BODY-WEIGHT, WEIGHT CHANGE, AND RISK FOR HYPERTENSION IN WOMEN

Background: Obesity increases the risk for hypertension, but the effec ts of modest long-term weight changes have not been precisely quantifi ed. Objective: To investigate body mass index (BMI) and weight change in relation to risk for hypertension. Design: Cohort study. Setting: G eneral community. Participants: Cohort of 82 473 U.S. female nurses 30 to 55 years of age followed every 2 years since 1976. The follow-up r ate was 95%. Measurements: Primary risk factors examined were 1) BMI a t age 18 years and midlife and 2) long-term and medium-term weight cha nges. The outcome was incident cases of hypertension. Results: By 1992 , 16 395 incident cases of hypertension had been diagnosed. After adju stment for multiple covariates, BMI at 18 years of age and midlife wer e positively associated with occurrence of hypertension (P for trend < 0.001). Long-term weight loss after 18 years of age was related to a significantly lower risk for hypertension, and weight gain dramaticall y increased the risk for hypertension (compared with weight change les s than or equal to 2 kg, multivariate relative risks were 0.85 for a l oss of 5.0 to 9.9 kg, 0.74 for a loss greater than or equal to 10 kg, 1.74 for a gain of 5.0 to 9.9 kg, and 5.21 for a gain greater than or equal to 25.0 kg). Among women in the top tertile of baseline BMI at a ge 18 years, weight loss had a greater apparent benefit. The associati on between weight change and risk for hypertension was stronger in you nger (<45 years of age) than older women (greater than or equal to 55 years of age). Medium-term weight changes after 1976 showed similar re lations to risk for hypertension. Conclusions: Excess weight and even modest adult weight gain substantially increase risk for hypertension. Weight loss reduces the risk for hypertension.