UC Berkeley

Purpose

The relationship between socioeconomic status (SES) and menarche has implications for understanding social level influences on early life development and adult disease, including breast cancer, but remains ill defined. We report here results from the Breast Cancer and the Environment Research Program, which permitted a longitudinal study of age at menarche in relationship to childhood SES in a diverse cohort of 1,069 girls across three urban areas of the United States.

Methods

We assessed the association of SES index quintiles with age at pubertal onset with breast budding and subsequent tempo to the age at menarche between 2004 and 2015 using multiple-event Cox regression models to estimate hazard ratios and 95% confidence intervals.

Results

In an unadjusted model, lower SES was predictive of both earlier pubertal onset and tempo and thus earlier age at menarche in trends across quintiles. After adjusting for the potentially mediating effects of body mass index, SES trends remained significant for both outcomes. After adjusting for both body mass index and race/ethnicity, the association with SES remained substantial for pubertal onset but was much diminished and nonsignificant for tempo and thus age at menarche.

Conclusions

These results suggest that a lower SES environment and social adversity affect the age at menarche primarily by hastening pubertal onset rather than by shortening tempo.