DIABETICMedicine DOI: 10.1111/dme.12542
Short Report: Epidemiology Prevalence of diabetes and impaired fasting glucose in Poland—the NATPOL 2011 Study M. Rutkowski1, P. Bandosz1, L. Czupryniak2, Z. Gaciong3, B. Solnica4, H. Jasiel-Wojculewicz1, B. Wyrzykowski1, M. J. Pencina5 and T. Zdrojewski1 1 Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, 2Department of Internal Medicine and Diabetology, Medical University of Lodz, Lodz, 3Department of Internal Medicine, Hypertension and Vascular Disease, Medical University of Warsaw, Warsaw, 4Department of Diagnostics, Chair of Clinical Biochemistry, Jagiellonian University Medical College, Krakow, Poland and 5Duke Clinical Research Institute, Biostatistics and Bioinformatics, Duke University, Durham, NC, USA
Accepted 26 June 2014
Abstract Aims
The aim of the analysis was to assess the prevalence of diabetes and impaired fasting glucose in Poland.
Methods A questionnaire survey on a representative sample of 2411 Polish adults, complemented by blood pressure, anthropometric and fasting plasma glucose measurements. The research was part of the national cross-sectional NATPOL 2011 Study. Diabetes was assessed as self-reported (diagnosed) or screened (fasting plasma glucose level ≥ 7 mmol/l, based on one blood draw).
Total prevalence of diabetes in 2011 was 6.7% (95% CI 5.6–7.9); 6.4% (95% CI 5.0–8.0) in women and 7.0% (95% CI 5.4–8.8) in men and did not change from 2002 (6.8%, 95% CI 95% CI 5.8–7.9). Over one quarter of individuals with diabetes were not aware of having the condition. Obesity, arterial hypertension and male gender were strong predictors of screened diabetes. Total prevalence of impaired fasting glucose in the surveyed population was 15.6% (95% CI 14.0–17.2).
Results
Conclusions The prevalence of diabetes in Poland is similar to that observed in other European populations and has not changed over the last decade. The fact that every fourth person with diabetes is unaware of the disease creates important opportunities for screening and detection of the disease.
Diabet. Med. 31, 1568–1571 (2014)
Introduction An increase in the prevalence of diabetes has been recently observed worldwide, in both developed and developing countries [1]. In 2006, diabetes was declared an epidemic by the United Nations and, in 2012, the European Parliament passed a resolution calling upon all member states to formulate national diabetes programmes, which would include setting up national diabetes registers, assessing the costs and implementing preventive measures against diabetes and its complications [2,3]. To create a programme like this, data on the prevalence of diabetes are required. In Poland, these data have been collected through the series of cross-sectional epidemiological studies called ‘NATPOL’. The first survey was performed in 2002 and focused on collection of risk factors for cardiovascular disease [4]. The aim of the present analysis was to describe the prevalence of Correspondence to: Tomasz Zdrojewski. E-mail: [email protected]
1568
glucose metabolism disturbances according to the NATPOL 2011 survey [5].
Material and methods The NATPOL studies are cross-sectional surveys intended to assess the prevalence and control of cardiovascular disease risk factors in Poland. Research participants were randomly recruited using multistage, stratified (by age, sex and place of living) and clustered sample design. In the first stage of the 2011 survey, 60 territorial strata were defined according to geographic location and population density. Then, 248 municipalities were drawn, each with a probability proportional to their population sizes. In each municipality, streets (in urban municipalities) and villages (in rural ones) were randomly selected. In the last stage, individual respondents were drawn, using the Polish Universal Electronic System for Registration of the Population (PESEL) database. The survey fieldwork was carried out by 234 nurses, and the response
ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
Research article
What’s new? • In view of a rising epidemic of diabetes, monitoring the prevalence of the disease and focus on prevention represent issues of major importance for any society. Based on a study of a representative sample of the adult Polish population we found that: • the prevalence of diabetes in Poland is 6.7% and is similar to other European countries; • every fourth person with diabetes is unaware of having the condition. rate was 67%. The 2002 survey was designed similarly and had a response rate of 79%. The sample used in this analysis included 2411 responders aged 18–79 years. Because of a slight under-representation of the youngest age group, weights were applied to adjust the age and sex structure of the sample to match the general Polish population in 2011. Self-reported information about diabetes was collected as responses to the following questions: ‘Do you have diabetes?’; ‘How old were you when you were diagnosed with diabetes?’; ‘What treatment do you use for your diabetes?’ Venous blood samples were drawn at the patient’s home, after at least 10 h of fasting and were transported within a maximum of 2 h to a local laboratory responsible for separating plasma samples by centrifugation and freezing the samples at –20 °C. Within a maximum of 6 weeks, all frozen biological material was transported to the central laboratory. Glucose metabolism abnormalities were defined in the following hierarchical fashion. First, individuals on insulin immediately after the diagnosis of diabetes (n = 7) were considered as potentially having Type 1 diabetes and not included in the following categories. Then, those who answered ‘yes’ to the question ‘do you have diabetes?’, we considered as having and being aware of Type 2 diabetes. Next, those who did not answer ‘yes’ to the above question, but whose fasting plasma glucose was ≥ 7 mmol/l, were considered as having diabetes but not being aware of it. Participants not belonging to any of the above groups, but whose fasting plasma glucose was between 5.6 and 6.9 mmol/l were classified as having impaired fasting glucose. To keep our results comparable with other studies, in this report we assumed that one measurement of fasting plasma glucose is sufficient to define diabetes and impaired fasting glucose. In sensitivity analysis, we investigated what happens to the prevalence of impaired fasting glucose if two separate measurements are required. Statistical analyses accounted for the complex survey design of the data using the SURVEYFREQ procedure in the SAS statistical software (SAS Institute, Cary, NC, USA). Confidence limits for reported proportions were constructed using the Clopper–Pearson method. Results from the 2011
ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
DIABETICMedicine
survey were compared with the assessment wave in 2002. The same definition of diabetes (self-report or fasting plasma glucose ≥ 7 mmol/l) was applied to both databases. Analyses were performed on the two samples without modification, as well as after standardizing age of the 2002 wave to the one from 2011. To identify factors related to screened diabetes, we employed logistic regression, which included all the variables that are easy to obtain in clinical practice: gender (with men as reference group), age (as continues variable), obesity (with non-obese as reference) and hypertension status (with no hypertension as reference). BMI was assessed using measured weight and height. Hypertension was diagnosed on the basis of four measurements during two visits if mean values of blood pressure were ≥ 140 mmHg systolic or ≥ 90 mmHg diastolic or study subject was using any anti-hypertensive pharmacological therapy.
Results Of the 2404 survey participants aged 18–79 years, 5.0% (95% CI 4.1–6.0) reported having diabetes: 4.5% (95% CI 3.4–5.9) in men and 5.5%, (95% CI 4.2–7.1) in women, representing 1.5 million Poles in this age group. An additional 1.7% (95% CI 1.2–2.3) met the criteria for diabetes based on their fasting blood glucose collected in our study without reporting diabetes awareness (2.5%, 95% CI 1.6– 3.6 in men and 0.9%, 95% CI 0.4–1.7 in women), representing 0.5 million Polish adults. Furthermore, an additional 15.6% (95% CI 14.0–17.2) adults qualified for the diagnosis impaired fasting glucose based on a single blood glucose measurement (Table 1). This percentage decreased to 8.3% (95% CI 6.6–10.2) when two measurements were required. Among those aware of having diabetes, the median time from diagnosis was 4.9 years (95% CI 3.5–6.2). In this group, 71.3% (95% CI 62.9–78.7) reported receiving only glucose-lowering agents, 11.6% (95% CI 6.7–18.1) initially received glucose-lowering agents, but now are on insulin, 11.2% (95% CI 6.3–18.0) started and continue on glucose-lowering agents, but now also receive insulin, and, finally, 4.2% (95% CI 1.5–9.0) report only following a special diet. To assess the time trends in the prevalence of diabetes in the Polish population, we contrasted the prevalence estimates based on the current NATPOL survey (2011) and the previous one conducted in 2002. Without adjustments, 6.7% (95% CI 5.6–7.9) of the current sample reported awareness of diabetes or had fasting glucose above 7.0 mmol/l, compared with 6.4% (95% CI 5.4–7.5) in the 2002 survey. When we adjusted the 2002 number for the age distribution from the 2011 sample, the prevalence increased to 6.8% (95% CI 5.8–7.9), suggesting virtually no change in prevalence between the two periods. As indicated earlier, 1.7% (95% CI 1.2–2.3) of individuals were not aware of having diabetes, representing approximately 25% of all subjects with the condition. In our logistic
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Prevalence of diabetes and impaired fasting glucose in Poland M. Rutkowski et al.
