Determinants of Age at Menarche in the Newcastle Thousand Families Study

Abstract

Early life determinants of age at menarche were investigated for female participants in the longitudinal Thousand Families Study based in Newcastle upon Tyne. Age at menarche was collected retrospectively from 276 participants at the age 50 follow-up in 1997. Birth weight, length of gestation, height, weight, duration of breast feeding, social class, periods of infection, and quality of housing conditions in childhood were collected prospectively. Ordinal logistic regression was used to test univariate and multivariable associations of fetal and childhood data with menarcheal age group membership. Separation into 3 menarcheal age groups was made with respect to distance in standard deviations from the sample mean: early (μ->1 SD), middle (μ±<1 SD), late (μ+>1SD). Regression models were also used to test univariate and multivariable associations between fetal and childhood data and age at menarche as a continuous variable. Two main independent associations were observed: girls who experienced a shorter gestation and girls who were heavier at age 9 had earlier menarche. Birth weight adjusted for gestational age was found to have different relationships with age at menarche depending upon how heavy or light a girl was at age 9. The results of this study support the hypothesis that fetal conditions are associated with the timing of menarche and the hypothesis that greater childhood tissue growth is associated with earlier menarche. It is suggested that future work should focus on illuminating the mechanisms underlying these statistical relationships.