C levels in the Turkish population. In our study, the frequency of high LDL-C in 36.2% (35% of men and 37.2% of women) of the population. Borderline high and high values of LDL-C ($130 mg/dL) were noted in the Turkish Heart Study in 37% of men and 38% of women.6 The prevalence in the TEKHARF 2001/ 2002 cohort was 35% (31% for men and 38% for women) in Turkey.25 Erem et al. reported the prevalence of high LDL-C as 44.5% in Trabzon.5 Compared with studies in some other countries, the serum lipid levels in Turkey are lower than those in Germany,31 Greece,32 England,33 and the United States,34 but they are higher than those in Bangladesh35 and Vietnam.36 Hypertriglyceridemia is an important marker of metabolic disease. In Turkey, limited numbers of studies have been reported about the prevalence of hypertriglyceridemia.5,6,25 Onat et al. reported a prevalence of hypertriglyceridemia of 39.6% for men and 29.2% for women in Turkey.25 In the Turkish Heart Study, the prevalence was 15% for men and 6% for women,6 and Erem et al. reported the prevalence of hypertriglyceridemia as 30.4% in Trabzon.5 We estimated a prevalence for hypertriglyceridemia of 35.7% (33.5% for women and 38.3% for men). This study was performed in 7 regions of Turkey. According to regions, the prevalence of high LDL-C, low HDL-C, and mixed dyslipidemia (high LDL-C and TG, low HDL-C) were higher in the Marmara region, whereas the
Journal of Clinical Lipidology, Vol 8, No 2, April 2014 prevalence of high TG was higher in the Mediterranean region. In this present study, gender did appear to influence dyslipidemia risk. Men had a higher prevalence of hypertriglyceridemia and a combination of high TG and high LDL-C compared with women. In contrast, women had a higher prevalence of low HDL-C as well as a combination of high LDL-C and low HDL-C compared to men. Most studies reported that dyslipidemia is more prevalent among men than women,6,7,22,29 but some other studies indicate that the prevalence is more prevalent among women than among men.33,37 The variation may be explained by differential distributions of risk factors (eg, genetic predisposition, smoking, alcohol consumption, dietary factors, lack of physical activity) between women and men across populations.38 In our study, mean lipid levels increased with age. Our results were consistent with some previous studies.24,37,39 The mechanisms of the effect of age on lipid levels are not exactly known—they may be related to hereditary characteristics and degenerative processes as well as creeping weight gain and progressive development of insulin resistance. Age is associated with dyslipidemia. Many studies have reported that the prevalence of dyslipidemia increases with age.6,22,24,27,28,37,39 The highest prevalence of dyslipidemia was in the 51- to 60-year-old group for men and women. However, the prevalence was lower in study participants who were older than 70 years and did not increase further. We observed associations between dyslipidemia, abdominal obesity, and HTN. The prevalence of dyslipidemia increased with WC, BMI, and blood pressure. Also, we determined that subjects with 3 components of dyslipidemia had the highest risk of obesity, HTN, DM, and MS. According to these results, there is a biological interrelation between blood lipid levels and blood pressure. In addition, dyslipidemia was significantly associated with FBG in this study. The lipid abnormalities in abdominal obesity and in DM are likely a consequence of insulin resistance.40,41 Given the high prevalence of dyslipidemias in patients with HTN, it is imperative that any patient with HTN be screened for dyslipidemia. In Turkey, locations are generally categorized as city, district, and village. When the prevalence of dyslipidemia components are evaluated according to locations, the prevalence of high LDL-C, low HDL-C, and triple combination of dyslipidemia were higher in district locations, whereas the prevalence of high TG was higher in city centers. Also, in multivariate logistic regression analysis, the OR for dyslipidemia was significantly lower in subjects living in villages than in cities. The present study is the first to evaluate the prevalence of dyslipidemia according to altitude. We observed a lower prevalence of dyslipidemia in high altitudes than coastal regions. Dietary changes and less physical activity resulting from rapid changes in living conditions may be etiologic for the increases in dyslipidemia prevalence in subjects living in coastal areas.
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The potential limitations of this study included the greater participation of women and elderly persons. These factors might reduce generalizability of our findings. Also, the lack of information concerning dietary variation across the country, socioeconomic status, and physical activity as well as urbanization are further limitations of the present work. Finally, the prevalence of high TG/low HDL-C was unexpectedly low and needs to be confirmed in future studies.
Conclusions Dyslipidemia is an important public health problem. The prevalence of dyslipidemia is rising throughout the world. The prevalence of all forms of dyslipidemia is high in Turkey among both men and women. There is an urgent need to institute more aggressive nationwide public health measures and screening programs and to treat patients diagnosed with dyslipidemia. Among Turkish people, dyslipidemia is highly correlated with HTN, abdominal obesity, and MS.
Acknowledgments The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.
