Diabetes Care 30:2007-2012, 2007 DOI: 10.2337/dc06-2319 © 2007 by the American Diabetes Association
Prevalence and Management of Diabetes and Associated Risk Factors by Regions of ThailandThird National Health Examination Survey 2004
1 Community Medicine Center, Ramathibodi Hospital, Bangkok, Thailand Address correspondence and reprint requests to Dr. Wichai Aekplakorn, MD, PhD, Community Medicine Center, Ramathibodi Hospital, Rama 6 Road, Bangkok 10400 Thailand. E-mail: rawap{at}mahidol.ac.th
OBJECTIVE—The aim of this study was to determine the prevalence of diabetes and impaired fasting glucose (IFG) and their association with cardiovascular risk factors and to evaluate the management of blood glucose, blood pressure, and cholesterol in individuals with diabetes by geographical regions of Thailand.
RESEARCH DESIGN AND METHODS—With the use of a stratified, multistage sampling design, data from a nationally representative sample of 37,138 individuals aged
RESULTS—The prevalence of diabetes and IFG weighted to the national 2004 population was 6.7% (6.0% in men and 7.4% in women) and 12.5% (14.7% in men and 10.4% in women), respectively. Diabetes was more common in urban than in rural men but otherwise prevalence was relatively uniform across geographical regions. In more than one-half of those with diabetes, the disease had not been previously diagnosed, although the majority of those with diabetes were treated with oral antiglycemic agents or insulin. The prevalence of associated risk factors was high among individuals with diabetes as well as those with IFG. Two-thirds of those with diabetes and concomitant high blood pressure ( CONCLUSIONS—The prevalences of diabetes and IFG were uniformly high in all regions. Improvements in prevention, diagnosis, and treatment of diabetes and associated risk factors are required if the health burden of diabetes in Thailand is to be averted.
Abbreviations: FPG, fasting plasma glucose IFG, impaired fasting glucose NHESIII, Third National Health Examination Survey PPS, probability proportional to size
Diabetes and its associated complications are a major health and economic burden worldwide (1,2), and the burden is expected to continue to increase (3). This problem is particularly relevant to the Asia-Pacific region, where lifestyle changes associated with rapid economic development, improved survival from communicable diseases, and genetic susceptibility have led to rising diabetes prevalence (4,5).
Thailand provides a prime example of this trend (6). A survey in 1999 estimated that 9.6% of Thai adults aged
To monitor the effectiveness of the health system response, routine measurement of the prevalence and management of diabetes is crucial. In Thailand, subnational monitoring is also essential, given health administration decentralization, as well as differences in economic development and lifestyle between geographical regions (8). In this article, we describe the prevalence of diabetes and IFG as well as the diagnosis, treatment, and control of blood glucose, blood pressure, and cholesterol in those with diabetes in five geographic regions of Thailand. We used data from the 2004 Third National Health Examination Survey (NHESIII) of >37,000 fasting individuals aged
The NHESIII was conducted between January and May 2004 by the Health Systems Research Institute (see ACKNOWLEDGMENTS). The study was approved by the Ethical Review Committee for Research in Human Subjects, Ministry of Public Health. All participants provided written informed consent.
A multistage sampling frame based on government registers was used. For areas except for Bangkok, three provinces were chosen by probability proportional to size (PPS) for each of the 12 health administration areas. At the second stage, nine electoral units or villages were selected by PPS from both urban and rural areas for each province. At the final stage, 15 individuals were selected by simple random sampling with replacement from four broad groups (male or female sex and 15–59 or
Data collection and measurement
Definition
Statistical methods
FPG was 5.2 ± 0.04 mmol/l (mean ± SE), 5.3 ± 0.04 mmol/l in men, and 5.2 ± 0.04 mmol/l in women. Prevalences of diabetes and IFG in Thais aged 15 years were 6.7% (95% CI 5.9–7.6%) and 12.5% (11.0–14.2%), respectively. Diabetes prevalence in men was lower than that in women (6.0 vs. 7.4%; P < 0.05 for the age-standardized comparison), whereas prevalence of IFG was higher in men than in women (14.7 vs. 10.4%; P < 0.001 for the age-standardized comparison) These figures equate to an estimated 3.0 million Thais with diabetes (1.3 million men and 1.7 million women), and 5.6 million with IFG (3.2 million men and 2.4 million women). Diabetes prevalence was notably higher among women aged 55–74 years than among men of the same age (Table 1) (P < 0.001), whereas IFG prevalence was higher among men aged 25–54 years than among women of the same age (Table 1) (P < 0.001). Diabetes was more common in urban men than in rural men (Fig. 1) (P < 0.01) but was similar in urban and rural women (P > 0.05). Male prevalence was higher in Bangkok than in the urban North (Fig. 1) (P < 0.01). Bangkok and the urban and rural Northeast had the highest female prevalence of diabetes, which was higher than that in the urban North and rural South (Fig. 1) (P < 0.05 for all comparisons).
