LAUSR

Earlier pubertal development is only partially explained by childhood body mass index (BMI); the role of other factors like childhood infections is less understood. Using data from the LEGACY Girls Study (2011 - 2016), we prospectively examined the associations between childhood viral infections (Cytomegalovirus (CMV), Epstein Barr Virus (EBV), Herpes Simplex Virus 1 (HSV1), HSV2 and pubertal timing. We measured exposures based on seropositivity in pre-menarcheal girls (n=490). Breast and pubic hair development were classified based on mother-reported Tanner Stage (TS: TS2+ compared with TS1), adjusting for age, BMI, and sociodemographic factors. The average age at first blood draw was 9.8 years (Stdev=1.9 years). The prevalences were 31% CMV+, 37% EBV+, 14% HSV1+, 0.4% HSV2+, and 16% for both CMV+/EBV+. CMV+ infection without co-infection was associated with developing breasts an average of 7 months earlier (Hazard Ratio (HR)=2.12, 95% CI 1.32, 3.40). CMV+ infection without co-infection and HSV1+ and/or HSV2+ infection were associated with developing pubic hair 9 months later (HR 0.41, 95% CI 0.24, 0.71, HR 0.42, 95% CI 0.22, 0.81, respectively). Infection was not associated with menarche. If replicated in larger cohorts with blood collection prior to any breast development, this study supports that childhood infections may play a role in altering pubertal timing.