DIABETICMedicine
Table 1 Prevalence of glucose metabolism abnormalities among men and women, based on one fasting plasma glucose measurement and questionnaire (see also Supporting Information, Appendix S1 for results stratified by age) Men
Women
Group
Point estimate (%)
Lower confidence limit (%)‡
Upper confidence limit (%)‡
Number of study subjects
Point estimate (%)
Lower confidence limit (%)‡
Upper confidence limit(%)‡
Number of study subjects
Self-reported Type 2 diabetes Screened Type 2 diabetes* Screened impaired fasting glucose† Normal glucose tolerance Total diabetes
4.5 2.5 19.4 73.6 7.0
3.4 1.6 17.0 70.7 5.4
5.9 3.6 22.0 76.4 8.8
52 29 226 856 81
5.5 0.9 12.0 81.7 6.4
4.2 0.4 10.2 79.4 5.0
7.1 1.7 13.9 83.8 8.0
68 11 148 1014 79
Defined as fasting plasma glucose ≥ 7.0 mmol/l and no earlier established diagnosis of diabetes. Defined as fasting plasma glucose 5.6–6.9 mmol/l and no diagnosis of diabetes. ‡ Clopper–Pearson lower and upper 95% confidence limits. * †
regression model, the following risk factors were associated with the screened diabetes: obesity, arterial hypertension and male gender (Table 2).
Discussion Eastern Europe in general, and Poland in particular, have seen rapid social and economic changes since 1990. As a result, cardiovascular mortality started to decline, but this process is at least 20 years delayed compared with Western Europe [6]. We investigated the prevalence of diabetes as a cardiovascular risk factor in 2011 in Poland. We estimate that the prevalence of diabetes in Poland in 2011 was 6.7%. This is similar to the results published in the actual International Diabetes Federation Diabetes Atlas for most European countries [7], but lower than found in the studies from the USA or the Gulf region [7–11]. Interestingly, this number is not larger than the corresponding age-adjusted proportion of 6.8% observed in the 2002 survey. We have also discovered that one quarter of individuals with diabetes are unaware of having the condition. This offers an opportunity for new or existing prevention or early detection programmes. Based on our analysis, the attractive targets for these programmes include men and people with obesity and hypertension, as they are much more likely to
have screened diabetes. Obesity and hypertension are well-known variables related to diabetes, while men in Poland are in general less interested in their health, and are less likely to undergo any screening [4,12]. This could be a possible reason for the higher rates of screened diabetes in this group. Impaired fasting glucose, introduced as a clinical entity recently, is regarded as a risk factor for cardiovascular disease [13]. Persons with impaired fasting glucose should be subject to diabetes prevention measures [14,15]. In the present study, the prevalence of impaired fasting glucose in the adult population was 15.6%. This high proportion can be partially explained by using only one measurement to define impaired fasting glucose, but also identifies a large cohort potentially at risk of developing diabetes or cardiovascular disease. Our study has several limitations. First, the diagnosis of diabetes is based on self-report or a single blood glucose measurement. This can add bias to our estimates. However, this is the approach widely used in epidemiological studies because of cost and feasibility. The advantage of this approach is that our results are comparable with numerous studies in other populations. Furthermore, study participants were instructed to fast and they confirmed this just before the blood sample collection, but some non-compliance cannot be excluded. Finally, our sample size did not allow the analysis of smaller subgroups.
Table 2 Logistic regression model Screened Type 2 diabetes†
Impaired fasting glucose* ‡
Self-reported Type 2 diabetes
Variable
Odds ratio
95% CI
P-value
Odds ratio‡
95% CI
P-value
Odds ratio‡
95% CI
P-value
Obesity Arterial hypertension Male gender Age (for 1 year change)
1.52 1.43 1.94 1.04
1.12–2.07 1.09–1.90 1.55–2.43 1.03–1.05
0.007 0.011 < 0.001 < 0.001
3.62 3.54 2.67 1.01
1.87–7.01 1.43–8.74 1.28–5.57 0.98–1.03
< 0.001 0.006 0.009 < 0.001
3.16 4.30 0.97 1.07
2.09–4.78 2.56–7.27 0.62–1.52 1.05–1.09
< 0.001 < 0.001 0.886 < 0.001
*
Impaired fasting glucose defined as fasting plasma glucose 5.6–6.9 mmol/l and no self-reported diabetes. Fasting plasma glucose ≥ 7.0 mmo/l and no self-reported diabetes. Odds ratios for having impaired fasting glucose, screened Type 2 diabetes or self-reported Type 2 diabetes (odds ratio, 95% CI, 95% confidence interval for odds ratio). All odds ratios are adjusted for all other predictor variables presented in the table.
† ‡
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ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
Research article
In summary, the prevalence of diabetes in Poland (6.7%) is similar to that observed in other European populations and has not increased in the last decade. The fact that every fourth person with diabetes is unaware of the disease creates important opportunities for screening and detection of the disease.