Cardiovascular risk factors among those with IFG and diabetes Individuals with diabetes have high levels of concomitant cardiovascular risk factors (Table 2), except for smoking, with 72.7% (95% CI 68.7–76.4%) having high blood pressure ( 130/80 mmHg or receiving medication), 33.0% (28.6–37.8%) having high total cholesterol ( 6.2 mmol/l or receiving medication), 48.8% (43.6–54.1%) being overweight (BMI 25 kg/m2), and 53.5% (48.3–58.6%) having central obesity (waist circumference 90 cm in men and 80 cm in women). Those with diagnosed diabetes tended to have a higher prevalence of high blood pressure, high cholesterol, and overweight but a lower prevalence of smoking than those in whom diabetes had not been previously diagnosed (Table 2). Individuals with IFG had more concomitant cardiovascular risk factors, except for smoking, than those with normal FPG (Table 2).
Diagnosis of diabetes and treatment and control of blood glucose, blood pressure, and cholesterol in individuals with diabetes Of those identified as having diabetes in the survey, 53.3% (95% CI 47.8–58.8%) had not previously had the diagnosis of diabetes. Nondiagnosis was higher in men (62.6%) than in women (62.6 vs. 46.2%, respectively; P < 0.001 for the age-standardized comparison). This equates to an estimated 1.6 million (0.8 million men and 0.8 million women) Thais aged 15 years with undiagnosed diabetes. Although diagnosis rates increased with age, 48.1% of men and 36.7% of women aged 55 years had diabetes that remained undiagnosed. Of those in whom diabetes was previously diagnosed, 90.7% (95% CI 87.7–92.9%) were receiving either oral antiglycemic agents or insulin, and of those receiving treatment, 41.6% (37.8–45.5%) had FPG controlled to <7.8 mmol/l. Glycemic control was higher in women than in men (44.6 vs. 35.8%; P < 0.01). Of those in whom diabetes had been diagnosed, 71.1% had received advice from health personnel to reduce their weight, 90.3% to increase their physical activity levels, and 92.5% to consume a healthier diet. Diagnosis rates tended to be higher in urban than in rural men, but the difference was not significant (42.2 vs. 34.6% diagnosed, respectively; P = 0.057). Rates of diagnosis were similar for urban and rural females (55.0 vs. 52.7%). Rates of glycemic control were higher in rural than in urban women receiving treatment (47.3 vs. 38.3%; P < 0.05). Both Bangkok and the South had higher rates of diagnosis than the Central and Northeast regions (Fig. 2) (P < 0.01 for both compared with Bangkok; P < 0.05 compared with the South). The fraction of treated individuals achieving glycemic control was lower in Bangkok than in the Central and North regions (P < 0.01 for both comparisons) and higher in the North compared with the South and Northeast (P < 0.05 for both).
Of those individuals with diabetes and concomitant high blood pressure, 65.9% were not previously aware that they had high blood pressure. Of those who were aware, 82.2% were taking blood pressure–lowering medication, and of those taking medication, 14.9% had blood pressure controlled to <130/80 mmHg. Rates of awareness were lower in rural than in urban areas for both men (26.3 vs. 37.0%; P < 0.01) and women (34.9 vs. 43.5%; P < 0.05). The Northeast region had the lowest rates of awareness (Fig. 2) (P < 0.01 for all comparisons), whereas Bangkok had the highest (P < 0.05 for all comparisons). The fraction of those receiving blood pressure–lowering medication who had blood pressure <130/80 mmHg was universally low but higher in Bangkok than in other regions (Fig. 2) (P < 0.01 for all comparisons). Diagnosis, treatment, and control levels of high cholesterol were low. Of individuals with diabetes and high cholesterol, high cholesterol had not been previously diagnosed in 72.0%. Of those in whom it had been diagnosed, 80.7% were receiving cholesterol-lowering medication, and of those receiving medication, 63.1% had total cholesterol controlled to <6.2 mmol/l. Rates of diagnosis were lower in rural than in urban women (21.0 vs. 36.3%; P < 0.001) but similar in rural and urban men (30.2 vs. 32.2%). The Northeast had the lowest rates of diagnosis (Fig. 2) (P < 0.05 compared with the North and South and P < 0.01 compared with Bangkok and Central). The fraction of those taking cholesterol-lowering drugs who achieved total cholesterol <6.2 mmol/l was lower in Bangkok and the South than in other regions (Fig. 2) (P < 0.01 for all comparisons).
