Obesity is associated with hypertension in high income countries, but less is known about this association in rural regions of low- to middle-income countries. We aimed to assess the risk of hypertension associated with obesity in a disadvantaged region of rural South India.Design and Method:
We undertook a case-control study in 58 villages in southwestern Andhra Pradesh. Three hundred cases with hypertension were age- and sex-matched to 300 controls without hypertension. Blood pressure (BP), waist circumference, waist-hip ratio (WHR), and body mass index (BMI) were measured according to strict protocols. Percent body fat was estimated using skinfold thickness measured at the biceps, triceps, subscapular and supra-iliac regions. Conditional logistic regression was used to determine associations between each measurement of body fat and hypertension (BP ≥ 140/90 mmHg), adjusted for age and disadvantage. Linear regression was used to determine the relationship between continuous measurements of adiposity and systolic and diastolic BP.Results:
Overall, mean BMI was 20.5 kg/m2, 29% of people were underweight, 9% were overweight and 14% were obese. Hypertension was positively associated with obesity, as defined by a BMI ≥ 23 kg/m2 (Odds Ratio (OR) 1.8, 95% Confidence Interval (CI) 1.1–3.0), waist circumference (OR 2.2, 95% CI 1.3–3.8) and WHR (OR 2.1, 95% CI 1.4–3.0), but not percent body fat. WHR was a better predictor of hypertension in women (OR 3.3, 95% CI 1.8–6.0) than men (OR 1.5, 95% CI 0.92–2.4, p for difference 0.04). All measures of adiposity were associated with diastolic BP (p < 0.05), but not systolic BP. Similar patterns were observed in men and women.Conclusions:
Our findings confirm that even in this relatively thin rural sample in India, BMI, waist circumference and WHR are strongly associated with hypertension. Central adiposity may play a greater role in the pathogenesis of hypertension in women in these populations. Those with high waist circumference, particularly women, should be screened for hypertension.