DIABETICMedicine DOI: 10.1111/dme.12842
Short Report: Epidemiology Prevalence, awareness, treatment and control of diabetes mellitus in rural China: results from Shandong Province F. Yang1, D. Qian1, J. Chen2, D. Hu1, M. Hou1, S. Chen1 and P. Wang1 for the LWS Project Group 1 School of Health Policy & Management, Nanjing Medical University, Nanjing and 2Department of Hand Surgery, Affiliated Hospital of Nantong University, Nantong, China
Accepted 22 June 2015
Abstract Aims
To estimate the prevalence, awareness, treatment and control of diabetes in rural areas in Shandong Province,
China. Methods The Luxemburg–WHO–Shandong Project on Rural Health Personnel Training and Chronic Disease Control, a cross-sectional study, examined 16 375 rural residents aged 25 years and over using multistage cluster sampling in April 2007. An overnight fasting blood specimen was collected to measure plasma glucose and a 2–h 75–g oral glucose tolerance test was conducted among people with a fasting blood glucose of ≥ 6.1 mmol/l. Information on the history of diabetes and hypoglycaemic medication was obtained using a standard questionnaire. Diabetes and prediabetes were defined according to the 1999 World Health Organization diagnostic criteria.
Overall, the prevalence rates for diabetes, prediabetes and previously diagnosed diabetes in the rural population were estimated to be 3.5%, 6.0% and 1.2%, respectively. Among those with diabetes, only 34.8% were aware of their condition, 30.6% were currently undergoing medication treatment, and 11.5% achieved glycaemic control.
Results
Conclusions These results indicate that diabetes has become a public health problem in poor rural areas of China and the rates of awareness, treatment and control of diabetes were relatively low. There is an urgent need for strategies aimed at the prevention and treatment of diabetes in the rural population in Shandong Province, China.
Diabet. Med. 33, 454–458 (2016)
Introduction China, the world’s largest developing economy, has one of the largest populations of diabetes mellitus in the world [1]. Rural residents account for the vast majority of the Chinese population, and the prevalence of diabetes in the rural population has grown from 1.66% in 1995 to 5.31% in 2008 [3]. In 2010, the mortality rate for diabetes reached 8.71 per 100 000. There have been a number of studies in urban and rural areas in China [2–5], however, some of these did not provide information about the awareness, treatment and control of diabetes mellitus, and a large-scale, representative survey that specifically targets poor rural areas is lacking. Large numbers of rural residents in Shandong Province are poor (annual per capita income was $426 in 2004), and the residents of these rural areas tend to have poorer medical services [6]. In order to elucidate the current situation concerning diabetes mellitus in these areas, the Correspondence to: Fan Yang. E-mail: [email protected]
454
Luxemburg–WHO–Shandong Project on Rural Health Personnel Training and Chronic Disease Control (LWS Project) was undertaken. The LWS Project was designed to provide reliable data on the prevalence of awareness, treatment and control of diabetes mellitus in a rural population, and provide information for making health policy.
Methods The LWS Project used a multistage cluster sampling method to select a representative sample of the rural population aged 25 years and over in Shandong Province. In the first stage, sampling was stratified according to geographical characteristics and economic development status, and eight rural counties were selected using probability-proportional-to-size (PPS) sampling. In the second stage, two townships were randomly selected in each chosen county using PPS sampling. In the third stage, two villages were randomly chosen in each selected township using PPS sampling. In the final stage, all households within each selected village were listed and a
ª 2015 Diabetes UK
Research article
What’s new? A large number of rural residents are poor, and residents of rural areas tend to have poorer medical services. The ‘Luxemburg–WHO–Shandong Rural Health Personnel Training and Chronic Disease Control Project’ was initiated to explore a sustainable mechanism for chronic disease prevention and control in rural areas. However, a large-scale population-based survey into the prevalence of diabetes that is specifically targeted at poor rural areas is lacking. This article estimates the levels of prevalence, awareness, treatment and control of diabetes in a rural population of Shandong Province, China, which might be useful for diabetes mellitus intervention programmes in rural China. These results indicate that diabetes has become a public health problem in poor rural China and the