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215 11. Ozsahin AK, Gokcel A, Sezgin N, et al. Prevalence of the metabolic syndrome in a Turkish adult population. Diabetes Nutr Metab. 2004; 17:230–234. 12. Erem C, Hacihasanoglu A, Deger O, et al. Prevalence of metabolic syndrome and associated risk factors among Turkish adults: Trabzon MetS study. Endocrine. 2008;33:9–20. 13. Gundogan K, Bayram F, Capak M, et al. Prevalence of metabolic syndrome in the Mediterranean region of Turkey: evaluation of hypertension, diabetes mellitus, obesity, and dyslipidemia. Metab Syndr Relat Disord. 2009;7:427–434. 14. National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) final report. Circulation. 2002;106:3143–3421. 15. Alberti KG, Eckel RH, Grundy SM, et al, International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; International Association for the Study of Obesity. Harmonizing the metabolic syndrome: a joint interim statement of the International Diabetes Federation Task Force on Epidemiology and Prevention; National Heart, Lung, and Blood Institute; American Heart Association; World Heart Federation; International Atherosclerosis Society; and International Association for the Study of Obesity. Circulation. 2009;120: 1640–1645. 16. Verschuren WM, Jacobs DR, Bioemberg BP, et al. Serum total cholesterol and long-term coronary heart disease mortality in different cultures: twenty-five year follow-up of the Seven Countries Study. JAMA. 1995;274:131–136. 17. US Department of Health and Human Services. The Health Benefits of Smoking Cessation. A report of the Surgeon General. Rockville, MD: DHHS publication (CDC); 1990. p. 90–8416. 18. Stamler J, Vaccaro O, Neaton JD, Wentworth D. Diabetes, other risk factors and 12-yr cardiovascular mortality for men screened in the Multiple Risk Factor intervention trial. Diabetes Care. 1993;16: 434–444. 19. MacMahon S, Peto R, Culter J, et al. Blood pressure, stroke and coronary heart disease, 1: prolonged differences in blood pressure: prospective observational studies corrected for the regression dilution bias. Lancet. 1990;335:765–774. 20. Yarnell J, Yu S, McCrum E, et al, PRIME study group. Education, socioeconomic and lifestyle factors, and risk of coronary heart disease: the PRIME Study. Int J Epidemiol. 2005;34:268–275. 21. Fuentes R, Uusitalo T, Puska P, Tuomilehto J, Nissinen A. Blood cholesterol level and prevalence of hypercholesterolaemia in developing countries: a review of population-based studies carried out from 1979 to 2002. Eur J Cardiovasc Prev Rehabil. 2003;10:411–419. 22. Li Z, Yang R, Xu G, Xia T. Serum lipid concentrations and prevalence of dyslipidemia in a large professional population in Beijing. Clin Chem. 2005;51:144–150. 23. Grabauskas V, Miseviciene I, Klumbiene J, et al. Prevalence of dyslipidemias among Lithuanian rural population (CINDI pro- gram). Medicina (Kaunas). 2003;39:1215–1222. 24. Azizi F, Rahmani M, Ghanbarian A, et al. Serum lipid levels in an Iranian adults population: Tehran Lipid and Glucose Study. Eur J Epidemiol. 2003;18:311–319. 25. Onat A. Lipids, lipoproteins and apolipoproteins among Turks, and impact on coronary heart disease. Anadolu Kardiyol Derg. 2004;4: 236–245. 26. Ujcic-Voortman JK, Bos G, Baan CA, Uitenbroek DG, Verhoeff AP, Seidell JC. Ethnic differences in total and HDL cholesterol among Turkish, Moroccan and Dutch ethnic groups living in Amsterdam, the Netherlands. BMC Public Health. 2010;10:740. 27. Aguilar-Salinas CA, Olaiz G, Valles V, et al. High prevalence of low HDL cholesterol concentrations and mixed hyperlipidemia in a Mexican nationwide survey. J Lipid Res. 2001;42:1298–1307.
216 28. Foucan L, Kangambega P, Koumavi Ekouevi D, Rozet J, Bangou-Bredent J. Lipid profile in an adult population in Guadeloupe. Diabetes Metab. 2000;26:473–480. 29. Patel JV, Kırby M, Hughes EA. The Lipid Audit: analysis of lipid management in two centres in Britain 2003. Br J Cardiol. 2004;11:214–217. 30. Khader YS, Batieha A, El-Khateeb M, Al Omari M, Ajlouni K. Prevalence of dyslipidemia and its associated factors among Jordanian adults. J Clin Lipidol. 2010;4:53–58. 31. Assmann G, Cullen P, Schulte H. The M€unster Heart Study (PROCAM). Results of follow-up at 8 years. Eur Heart J. 1998;19:2–11. 32. Benetou V, Chloptsios Y, Zavitsanos X, Karalis D, Naska A, Trichopoulou A. Total cholesterol and HDL-cholesterol in relation to socioeconomic status in a sample of 11,645 Greek adults: the EPIC study in Greece. European Prospective Investigation into Nutrition and Cancer. Scand J Public Health. 2000;28:260–265. 33. Primatesta P, Poulter NR. Lipid concentrations and the use of lipid lowering drugs: evidence from a national cross sectional survey. BMJ. 2000;321:1322–1325. 34. Johnson CL, Rifkind BM, Sempos CT, et al. Declining serum total cholesterol levels among US adults. The National Health and Nutrition Examination Surveys. JAMA. 1993;269:3002–3008.
Journal of Clinical Lipidology, Vol 8, No 2, April 2014 35. Mostafa Zaman M, Choudhury SR, Ahmed J, et al. Plasma lipids in a rural population of Bangladesh. Eur J Cardiovasc Prev Rehabil. 2006; 13:444–448. 36. Hanh TTM, Komatsu T, Hung NT, et al. Nutritional status of middleaged Vietnamese in Ho Chi Minh City. J Am Coll Nutr. 2001;20: 616–622. 37. al-Nuaim AR, Mirdad S, al-Rubeaan K, et al. Population-based epidemiological study on characteristics of risk factors of hypercholesterolemia in Saudi Arabia. Int J Cardiol. 1997;62:47–54. 38. Lorenzo C, Serrano-Rios M, Martinez-Larrad MT, et al. Prevalence of hypertension in Hispanic and non- Hispanic white populations. Hypertension. 2002;39:203–208. 39. Brown CD, Higgins M, Donato KA, et al. Body mass index and the prevalence of hypertension and dyslipidemia. Obes Res. 2000;8: 605–619. 40. Houston MC, Basile J, Bestermann WH, et al. Addressing the global cardiovascular risk of hypertension, dyslipidemia, and insulin resistance in the southeastern United States. Am J Med Sci. 2005;329: 276–291. 41. Betteridge DJ. Diabetic dyslipidemia. Diabetes Obes Metab. 2000;1: 31–36.
