The influence of body mass index, age and gender on current illness: a cross-sectional study.

CONTEXT: Obesity poses a significant health risk, but health risk is not equivalent to actual health status. Further, age and gender might alter the effect of body weight on physical health.

OBJECTIVE: To determine the relationship between body mass index (BMI), age, gender and current health status.

DESIGN: Data from the 1988-1994, 2003-2004 and 2005-2006 National Health & Nutrition Examination Surveys were weighted to represent the US population. BMI, age, gender and current medication use were analyzed in a sample-adjusted 9071 women and 8880 men.

MAIN OUTCOME MEASURES: The percentage of participants taking medication and the total number of medications taken.

RESULTS: In both the 1988-1994 and 2003-2006 data sets, with few exceptions, medication loads did not increase significantly in overweight compared with normal-weight people. Medication loads increased significantly in obese compared with normal-weight people aged 40+, but only marginally at 25-39 years. Medication loads were higher in women than men, but significantly less so in people aged 55-70.

CONCLUSIONS: First, medication loads, a measure of current health status, were increased in obese compared with the normal-weight people, but the effect was mainly at ages over 40 years. In addition, BMI category contributed less to medication loads at ages 25-39 than in older groups. Second, there was little difference in current health status in normal-weight versus overweight people at all ages. Finally, higher medication loads in women than men are more apparent in younger than older people. Although obesity does not substantially affect current health in young people, it is likely that the increased medication loads in obese compared with normal-weight older people originates at least in part from an increased BMI starting at a younger age. Thus, age, gender and onset of high BMI all require consideration when using BMI to assess current health status.