rates of awareness, treatment, and control of DM were relatively low. sample size of 300 households was randomly recruited from each of the villages by systematic sampling based on feasibility and cost. In each selected household, all resident family members aged 25 years and above were invited to participate in our survey. By modifying a previously validated questionnaire from the 2002 National Health and Nutrition Survey (NHANS) [7], the LWS Project developed a multi-item structured questionnaire to obtain information on demographic characteristics, personal and family medical history. Data collection was performed door-to-door and face-to-face by trained interviewers. All surveys were implemented simultaneously between 15 April 2007 and 2 May 2007. In total, 20 087 people were invited to take part in the study; 16 375 people (7008 men) completed both the questionnaire survey and physical examination, giving a response rate of 81.5% (76.8% men and 85.5% women). Written informed consent was obtained from all participants prior to data collection. Height, weight, waist circumference and blood glucose were measured by trained and certified observers according to a common protocol [8]. Height was measured to the nearest 0.1 cm using a wall-mounted stadiometer and body weight was measured to the nearest 0.5 kg with calibrated weighing scales while participants were wearing light indoor clothing and were bare foot. Waist circumference was measured to the nearest 0.1 cm at the end of exhalation, using a non-elastic tape in a horizontal plane at a midway point between the lowest rib and the iliac crest. BMI was calculated as [weight (kg)]/[height (m)]2 and was classified as
ª 2015 Diabetes UK
DIABETICMedicine
follows: overweight, 24–27.9 kg/m2; general obesity, ≥ 28 kg/m2 [9]. Central obesity was defined as a waist circumference of ≥ 85 cm for men and ≥ 80 cm for women [10]. A family history of diabetes was noted if a participant’s first-degree relatives had diabetes. Blood glucose was measured in on-site laboratories that had been accredited to national standards [11]. All participants were instructed to fast for at least 10 h before the glucose test. A venous blood specimen was collected in a vacuum tube containing sodium fluoride. Blood plasma was separated within 2 h and blood glucose was measured within 3 h using the glucose oxidase method [12]. Participants with a fasting blood glucose (FBG) ≥ 6.1 mmol/l were given a standard 2–h 75–g oral glucose tolerance test (OGTT), and those with a FBG ≥ 7.0 mmol/l were invited to retest plasma glucose the following morning. Blood glucose was measured at 0 and 2 h after administration during the OGTT. Diabetes was defined as a self-reported previous diagnosis by a healthcare professional (diagnosed diabetes), or FBG ≥7.0 mmol/l, and/or 2–h glucose level ≥ 11.1 mmol/l. Prediabetes was defined as FBG ≥ 6.1 mmol/l and < 7.0 mmol/l, and 2–h glucose level < 7.8 mmol/l, and/or FBG < 6.1 mmol/l and 2–h glucose level ≥ 7.8 mmol/l and < 11.1 mmol/l in participants without a prior diagnosis of diabetes [13]. Awareness of diabetes was determined as self-reported previous physician-diagnosed diabetes. Treatment of diabetes was defined as self-reported use of antidiabetic medications. Adequate control of diabetes was taken as a FBG < 7.0 mmol/l among people with treated diabetes. Standard protocols [8] along with strict training for data collection were used, and a vigorous quality assurance was implemented at every phase to ensure the validity and reliability of the data. Sample sizes were estimated to meet generally recommended requirements for precision in a complex survey design [14]. Age- and sex-standardized prevalence rates were also calculated from the 2000 rural population census data [15]. Weight coefficients were derived from the 2000 rural population census data, the sampling scheme and non-response rates [16]. Standard errors were calculated using the Taylor linearization method, which was appropriate to the complex survey design. Chi-squared (v2) was used to test the difference in prevalence and a value of P < 0.05 was considered statistically significant. All data analyses involved use of the SAS system, v. 9.1 (SAS Institute Inc., Cary, NC, USA).
Results The demographic characteristics of the study population are given in Table 1. Overall, the prevalence of diabetes was estimated to be 3.5%, with prevalence of 2.3% and 1.2% for newly and previously diagnosed diabetes, respectively. The prevalence rates of diabetes and diagnosed diabetes increased with age in both genders, and were higher in people with a family history of diabetes, or who were overweight and