Prevalence of dyslipidemia and associated risk factors in Turkish adults Fahri Bayram, MD, Derya Kocer, MD, Kursat Gundogan, MD, Ahmet Kaya, MD, Ozgur Demir, MD, Ramazan Coskun, MD, Tevfik Sabuncu, MD, Ahmet Karaman, MD, Mustafa Cesur, MD, Manfredi Rizzo, MD, Peter P. Toth, MD, PhD*, Vedia Gedik, MD Faculty of Medicine, Department of Endocrinology and Metabolism, Erciyes University, Kayseri, Turkey (Dr. Bayram); Department of Biochemistry, Kayseri Research and Training Hospital, Kayseri, Turkey (Dr. Kocer); Faculty of Medicine, Department of Intensive Care, Erciyes University, Kayseri, Turkey (Dr. Gundogan, Dr. Coskun); Division of Endocrinology and Metabolism, Department of Internal Medicine, Meram Medical Faculty, Selcuk University, Konya, Turkey (Dr. Kaya); Faculty of Medicine, Department of Endocrinology and Metabolism, Ankara University, Ankara, Turkey (Dr. Demir, Dr. Gedik); Faculty of Medicine, Department of Endocrinology and Metabolism, Harran University, S¸anlıurfa, Turkey (Dr. Sabuncu); Department of Gastroenterology, Kayseri Training and Research Hospital, Kayseri, Turkey (Dr. Karaman); Department of Endocrinology and Metabolic Disease, Ankara Guven Hospital, Ankara, Turkey (Dr. Cesur); BioMedical Department of Internal Medicine and Medical Specialties, University of Palermo, Palermo, Italy (Dr. Rizzo); Euro–Mediterranean Institute of Science and Technology, Italy (Dr. Rizzo); Department of Preventative Cardiology, CGH Medical Center, Sterling, IL (Dr. Toth); and University of Illinois College of Medicine, Peoria, IL (Dr. Toth) KEYWORDS: Dyslipidemia; Cholesterol; Low-density lipoprotein; Triglycerides; High-density lipoprotein; Prevalence; Turkey
BACKGROUND AND OBJECTIVES: Dyslipidemia is a modifiable major risk factor for coronary heart disease. The objective of this study was to determine the prevalence of dyslipidemia among Turkish adults and its associations with other cardiovascular risk factors. METHODS: This study included 4309 people ages 20 to 83 years old from 7 provinces of Turkey. People from the city centers, districts, and villages were selected by a stratified sampling method. Weight, height, and waist and hip circumferences were measured. Blood samples were obtained to determine glucose, total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG); these parameters were measured with an autoanalyzer. Dyslipidemia was defined according to National Cholesterol Education Program Adult Treatment Panel III diagnostic criteria. RESULTS: Of 4309 subjects, 43% had high TC, 41.5% had low HDL-C, 36.2% had high LDL-C, and 35.7% had high TG. Of these measures, at least 1 lipid abnormality was diagnosed in 78.7% of men and 80.4% of women. The prevalence of high TC, LDL-C, and TG increased with age, with the highest prevalence in the 46-to-65-year-old age group. The mean values (mg/dL) of TC, LDL-C, HDL-C, and TG were 194.2 6 47.7, 117.7 6 41.1, 50.3 6 16.3, and 145.4 6 96.3, respectively. Dyslipidemia was positively associated with age, body mass index, waist circumference, fasting blood glucose, and blood pressure, and negatively associated with altitude.
* Corresponding author. E-mail address: [email protected] Submitted May 16, 2013. Accepted for publication December 26, 2013. 1933-2874/$ - see front matter Ó 2014 National Lipid Association. All rights reserved. http://dx.doi.org/10.1016/j.jacl.2013.12.011
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CONCLUSIONS: The high prevalence of dyslipidemia in Turkey is an important public health problem. Enhanced public health preventive measures should be implemented to better diagnose and comprehensively treat dyslipidemia in Turkey. Ó 2014 National Lipid Association. All rights reserved.
Dyslipidemia is a major independent modifiable risk factor for cardiovascular diseases.1 The prevalence of dyslipidemia is high and increasing in most developed countries as well as in many developing countries as a result of the Westernization of diet, obesity, reduced physical activity, and other adverse lifestyle changes2 Hypertriglyceridemia, low serum high-density lipoprotein cholesterol (HDL-C) concentrations, and elevated low-density lipoprotein cholesterol (LDL-C) are established, defining features of dyslipidemia. Dyslipidemia is highly prevalent worldwide and risk for mixed forms of dyslipidemia is increased by visceral adiposity, metabolic syndrome (MS)/insulin resistance, and diabetes mellitus (DM).3,4 Although the measurement of plasma lipid and lipoprotein levels in different regions of Turkey was examined in previous studies,5–7 the relationship of dyslipidemia with other risk factors such as hypertension (HTN), DM, obesity, and MS has not been previously reported. Several studies have reported a high prevalence of DM, obesity, HTN, and MS in Turkish adults.8–13 In Turkey, the relationship between dyslipidemia and associated risk factors is inadequately defined. It has been shown that the effective treatment of dyslipidemia reduces the rate of cardiovascular morbidity and mortality. Therefore, estimation of the prevalence of dyslipidemia ensures proper planning of health actions for both the primary and secondary prevention of cardiovascular events. In this study, we present the findings of a study that evaluated the prevalence of dyslipidemia and its association with other risk factors that includes 23 provinces from 7 regions of Turkey.
Materials and methods
Giresun, Hatay, Istanbul, Izmir, Kars, Kayseri, Konya, Mersin, Samsun, Sivas, Sanliurfa, Van, Zonguldak) from 7 regions of Turkey (Fig. 1). Approval from the Ministry of Health was obtained and the household identification form data from the Primary Health Care Centers of Provincial Health Directorates, affiliated with the Ministry of Health, was used. The study sample included males and nonpregnant females between 20 and 83 years of age. Populations of city centers, districts, and villages were classified by using the stratified sampling method and then were selected from the household identification form data by a simple random sampling method. According to the 2000 census, population distribution of regions and number of received people are shown in Table 1. The age groups were also classified according to results from the 2000 census as 20 to 25 years, 26 to 30 years, 31 to 35 years, 36 to 40 years, 41 to 45 years, 46 to 50 years, 51 to 55 years, 56 to 60 years, 61 to 65 years, 66 to 70 years, and 70 and older. Descriptive features of the provincial district centers and villages, including gender, demographics, economic, social, and geographical status, were taken into consideration. Information was sent to the regions’ health units (primary health care centers, hospitals, and health houses) about 2 weeks before the study was to be conducted. Although it varies depending on the region, 83% of invited subjects actually participated in this study. The participants were told to fast for 10 to 12 hours before the sampling. Between 7:00 and 10:00 AM, about 100 people were evaluated in health units affiliated with the Ministry of Health. Informed consent was obtained from all participants. Structured questionnaires were completed with faceto-face interviews. The study was performed in accordance with the Declaration of Helsinki.
