Associations of sport and exercise participation in adolescence with body composition and device-measured physical activity in adulthood: longitudinal data from the Norwegian HUNT study.

Background: To examine whether adolescent sport and exercise participation is associated with adulthood moderate-to-vigorous physical activity (MVPA), body fat, skeletal muscle mass, and body mass index (BMI), and to explore whether the association between sport and exercise participation and adult body composition depends on adulthood MVPA level.

Methods: Prospective study of 4603 adolescents aged 13-18 year (57.2% female) in the Norwegian Young-HUNT Study and follow-up ~ 11 or ~ 22 years later. Linear regression was used to estimate mean differences in accelerometer-measured MVPA and bioimpedance-measured body fat, muscle mass, and BMI in adulthood according to self-reported sport and exercise participation in adolescence.

Results: Adolescents participating in sport/exercise every day accumulated more MVPA (48 min/week, 95% CI 23 to 73), had less body fat (-4.4%, 95% CI -5.4 to -3.2), more muscle mass (2.6%, 95% CI 2.0 to 3.2), and lower BMI (-1.1 kg/m², 95% CI -1.7 to -0.5) as adults, compared to adolescents participating < 1 day/week. Joint analysis showed that adolescents who participated in sport/exercise ≥ 4 days/week, and who accumulated 150-299 min/week MVPA in adulthood, had less body fat (-5.8%, 95% CI -7.4 to -4.3) and more muscle mass (3.4%, 95% CI, 2.5 to 4.3) compared to those participating in sport/exercise ≤ 1 day/week and who accumulated < 150 MVPA min/week as adults. Compared to the same reference group, these associations were further strengthened among those who accumulated ≥ 300 min/week MVPA in adulthood and reported ≥ 4 days/week of sport/exercise for both body fat (-8.8%, 95% CI -10.3 to -7.4) and muscle mass (5.1%, 95% CI 4.3 to 5.9).

Conclusions: Adolescent sport and exercise participation is positively associated with MVPA, and skeletal muscle mass, and inversely associated with body fat and BMI in adulthood. These associations remained significant after adjusting for adult MVPA levels. A higher MVPA level in adulthood strengthens the association between adolescent sport/exercise participation and adult body composition.