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Table 1 Sociodemographic characteristics of the study sample and age- and aShandong Province, China, 2007* % (95% CI) Previously diagnosed diabetes
Characteristics
N† (%)
Overall Sex Men Women P Age 25–44 45–54 55+ P Men 25–44 45–54 55+ P Women 25–44 45–54 55+ P Marital status Married Others P Family history of diabetes Yes No P BMI (kg/m2) < 24.0 24.0–28.0 ≥ 28.0 P Waist circumference (cm) < 90 in men; < 80 in women ≥ 90 in men; ≥ 80 in women P
16,375 (100.0)
3.5 (3.0, 4.0)
6.0 (5.4, 6.7)
1.2 (1.0, 1.4)
7,008 (42.8) 9,376 (57.2)
3.2 (2.6, 3.9) 3.6 (2.9, 4.3) 0.4216
6.5 (5.8, 7.2) 5.6 (4.8, 6.4) 0.0271
1.1 (0.9, 1.3) 1.3 (1.0, 1.6) 0.192
6,141 (37.5) 4,174 (25.5) 6,060 (37.0)
1.6 (1.3, 2.0) 4.2 (3.7, 4.8) 6.2 (4.7, 7.6) < 0.0001
4.4 (3.9, 4.9) 7.2 (5.7, 8.6) 8.0 (7.4, 8.6) < 0.0001
0.4 (0.3, 0.5) 1.3 (0.7, 1.8) 2.7 (2.2, 3.2) < 0.0001
2,304 (32.9) 1,820 (26.0) 2,884 (41.2)
2.0 (1.1, 2.9) 4.0 (3.1, 4.8) 4.8 (3.5, 6.0) < 0.0001
5.3 (4.7, 5.8) 7.7 (5.7, 9.7) 7.8 (7.0, 8.5) 0.0001
0.5 (0.3, 0.7) 1.1 (0.6, 1.5) 2.2 (1.4, 3.1) < 0.0001
3,837 (41.0) 2,354 (25.1) 3,176 (33.9)
1.3 (0.8, 1.9) 4.4 (3.3, 5.6) 7.4 (5.6, 9.2) < 0.0001
3.8 (3.0, 4.5) 6.7 (5.4, 8.0) 8.2 (7.2, 9.3) < 0.0001
0.3 (0.2, 0.5) 1.4 (0.4, 2.5) 3.1 (2.4, 3.7) < 0.0001
14,913 (91.2) 1,433 (8.8)
3.3 (2.8, 3.8) 4.0 (2.8, 5.3) 0.3590
5.9 (5.3, 6.5) 7.9 (6.0, 9.8) 0.0040
1.2 (0.9, 1.5) 1.7 (0.9, 2.5) 0.2586
554 (3.4) 15,779 (96.6)
10.1 (8.4, 11.8) 3.2 (2.7, 3.7) < 0.0001
6.7 (3.7, 9.6) 6.0 (5.4, 6.6) 0.6040
6.0 (3.9, 8.2) 1.0 (0.8, 1.2) < 0.0001
8,036 (49.3) 5,760 (35.4) 2,499 (15.3)
2.2 (1.9, 2.6) 3.9 (3.4, 4.4) 6.2 (5.1, 7.2) < 0.0001
5.1 (4.6, 5.6) 6.1 (5.2, 7.1) 9.1 (7.3, 10.9) < 0.0001
10,665 (65.6) 5,590 (34.4)
2.0 (1.7, 2.3) 6.1 (5.1, 7.2) < 0.0001
5.0 (4.6, 5.3) 8.1 (7.0, 9.3) < 0.0001
Diabetes
Prediabetes
0.9 (0.7, 1.0) 1.4 (0.9, 1.9) 1.5 (0.9, 2.1) 0.0211 0.7 (0.6, 0.8) 2.1 (1.3, 2.9) < 0.0001
*Age- and sex-adjusted to the 2000 China population. Totals may vary due to missing values.
†
obese. The estimated prevalence of prediabetes was 6.0% and this increased significantly with age. In addition, prediabetes was more prevalent in men, and those who were overweight and obese. Among people with diabetes, only 34.8% were aware of their condition, 30.6% were currently receiving treatment, and 11.5% had a FBG < 7.0 mmol/l. The control rate was 35.4% among those treated, with higher rates among males than females (Fig. 1). The rates of awareness and treatment increased with age.
Discussion A nationally survey with a representative sample of 42 751 people aged 20–75 years, from 11 provinces and municipalities in 1995–1996, showed that the diabetes mellitus prevalence rates for affluent and poor rural areas in China were 2.65% and 1.71%, respectively [17]. Data for a total of
456
52 416 respondents over the age of 18 years, collected in the 2002 NHANS, showed that the prevalence of diabetes in rural areas of classes 1, 2, 3 and 4 was 1.96%, 1.75%, 2.28% and 0.79%, respectively [5]. A nationally representative sample of 46 239 adults aged 20 years and above, from 14 provinces and municipalities from 2007 to 2008, showed that the prevalence of diabetes mellitus in developed, intermediately developed and underdeveloped rural areas was 12.0%, 6.7% and 5.8%, respectively [2]. Compared with our survey, the prevalence had increased in recent years. In addition, 6.0% of rural adults were estimated to have prediabetes. Taking into account the large poor rural population, along with the potential for a major epidemic of diabetes-related complications [18,19], this suggests a very serious public health problem in rural areas if there is no effective intervention. The prevalence of diabetes mellitus increased with age, and this trend was particularly evident among women. Prediabetes was more common in men and increased with age; both
ª 2015 Diabetes UK
Research article
DIABETICMedicine
Treated, controlled 100
2.8 2.4
2.5 3.7
8.2
4.6
Treated, uncontrolled
100
2.0 2.8
10.4
3.1
Untreated, unaware 100
24.3
70
80
90
25.9
24.2
50
50
50
40
30
40
76.8 67.6
65.7 30
64.7 59.2
53.0
20
10
10
10
0 45–55 Men
55–
total
76.3 70.0
20
25–45
26.9
30
20
0
22.1
70
60
72.8
3.8 6.9
24.1
60
75.9
5.2 11.0
80
22.8
60
40
2.8 5.2
18.7
70
28.4
2.4 2.6
8.1
18.4
21.0
80
Percentage (%)
11.3
90 18.9
3.6
6.6
5.5 90
3.0
Untreated, aware
65.2 56.9
0 25–45
45–55 55– Women
total
25–45
45–55 55– Total
total
FIGURE 1 Age- and Sex- Standardized Rates of Awareness, Treatment and Control of DM