Study plan and sampling
Study protocol
This study was a cross-sectional survey conducted in Turkey to assess the prevalence of abnormal lipid values among different Turkish populations. The sampling design was based on multistage probability sampling. According to this method, 7 regions of Turkey were taken as stratum (the populations of these 7 regions were obtained from the results of a 2000 national Turkish census). At least 3 provinces were selected from each region by a simple random sampling method. A total of 23 provinces were taken as ‘‘clusters.’’ This study was conducted in these 23 provinces (Ankara, Antalya, Bursa, Canakkale, Denizli, Diyarbakir, Edirne, Erzurum, Eskisehir, Gaziantep,
Medical histories and measurements of participants were obtained by well-trained nurses and specialist physicians. The age and gender of participants were recorded. Personal and family histories of HTN, DM, cardiovascular disease, and other chronic diseases were obtained. Heights and weights of participants were measured. Body mass index (BMI) was calculated by dividing the weight (in kilograms) by the square meters of the height. BMI lower than 19 kg/ m2 was classified as underweight and between 19 and 25 kg/m2 as normal. BMI values between 25 and 29.9 kg/ m2 were considered as overweight and above 30 kg/m2 as obese. Also, waist circumference (WC) of participants
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Figure 1
Seven regions of Turkey.
was measured at the level of the iliac processes and the umbilicus with a tape measure to evaluate abdominal obesity. Systolic blood pressure and diastolic blood pressure were measured twice in the sitting position, with an interval of 15 minutes between the measurements, by means of standard sphygmomanometers of appropriate width, after a rest period of 30 minutes. The normal limit for systolic HTN was 130 mm Hg and for diastolic HTN was 85 mm Hg, consistent with the Third Adult Treatment Panel (ATP III) cut points for blood pressure in the definition of metabolic syndrome. Patients taking antihypertensive medication were classified as hypertensive by definition. Blood samples were centrifuged at room temperature for 10 minutes at 3000 rpm. The extracted sera were stored in ice bags and placed into deep freezers at 270 C on the same day. Glucose, total cholesterol (TC), HDL-C and triglyceride (TG) levels were evaluated by an enzymatic spectrophotometric method with the Kone Lab Auto Analyzer (Thermo Clinical Labsystems Oy Vantaa, Finland). LDL-C was calculated by the Friedewald formula (in those with TG level ,400 mg/dL). DM was diagnosed according to the American Diabetes Association criteria. Accordingly, single fasting blood glucose (FBG) .126 mg/ dL was considered diagnostic of DM. Those with a previous DM diagnosis and the use of oral antidiabetic agents and/or insulin therapy were classified as being diabetic. Impaired fasting glucose was defined as FBG levels between 110 and 126 mg/dL. The diagnosis of MS was made depending on the presence of at least 3 of the Table 1
following parameters, according to ATP III criteria: abdominal obesity (WC .102 cm for males and .88 cm for females), HTN (systolic blood pressure .130 mm Hg and/or diastolic blood pressure .85 mm Hg), hypertriglyceridemia ($150 mg/dL), low HDL-C (,40 mg/dL in males and ,50 mg/dL in females), and elevated FBG ($100 mg/dL). Dyslipidemias were defined according to National Cholesterol Education Program ATP III criteria14 High TC was defined as TC $200 mg/dL and hypertriglyceridemia was defined as serum TG level $150 mg/dL. Low HDL-C was defined as serum HDL-C level ,40 mg/dL in males and ,50 mg/dL in females. High LDL-C was defined as serum LDL-C $130 mg/dL.14 Although we considered using the International Diabetes Federation diagnostic criteria for Mediterranean populations,15 these were not widely applicable because not all of the indigenous populations in Turkey are ‘‘Mediterranean.’’ Therefore, we elected to use the ATP III criteria to make our study more comparable with previous studies performed in other populations, including Asian populations. We defined the coast as elevations between 0 and 300 m, medium altitude as elevations between 300 and 1000 m, and high altitude as elevations above 1000 m.
Statistical analysis Unbalanced sampling selections were made during the multistage sampling process. Because of this unbalanced
Population distribution of regions and number of received people according to the 2000 census
Regions
Turkey-wide population status
Turkey-wide over 20 years Population status (%)
Received by regions Number of people (%)
Weight
Marmara Center Anatolia Aegean Mediterranean Black Sea Southeastern Anatolia Eastern Anatolia Total
17,365,027 11,608,868 8,938,781 8,706,005 8,439,213 6,608,619 6,137,414 67,803,927
13,730,962 8,039,036 5,495,575 5,204,203 4,137,466 4,143,136 3,255,896 44,006,274
820 816 424 674 535 603 437 4309
1.63 0.95 1.33 0.77 0.77 0.68 0.69 —
31 18 13 12 9.5 9.5 7 100
19.0 18.9 9.8 15.6 12.4 14.0 10.1 100
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selection, we calculated post-stratification weights using the results of the 2000 national Turkish census to adjust our data to conform more to the population’s parameters. To make this calculation, we used Statistical Package for the Social Sciences Syntax Editor and wrote syntax codes to calculate post-stratification weights. Weights are given in the last column of Table 1; syntax codes were as follows:
Marmara, 820 (19.0%); Center Anatolia, 816 (18.9%); Aegean, 424 (9.8%); Mediterranean, 674 (15.6%); Black Sea, 535 (12.4%); Southeastern Anatolia, 437 (10:1%); and Eastern Anatolia, 603 (14.0%) (Table 1). The mean age of participants was 47.1 6 14.7 years (20–83); that of males was 49.0 6 14.5 years and of females was 45.5 6 14.7 years. The distribution of age classifications was: 7.4% (n 5 319) between 20 and 25 years, 6.8% (n 5 294) between 26 and 30 years, 10.0% (n 5 433) between 31 and 35 years, 12.0% (n 5 519) between 36 and 40 years, 11.4% (n 5 492) between 41 and 45 years, 11.6% (n 5 498) between 46 and 50 years, 11.3% (n 5 487) between 51 and 55 years, 9.0% (n 5 387) between 56 and 60 years, 7.3% (n 5 314) between 61 and 65 years, 6.3% (n 5 273) between 66 and 70 years, and 6.8% (n 5 293) older than 70 years. Locations of participants were: 40.1% (n 5 1729) living in city centers, 36.9% (n 5 1589) in districts, and 23% (n 5 991) in the villages. Clinical characteristics of the participants are shown in Table 2.
