Secular trends in earlier initiation of puberty have been observed in recent decades. One risk factor appears to be increases in adiposity, as measured by body mass index. This trend is particularly notable among Latino populations, who have higher rates of overweight/obesity compared with non-Latino White youth. Previous research has focused primarily on White girls, resulting in data gaps regarding male puberty and among potentially high-risk populations. Using data from the Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) study, we examined body mass index at age 5 years (2005-2006) and multiple markers of pubertal onset, assessed repeatedly and longitudinally at 7 in-person visits, starting at age 9 and continuing through age 14 (2009-2015), among 336 Mexican Americans in Salinas, California. We observed no associations among boys, but found significantly earlier thelarche in overweight (HR = 1.7, 95% CI: 1.1, 2.7) and obese girls (HR = 1.5, 95% CI: 1.0, 2.4), menarche in overweight girls (HR = 1.6; CI: 1.0, 2.4), and pubarche in obese girls (HR = 1.9; CI: 1.2, 3.0), compared with normal-weight girls. This study examined an understudied population and included key covariates, such as birth weight and early adverse events, which are typically omitted in studies.

Purpose

Earlier timing and faster tempo of puberty have been linked to adolescents' poor mental health. Previous research rarely adjusted for childhood mental health, did not use physical examination to assess puberty, and excluded Latinas and Asian Americans. This study addressed these limitations.

Methods

We followed 822 girls, recruited at ages 6-8, for 8 years. Breast and pubic hair development and anxiety and depressive symptoms were assessed prospectively and repeatedly. Structural equation models tested whether pubertal timing and tempo were associated with adolescent mental health symptoms and whether associations varied by ethnicity. Models were adjusted for childhood mental health symptoms, body mass index, and family income.

Results

Earlier breast development was associated with higher depressive symptoms among whites (β = -.19; p < .01) and higher anxiety symptoms among Latinas (β = -.26; p < .05), but lower depressive symptoms among Asians (β = .24, p < .05). Later pubic hair development (b = .24; p < .05) and faster pubic hair tempo (β = .26; p < .01) were associated with higher anxiety symptoms among Latinas. Faster pubic hair tempo was associated with lower depressive symptoms among Asians (β = -.34; p < .05). Tempo of breast development showed no associations.

Conclusions

Findings confirmed that earlier breast development was associated with higher mental health symptoms for Latina and white girls but was protective among Asians. Results for pubic hair and pubertal tempo were inconsistent, requiring future examination. While targeted interventions to prevent mental health problems among early-maturing girls are critical, there is variability among who might benefit most.