Physical Activity May Attenuate the Association of Early Adolescent Adiposity With PCOS Assessed in Later Adolescence: Findings From a Prospective Cohort, Project Viva.

Objective: To assess how moderate-vigorous physical activity (MVPA) may modify the association of early adolescent adiposity with late adolescent polycystic ovary syndrome (PCOS).

Methods: Within the Project Viva prospective cohort, we assessed the association of body mass index z-score (BMIz) at early adolescence (mean age 13.1 years) with later PCOS (self-reported diagnosis or oligo-anovulation with clinical/biochemical hyperandrogenism) at mean age 17.7 years. We stratified our analyses by tertile of actigraphy-assessed moderate-vigorous physical activity (MVPA) during early adolescence . In multivariable logistic regression models, we adjusted for maternal education and PCOS, child race and ethnicity, and child health behaviors.

Results: Among 341 female adolescents, n = 47 (14%) met criteria for PCOS in late adolescence. In early adolescence (∼13 years old), mean (SD) BMIz was 0.32 (1.10) units and mean (SD) MVPA was 27.1 (17.9) min/day. After adjusting for covariates, early adolescent BMIz was associated with later PCOS (OR=1.72 95% CI = 1.15, 2.56 per unit increase in BMIz). In stratified analyses, the association of early adolescent BMIz with later PCOS was apparent for those in the lowest tertile of MVPA (OR 3.22; 95% CI 1.25, 8.31) however was weaker among those more active (MVPA tertile 2 OR = 1.65; 95% CI 0.74, 3.67 and tertile 3 OR = 1.34; 95% CI = 0.63, 2.86, respectively).The interaction term p-value was non-significant (P = .36).

Conclusion: Our findings suggest that the detrimental effect of adiposity in relation to PCOS risk is most apparent only among those with lower MVPA. Maintaining adequate MVPA during the early teen years may mitigate PCOS risk associated with excess adiposity.