IF (bolge1 5 IF (bolge1 5 IF (bolge1 5 IF (bolge1 5 IF (bolge1 5 IF (bolge1 5 IF (bolge1 5 EXECUTE.
1) 2) 3) 4) 5) 6) 7)
weight weight weight weight weight weight weight
5 5 5 5 5 5 5
0.77. 0.95. 0.68. 1.33. 1.63. 0.77. 0.69.
After this process, we weighted our data based on the recently calculated weights and followed classical statistical procedures using the tests written in the following section. The chi-squared test was used to determine significant differences in proportions among categorical variables. The Student t-test and Mann-Whitney U-test were used to compare differences of continuous variables. The univariate and multiple binary logistic regression models were used to investigate the probability of having dyslipidemia according to sociodemographic variables. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using binary logistic regression for each model. All statistical analyses were calculated with the Statistical Package for the Social Sciences, version 15.0 (Chicago, IL). Two-tailed P values of ,.05 were considered to be statistically significant.
As shown in Table 2, the mean level of TG was higher in men than women (P , .05), whereas the mean levels of TC and HDL-C were higher in women than in men (P , .05). Mean levels of TG, LDL-C, and HDL-C concentrations according to gender and age groups are presented in Table 3. The levels of TC, LDL-C, and TG in both women and men increased with age, with the highest values being observed in the 46-to-60-year-old group.
Prevalence of dyslipidemia and associated factors
Results Demographic features A total of 4309 adults participated in the study (1947 males, 45.2%; 2362 females, 54.8%) from 7 regions: Table 2
Mean plasma lipid levels
Of 4309 subjects, 43% had high TC, 41.5% had low HDL-C, 36.2% had high LDL-C, and 35.7% had high TG. The prevalence of binary and ternary combinations of dyslipidemia components are shown in Figure 2. Of these
Clinical characteristics of participants
Variants
General n 5 4309 x6sd
Age (years) SBP (mm Hg) DBP (mm Hg) BMI (kg/m2) WC (cm) FBG (mg/dL) TC (mg/dL) TG (mg/dL) LDL-C (mg/dL) HDL-C (mg/dL)
47.1 133.5 81.4 28.3 92.6 103.7 194.2 145.4 117.7 50.3
6 6 6 6 6 6 6 6 6 6
14.7 27.2 15.1 5.2 12.9 44.8 47.7 96.3 41.1 16.3
Gender Males n 5 1947 x6sd 49.0 133.0 81.2 27.4 95.6 102.7 191.2 152.7 117.1 46.9
6 6 6 6 6 6 6 6 6 6
14.5 26.6 15.3 4.3 11.9 41.7 47.5 103.2 40.8 15.8
Females n 5 2362 x6sd 45.5 133.9 81.5 29.1 90.2 104.5 196.7 139.4 118.3 53.1
6 6 6 6 6 6 6 6 6 6
14.7 27.7 14.9 5.6* 13.2* 47.2 47.7* 89.7* 41.2 16.2*
BM, body mass index; DBP, diastolic blood pressure; FBG, fasting blood glucose; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; SBP, systolic blood pressure; SD, standard deviation; TC, total cholesterol; TG, triglyceride; WC, waist circumference. *P , .05 significantly different between the males and females.
210
Journal of Clinical Lipidology, Vol 8, No 2, April 2014
Table 3
Mean of TG, LDL-C, and HDL-C concentrations according to gender and age decades
Gender/age Male 21–25 26–30 31–35 36–40 41–45 46–50 51–55 56–60 61–65 66–70 .70 Total Female 21–25 26–30 31–35 36–40 41–45 46–50 51–55 56–60 61–65 66–70 .70 Total Total P (men vs. women)
n
TG (mg/DL) x6sd
109 100 161 207 242 252 230 177 166 129 174 1947
110.9 139.3 155.2 162.6 158.2 164.3 172.9 157.4 140.5 133.1 143.0 152.7
6 6 6 6 6 6 6 6 6 6 6 6
84.9 116.0 117.2 106.4 101.3 100.8 118.4 84.1 92.7 71.7 109.8 103.2
91.1 109.4 113.5 115.2 115.4 122.8 121.8 121.9 118.2 121.9 121.6 117.1
6 6 6 6 6 6 6 6 6 6 6 6
34.1 34.8 38.2 42.4 37.2 42.1 41.8 42.9 39.0 45.2 39.2 40.8
47.2 44.9 46.9 44.9 48.3 46.5 47.7 48.2 45.8 45.4 48.9 46.9
6 6 6 6 6 6 6 6 6 6 6 6
12.8 13.6 17.4 15.1 18.9 15.3 17.7 16.4 14.2 12.3 14.5 15.8
210 194 272 312 250 246 257 210 148 144 119 2362 4309
100.0 6 111.5 6 125.1 6 134.1 6 144.4 6 147.3 6 162.9 6 162.3 6 165.5 6 142.7 6 147.0 6 139.4 6 145.4 6 ,.001
50.8 62.9 72.6 86.2 110.9 81.6 94.2 110.3 113.6 80.1 77.5 89.7 96.3
87.1 99.7 105.3 114.6 116.3 135.6 134.0 129.2 134.4 125.2 129.1 118.3 117.7 .353
6 6 6 6 6 6 6 6 6 6 6 6 6
33.2 35.3 33.7 37.6 35.6 44.8 41.8 38.8 39.4 42.3 40.9 41.2 41.1
55.2 6 53.7 6 51.9 6 52.8 6 52.8 6 55.2 6 51.6 6 52.0 6 49.9 6 45.4 6 53.0 6 53.1 6 50.3 6 ,.001
15.7 16.5 14.1 16.6 16.5 18.3 16.2 15.5 15.3 12.3 14.3 16.2 16.3
LDL-C (mg/DL) x6sd
HDL-C (mg/DL) x6sd
HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; SD, standard deviation; TG, triglyceride.
