Age of Menarche in a Longitudinal US Cohort

Abstract

Study objective: Menarche is a critical milestone in a woman's life, and historically has been determined using several approaches. The goals of this study were to: (1) determine age at menarche from multiple reports of parents and adolescent participants in a prospective study; (2) examine factors affecting age at menarche; and (3) determine correlates of menarche and pubertal tempo.

Design: Longitudinal observational study.

Setting: Three sites of the Breast Cancer and the Environment Research Program.

Participants: Girls enrolled at 6-8 years of age.

Interventions and main outcome measures: Parental and participant reported age of menarche, and tempo of puberty.

Results: There were 946 girls who were assigned an age of menarche. The correlation between parent and participant reports was high (Spearman R = 0.799, P < .001), and the difference was insignificant. Median age at menarche overall was 12.25 years. Compared with black participants, Hispanic girls were more likely to have menarche earlier, whereas white and Asian girls were more likely to have menarche later. Age of menarche was highly correlated with age of breast development (Spearman R = 0.547; P < .001), and inversely with body mass index (Spearman R = -0.403; P < .001). Tempo (interval of age of breast development to menarche) was slower in those with earlier breast development.

Conclusion: Parental and adolescent reports of menarche are highly correlated. Earlier breast maturation was associated with slower tempo through puberty. Body mass index had a greater effect on age at menarche than did race and ethnicity.

Keywords: Breast development; Menarche; Pubertal tempo; Puberty.

Figure 1:

Flow chart of the age at menarche assignment algorithm for 946 girls with an ascertained age. Median and IQR were computed from the survival distribution using SAS Proc PHREG with an additional strata statement adjusting for site. 1. Agree = difference within 6 months. 2. Disagree = difference 6+ months. 3. At least one report. A. First reported date/age was used to determine age at menarche. B. The first girl reported date was used as a tie breaker. If the first girl reported date was within 6 months of the first parent reported date, then first parent reported date was used. If the first girl reported date was within 6 months of the second parent reported date, then the second parent reported date was used. If there is no agreement among all dates, the first parent reported date was used. C. The third girl reported date was used as a tie breaker. If the third girl reported date was within 6 months of the first girl reported date, then the first girl reported date was used. If the third girl reported date was within 6 months of the second girl reported date, then the second girl reported date was used. If there is no agreement among all dates, the first girl reported date was used. D. Third parent reported age was used as a tie breaker. If the third parent reported age was within 6 months of the first parent reported age, then the first parent reported age was used. If the third parent reported age was within 6 months of the second parent reported age, the second parent reported age was used. If there is no agreement among all ages, the first parent reported age was used. E. Age at menarche was computed as nine months prior to first affirmative response to menarche.