Body mass index and risk of ESRD in China.

BACKGROUND: The relationship between body mass index (BMI) and risk of end-stage renal disease (ESRD) in Asians has not been well established.

STUDY DESIGN: Prospective cohort study.

SETTING & PARTICIPANTS: 143,802 men and women 40 years and older in China.

PREDICTOR: Body weight, height, and covariables were obtained at a baseline examination in 1991 by following a standardized protocol. BMI was calculated as weight in kilograms divided by the square of height in meters.

OUTCOMES: Time to onset of ESRD, ascertained in 1999 to 2000 from medical records, death certificates, and interviews with participants or their proxies.

RESULTS: During 1,112,667 person-years of follow-up, 350 participants initiated renal replacement therapy or died of renal failure. After adjustment for age, sex, geographic region (north versus south China), urbanization (urban versus rural residence), education, physical activity, cigarette smoking, and alcohol consumption, a J-shaped association between BMI and all-cause ESRD was observed. Compared with those with normal body weight (BMI, 18.5 to 24.9 kg/m(2)), multivariate-adjusted relative risks for all-cause ESRD for underweight (BMI < 18.5 kg/m(2)), overweight (BMI, 25.0 to 29.9 kg/m(2)), and obese subjects (BMI >or= 30 kg/m(2)) were 1.39 (95% confidence interval [CI], 1.02 to 1.91), 1.21 (95% CI, 0.92 to 1.59), and 2.14 (95% CI, 1.39 to 3.29), respectively. The J-shaped association existed even after additional adjustment for systolic blood pressure and history of diabetes and cardiovascular disease.

LIMITATIONS: Although patients with ESRD at baseline were excluded, information for chronic kidney disease at the baseline examination was not available.

CONCLUSION: Strategies aimed at preventing the development of ESRD should incorporate measures to maintain a normal body weight.