Overweight and obesity associated with all-cause mortality

Overweight and obesity are associated with increased all-cause mortality in non-Hispanic white adults; underweight also may be associated. All-cause mortality generally is lowest within the body mass index (BMI) range of 20.0 to 24.9.

Berrington de Gonzalez and colleagues estimated hazard ratios (HRs) and 95% confidence intervals (CIs) in pooled data from 19 prospective studies involving 1.46 million white adults aged 19 to 84 years. They adjusted for age, study, physical activity, alcohol consumption, and other factors.

The age-standardized rate of death from any cause generally was lowest among those with a BMI of 22.5 to 24.9. Compared with this referent group, the HRs increased with progressively higher and lower levels of BMI. Those among women who never smoked were 1.13 (95% CI, 1.09 to 1.17) for a BMI of 25.0 to 29.9; 1.44 (95% CI, 1.38 to 1.50) for a BMI of 30.0 to 34.9; 1.88 (95% CI, 1.77 to 2.00) for a BMI of 35.0 to 39.9; and 2.51 (95% CI, 2.30 to 2.73) for a BMI of 40.0 to 49.9. The HRs were similar for men.

The authors noted that the association between a low BMI and increased mortality may be an artifact of preexisting disease.