Funding sources
The NATPOL 2011 Study was partially funded by the Polish Ministry of Health as a publicly funded project representing part of the National Cardiovascular Disease Prevention and Treatment Programme and by statutory grants from the Medical University of Gdansk and the Medical University of Warsaw. It was also partly funded by the following industry sponsors. The main sponsor of the project: Sanofi-Aventis— unrestricted educational grant; Abbott Laboratories Poland Ltd—sponsor with unrestricted educational grant; Siemens Ltd—partner of the project—unrestricted educational grant; Polpharma—partner of the project—unrestricted educational grant—in the part of the project dedicated to heart failure. The funding agencies had no involvement in the design or conduct of the study; collection, management, analysis and interpretation of data; or drafting of the manuscript.
Competing interests
None declared.
References 1 IDF. Diabetes Atlas: the Global Burden. Available at http://www. idf.org/diabetesatlas/5e/the-global-burden Last accessed 2 January 2014. 2 IDF. Diabetes Atlas: UN-Resolution 61/225. Available at http:// www.idf.org/diabetesatlas/un-resolution 6th edn. Last accessed 2 January 2014. 3 European Parliament. Legislative Observatory. 2011/2911(RSP). 2012. Available at http://www.europarl.europa.eu/oeil/popups/summary.do?id=1197528&t=d&l=en Last accessed 2 January 2014. 4 Zdrojewski T, Bandosz P, Szpakowski P, Konarski R, Jakubowski Z, Manikowski A et al. Rozpowszechnienie gł ownych czynnik ow ryzyka chor ob układu sercowo-naczyniowego w Polsce. Wyniki badania NATPOL PLUS (Prevalence of main cardiovascular risk factors in Poland. The NATPOL PLUS study). Kardiol Pol 2004; 61: S546–S558.
ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
DIABETICMedicine
5 Zdrojewski T, Rutkowski M, Bandosz P, Gaciong Z, Jez drzejczyk T, Solnica B et al. Prevalence and control of cardiovascular risk factors in Poland. Assumptions and objectives of the NATPOL 2011 Survey. Kardiol Pol 2013; 71: 381–392. 6 Bandosz P, O’Flaherty M, Drygas W. Decline in mortality from coronary heart disease in Poland after socio-economic transformation: modeling study. Br Med J 2012; 344: d8136. doi:10.1136/ bmj.d8136. 7 IDF. Diabetes Atlas, 6th edn. Brussels: International Diabetes Federation, 2013. Available at http://www.idf.org/diabetesatlas Last accessed 2 January 2014. 8 Saadi H, Carruthers SG, Nagelkerke N, Al-Maskari F, Afandi B, Reed R et al. Prevalence of diabetes mellitus and its complications in a population-based sample in Al Ain, United Arab Emirates. Diabetes Res Clin Pract 2007; 78: 369–377. 9 Ng SW, Zaghloul S, Ali HI, Harrison G, Popkin BM. The prevalence and trends of overweight, obesity and nutrition-related non-communicable diseases in the Arabian Gulf States. Obes Rev 2011; 12: 1–13. 10 Thorpe LE, Upadhyay UD, Chamany S. Prevalence and control of diabetes and impaired fasting glucose in New York City. Diabetes Care 2009; 32: 57–62. 11 Cowie CC, Rust KF, Byrd-Holt DD. Prevalence of diabetes and impaired fasting glucose in adults in the US population: National Health And Nutrition Examination Survey 1999–2002. Diabetes Care 2006; 29: 1263–1268. 12 Zdrojewski T, Wyrzykowski B, Szczez ch R. Epidemiology and prevention of arterial hypertension in Poland. Blood Press Suppl 2005; 14: 10–16. 13 Sarwar N, Gao P, Seshasai SR. Diabetes mellitus, fasting blood glucose concentration and risk of vascular disease: a collaborative meta-analysis of 102 prospective studies. The Emerging Risk Factors Collaboration. Lancet 2010; 375: 2215–2222. 14 Pontiroli AE, Pizzocri P, Caumo A, Perseghin G, Luzi L. Evaluation of insulin release and insulin sensitivity through oral glucose tolerance test: differences between NGT, IFG, IGT, and type 2 diabetes mellitus. A cross-sectional and follow-up study. Acta Diabetol 2004; 41: 70–76. 15 Tuomilehto J, Lindstr€ om J, Eriksson JG, Valle TT, H€ am€ al€ ainen H, Ilanne-Parikka P et al. Finnish Diabetes Prevention Study Group. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001; 344: 1343–1350.
Supporting Information Additional Supporting Information may be found in the online version of this article: Appendix S1. Prevalence of glucose metabolism abnormalities among men, based on one fasting plasma glucose measurement and questionnaire.
