Explaining the obesity paradox: cardiovascular risk, weight change, and mortality during long-term follow-up in men

Abstract

To examine life-long weight trajectories behind the ‘obesity paradox’, and whether cardiovascular disease (CVD) risk contributes. Cardiovascular disease risk and body mass index (BMI) at mean ages of 25, 47 (year 1974), and 73 years (year 2000) were available of a socioeconomically homogenous sample of 1114 men, without chronic diseases and diabetes in 1974. Overweight was defined as BMI > 25 kg/m², and 7-year mortality (2000–06) from the mean age of 73 years determined (188 deaths). Between 1974 and 2000, 44.3% (n = 494) were constantly overweight, 31.0% (n = 345) constantly normal weight, 12.2% (n = 136) moved from normal to overweight, and 12.5% (n = 139) moved from overweight to normal. The last group had highest CVD risk in midlife, and in late life more co-morbidities and greatest total mortality (P < 0.001). Adjusted mortality hazard ratio was 2.0 (95% confidence interval, CI 1.3–3.0; constantly normal weight group as referent). The hazard ratio remained similar (1.9, 95% CI 1.2–3.0) after adjustment for prevalent diseases in 2000. In old age, both normal weight and overweight men are a mixture of individuals with different weight trajectories during their life course. Overweight and high-CVD risk in midlife with subsequent weight decrease predict the worst prognosis in late life.