Body mass index gain between ages 20 and 40 years and lifestyle characteristics of men at ages 40-60 years: the Adventist Health Study-2.

BACKGROUND: Obesity increases risk of premature disease, and may be associated with unfavorable lifestyle changes that add to risk. This study analyzed the association of midlife BMI change with current lifestyle patterns among multiethnic men.

METHODS: Men aged 40-60 years (n=9864) retrospectively reported body weight between ages 20-40 years and current dietary, TV, physical activity and sleep practices in the Adventist Health Study II, a study of church-goers in the US and Canada. In multivariate logistic regression analysis, odds ratios for BMI gain were calculated for each lifestyle practice controlling for sociodemographic and other lifestyle factors and current BMI.

RESULTS: Men with median or higher BMI gain (2.79 kg/m(2)) between ages 20-40 years were more likely to consume a non-vegetarian diet, and engage in excessive TV watching and little physical activity and had a shorter sleep duration compared to men with BMI gain below the median (all p<0.001). In multivariate logistic analysis current BMI was significantly associated with all lifestyle factors (all p≤0.005). BMI gain was associated with lower odds of vegetarian diet (odds ratio [OR] 0.939; 95% confidence interval [CI] 0.921-0.957) and of physical activity ≥150 min/week (OR 0.979, 95% CI 0.960-0.999).

CONCLUSIONS: These findings imply that diet and less physical activity are associated with both gained and attained BMI, while inactivity (TV watching) and short sleep duration correlated only with attained BMI. Unhealthy lifestyle may add risk to that associated with BMI. Longitudinal and intervention studies are needed to infer causal relationships.