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Short Report: Epidemiology Prevalence of diabetes and impaired fasting glucose in Poland—the NATPOL 2011 Study M. Rutkowski1, P. Bandosz1, L. Czupryniak2, Z. Gaciong3, B. Solnica4, H. Jasiel-Wojculewicz1, B. Wyrzykowski1, M. J. Pencina5 and T. Zdrojewski1 1 Department of Hypertension and Diabetology, Medical University of Gdansk, Gdansk, 2Department of Internal Medicine and Diabetology, Medical University of Lodz, Lodz, 3Department of Internal Medicine, Hypertension and Vascular Disease, Medical University of Warsaw, Warsaw, 4Department of Diagnostics, Chair of Clinical Biochemistry, Jagiellonian University Medical College, Krakow, Poland and 5Duke Clinical Research Institute, Biostatistics and Bioinformatics, Duke University, Durham, NC, USA
Accepted 26 June 2014
Abstract Aims
The aim of the analysis was to assess the prevalence of diabetes and impaired fasting glucose in Poland.
Methods A questionnaire survey on a representative sample of 2411 Polish adults, complemented by blood pressure, anthropometric and fasting plasma glucose measurements. The research was part of the national cross-sectional NATPOL 2011 Study. Diabetes was assessed as self-reported (diagnosed) or screened (fasting plasma glucose level ≥ 7 mmol/l, based on one blood draw).
Total prevalence of diabetes in 2011 was 6.7% (95% CI 5.6–7.9); 6.4% (95% CI 5.0–8.0) in women and 7.0% (95% CI 5.4–8.8) in men and did not change from 2002 (6.8%, 95% CI 95% CI 5.8–7.9). Over one quarter of individuals with diabetes were not aware of having the condition. Obesity, arterial hypertension and male gender were strong predictors of screened diabetes. Total prevalence of impaired fasting glucose in the surveyed population was 15.6% (95% CI 14.0–17.2).
Results
Conclusions The prevalence of diabetes in Poland is similar to that observed in other European populations and has not changed over the last decade. The fact that every fourth person with diabetes is unaware of the disease creates important opportunities for screening and detection of the disease.
Diabet. Med. 31, 1568–1571 (2014)
Introduction An increase in the prevalence of diabetes has been recently observed worldwide, in both developed and developing countries [1]. In 2006, diabetes was declared an epidemic by the United Nations and, in 2012, the European Parliament passed a resolution calling upon all member states to formulate national diabetes programmes, which would include setting up national diabetes registers, assessing the costs and implementing preventive measures against diabetes and its complications [2,3]. To create a programme like this, data on the prevalence of diabetes are required. In Poland, these data have been collected through the series of cross-sectional epidemiological studies called ‘NATPOL’. The first survey was performed in 2002 and focused on collection of risk factors for cardiovascular disease [4]. The aim of the present analysis was to describe the prevalence of Correspondence to: Tomasz Zdrojewski. E-mail: [email protected]
1568
glucose metabolism disturbances according to the NATPOL 2011 survey [5].
Material and methods The NATPOL studies are cross-sectional surveys intended to assess the prevalence and control of cardiovascular disease risk factors in Poland. Research participants were randomly recruited using multistage, stratified (by age, sex and place of living) and clustered sample design. In the first stage of the 2011 survey, 60 territorial strata were defined according to geographic location and population density. Then, 248 municipalities were drawn, each with a probability proportional to their population sizes. In each municipality, streets (in urban municipalities) and villages (in rural ones) were randomly selected. In the last stage, individual respondents were drawn, using the Polish Universal Electronic System for Registration of the Population (PESEL) database. The survey fieldwork was carried out by 234 nurses, and the response
ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
Research article
What’s new? • In view of a rising epidemic of diabetes, monitoring the prevalence of the disease and focus on prevention represent issues of major importance for any society. Based on a study of a representative sample of the adult Polish population we found that: • the prevalence of diabetes in Poland is 6.7% and is similar to other European countries; • every fourth person with diabetes is unaware of having the condition. rate was 67%. The 2002 survey was designed similarly and had a response rate of 79%. The sample used in this analysis included 2411 responders aged 18–79 years. Because of a slight under-representation of the youngest age group, weights were applied to adjust the age and sex structure of the sample to match the general Polish population in 2011. Self-reported information about diabetes was collected as responses to the following questions: ‘Do you have diabetes?’; ‘How old were you when you were diagnosed with diabetes?’; ‘What treatment do you use for your diabetes?’ Venous blood samples were drawn at the patient’s home, after at least 10 h of fasting and were transported within a maximum of 2 h to a local laboratory responsible for separating plasma samples by centrifugation and freezing the samples at –20 °C. Within a maximum of 6 weeks, all frozen biological material was transported to the central laboratory. Glucose metabolism abnormalities were defined in the following hierarchical fashion. First, individuals on insulin immediately after the diagnosis of diabetes (n = 7) were considered as potentially having Type 1 diabetes and not included in the following categories. Then, those who answered ‘yes’ to the question ‘do you have diabetes?’, we considered as having and being aware of Type 2 diabetes. Next, those who did not answer ‘yes’ to the above question, but whose fasting plasma glucose was ≥ 7 mmol/l, were considered as having diabetes but not being aware of it. Participants not belonging to any of the above groups, but whose fasting plasma glucose was between 5.6 and 6.9 mmol/l were classified as having impaired fasting glucose. To keep our results comparable with other studies, in this report we assumed that one measurement of fasting plasma glucose is sufficient to define diabetes and impaired fasting glucose. In sensitivity analysis, we investigated what happens to the prevalence of impaired fasting glucose if two separate measurements are required. Statistical analyses accounted for the complex survey design of the data using the SURVEYFREQ procedure in the SAS statistical software (SAS Institute, Cary, NC, USA). Confidence limits for reported proportions were constructed using the Clopper–Pearson method. Results from the 2011
ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
DIABETICMedicine
survey were compared with the assessment wave in 2002. The same definition of diabetes (self-report or fasting plasma glucose ≥ 7 mmol/l) was applied to both databases. Analyses were performed on the two samples without modification, as well as after standardizing age of the 2002 wave to the one from 2011. To identify factors related to screened diabetes, we employed logistic regression, which included all the variables that are easy to obtain in clinical practice: gender (with men as reference group), age (as continues variable), obesity (with non-obese as reference) and hypertension status (with no hypertension as reference). BMI was assessed using measured weight and height. Hypertension was diagnosed on the basis of four measurements during two visits if mean values of blood pressure were ≥ 140 mmHg systolic or ≥ 90 mmHg diastolic or study subject was using any anti-hypertensive pharmacological therapy.
Results Of the 2404 survey participants aged 18–79 years, 5.0% (95% CI 4.1–6.0) reported having diabetes: 4.5% (95% CI 3.4–5.9) in men and 5.5%, (95% CI 4.2–7.1) in women, representing 1.5 million Poles in this age group. An additional 1.7% (95% CI 1.2–2.3) met the criteria for diabetes based on their fasting blood glucose collected in our study without reporting diabetes awareness (2.5%, 95% CI 1.6– 3.6 in men and 0.9%, 95% CI 0.4–1.7 in women), representing 0.5 million Polish adults. Furthermore, an additional 15.6% (95% CI 14.0–17.2) adults qualified for the diagnosis impaired fasting glucose based on a single blood glucose measurement (Table 1). This percentage decreased to 8.3% (95% CI 6.6–10.2) when two measurements were required. Among those aware of having diabetes, the median time from diagnosis was 4.9 years (95% CI 3.5–6.2). In this group, 71.3% (95% CI 62.9–78.7) reported receiving only glucose-lowering agents, 11.6% (95% CI 6.7–18.1) initially received glucose-lowering agents, but now are on insulin, 11.2% (95% CI 6.3–18.0) started and continue on glucose-lowering agents, but now also receive insulin, and, finally, 4.2% (95% CI 1.5–9.0) report only following a special diet. To assess the time trends in the prevalence of diabetes in the Polish population, we contrasted the prevalence estimates based on the current NATPOL survey (2011) and the previous one conducted in 2002. Without adjustments, 6.7% (95% CI 5.6–7.9) of the current sample reported awareness of diabetes or had fasting glucose above 7.0 mmol/l, compared with 6.4% (95% CI 5.4–7.5) in the 2002 survey. When we adjusted the 2002 number for the age distribution from the 2011 sample, the prevalence increased to 6.8% (95% CI 5.8–7.9), suggesting virtually no change in prevalence between the two periods. As indicated earlier, 1.7% (95% CI 1.2–2.3) of individuals were not aware of having diabetes, representing approximately 25% of all subjects with the condition. In our logistic
1569
Prevalence of diabetes and impaired fasting glucose in Poland M. Rutkowski et al.
