Impacts of weight change on prehypertension in middle-aged and elderly women

Background: Individuals with prehypertension, a new blood pressure category defined as systolic blood pressure of 120-139mm Hg and/or diastolic blood pressure of 80-89mm Hg, are at an increased risk for heart diseases and are strongly recommended to practice lifestyle changes, including weight control. Data on impacts of long-term weight change on prehypertension are sparse. Objective: To evaluate the association between weight change since age 20 and prehypertension risk. Methods: In this cross-sectional analysis of 36 075 non-hypertensive women aged 40-70 years, information on weight history was collected at enrollment in the Shanghai Women's Health Study; blood pressures were measured 2-3 years later by medical professionals. The odds ratios (ORs) of prehypertension were calculated for women who gained or lost weight since age 20 compared with those with stable weight ( gain or loss < 5 kg), adjusting for age, lifestyle factors, sodium intake and body mass index at age 20. Results: A total of 47% of the study participants ( n = 16 981) had prehypertension. For a 6- to 10-kg gain, the OR (95% CI) was 1.36 (1.28-1.45); for 11- to 15-kg gain, 1.64 (1.54-1.75); for 16- to 20-kg gain, 2.32 (2.14-2.51); for 21- to 25-kg gain, 2.91 (2.60-3.26); and for a gain > 25 kg; 3.65 (3.13-4.26). While for a 6- to 10-kg loss and a loss > 10 kg, the respective ORs were 0.76 (0.67-0.87) and 0.47 (0.38-0.59). The increase in prehypertension risk associated with each 1-kg gain was similar to that associated with a 1-year increase in age. Although weight gain during early adulthood appeared to have a more pronounced effect on the risk of prehypertension, weight gain later in life also contributed significantly to an elevated risk. Conclusion: Weight gain since age 20 substantially increases risk for prehypertension in non-hypertensive individuals, while weight loss significantly lowers the risk, emphasizing the importance of weight control throughout adulthood in preventing hypertension.