Weight variability and incident disease in older women: the Iowa Women's Health Study.

Abstract

To evaluate the association between weight variability and disease incidence in women. Prospective cohort study, following women from 1986 through 1992. A population-based sample of 33834 women aged 55-69 y, free of cancer and heart disease, completed a mail-based survey that included self-reported body weights at ages 18, 30, 40, 50 y, and currently. Weight variability was defined as (1) the root mean square error around the slope of weight on age (RMSE); and (2) categorical measures of weight change. Outcome measures were incidence of myocardial infarction (MI); stroke; diabetes; breast, endometrial, lung, or other cancer; total and hip fractures. Adjusted relative risks of MI, stroke, diabetes, and hip fracture increased with increasing weight variability. The age and body mass index-adjusted relative risks (RR) for highest vs lowest quartile of RMSE were: MI: 2.03; stroke: 1.61; diabetes: 1.42; breast cancer: 0.85; endometrial cancer: 0.88; lung cancer: 1.70; other cancer: 0.93; total fractures: 1.15; hip fractures: 1.45. The strongest associations between weight change categories and disease were for diabetes (RR compared to small gain/stable weight: large cycle, 1.72; small cycle, 1.55; large gain, 1.80; weight loss, 1.91; other pattern, 1.55). Large weight cycles were associated with higher risk of MI (RR = 1.89) and stroke (RR = 1.71). These findings are consistent with previous studies and suggest that weight variability is associated with higher risk of developing chronic diseases.