DIABETICMedicine
Table 1 Prevalence of glucose metabolism abnormalities among men and women, based on one fasting plasma glucose measurement and questionnaire (see also Supporting Information, Appendix S1 for results stratified by age) Men
Women
Group
Point estimate (%)
Lower confidence limit (%)‡
Upper confidence limit (%)‡
Number of study subjects
Point estimate (%)
Lower confidence limit (%)‡
Upper confidence limit(%)‡
Number of study subjects
Self-reported Type 2 diabetes Screened Type 2 diabetes* Screened impaired fasting glucose† Normal glucose tolerance Total diabetes
4.5 2.5 19.4 73.6 7.0
3.4 1.6 17.0 70.7 5.4
5.9 3.6 22.0 76.4 8.8
52 29 226 856 81
5.5 0.9 12.0 81.7 6.4
4.2 0.4 10.2 79.4 5.0
7.1 1.7 13.9 83.8 8.0
68 11 148 1014 79
Defined as fasting plasma glucose ≥ 7.0 mmol/l and no earlier established diagnosis of diabetes. Defined as fasting plasma glucose 5.6–6.9 mmol/l and no diagnosis of diabetes. ‡ Clopper–Pearson lower and upper 95% confidence limits. * †
regression model, the following risk factors were associated with the screened diabetes: obesity, arterial hypertension and male gender (Table 2).
Discussion Eastern Europe in general, and Poland in particular, have seen rapid social and economic changes since 1990. As a result, cardiovascular mortality started to decline, but this process is at least 20 years delayed compared with Western Europe [6]. We investigated the prevalence of diabetes as a cardiovascular risk factor in 2011 in Poland. We estimate that the prevalence of diabetes in Poland in 2011 was 6.7%. This is similar to the results published in the actual International Diabetes Federation Diabetes Atlas for most European countries [7], but lower than found in the studies from the USA or the Gulf region [7–11]. Interestingly, this number is not larger than the corresponding age-adjusted proportion of 6.8% observed in the 2002 survey. We have also discovered that one quarter of individuals with diabetes are unaware of having the condition. This offers an opportunity for new or existing prevention or early detection programmes. Based on our analysis, the attractive targets for these programmes include men and people with obesity and hypertension, as they are much more likely to
have screened diabetes. Obesity and hypertension are well-known variables related to diabetes, while men in Poland are in general less interested in their health, and are less likely to undergo any screening [4,12]. This could be a possible reason for the higher rates of screened diabetes in this group. Impaired fasting glucose, introduced as a clinical entity recently, is regarded as a risk factor for cardiovascular disease [13]. Persons with impaired fasting glucose should be subject to diabetes prevention measures [14,15]. In the present study, the prevalence of impaired fasting glucose in the adult population was 15.6%. This high proportion can be partially explained by using only one measurement to define impaired fasting glucose, but also identifies a large cohort potentially at risk of developing diabetes or cardiovascular disease. Our study has several limitations. First, the diagnosis of diabetes is based on self-report or a single blood glucose measurement. This can add bias to our estimates. However, this is the approach widely used in epidemiological studies because of cost and feasibility. The advantage of this approach is that our results are comparable with numerous studies in other populations. Furthermore, study participants were instructed to fast and they confirmed this just before the blood sample collection, but some non-compliance cannot be excluded. Finally, our sample size did not allow the analysis of smaller subgroups.
Table 2 Logistic regression model Screened Type 2 diabetes†
Impaired fasting glucose* ‡
Self-reported Type 2 diabetes
Variable
Odds ratio
95% CI
P-value
Odds ratio‡
95% CI
P-value
Odds ratio‡
95% CI
P-value
Obesity Arterial hypertension Male gender Age (for 1 year change)
1.52 1.43 1.94 1.04
1.12–2.07 1.09–1.90 1.55–2.43 1.03–1.05
0.007 0.011 < 0.001 < 0.001
3.62 3.54 2.67 1.01
1.87–7.01 1.43–8.74 1.28–5.57 0.98–1.03
< 0.001 0.006 0.009 < 0.001
3.16 4.30 0.97 1.07
2.09–4.78 2.56–7.27 0.62–1.52 1.05–1.09
< 0.001 < 0.001 0.886 < 0.001
*
Impaired fasting glucose defined as fasting plasma glucose 5.6–6.9 mmol/l and no self-reported diabetes. Fasting plasma glucose ≥ 7.0 mmo/l and no self-reported diabetes. Odds ratios for having impaired fasting glucose, screened Type 2 diabetes or self-reported Type 2 diabetes (odds ratio, 95% CI, 95% confidence interval for odds ratio). All odds ratios are adjusted for all other predictor variables presented in the table.
† ‡
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ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
Research article
In summary, the prevalence of diabetes in Poland (6.7%) is similar to that observed in other European populations and has not increased in the last decade. The fact that every fourth person with diabetes is unaware of the disease creates important opportunities for screening and detection of the disease.