general and central obesity were associated with increased prevalence’s of diabetes and prediabetes. This indicates that these rural residents had high risk of developing diabetes mellitus and were focus groups for diabetes prevention. In our study population, the rates of awareness, treatment and control were 34.8%, 30.6% and 11.5%; only 35.4% of people aware of their diabetes diagnosis had their glucose level under control, which is slightly more than in the limited large representative data available for 1998–2007. In 1998, the rates of awareness, treatment and control in rural areas were 29.0, 23.7% and 8.1%, and 34.3% for control among those aware of their diabetes diagnosis, as estimated by a representative sample of 13 643 Chinese adults ages 35–59 years from 14 cohorts [20]. In 2000–2001, the rates of awareness, treatment and control in rural areas were 18.77%, 6.18% and 8.02%, respectively, as surveyed by a nationally representative sample of 15 236 Chinese adults aged 35–74 years [4]. But the rates in our study are still much lower than in urban areas [3]. Residents in poor rural areas tend to have low levels of education and a lack of health education about diabetes. Knowledge of diabetes among the rural residents in our study was very limited (results not shown), so they may not seek effective and suitable therapies, which highlights a need for the effective detection and control of diabetes mellitus. In summary, this study indicates that diabetes and prediabetes are very common in the rural population in Shandong Province; rates of awareness, treatment and control of diabetes mellitus are relatively low, and such poor rural areas urgently need strategies aimed at the prevention and treatment of diabetes.
Funding sources
This work is supported by the project ‘Noncommunicable Chronic Diseases Community-Based Intervention in Shan-
ª 2015 Diabetes UK
dong Province, China’ (grant no. WP-2006-CHN-NCD-2.4001) from the Luxemburg government, ‘Study on the Vertical Integration Strategies in Health Services for Rural Patients with Chronic Diseases Based on Comprehensive Incentive Model’ from the National Natural Science Fund of China (grant no. 71473130), and ‘Socioeconomic Inequalities in the Prevalence and Control of Diabetes Mellitus in Rural Shandong, China’ (grant no. 2013NJMU029) form Nanjing Medical University School. However, the funding agencies had no role in the design, conduct analysis and interpretation of this article.
Competing interests
None declared.
Acknowledgements
The authors would also like to thank all the participants in survey design and data collection, the LWS Project Group, Shandong University, The Centers for Disease Control and Prevention in Shandong Province, and all staff of the Centers for Disease Control and Prevention in Guangrao, Cangshan, Laicheng, Lingxian, Ningyang, Shouguang, Ziyuan and Shanghe counties.
References 1 Hu FB. Globalization of diabetes: the role of diet, lifestyle, and genes. Diabetes Care 2011; 34: 1249–1257. 2 Yang W, Lu J, Weng J, Jia W, Ji L, Xiao J. Prevalence of diabetes among men and women in China. N Engl J Med 2010; 362: 1090–1101. 3 Li MZ, Su L, Liang BY, Tan JJ, Chen Q, Long JX et al. Trends in prevalence, awareness, treatment, and control of diabetes mellitus in Mainland China from 1979 to 2012. Int J Endocrinol 2013; Article ID 753150: 1–14.
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4 Hua D, Fu P, Xie J, Chen CS, Yu DH, Whelton PK et al. Increasing prevalence and low awareness, treatment and control of diabetes mellitus among Chinese adults: The InterASIA study. Diabet Res Clin Prac 2008; 81: 250–257. 5 Liu SY, Wand JS. Estimation of the prevalence of diabetes mellitus and the rate of impaired fasting glucose for Chinese adults. Chin J Prev Contr Chron Dis 2010; 18: 331–334. (in Chinese). 6 Liming L, Wenzhi W, Yangfeng W, Chonghua Y, Bo W, Wenzhi W et al. (Eds). The Fourth Report of the China National Health and Nutrition Examination Survey: hypertension 2002. Beijing: People’s Health, 2008 (in Chinese). 7 China Ministry of Health. A Description of the Chinese National Nutrition and Health Survey in 2002. Beijing: People’s Medical Publishing House, 2006. (in Chinese). 8 Yu Y. Epidemiological studies of diabetes mellitus and impaired glucose regulation among a rural population aged more than 25 years in midwestern areas of Shandong Province, China 2008. Jinan: Shandong University, 2008. (in Chinese). 9 Coorperative Meta-analysis Group of China Obesity Task Force. Predictive values of body mass index and waist circumference to risk factors of related diseases in Chinese adult population. Chin J Epidemiol 2002; 23: 5–10. 10 Alberti KG, Zimmet P, Shaw J. IDF epidemiology task force consensus group: the metabolic syndrome – a new worldwide definition. Lancet 2005; 366: 1059–1062. 11 China Ministry of Health. Notice on Strengthening the Management of Diagnostic Drug Approval. Beijing: China Ministry of Health, 1992 (in Chinese). 12 Ye Y, Wang Y, Shen ZY. National Clinical Test Regulation of Operation, 3rd ed. Nanjing: Southeast University Press, 2006:. (in Chinese).