This study demonstrates a continued high prevalence of diabetes and IFG in Thailand consistent with a previous survey (7). These rates are similar to those in the U.S. (14) and higher than those of China (15). A higher prevalence of diabetes was found in middle to older aged women compared with men of the same age, whereas the prevalence of IFG was higher among younger to middle aged men compared with women of the same age. This pattern is similar to that of a recent Korean survey (16). Urban men were more likely to have diabetes than rural men, whereas the prevalence of diabetes was similar in rural and urban women. This finding may be related to the shift in obesity from high to low socioeconomic groups occurring earlier in women, as has been noted in other populations (17). Despite these differentials, diabetes prevalence is relatively uniform throughout Thailand. In two-thirds of individuals with diabetes in the current survey (1.6 million individuals), the disease had not been previously diagnosed. Subsequently, there were low rates of treatment and control of plasma glucose with insulin or oral antiglycemic agents. Of further concern are the high levels of cardiovascular risk factors, such as high blood pressure and high cholesterol in those with diabetes. Diagnosis, treatment, and control rates of these risk factors among those with diabetes are also low. As diabetes itself is an independent risk factor for coronary heart disease, stroke, and renal disease (2,18), control of cholesterol and blood pressure is essential to reduce the risk of these events. The economic burden associated with these outcomes is highlighted by the potentially large financial burden of including renal dialysis on the Thai universal health insurance scheme (19). A crucial finding is that a large proportion of older individuals have undiagnosed diabetes, and these individuals have the greatest risk of macro- and microvascular diseases. When these findings are combined with the presence of an aging population and the 5.7 million individuals with IFG, it is clear that a scaled-up response is needed to better diagnose and treat diabetes and prevent progression to diabetes in those with IFG (20) if the health and economic burden of the condition is to be reduced.
Recognizing the growing burden of diabetes and other noncommunicable diseases and risk factors, the Ministry of Public Health launched a nationwide program, "Healthy Thailand," in 2004. This program includes components promoting healthier lifestyles (physical activity and diet) and set a target for 60% of Thai people aged Several limitations should be considered. Although replacements were made based on age, sex, and cluster, information to determine the response rate before replacement was not available. Differentials in the final collection rate may also obscure variation across geographic regions. Oral glucose tolerance tests were not conducted in the NHESIII, preventing an estimation of the exact prevalence of pre-diabetes. Long-term glycemic control could also not be assessed as A1C was not measured. Likewise, cholesterol fractions were not measured. Despite these limitations, a clear strength of the study is the large sample size and the ability to monitor diabetes prevalence and management at a subnational level. This study demonstrates a high prevalence of diabetes and IFG across all regions of Thailand with low levels of diagnosis and appropriate management of blood glucose, blood pressure, and cholesterol among individuals with diabetes. These findings serve to emphasize to other countries undergoing similar epidemiological transitions the importance of establishing monitoring systems for diabetes built on valid and representative data. In Thailand, without increased efforts to prevent diabetes by promoting and facilitating healthier lifestyles along with improvements in the diagnosis and control of diabetes and associated risk factors, the health burden of diabetes has the potential to overwhelm the health care system.
The NHESIII was supported by the Bureau of Policy and Strategy, Ministry of Public Health. Participating individuals included the following: Suwit Wibulpolprasert, Wiput Phoolcharoen, Siriwat Tiptaradol, Yawarat Porapakkham, Porapan Punyaratabandhu, Yongyuth Chaiyapong, and Kasame Vejsutanonth (coordinating team); Bodi Dhanamun, Narin Hiransuthikul, Thosporn Vimolkej, Somrat Lertmaharit, Pornarong Chotiwan, Wiroj Jiamjarasrangsi, Poranee Laoitthi, Mayuri Chiravisit, and Sarawuth Urith (Chulalongkorn University); Chalermchai Chaikittiporn, Kanda Vathanophas, Chaovayut Phornpimolthape, Rawiwan Sangchai, and Chanya Siengsanor (Mahidol University); Virasakdi Chongsuvivatwong, Mafausis Dueravee, Somsak Vanseng, Arpapak Kiatkittipong, and Siriwan Deawsurintr (Prince of Songkla University); Thanaruk Suwanprapisa, Nongyao Udomvong, Darunee Tayati, Decha Tamdee, and Thanapan Junyasiri (Chiang Mai University); and Amorn Premgamone, Somdej Pinijsoontorn, Manop Kanato, Suchada Paileeklee, Wattana Ditsathaporncharoen, and Piyatat Tatsanavivat (Khon Kaen University). Data analysis was conducted by the Setting Priorities Using Information on Cost-Effectiveness (SPICE) Project which is funded by Wellcome Trust, U.K. (071842/Z/03/Z) and the National Health and Medical Research Council of Australia (301199).
Published ahead of print at http://care.diabetesjournals.org on 27 April 2007. DOI: 10.2337/dc06-2319. A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C Section 1734 solely to indicate this fact. Received for publication November 13, 2006. Accepted for publication April 24, 2007.
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