Funding sources
The NATPOL 2011 Study was partially funded by the Polish Ministry of Health as a publicly funded project representing part of the National Cardiovascular Disease Prevention and Treatment Programme and by statutory grants from the Medical University of Gdansk and the Medical University of Warsaw. It was also partly funded by the following industry sponsors. The main sponsor of the project: Sanofi-Aventis— unrestricted educational grant; Abbott Laboratories Poland Ltd—sponsor with unrestricted educational grant; Siemens Ltd—partner of the project—unrestricted educational grant; Polpharma—partner of the project—unrestricted educational grant—in the part of the project dedicated to heart failure. The funding agencies had no involvement in the design or conduct of the study; collection, management, analysis and interpretation of data; or drafting of the manuscript.
Competing interests
None declared.
References 1 IDF. Diabetes Atlas: the Global Burden. Available at http://www. idf.org/diabetesatlas/5e/the-global-burden Last accessed 2 January 2014. 2 IDF. Diabetes Atlas: UN-Resolution 61/225. Available at http:// www.idf.org/diabetesatlas/un-resolution 6th edn. Last accessed 2 January 2014. 3 European Parliament. Legislative Observatory. 2011/2911(RSP). 2012. Available at http://www.europarl.europa.eu/oeil/popups/summary.do?id=1197528&t=d&l=en Last accessed 2 January 2014. 4 Zdrojewski T, Bandosz P, Szpakowski P, Konarski R, Jakubowski Z, Manikowski A et al. Rozpowszechnienie gł ownych czynnik ow ryzyka chor ob układu sercowo-naczyniowego w Polsce. Wyniki badania NATPOL PLUS (Prevalence of main cardiovascular risk factors in Poland. The NATPOL PLUS study). Kardiol Pol 2004; 61: S546–S558.
ª 2014 The Authors. Diabetic Medicine ª 2014 Diabetes UK
DIABETICMedicine
5 Zdrojewski T, Rutkowski M, Bandosz P, Gaciong Z, Jez drzejczyk T, Solnica B et al. Prevalence and control of cardiovascular risk factors in Poland. Assumptions and objectives of the NATPOL 2011 Survey. Kardiol Pol 2013; 71: 381–392. 6 Bandosz P, O’Flaherty M, Drygas W. Decline in mortality from coronary heart disease in Poland after socio-economic transformation: modeling study. Br Med J 2012; 344: d8136. doi:10.1136/ bmj.d8136. 7 IDF. Diabetes Atlas, 6th edn. Brussels: International Diabetes Federation, 2013. Available at http://www.idf.org/diabetesatlas Last accessed 2 January 2014. 8 Saadi H, Carruthers SG, Nagelkerke N, Al-Maskari F, Afandi B, Reed R et al. Prevalence of diabetes mellitus and its complications in a population-based sample in Al Ain, United Arab Emirates. Diabetes Res Clin Pract 2007; 78: 369–377. 9 Ng SW, Zaghloul S, Ali HI, Harrison G, Popkin BM. The prevalence and trends of overweight, obesity and nutrition-related non-communicable diseases in the Arabian Gulf States. Obes Rev 2011; 12: 1–13. 10 Thorpe LE, Upadhyay UD, Chamany S. Prevalence and control of diabetes and impaired fasting glucose in New York City. Diabetes Care 2009; 32: 57–62. 11 Cowie CC, Rust KF, Byrd-Holt DD. Prevalence of diabetes and impaired fasting glucose in adults in the US population: National Health And Nutrition Examination Survey 1999–2002. Diabetes Care 2006; 29: 1263–1268. 12 Zdrojewski T, Wyrzykowski B, Szczez ch R. Epidemiology and prevention of arterial hypertension in Poland. Blood Press Suppl 2005; 14: 10–16. 13 Sarwar N, Gao P, Seshasai SR. Diabetes mellitus, fasting blood glucose concentration and risk of vascular disease: a collaborative meta-analysis of 102 prospective studies. The Emerging Risk Factors Collaboration. Lancet 2010; 375: 2215–2222. 14 Pontiroli AE, Pizzocri P, Caumo A, Perseghin G, Luzi L. Evaluation of insulin release and insulin sensitivity through oral glucose tolerance test: differences between NGT, IFG, IGT, and type 2 diabetes mellitus. A cross-sectional and follow-up study. Acta Diabetol 2004; 41: 70–76. 15 Tuomilehto J, Lindstr€ om J, Eriksson JG, Valle TT, H€ am€ al€ ainen H, Ilanne-Parikka P et al. Finnish Diabetes Prevention Study Group. Prevention of type 2 diabetes mellitus by changes in lifestyle among subjects with impaired glucose tolerance. N Engl J Med 2001; 344: 1343–1350.
Supporting Information Additional Supporting Information may be found in the online version of this article: Appendix S1. Prevalence of glucose metabolism abnormalities among men, based on one fasting plasma glucose measurement and questionnaire.
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