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Diabetes mellitus in rural China F. Yang et al. 13 World Health Organization. Definition, Diagnosis and Classification of Diabetes Mellitus and its Complications: Report of a WHO consultation. Part 1: Diagnosis and classification of diabetes mellitus. Geneva, WHO, 1999. 14 National Center for Health Statistics. Plan and Operation of the Third National Health and Nutrition Examination Survey, 1988– 1994. Vital Health Stat. Ser. 1, No. 32. Washington, DC: National Center for Health Statistics, 1994. 15 National Bureau of Statistics of China. The fifth national population statistics primary data. Available at http://www.stats.gov.cn/ tjsj/ndsj/renkoupucha/2000pucha/pucha.htm. 16 Lehtonen R, Pahkinen E. Wangtainfu translate. Practical Methods for the Design and Analysis of Complex Surveys. Chongqing: Chongqing University Press, 2008. (in Chinese). 17 Xiang H, Wu W, Liu C, Li K, Feng J, Zhang Y et al. A epidemiological study on DM 1995–1996, in China. Chinese J Diabetes 1998; 6: 131–133. 18 Levitzky YS, Pencina MJ, D’Agostino RB, Meigs JB, Murabito JM, Vasan RS et al. Impact of impaired fasting glucose on cardiovascular disease: the Framingham Heart Study. J Am Coll Cardiol 2008; 51: 264–270. 19 Schramm TK, Gislason GH, Køber L, Rasmussen S, Rasmussen JN, Abildstrøm SZ et al. Diabetes patients requiring glucose lowering therapy and nondiabetics with a prior myocardial infarction carry the same cardiovascular risk: a population study of 3.3 million people. Circulation 2008; 117: 1945–1954. 20 Wu YF, Xie GQ, Li Y, Zhao LC, Zhou BF. The current status on the prevalence, awareness, treatment and control of diabetes mellitus in several Chinese subpopulations. Chin J Epidemiol 2005; 26: 564–569 (in Chinese.)
ª 2015 Diabetes UK
Short Report: Epidemiology Prevalence, awareness, treatment and control of diabetes mellitus in rural China: results from Shandong Province F. Yang1, D. Qian1, J. Chen2, D. Hu1, M. Hou1, S. Chen1 and P. Wang1 for the LWS Project Group 1 School of Health Policy & Management, Nanjing Medical University, Nanjing and 2Department of Hand Surgery, Affiliated Hospital of Nantong University, Nantong, China
Accepted 22 June 2015
Abstract Aims
To estimate the prevalence, awareness, treatment and control of diabetes in rural areas in Shandong Province,
China. Methods The Luxemburg–WHO–Shandong Project on Rural Health Personnel Training and Chronic Disease Control, a cross-sectional study, examined 16 375 rural residents aged 25 years and over using multistage cluster sampling in April 2007. An overnight fasting blood specimen was collected to measure plasma glucose and a 2–h 75–g oral glucose tolerance test was conducted among people with a fasting blood glucose of ≥ 6.1 mmol/l. Information on the history of diabetes and hypoglycaemic medication was obtained using a standard questionnaire. Diabetes and prediabetes were defined according to the 1999 World Health Organization diagnostic criteria.
Overall, the prevalence rates for diabetes, prediabetes and previously diagnosed diabetes in the rural population were estimated to be 3.5%, 6.0% and 1.2%, respectively. Among those with diabetes, only 34.8% were aware of their condition, 30.6% were currently undergoing medication treatment, and 11.5% achieved glycaemic control.
Results
Conclusions These results indicate that diabetes has become a public health problem in poor rural areas of China and the rates of awareness, treatment and control of diabetes were relatively low. There is an urgent need for strategies aimed at the prevention and treatment of diabetes in the rural population in Shandong Province, China.
Diabet. Med. 33, 454–458 (2016)
Introduction China, the world’s largest developing economy, has one of the largest populations of diabetes mellitus in the world [1]. Rural residents account for the vast majority of the Chinese population, and the prevalence of diabetes in the rural population has grown from 1.66% in 1995 to 5.31% in 2008 [3]. In 2010, the mortality rate for diabetes reached 8.71 per 100 000. There have been a number of studies in urban and rural areas in China [2–5], however, some of these did not provide information about the awareness, treatment and control of diabetes mellitus, and a large-scale, representative survey that specifically targets poor rural areas is lacking. Large numbers of rural residents in Shandong Province are poor (annual per capita income was $426 in 2004), and the residents of these rural areas tend to have poorer medical services [6]. In order to elucidate the current situation concerning diabetes mellitus in these areas, the Correspondence to: Fan Yang. E-mail: [email protected]
454
Luxemburg–WHO–Shandong Project on Rural Health Personnel Training and Chronic Disease Control (LWS Project) was undertaken. The LWS Project was designed to provide reliable data on the prevalence of awareness, treatment and control of diabetes mellitus in a rural population, and provide information for making health policy.
