The association between BMI and health-related quality of life in the US population: sex, age and ethnicity matters.

Abstract

Obesity is a major public health problem. Detailed knowledge about the relationship between body mass index (BMI) and health-related quality of life (HRQL) is important for deriving effective and cost-effective prevention and weight management strategies. This study aims to describe the sex-, age- and ethnicity-specific association between BMI and HRQL in the US adult population. Analyses are based on pooled cross-sectional data from 41 459 participants of the Medical Expenditure Panel Survey (MEPS) Household Component (HC) for the years 2000-2003. BMI was calculated using self-reported height and weight, and HRQL was assessed with the EuroQol five-dimensional questionnaire. Generalized additive models were fitted with a smooth function for BMI and a smooth-factor interaction for BMI with sex adjusted for age, ethnicity, poverty, smoking and physical activity. Models were further stratified by age and ethnicity. The association between BMI and HRQL is inverse U-shaped with a HRQL high point at a BMI of 22 kg m-2 in women and a HRQL high plateau at BMI values of 22-30 kg m-2 in men. Men aged 50 years and older with a BMI of 29 kg m-2 reported on average five-point higher visual analog scale (VAS) scores than peers with a BMI of 20 kg m-2. The inverse U-shaped association is more pronounced in older people, and the BMI-HRQL relationship differs between ethnicities. In Hispanics, the BMI associated with the highest HRQL is higher than in white people and, in black women, the BMI-HRQL association has an almost linear negative slope. The results show that a more differentiated use of BMI cutoffs in scientific discussions and daily practice is indicated. The findings should be considered in the design of future weight loss and weight management programs.