Changes in bmi before and during economic development and subsequent risk of cardiovascular disease and total mortality: A 35-Year follow-up study in China

OBJECTIVE: It is unclear whether changes in BMI during rapid economic development influence subsequent mortality. RESEARCH DESIGN AND METHODS We analyzed whether BMI in 1976 and 1994 and changes in BMI during 1976-1994 predict cardiovascular disease (CVD) and all-cause mortality in a 35-year follow-up cohort of 1,696 Chinese (1,124 men and 572 women, aged 35-65 years) in Xi'an, China. Participants were categorized as underweight (<18.5 kg/m ₂), normal weight (18.5-24.9 kg/m₂), and overweight (≥25.0 kg/m₂). RESULTS: During 51,611 person-years of follow-up, we identified 655 deaths from all causes and 234 from CVD. From1976 to 1994, the prevalence of overweight rose from9.2 to 27.8%. With each unit increment in 1976 BMI, multivariate hazard ratios (HRs) (95%CI)were 0.78 (0.72-0.84) for CVD and 0.91 (0.87-0.95) for all-causemortality. In contrast, corresponding HRs were 1.14 (1.08-1.19) and 1.05 (1.01-1.08) in 1994 BMI. The HRs for each unit increment in BMI change from 1976 to 1994 were 1.35 (1.25-1.41) for CVD and 1.09 (1.05-1.13) for all-cause mortality. Compared with participants with stable normal weight in 1976 and 1994, HRs of all-cause mortality for those who had normal weight in 1976 but became overweight in 1994 and for those who were persistently overweight during 1976-1994 were 1.42 (1.12-1.80) and 1.80 (1.04-3.14), respectively. CONCLUSIONS: Gaining weight with increased BMI at middle age in Chinese during economic development was associated with elevated risks of all-cause and CVD mortality. Higher BMI measured before economic development was associated with lower mortality risk, whereas BMI measured afterward was associated with increased mortality.