measures, at least 1 abnormal lipid concentration was recorded in 78.7% in men and 80.4% in women. The prevalence of dyslipidemia components according to gender, age, BMI, and location is shown in Table 4. The prevalence of high TG, high LDL-C, and low HDL-C were 35.7% (33.5% for women and 38.3% for men (P , .05), 36.2% (37.2% for women and 35.0% for men, (P . .05), and 41.5% (46.2% for women and 35.9% for men (P , .05), respectively. The higher prevalence of low HDL-C and high LDL-C/low HDL-C in women compared with men is particularly striking. The prevalence of dyslipidemia components increased with age, with the highest values being observed in the 46-to-65-year-old group, except HDL-C. In addition, the highest prevalence of dyslipidemia components was observed in obese subjects with trends for increasing prevalence of a variety of dyslipidemias as patients go from normal weight to overweight and then becoming obese (elevated TG, elevated LDL-C, low HDL-C, high LDL-C/low HDL-C, high LDL-C/high TG, and high LDL-C/high TG/low HDL-C). The highest prevalence of high LDL-C and low HDL-C were observed in district centers, whereas the prevalence of high TG was greatest in city centers. Table 5 shows the frequency of dyslipidemia components according to regions. The highest prevalence of high LDL-C
and low HDL-C were observed in the Marmara region, whereas the highest prevalence of hypertriglyceridemia occurred in the Mediterranean region. The highest prevalence of binary and ternary combinations of dyslipidemia
Figure 2 The frequency of dyslipidemia components and the prevalence ratio (%). HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TG, triglyceride.
Bayram et al
The prevalence of dyslipidemia components according to gender, age, BMI, and location (%)
Variants Gender Male Female Age groups 21–25 26–30 31–35 36–40 41–45 46–50 51–55 56–60 61–65 66–70 .70 BMI Normal Overweight Obese Location City center District Village
High TG (%)
High LDL-C (%)
Low HDL-C (%)
High LDL-C 1 low HDL-C (%)
High LDL-C 1 high TG (%)
Low HDL-C 1 high TG (%)
High LDL-C 1 low HDL-C 1 high TG (%)
38.3* 33.5
35.0 37.2
35.9 46.2†
8.7 13.6†
12.7† 8.5
8.0 7.5
11.2 14.2
15.4 25.2 31.2 37.2 38.2 41.6 48.3† 41.6 38.5 30.8 30.7
12.5 20.1 22.9 33.6 34.9 47.6† 47.2 43.4 45.1 39.3 45.4
37.0 42.2 43.0 45.9 41.5 40.6 43.5 42.1 44.6* 39.6 32.4
3.9 8.1 10.0 11.7 12.3 14.3 10.6 11.9 14.1 14.9 11.7
4.9 7.1 5.7 9.7 10.0 13.4 15.4 13.0 10.9 9.7 11.0
4.6 6.4 10.0 10.5 9.4 6.2 8.9 8.2 8.0 4.8 3.4
2.6 6.4 10.0 12.3 12.8 15.7 19.5 15.3 17.0 12.3 12.1
21.0 36.8 45.2†
25.6 35.0 45.9†
35.5† 41.6 45.5
8.3 9.9 15.2†
5.8 10.4 14.0
5.2 10.2 8.0
5.7 11.1 22.7
37.9 35.1 32.6
37.5 39.9† 28.3
41.9 46.3† 33.4
10.9 14.3† 7.5
11.1 9.5 10.3
8.3 7.8 6.4
13.1 13.9 10.5
Prevalence of dyslipidemia in Turkish adults
Table 4
BMI, body mass index; HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TG, triglyceride. *P , .05. †P , .001.
211
10.6 12.4 22.7 7.1 10.2 11.5 25.5* 9.6 322 Marmara Mediterranean Center Anatolia Aegean Black Sea Eastern Anatolia Southeastern Anatolia General (%) n
HDL-C, high-density lipoprotein cholesterol; LDL-C, low-density lipoprotein cholesterol; TG, triglyceride. *P , .001.
39.5* 6.1 18.5 17.6 5.5 4.4 8.4 14.2 476 37.6 43.8* 38.0 32.3 30.8 27.0 33.8 35.7 1537
Regions
63.9* 35.3 32.2 53.1 25.0 17.1 16.9 36.2 2205
52.4* 23.6 45.7 50.9 26.0 37.1 51.6 41.5 1790
17.5 27.2* 17.5 9.2 13.1 6.5 9.0 13.0 434
Low HDLC 1 high TG (%) High LDLC 1 high TG (%) High LDLC 1 low HDL-C (%) Low HDL-C (%) High LDL-C (%) High TG (%)
Dyslipidemia components
The frequency of dyslipidemia components according to regions (%) Table 5
33.5* 10.2 21.2 12.3 6.3 6.1 10.2 16.0 537
Journal of Clinical Lipidology, Vol 8, No 2, April 2014 High LDL-C 1 low HDL-C 1 high TG (%)
212
components were observed in the Marmara region, except for the low HDL-C and high TG combination. The frequencies of HTN, DM, MS, and abdominal obesity in the dyslipidemic population are presented in Table 6. The participants who have 3 components of dyslipidemia had the highest prevalence of abdominal obesity, HTN, hyperglycemia, and MS (63.3%, 69.1%, 19.9%, and 91.8%, respectively). The high prevalence of all forms of dyslipidemia in patients with HTN is striking. Table 7 shows univariate and multivariate analysis of factors associated with dyslipidemia. According to multivariate analysis, age was associated with dyslipidemia. Compared with subjects 18 to 25 years of age, those who were 56 to 60 years of age had a greater prevalence of dyslipidemia (2.93; 95% CI, 1.92–4.47; P , .001). Each unit of increase in BMI is associated with a 1.09-fold increase in the risk of dyslipidemia (95% CI, 1.08–1.12; P , .001). With regard to altitude, compared with subjects living along coastal areas, subjects living in high altitudes had a 0.88-fold decreased prevalence of dyslipidemia (0.88; 95% CI, 0.68–1.00; P 5 .057). Evaluation of location showed that, compared with subjects living in cities, subjects living in district centers had a 1.21-fold increased prevalence of dyslipidemia (95% CI, 0.99–1.46; P 5 .054), and subjects living in villages had a 0.66-fold decreased prevalence of dyslipidemia (95% CI, 0.54–0.80; P , .001). Dyslipidemia was significantly associated with WC. Subjects who have high WC had a 1.31-fold greater prevalence of dyslipidemia (95% CI, 1.06–1.64; P 5 .014). Also, subjects with type 2 diabetes had a 1.59-fold increased prevalence of dyslipidemia (95% CI, 1.22–2.07; P 5 .001), and subjects with HTN had 1.51-fold increased prevalence of dyslipidemia (95% CI, 1.27–1.81; P , .001).
