Background: Asians have different body fat distributions and disease characteristics compared with Caucasians. The purpose of this study was to evaluate general and central obesity, combined oral contraceptive (COC) use, and their joint effects on the risk of hypertension in Chinese women.
Methods: A case-control study including 1,760 women (878 hypertensive cases and 882 normotensive controls) was conducted in China. Body weight, height, waist circumference (WC), blood pressure, serum lipids, and apolipoproteins were measured. History of contraceptive use and relevant factors were investigated. Odds ratio (OR) with 95% confidence interval (CI) was estimated for hypertension-related factors under unconditional logistic regression model.
Results: Our study showed that increased body mass index (BMI), increased WC, and COC use were risk factors for hypertension with an OR (95% CI) of 2.19 (1.69-2.83), 1.46 (1.13-1.88), and 1.26 (1.02-1.56), respectively. Compared with WC, BMI was more strongly associated with hypertension risk (OR 3.40, 95% CI 2.28-5.05, for highest vs. lowest quartile) and was a better predictor for blood pressure. COC users had a 1.39-fold (OR 1.39, 95% CI 1.14-1.69) increased risk compared with the nonusers, while stopping COC was associated with a 36% reduced risk (OR 0.64, 95% CI 0.42-0.98). The risk increased dramatically in combination of COC use with a BMI ≥28 kg/m(2) or WC ≥90 cm (OR 8.02, 95% CI 5.05-12.74; OR 5.76, 95% CI 3.65-9.12, respectively).
Conclusions: General and central obesity, COC use, and their joint effects significantly increased the risk of hypertension in Chinese women.