Background: Individuals with prehypertension, a new blood pressure category defined as systolic blood pressure of 120-139 mm Hg and/or diastolic blood pressure of 80-89 mm 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.