Total and abdominal obesity among rural Chinese women and the association with hypertension

Abstract

Objective Obesity increases the risk of hypertension and other chronic diseases, which are little known in rural China. This study aimed to investigate the epidemiologic features and the association with hypertension of obesity in rural Chinese women. Methods A cross-sectional survey was conducted during 2004 through 2006, which used a multistage cluster sampling method to select a representative sample in Liaoning Province, China. In total 23 178 rural participants at least 35 y of age were examined (the percentage of subjects >64 y old was 14.5%). Data on demographic variables (age, sex, and race), smoking status, use of alcohol, physical activity, and education level were obtained by interview. Overweight and obesity were defined according to the World Health Organization classification. Hypertension was defined according to the criteria established by the Seventh Report of the Joint National Committee, and untreated hypertensive subjects were further classified into three subtypes: isolated systolic hypertension, isolated diastolic hypertension, and systolic and diastolic hypertension. Multivariable models and performed Poisson logistic regression analysis were used to determine associations among body mass index (BMI), waist circumference, and variables. Results Overall, the prevalences of overweight and obesity were 24.4% and 2.7%, respectively, as defined by BMI, whereas the prevalences were 48.6% and 4.9% as defined by waist circumference. Poisson regression revealed that high levels of physical activity (defined by BMI, moderate: prevalence ratio [PR] 0.976, 95% confidence interval [CI] 0.965–0.988, high: PR 0.985, 95% CI 0.971–0.999; defined by waist circumference, moderate: PR 0.955, 95% CI 0.944–0.965, high: PR 0.973, 95% CI 0.960–0.985) and current smoking status (defined by BMI, PR 0.950, 95% CI 0.938–0.962; defined by waist circumference, PR 0.966, 95% CI 0.954–0.978) were protective factors and ethnicity was a risk factor (defined by BMI, Mongolian nationality: PR 1.042, 95% CI 1.030–1.054; defined by waist circumference, PR 1.043, 95% CI 1.033–1.054) for overweight or obese participants. There were other risk factors for overweight or obese participants such as high levels of education defined by BMI (PR 1.033, 95% CI 1.010–1.058) and diet score defined by waist circumference (PR 1.004, 95% CI 1.000–1.008). After adjustment, BMI and waist circumference were associated with the greatest likelihood of systolic and diastolic hypertension (for BMI ≥30 kg/m 2, PR 2.455, 95% CI 1.786–3.374; for waist circumference ≥88 cm, PR 1.517, 95% CI 1.133–2.031). BMI was more related to isolated diastolic hypertension than to isolated systolic hypertension, whereas waist circumference was more related to isolated systolic hypertension than to isolated diastolic hypertension. Conclusion Although the prevalence of overweight and obesity as defined by BMI was low, it was relatively high as defined by waist circumference in rural Chinese women. High levels of physical activity and current smoking status had negative relations to overweight or obesity, whereas ethnicity, high levels of education, and diet score showed positive relations. Obese women defined by BMI or waist circumference had an increased risk of hypertension.