Weight change during middle age and risk of stroke and coronary heart disease: The Japan Public Health Center–based Prospective Study

Background and aims: The impact of weight changes in middle age on the incidence of cardiovascular disease has not been well elucidated. We investigated whether a 5-year weight change was associated with risk of stroke and coronary heart disease (CHD) in middle-aged individuals. Methods: We analyzed data of 74,928 participants aged 40–69 years who provided responses to the baseline and 5-year follow-up questionnaires in the Japan Public Health Center–based Prospective Study. Weight change was calculated by subtracting self-reported weight at baseline from that at 5-year follow-up. Stroke and CHD events were confirmed by reviewing hospital records. Results: During 997,406 person-years of follow-up, we documented 3,975 stroke and 914 CHD events. The multivariable HRs of stroke for losing ≥5 kg compared to stable weight (change ≤2 kg) was 1.17 (95% CI, 1.01–1.37) in men versus 1.33 (1.13–1.57) for losing ≥5 kg and 1.61 (1.36–1.92) for gaining ≥5 kg in women (U-shaped association). These associations did not change after the exclusion of early events. The multivariable HR of CHD for gaining ≥5 kg was 1.22 (0.95–1.58) in men. After exclusion of early events within another 5 years, that positive association became stronger [multivariable HR 1.34 (1.00–1.82)]. Conclusions: Weight gain during middle age was associated with an increased risk of stroke in women and an increased risk of CHD in men. Weight loss was associated with an increased risk of stroke in both men and women.