Methods The LWS Project used a multistage cluster sampling method to select a representative sample of the rural population aged 25 years and over in Shandong Province. In the first stage, sampling was stratified according to geographical characteristics and economic development status, and eight rural counties were selected using probability-proportional-to-size (PPS) sampling. In the second stage, two townships were randomly selected in each chosen county using PPS sampling. In the third stage, two villages were randomly chosen in each selected township using PPS sampling. In the final stage, all households within each selected village were listed and a
ª 2015 Diabetes UK
Research article
What’s new? A large number of rural residents are poor, and residents of rural areas tend to have poorer medical services. The ‘Luxemburg–WHO–Shandong Rural Health Personnel Training and Chronic Disease Control Project’ was initiated to explore a sustainable mechanism for chronic disease prevention and control in rural areas. However, a large-scale population-based survey into the prevalence of diabetes that is specifically targeted at poor rural areas is lacking. This article estimates the levels of prevalence, awareness, treatment and control of diabetes in a rural population of Shandong Province, China, which might be useful for diabetes mellitus intervention programmes in rural China. These results indicate that diabetes has become a public health problem in poor rural China and the rates of awareness, treatment, and control of DM were relatively low. sample size of 300 households was randomly recruited from each of the villages by systematic sampling based on feasibility and cost. In each selected household, all resident family members aged 25 years and above were invited to participate in our survey. By modifying a previously validated questionnaire from the 2002 National Health and Nutrition Survey (NHANS) [7], the LWS Project developed a multi-item structured questionnaire to obtain information on demographic characteristics, personal and family medical history. Data collection was performed door-to-door and face-to-face by trained interviewers. All surveys were implemented simultaneously between 15 April 2007 and 2 May 2007. In total, 20 087 people were invited to take part in the study; 16 375 people (7008 men) completed both the questionnaire survey and physical examination, giving a response rate of 81.5% (76.8% men and 85.5% women). Written informed consent was obtained from all participants prior to data collection. Height, weight, waist circumference and blood glucose were measured by trained and certified observers according to a common protocol [8]. Height was measured to the nearest 0.1 cm using a wall-mounted stadiometer and body weight was measured to the nearest 0.5 kg with calibrated weighing scales while participants were wearing light indoor clothing and were bare foot. Waist circumference was measured to the nearest 0.1 cm at the end of exhalation, using a non-elastic tape in a horizontal plane at a midway point between the lowest rib and the iliac crest. BMI was calculated as [weight (kg)]/[height (m)]2 and was classified as
ª 2015 Diabetes UK
DIABETICMedicine
follows: overweight, 24–27.9 kg/m2; general obesity, ≥ 28 kg/m2 [9]. Central obesity was defined as a waist circumference of ≥ 85 cm for men and ≥ 80 cm for women [10]. A family history of diabetes was noted if a participant’s first-degree relatives had diabetes. Blood glucose was measured in on-site laboratories that had been accredited to national standards [11]. All participants were instructed to fast for at least 10 h before the glucose test. A venous blood specimen was collected in a vacuum tube containing sodium fluoride. Blood plasma was separated within 2 h and blood glucose was measured within 3 h using the glucose oxidase method [12]. Participants with a fasting blood glucose (FBG) ≥ 6.1 mmol/l were given a standard 2–h 75–g oral glucose tolerance test (OGTT), and those with a FBG ≥ 7.0 mmol/l were invited to retest plasma glucose the following morning. Blood glucose was measured at 0 and 2 h after administration during the OGTT. Diabetes was defined as a self-reported previous diagnosis by a healthcare professional (diagnosed diabetes), or FBG ≥7.0 mmol/l, and/or 2–h glucose level ≥ 11.1 mmol/l. Prediabetes was defined as FBG ≥ 6.1 mmol/l and < 7.0 mmol/l, and 2–h glucose level < 7.8 mmol/l, and/or FBG < 6.1 mmol/l and 2–h glucose level ≥ 7.8 mmol/l and < 11.1 mmol/l in participants without a prior diagnosis of diabetes [13]. Awareness of diabetes was determined as self-reported previous physician-diagnosed diabetes. Treatment of diabetes was defined as self-reported use of antidiabetic medications. Adequate control of diabetes was taken as a FBG < 7.0 mmol/l among people with treated diabetes. Standard protocols [8] along with strict training for data collection were used, and a vigorous quality assurance was implemented at every phase to ensure the validity and reliability of the data. Sample sizes were estimated to meet generally recommended requirements for precision in a complex survey design [14]. Age- and sex-standardized prevalence rates were also calculated from the 2000 rural population census data [15]. Weight coefficients were derived from the 2000 rural population census data, the sampling scheme and non-response rates [16]. Standard errors were calculated using the Taylor linearization method, which was appropriate to the complex survey design. Chi-squared (v2) was used to test the difference in prevalence and a value of P < 0.05 was considered statistically significant. All data analyses involved use of the SAS system, v. 9.1 (SAS Institute Inc., Cary, NC, USA).
