31st Jan 2024

Introduction: Adolescence is a critical period in the which high fat accrual is associated with increased risk of overweight (OW) in adulthood. Adolescent fitness, a component of physical activity, also influences adult weight status. This study investigated longitudinally the links between adolescent fat accrual and fitness on subsequent adult fat mass. Methods: 76 adult males from the Saskatchewan Growth and Development Study (SGDS) (1964-2010), were assessed serially from 7-17 years of age and again at 40-50 years of age. A biological age (BA; years from peak height velocity (PHV=0)) was calculated. Skinfold measures were used to derive TBF (%) and trunk fat (Tfat, mm). OW was defined by age and sex specific %TBF cut-offs. A fitness score was calculated from measures of VO2max, strength and fitness performance. In adulthood, participants were put into tertiles using DXA derived percent total body fat (TBF) (G1≤20.6%; G2 >20.6%<27%; G3 ≥27%). ANOVA was used to find mean differences. Results: In adolescence, prior to PHV, all subjects were normal weight (NW); however, TBF in G3 was significantly higher than G1 and G2 from BA’s -4 to 0 (p 23.6; 100% in G2 and G3). Only G3 became OW before emerging adulthood. Adolescent TBF, Tfat and fitness score differed between groups (p<0.05). Tfat was significantly higher in G3 compared to G1 from BA’s -4 to +3 (p<0.05) and G1 and G2 had higher fitness scores (p<0.05). Conclusion: These findings suggest that 5 years around the attainment of PHV is a critical period for fat accrual and physical fitness development on adult weight status. Results also suggest that OW adults may be at heightened health risk due to concomitant gains in Tfat around PHV, even those classified as normal weight during adolescence.