Developmental Trends and Determinants of Physical Activity From Adolescence to Adulthood Differ by Ethnicity/Race and Sex

Background: Interventions to raise population physical activity generally show modest effects; one possible reason is that trends and determinants of moderate to vigorous physical activity (MVPA) differ between population subgroups. This study examined differences in trends and determinants of reported MVPA by ethnicity/race and sex in a 15-year longitudinal study. Methods: Participants (n = 2092) in the Project Eating and Activity in Teens and Young Adults study were surveyed on MVPA behavior and potential determinants from adolescence to young adulthood. Generalized estimating equations were used to model age trends in MVPA and associations with determinants. Results: Mean MVPA declined by 2.1 hours per week over 15 years of follow-up from adolescence to young adulthood. Asian males reported the lowest levels of MVPA at each age. Nonwhite females reported less MVPA than white females at each age. The association of body mass index (BMI) with MVPA differed by sex and ethnicity/race. Asian males and females showed lower levels of MVPA at both low and high BMI. Conclusions: Interventions to increase MVPA may need to begin earlier among Asian men and nonwhite women than among other groups. Asian adolescents with lower BMI show lower MVPA and may benefit from additional intervention efforts compared with Asian adolescents with normal BMI.