Maternal age at menarche and atopy among offspring at the age of 31 years

Background-Influences of female hormones on the occurrence of allergic diso rders have been suggested. Age at menarche may be a marker of endogenous oe strogen levels. Data from a Finnish birth cohort followed to adulthood were analysed to determine whether there is any association between maternal ag e at menarche and the occurrence of atopy among offspring. Methods-The study was conducted in 5188 subjects born in northern Finland f or whom data collections were started during pregnancy and a follow up exam ination was completed at the age of 31 years. Atopy was determined by skin prick tests with cat, birch, grass, and mite extracts, and doctor diagnosed asthma was ascertained by questionnaire at follow up. Maternal age at mena rche was obtained from perinatal data. Logistic regression models were used to adjust for maternal age, parity, smoking, season of birth, parental all ergy, and measures of adiposity and socioeconomic status. Results-The prevalence of atopy at the age of 31 years was lower in childre n whose mothers reached menarche at a later age, especially after age 15. C ompared with children whose mothers started menarche at the age of 16 or ov er, the adjusted odds ratios of being atopic for children whose mothers sta rted menarche younger than or at 12, 13, 14 and 15 years were 1.43 (95% CI 1.12 to 1.83), 1.29 (95% CT 1.03 to 1.60), 1.15 (95% CI 0.93 to 1.42), and 1.19 (95% CI 0.95 to 1.48), respectively. Among girls, the offspring's own age at menarche was not significantly associated with atopy. Conclusion-Our results encourage further evaluation of the potential effect of maternal age at menarche on the later development of atopy and possible biological mechanisms.