Discussion Dyslipidemia is one of the major risk factors for coronary heart disease besides age, family history, cigarette smoking, hyperglycemia/DM, and HT.16–19 The prevalence of dyslipidemia varies widely according to the ethnic, socioeconomic, and cultural characteristics of distinct population groups.20–24 This study was performed in 7 regions of Turkey to determine the prevalence of dyslipidemia as well as associated risk factors for the first time. In this study of 4309 subjects, 36.2% had elevated LDL-C, 35.7% had elevated TG, and 41.5% had low HDL-C concentrations. Males had significantly greater values of LDL-C and TG, and mean HDL-C levels were lower than for females. More than three quarters (79.6%) had at least 1 abnormal lipid measurement. We determined the prevalence of dyslipidemia as 78.7% in men and 80.4% in women. Onat et al. reported mean TC levels of 192 mg/dL in women and 185 mg/dL in men, with the highest values in the 40- to 49-year-old group in Turkey. The mean TG levels were 126 mg/dL for women and 149 mg/dL for men.7 In the Turkish Heart Study, Mahley and coworkers reported
Bayram et al Table 6
Prevalence of dyslipidemia in Turkish adults
213
Frequency of HT, DM, MS, AO in the dyslipidemic population (%)
Dyslipidemia components
AO M .102, F .88 cm
HT $ 130/85 mm Hg
Diabetes and FBG $126 mg/DL
MS (ATP III)
High TG High LDL-C Low HDL-C High LDL-C 1 low HDL-C High LDL-C 1 high TG Low HDL-C 1 high TG High LDL-C 1 high TG 1 low HDL-C
41.7 44.1 29.1 52.9 54.6 47.8 63.3*
55.3 66.4 38.4 65.5 69.1 57.8 70.3*
19.1 8.6 3.4 10.1 21.9 19.9 22.0
43.7 10.9 22.5 48.1 57.8 77.6 91.8*
AO, abdominal obesity; ATP III, Adult Treatment Panel III; DM, diabetes mellitus; FBG, fasting blood glucose; HDL-C, high-density lipoprotein cholesterol; HT, hypertension; LDL-C, low-density lipoprotein cholesterol; MS, metabolic syndrome; TG, triglyceride. *P , .001.
that the mean levels of LDL-C, HDL-C, and TG in Turkey were 118 mg/dL, 38 mg/dL, and 117 mg/dL, respectively.6 In the Turkish Adults Heart Disease and Risk Factors Study (TEKHARF) study from the survey of 1997/1998, Onat Table 7
et al. reported mean LDL-C values of 114.6 mg/dL in men and 122.4 mg/dL in women.25 Erem et al. reported that the mean levels of TC, LDL-C and HDL-C, and TG in Trabzon were 190, 127.5, 50.3, and 137.3 mg/dL,
Univariate and multiple analysis of factors associated with dyslipidemia Univariate analysis
Variables Gender Male Female Age groups 18–25 26–30 31–35 36–40 41–45 46–50 51–55 56–60 61–65 66–70 .70 Each unit of increase in BMI Altitude Coast Medium High Location City center District Village WC (ATP) M # 102, F # 88 cm M .102, F .88 cm Diabetes, FBG ,126 mg/dL $126 mg/dL HT ,130/85 mm Hg $130/85 mm Hg
Multiple analysis OR
95%CI
P
.002 ,.001 ,.001 ,.001 ,.001 ,.001 ,.001 ,.001 ,.001 ,.001 ,.001
1.00 1.25 1.41 1.80 1.63 2.12 2.29 2.93 2.08 1.82 1.77 1.09
0.88–1.78 1.01–1.96 1.29–2.51 1.16–2.28 1.48–3.04 1.57–3.34 1.92–4.47 1.37 -3.15 1.19–2.77 1.19–2.65 1.08–1.12
.211 .042 ,.001 .005 ,.001 ,.001 ,.001 .001 .005 .005 ,.001
0.57–0.85 0.59–0.84
,.001 ,.001
1.00 1.00 0.83
0.81–1.24 0.54–0.80
.960 .057
1.00 1.31 0.68
1.09–1.57 0.56–0.81
.003 ,.001
1.00 1.21 0.66
0.99–1.46 0.54–0.80
.054 ,.001
1.00 3.04
2.56–3.61
,.001
1.00 1.31
1.06–1.64
.014
1.00 2.46
1.92–3.15
,.001
1.00 1.59
1.22–2.07
.001
1.00 2.36
2.02–2.75
,.001
1.00 1.51
1.27–1.81
,.001
OR
95%CI
1.00 1.10
0.95–1.28
1.00 1.72 2.28 3.13 3.08 4.58 5.51 6.76 4.75 3.88 3.42 1.16
1.23–2.40 1.66–3.11 2.29–4.28 2.24–4.23 3.27–6.41 3.87–7.83 4.54–10.06 3.22- 6.98 2.63–5.72 2.36–4.95 1.14–1.18
1.00 0.70 0.71
P
.185
ATP, Adult Treatment Panel; BMI, body mass index; CI, confidence interval; F, female; FBG, fasting blood glucose; HDL-C, high-density lipoprotein cholesterol; HT, hypertension; M, male; LDL-C, low-density lipoprotein cholesterol; OR, odds ratio; WC, waist circumference.
