Overweight/obesity and substance use among adolescent girls: Mediation by health-related quality of life

Objective To examine the hypothesis that poor health-related quality of life (HRQOL) mediates the relationship between overweight/obesity and substance use among adolescent girls. Methods Data are from the 2006 Health Behaviors in School-Age Children survey, a nationally representative sample of students in grades 6-10 during the 2005/6 school-year. Girls who were either of normal weight, overweight, or obese were included (n=4024). Cigarette and alcohol use were categorized as never use/experimentation/frequent use. We measured four dimensions of HRQOL: Physical (general health; physical symptoms); emotional (psychological symptoms; depression); and a school/social dimension. For each substance, an initial model estimated the association between substance use and overweight/obesity. Mediation models that included dimensions of HRQOL were then compared to the initial model to determine the role of HRQOL in the relationship between substance use and overweight/obesity. Analyses were stratified by age (<15 or ≥15)

Results Higher odds of frequent smoking and drinking were associated with overweight among early adolescent girls (<15), and obesity among mid-adolescent girls (≥15). Dimensions of HRQOL were effective mediators of the relationship between overweight and substance use among younger girls, and obesity and substance use among older girls. While self-reported health was a strong mediator of these relationships for all ages and across substances, some age-related differences emerged for the other dimensions.

Conclusions Elements of HRQOL may be significant mediators of the relationship between overweight/obesity and substance use. These associations are particularly troublesome for overweight/obese girls who are facing the multiple burdens of unhealthy weight, poor HRQOL and substance use.