To the Editor:
To investigate the prevalence of diabetes mellitus in a typical rural society, we performed a population-based study in rural Central India. We included 2414 subjects aged 30 years or more. Diabetes was defined as postprandial blood glucose concentration ≥200 mg/dL, glycosylated hemoglobin ≥6%, or self-reported medical diagnosis. The prevalence of diabetes (5.6% ± 0.5%) increased up to the age of 60 to 64 years and decreased thereafter.
Despite the worldwide importance of diabetes mellitus, relatively little has been known about its actual prevalence and its associations in India, particularly in rural India.1–6 The Central India Eye and Medical Study is a population-based cross-sectional study in Central India. The first phase was carried out in 4 villages in the rural region of Central Maharashtra about 40 km from Nagpur.7 The villages were chosen because they are in a typical rural region of Central India, relatively far from the nearest city. The Medical Ethics Committee of the Ruprecht-Karls-University Heidelberg and of the Suraj Eye Institute/Nagpur approved the study, and all participants gave informed consent. Social workers mapping the villages invited villagers to participate in the study. Participation included a bus ride to and from the hospital, a day-long free examination, and free meals out of 3093 eligible villagers, 2423 (78%) subjects participated. Trained social workers filled out a questionnaire. Physical activity was assessed by questions about the daily working time, daily walking or cycling to work, time spent sitting or reclining, and whether the work involved mostly sitting or standing activities. Diabetes was defined as a postprandial blood glucose concentration ≥11.2 mmol/L (200 mg/dL a blood concentration of glycosylated hemoglobin (Hb1Ac) of ≥6%, or a self-reported medical diagnosis of diabetes (any prior diagnosis of diabetes by a health care professional). Treatment of diabetes was defined as use of prescribed medication for management of diabetes (oral medication or insulin) at the time of the interview. Successful control of diabetes was defined as pharmacologic treatment of diabetes associated with a postprandial blood glucose concentration of <11.2 mmol/L (200 mg/dL) and an Hb1Ac level of <7%.
Of the 2423 subjects, 789 (33%) were illiterate and 645 (27%) had attended school up to the fifth standard. Women comprised 54% of the study population. The distribution of the study population by age and sex was almost identical to that of India as a whole.8
Measurements of postprandial blood glucose and Hb1Ac were available for 2414 (99+%) of study participants). Mean age was 48.0 ± 13.7 years (median, 45 years; range, 30-85 years). The mean postprandial blood glucose concentration was 118 ± 29 mg/mL, and the mean blood concentration of glycosylated hemoglobin Hb1Ac was 4.6% ± 1.6%. A self-reported diagnosis of diabetes was given by 34 (1.4%) subjects. Out of these 34 subjects, 13 (38%) patients were on oral antidiabetic treatment, 2 (6%) subjects took insulin, 11 (32%) subjects were not aware of their treatment regimen, and 8 (24%) subjects were treated by diet only. Of 2414 subjects, we diagnosed 135 (5.6%) as patients with diabetes. Prevalence of diabetes was similar for men and women, and rose with age in both.
In univariate analysis, the prevalence of diabetes increased with age (Fig.), body weight, and body mass index. Prevalence was increased with higher mean serum concentrations of cholesterol, lower concentration of high-density lipoproteins, less physical activity, more time spent sitting or reclining, and more hyperopic refractive error.
In multiple logistic regression analysis, the association of diabetes persisted with higher age (odds ratio = 1.03 per year [95% confidence interval = 1.01-1.04]), higher body mass index (1.14 [1.09-1.19]), higher serum cholesterol levels (1.01 [1.01-1.02]), and lower serum high-density lipoprotein concentration (0.93 [0.89-0.97]).
Among the diabetic study participants (n = 135), 34 (25%) subjects were aware of their disease, and 15 (11%) reported a current antidiabetic medical treatment. Out of the treated subjects, 7 (47%) had abnormally high postprandial glucose levels, and 6 (40%) had Hb1Ac measurements equal to or higher than 7%.
In the rural population of Central India, we found evidence of diabetes in 5.6% ± 0.5% of subjects aged 30+ years. This figure is lower than previously reported in urban Indian populations.2–6 The relationship of age with diabetes prevalence followed an inverted U-shape with a decrease toward higher age. The lack of major medical services, with a potentially elevated mortality of elderly subjects with diabetes, may have led to a survivor bias. After adjustment for age, body mass index, and serum cholesterol levels, there was little evidence of associations between diabetes and educational level, family income, or physical activities. This is in contrast with other population-based studies. The reason for this lack of association may be the relatively low socioeconomic level of these villagers, with only small differences in life conditions among the study population. Among the diabetic study participants, 25% subjects were aware of their disease, and 15 (11%) subjects were under treatment. These figures are markedly lower than those reported from urban and semi-urban regions in India,2–6 suggesting that major improvements in medical infrastructure are needed to address this wide spread condition in India.
Jost B. Jonas
Suraj Eye Institute
Department of Ophthalmology
Medical Faculty Mannheim of the Ruprecht-Karls-University Heidelberg
Suraj Eye Institute
Prashant P. Joshi
Clinical Epidemiology Unit
Govt. Medical College
Suraj Eye Institute
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