Relations of body weight status in early adulthood and weight changes until middle age with hypertension in the Chinese population

We conducted a retrospective cohort study of adult participants from the China Multicenter Collaborative Study of Cardiovascular Epidemiology to explore the relationship between early adulthood weight status, body weight change from age 25 to middle age and hypertension in the Chinese population. Self-reported weight was used to calculate the body mass index (BMI) at age 25. The association between BMI at age 25, subsequent weight change and hypertension was examined using a logistic regression model. Of the 14 635 study participants sampled in 1998, 3525 were diagnosed with hypertension. After adjusting for age, sex and other potential confounding factors, both the BMI at age 25 and weight gain were positively associated with the risk of hypertension (P for trend <0.001). Weight loss could more effectively reduce the risk of hypertension for participants with a higher BMI (BMI >= 24 kg m(-2)) at age 25 than for those who experienced a weight change of -2.5-2.5 kg. The odds ratio (OR) and 95% confidence interval (CI) for a weight change of -7.5 to -2.6 kg were 0.63 (0.46-0.86); for a weight change of < -7.5 kg, these statistics were 0.45 (0.32-0.63). For participants who had a lower BMI (18.5-20.9 kg m(-2)) at age 25, the OR and 95% CI were 0.86 (0.58-1.26) for a weight change of -7.5 to -2.6 kg and 0.95 (0.44-2.05) for a weight change of < -7.5 kg. Being overweight and obesity in early adulthood and adult weight gain were both independently associated with marked increase in the risk of hypertension in middle-aged men and women. Weight loss may be a protective factor against hypertension for people who were overweight or obese in early adulthood.