Relation of Age at Menarche to Race, Time Period, and Anthropometric Dimensions: The Bogalusa Heart Study

Abstract

OBJECTIVE: To assess secular trends in menarcheal age between 1973 and 1994 and to determine whether childhood levels of height, weight, and skinfold thicknesses can account for racial (white/black) differences in menarcheal age. METHODS: Data from 7 cross-sectional examinations of school-aged children, with menarcheal age obtained through interviews, were used for both cross-sectional (11 218 observations) and longitudinal (n = 2058) analyses. In the latter analyses, the baseline examination was performed between ages 5.0 and 9.9 years, and the mean follow-up was 6 years. RESULTS: Black girls experienced menarche, on average, 3 months earlier than did white girls (12.3 vs 12.6 years), and during the 20-year study period, the median menarcheal age decreased by approximately 9.5 months among black girls versus approximately 2 months among white girls. As compared with 5- to 9-year-old white girls, black girls were taller and weighed more, characteristics that were predictive of a relatively early (before age 11.0 years) menarche. However, even after adjustment for weight, height, and other characteristics, the rate of early menarche remained 1.4-fold higher among black girls than among white girls. CONCLUSIONS: Additional study of the determinants of menarcheal age is needed, as the timing of pubertal maturation may influence the risk of various diseases in adulthood.