Results The demographic characteristics of the study population are given in Table 1. Overall, the prevalence of diabetes was estimated to be 3.5%, with prevalence of 2.3% and 1.2% for newly and previously diagnosed diabetes, respectively. The prevalence rates of diabetes and diagnosed diabetes increased with age in both genders, and were higher in people with a family history of diabetes, or who were overweight and
455
Diabetes mellitus in rural China F. Yang et al.
DIABETICMedicine
Table 1 Sociodemographic characteristics of the study sample and age- and aShandong Province, China, 2007* % (95% CI) Previously diagnosed diabetes
Characteristics
N† (%)
Overall Sex Men Women P Age 25–44 45–54 55+ P Men 25–44 45–54 55+ P Women 25–44 45–54 55+ P Marital status Married Others P Family history of diabetes Yes No P BMI (kg/m2) < 24.0 24.0–28.0 ≥ 28.0 P Waist circumference (cm) < 90 in men; < 80 in women ≥ 90 in men; ≥ 80 in women P
16,375 (100.0)
3.5 (3.0, 4.0)
6.0 (5.4, 6.7)
1.2 (1.0, 1.4)
7,008 (42.8) 9,376 (57.2)
3.2 (2.6, 3.9) 3.6 (2.9, 4.3) 0.4216
6.5 (5.8, 7.2) 5.6 (4.8, 6.4) 0.0271
1.1 (0.9, 1.3) 1.3 (1.0, 1.6) 0.192
6,141 (37.5) 4,174 (25.5) 6,060 (37.0)
1.6 (1.3, 2.0) 4.2 (3.7, 4.8) 6.2 (4.7, 7.6) < 0.0001
4.4 (3.9, 4.9) 7.2 (5.7, 8.6) 8.0 (7.4, 8.6) < 0.0001
0.4 (0.3, 0.5) 1.3 (0.7, 1.8) 2.7 (2.2, 3.2) < 0.0001
2,304 (32.9) 1,820 (26.0) 2,884 (41.2)
2.0 (1.1, 2.9) 4.0 (3.1, 4.8) 4.8 (3.5, 6.0) < 0.0001
5.3 (4.7, 5.8) 7.7 (5.7, 9.7) 7.8 (7.0, 8.5) 0.0001
0.5 (0.3, 0.7) 1.1 (0.6, 1.5) 2.2 (1.4, 3.1) < 0.0001
3,837 (41.0) 2,354 (25.1) 3,176 (33.9)
1.3 (0.8, 1.9) 4.4 (3.3, 5.6) 7.4 (5.6, 9.2) < 0.0001
3.8 (3.0, 4.5) 6.7 (5.4, 8.0) 8.2 (7.2, 9.3) < 0.0001
0.3 (0.2, 0.5) 1.4 (0.4, 2.5) 3.1 (2.4, 3.7) < 0.0001
14,913 (91.2) 1,433 (8.8)
3.3 (2.8, 3.8) 4.0 (2.8, 5.3) 0.3590
5.9 (5.3, 6.5) 7.9 (6.0, 9.8) 0.0040
1.2 (0.9, 1.5) 1.7 (0.9, 2.5) 0.2586
554 (3.4) 15,779 (96.6)
10.1 (8.4, 11.8) 3.2 (2.7, 3.7) < 0.0001
6.7 (3.7, 9.6) 6.0 (5.4, 6.6) 0.6040
6.0 (3.9, 8.2) 1.0 (0.8, 1.2) < 0.0001
8,036 (49.3) 5,760 (35.4) 2,499 (15.3)
2.2 (1.9, 2.6) 3.9 (3.4, 4.4) 6.2 (5.1, 7.2) < 0.0001
5.1 (4.6, 5.6) 6.1 (5.2, 7.1) 9.1 (7.3, 10.9) < 0.0001
10,665 (65.6) 5,590 (34.4)
2.0 (1.7, 2.3) 6.1 (5.1, 7.2) < 0.0001
5.0 (4.6, 5.3) 8.1 (7.0, 9.3) < 0.0001
Diabetes
Prediabetes
0.9 (0.7, 1.0) 1.4 (0.9, 1.9) 1.5 (0.9, 2.1) 0.0211 0.7 (0.6, 0.8) 2.1 (1.3, 2.9) < 0.0001
*Age- and sex-adjusted to the 2000 China population. Totals may vary due to missing values.
†
obese. The estimated prevalence of prediabetes was 6.0% and this increased significantly with age. In addition, prediabetes was more prevalent in men, and those who were overweight and obese. Among people with diabetes, only 34.8% were aware of their condition, 30.6% were currently receiving treatment, and 11.5% had a FBG < 7.0 mmol/l. The control rate was 35.4% among those treated, with higher rates among males than females (Fig. 1). The rates of awareness and treatment increased with age.
