Abstract
OBJECTIVES: To determine the prevalence of muscle-enhancing behaviors in adolescents and young adults using a nationally representative sample in the USA and to examine differences by sex, race/ethnicity, age, socioeconomic status, body mass index, and participation in team sports. METHODS: Prospective cohort data from the National Longitudinal Study of Adolescent to Adult Health, Waves I through III (1994-2002) were analyzed. Engagement in muscle-enhancing behaviors including dietary changes, exercise and weightlifting, supplement use, performance-enhancing substances, and anabolic androgenic steroids were recorded. Multiple logistic regression models using generalized estimating equations, incorporating robust standard errors with clustering by school and within persons, and using national sample weighting, were used to determine associations with muscle-enhancing behaviors across three data collection waves. RESULTS: Of the 18,924 adolescents at baseline, 29.2% of males and 7.0% of females reported weight gain attempts, while 25.2% of males and 3.8% of females reported any muscle-enhancing behavior. All muscle-enhancing behaviors were more common in males compared to females (p<0.001). Among young men 18-26 years old, 15.6% reported using legal performance enhancing substances and 2.7% reported using androgenic anabolic steroids. Factors that were associated with muscle-enhancing behaviors in males across three data collection waves included Black or Hispanic/Latino race/ethnicity, age over 14 years, higher parental education, lower body mass index, and participation in team sports. CONCLUSIONS: Muscle-enhancing behaviors ranging from dietary changes to supplement and androgenic anabolic steroid use are common among adolescent and young adult males. Clinicians should consider screening for muscle-enhancing behaviors in these populations.