214 respectively.5 We determined that the mean levels of TC, LDL-C, HDL-C, and TG were 194.2, 117.7, 50.3, and 145.4 mg/dL, respectively. Our results are fairly consistent with previous studies.5–7,25 In our study, the most prevalent component of dyslipidemia was decreased HDL-C, with a prevalence of 41.5% (35.9% in men and 46.2% in women, P , .001). The changes in normal values for HDL-C14 make direct comparison between studies problematic. In the Turkish Heart Study in which HDL-C levels were examined in more than 9000 Turkish adults, 53% of men and 26% of women in Turkey had HDL-C ,35 mg/dL.6 The TEKHARF cohort of 2001/2002 revealed that the prevalence of low HDL-C level (,40 mg/dL) was 64% in men and 35.5% in women.25 Erem et al. reported the prevalence of low HDL-C as 21.1% in Trabzon.5 Our results are not in agreement with those of previous studies from Turkey.5,6,25 Importantly, this study was conducted in a larger population that includes all regions and age groups. A study conducted in Turkish migrants living in The Netherlands reported that the prevalence of low HDL-C was 28.7% for men and 39.4% in women.26 Compared with the results of other surveys from other countries in the world, the prevalence of low HDL-C in Turkey is higher than that in Mexico,27 Iran,24 Guadeloupe,28 the United Kingdom,29 and China,22 and lower than in Jordan.30 Genetic predisposition and lifestyle factors that include less physical activity, obesity, cigarette smoking, and the proportion of calories consumed as carbohydrates might be associated with low HDL-C levels in the Turkish population. In our study, the frequency of high LDL-C in 36.2% (35% of men and 37.2% of women) of the population. Borderline high and high values of LDL-C ($130 mg/dL) were noted in the Turkish Heart Study in 37% of men and 38% of women.6 The prevalence in the TEKHARF 2001/ 2002 cohort was 35% (31% for men and 38% for women) in Turkey.25 Erem et al. reported the prevalence of high LDL-C as 44.5% in Trabzon.5 Compared with studies in some other countries, the serum lipid levels in Turkey are lower than those in Germany,31 Greece,32 England,33 and the United States,34 but they are higher than those in Bangladesh35 and Vietnam.36 Hypertriglyceridemia is an important marker of metabolic disease. In Turkey, limited numbers of studies have been reported about the prevalence of hypertriglyceridemia.5,6,25 Onat et al. reported a prevalence of hypertriglyceridemia of 39.6% for men and 29.2% for women in Turkey.25 In the Turkish Heart Study, the prevalence was 15% for men and 6% for women,6 and Erem et al. reported the prevalence of hypertriglyceridemia as 30.4% in Trabzon.5 We estimated a prevalence for hypertriglyceridemia of 35.7% (33.5% for women and 38.3% for men). This study was performed in 7 regions of Turkey. According to regions, the prevalence of high LDL-C, low HDL-C, and mixed dyslipidemia (high LDL-C and TG, low HDL-C) were higher in the Marmara region, whereas the
Journal of Clinical Lipidology, Vol 8, No 2, April 2014 prevalence of high TG was higher in the Mediterranean region. In this present study, gender did appear to influence dyslipidemia risk. Men had a higher prevalence of hypertriglyceridemia and a combination of high TG and high LDL-C compared with women. In contrast, women had a higher prevalence of low HDL-C as well as a combination of high LDL-C and low HDL-C compared to men. Most studies reported that dyslipidemia is more prevalent among men than women,6,7,22,29 but some other studies indicate that the prevalence is more prevalent among women than among men.33,37 The variation may be explained by differential distributions of risk factors (eg, genetic predisposition, smoking, alcohol consumption, dietary factors, lack of physical activity) between women and men across populations.38 In our study, mean lipid levels increased with age. Our results were consistent with some previous studies.24,37,39 The mechanisms of the effect of age on lipid levels are not exactly known—they may be related to hereditary characteristics and degenerative processes as well as creeping weight gain and progressive development of insulin resistance. Age is associated with dyslipidemia. Many studies have reported that the prevalence of dyslipidemia increases with age.6,22,24,27,28,37,39 The highest prevalence of dyslipidemia was in the 51- to 60-year-old group for men and women. However, the prevalence was lower in study participants who were older than 70 years and did not increase further. We observed associations between dyslipidemia, abdominal obesity, and HTN. The prevalence of dyslipidemia increased with WC, BMI, and blood pressure. Also, we determined that subjects with 3 components of dyslipidemia had the highest risk of obesity, HTN, DM, and MS. According to these results, there is a biological interrelation between blood lipid levels and blood pressure. In addition, dyslipidemia was significantly associated with FBG in this study. The lipid abnormalities in abdominal obesity and in DM are likely a consequence of insulin resistance.40,41 Given the high prevalence of dyslipidemias in patients with HTN, it is imperative that any patient with HTN be screened for dyslipidemia. In Turkey, locations are generally categorized as city, district, and village. When the prevalence of dyslipidemia components are evaluated according to locations, the prevalence of high LDL-C, low HDL-C, and triple combination of dyslipidemia were higher in district locations, whereas the prevalence of high TG was higher in city centers. Also, in multivariate logistic regression analysis, the OR for dyslipidemia was significantly lower in subjects living in villages than in cities. The present study is the first to evaluate the prevalence of dyslipidemia according to altitude. We observed a lower prevalence of dyslipidemia in high altitudes than coastal regions. Dietary changes and less physical activity resulting from rapid changes in living conditions may be etiologic for the increases in dyslipidemia prevalence in subjects living in coastal areas.
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Prevalence of dyslipidemia in Turkish adults
The potential limitations of this study included the greater participation of women and elderly persons. These factors might reduce generalizability of our findings. Also, the lack of information concerning dietary variation across the country, socioeconomic status, and physical activity as well as urbanization are further limitations of the present work. Finally, the prevalence of high TG/low HDL-C was unexpectedly low and needs to be confirmed in future studies.
Conclusions Dyslipidemia is an important public health problem. The prevalence of dyslipidemia is rising throughout the world. The prevalence of all forms of dyslipidemia is high in Turkey among both men and women. There is an urgent need to institute more aggressive nationwide public health measures and screening programs and to treat patients diagnosed with dyslipidemia. Among Turkish people, dyslipidemia is highly correlated with HTN, abdominal obesity, and MS.
Acknowledgments The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.
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