Discussion A nationally survey with a representative sample of 42 751 people aged 20–75 years, from 11 provinces and municipalities in 1995–1996, showed that the diabetes mellitus prevalence rates for affluent and poor rural areas in China were 2.65% and 1.71%, respectively [17]. Data for a total of
456
52 416 respondents over the age of 18 years, collected in the 2002 NHANS, showed that the prevalence of diabetes in rural areas of classes 1, 2, 3 and 4 was 1.96%, 1.75%, 2.28% and 0.79%, respectively [5]. A nationally representative sample of 46 239 adults aged 20 years and above, from 14 provinces and municipalities from 2007 to 2008, showed that the prevalence of diabetes mellitus in developed, intermediately developed and underdeveloped rural areas was 12.0%, 6.7% and 5.8%, respectively [2]. Compared with our survey, the prevalence had increased in recent years. In addition, 6.0% of rural adults were estimated to have prediabetes. Taking into account the large poor rural population, along with the potential for a major epidemic of diabetes-related complications [18,19], this suggests a very serious public health problem in rural areas if there is no effective intervention. The prevalence of diabetes mellitus increased with age, and this trend was particularly evident among women. Prediabetes was more common in men and increased with age; both
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Research article
DIABETICMedicine
Treated, controlled 100
2.8 2.4
2.5 3.7
8.2
4.6
Treated, uncontrolled
100
2.0 2.8
10.4
3.1
Untreated, unaware 100
24.3
70
80
90
25.9
24.2
50
50
50
40
30
40
76.8 67.6
65.7 30
64.7 59.2
53.0
20
10
10
10
0 45–55 Men
55–
total
76.3 70.0
20
25–45
26.9
30
20
0
22.1
70
60
72.8
3.8 6.9
24.1
60
75.9
5.2 11.0
80
22.8
60
40
2.8 5.2
18.7
70
28.4
2.4 2.6
8.1
18.4
21.0
80
Percentage (%)
11.3
90 18.9
3.6
6.6
5.5 90
3.0
Untreated, aware
65.2 56.9
0 25–45
45–55 55– Women
total
25–45
45–55 55– Total
total
FIGURE 1 Age- and Sex- Standardized Rates of Awareness, Treatment and Control of DM
general and central obesity were associated with increased prevalence’s of diabetes and prediabetes. This indicates that these rural residents had high risk of developing diabetes mellitus and were focus groups for diabetes prevention. In our study population, the rates of awareness, treatment and control were 34.8%, 30.6% and 11.5%; only 35.4% of people aware of their diabetes diagnosis had their glucose level under control, which is slightly more than in the limited large representative data available for 1998–2007. In 1998, the rates of awareness, treatment and control in rural areas were 29.0, 23.7% and 8.1%, and 34.3% for control among those aware of their diabetes diagnosis, as estimated by a representative sample of 13 643 Chinese adults ages 35–59 years from 14 cohorts [20]. In 2000–2001, the rates of awareness, treatment and control in rural areas were 18.77%, 6.18% and 8.02%, respectively, as surveyed by a nationally representative sample of 15 236 Chinese adults aged 35–74 years [4]. But the rates in our study are still much lower than in urban areas [3]. Residents in poor rural areas tend to have low levels of education and a lack of health education about diabetes. Knowledge of diabetes among the rural residents in our study was very limited (results not shown), so they may not seek effective and suitable therapies, which highlights a need for the effective detection and control of diabetes mellitus. In summary, this study indicates that diabetes and prediabetes are very common in the rural population in Shandong Province; rates of awareness, treatment and control of diabetes mellitus are relatively low, and such poor rural areas urgently need strategies aimed at the prevention and treatment of diabetes.
Funding sources
This work is supported by the project ‘Noncommunicable Chronic Diseases Community-Based Intervention in Shan-
ª 2015 Diabetes UK
dong Province, China’ (grant no. WP-2006-CHN-NCD-2.4001) from the Luxemburg government, ‘Study on the Vertical Integration Strategies in Health Services for Rural Patients with Chronic Diseases Based on Comprehensive Incentive Model’ from the National Natural Science Fund of China (grant no. 71473130), and ‘Socioeconomic Inequalities in the Prevalence and Control of Diabetes Mellitus in Rural Shandong, China’ (grant no. 2013NJMU029) form Nanjing Medical University School. However, the funding agencies had no role in the design, conduct analysis and interpretation of this article.
Competing interests
None declared.
Acknowledgements
The authors would also like to thank all the participants in survey design and data collection, the LWS Project Group, Shandong University, The Centers for Disease Control and Prevention in Shandong Province, and all staff of the Centers for Disease Control and Prevention in Guangrao, Cangshan, Laicheng, Lingxian, Ningyang, Shouguang, Ziyuan and Shanghe counties.
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