Association between body mass index and mortality in an 80-year-old population

Objectives: To evaluate the association between body mass index (BMI) and all-cause mortality and cardiovascular disease (CVD) in an 80-year-old population. Design: Cohort study. Setting: Community-based. Participants: Six hundred ninety-seven of 1,282 (54.4%) 80-year-old candidate individuals. Measurements: The dates and causes of all deaths were followed up for 4 years. Results: The relative hazard ratios (HRs) for all-cause mortality were lower in overweight subjects (BMI >= 25.0) than in underweight (BMI < 18.5) or normal-weight (BMI 18.5-24.9) subjects. Similarly, the HRs for mortality due to CVD in overweight subjects were 78% less (HR=0.22, 95% confidence interval (CI)=0.06-0.77) than those in underweight subjects, and those in normal weight subjects were 78% less (HR=0.22, 95% CI=0.08-0.60) than those in underweight subjects. Mortality due to CVD was 4.6 times (HR 4.64, 95% CI=1.68-12.80) as high in underweight subjects as in normal-weight subjects, and mortality due to cancers was 88% lower (HR=0.12, 95% CI=0.02-0.78) in the overweight group than in the underweight group. There were no differences in mortality due to pneumonia. Conclusion: Overweight status was associated with longevity and underweight with short life, due to lower and higher mortality, respectively, from CVD and cancer.