Determinants of age at menarche in the UK: analyses from the Breakthrough Generations Study

• Published in: British journal of cancer Vol. 103; no. 11; pp. 1760 - 1764
• Main Authors: Morris, D H, Jones, M E, Schoemaker, M J, Ashworth, A, Swerdlow, A J
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23.11.2010; Nature Publishing Group
• Subjects: 631/136; 631/443/494; 692/699/67/1347; 692/700/478/174; Adolescent; Adult; Age; Age Factors; Aged; Aged, 80 and over; Biological and medical sciences; Biomedical and Life Sciences; Biomedicine; Birth order; Birth Weight; Body Height; Breast cancer; Breast Neoplasms - etiology; Breastfeeding & lactation; Cancer Research; Drug Resistance; Epidemiology; Female; Hormones; Humans; Medical research; Medical sciences; Menarche; Middle Aged; Molecular Medicine; Multivariate Analysis; Oncology; Questionnaires; Siblings; Smoking - adverse effects; Social Class; Tumors; Variables; United Kingdom; Europe; United Kingdom > UK; British Isles; epidemiology; exercise; growth; puberty; diet; menarche; Physical exercise; Puberty; Cancerology; Nutrition; Diet; Growth; Menarche; Epidemiology; Age; Feeding
• ISSN: 0007-0920; 1532-1827
• DOI: 10.1038/sj.bjc.6605978

Background: Early menarche increases breast cancer risk but, aside from weight, information on its determinants is limited. Methods: Age at menarche data were collected retrospectively by questionnaire from 81 606 women aged 16–98, resident in the UK and participating in the Breakthrough Generations Study. Results: Menarche occurred earlier in women who had a low birthweight ( P trend <0.001), were singletons ( P <0.001), had prenatal exposure to pre-eclampsia ( P <0.001) or maternal smoking ( P =0.01), were not breastfed ( P trend =0.03), were non-white ( P <0.001), were heavy ( P trend <0.001) or tall ( P trend <0.001) compared with their peers at age 7 and exercised little as a child ( P trend <0.001). Menarcheal age increased with number of siblings ( P <0.001) independently of birth order, and had an inverse association with birth order after adjustment for sibship size ( P <0.001). In a multivariate model, birthweight, ethnicity, weight, height, exercise, sibship size and birth order remained significant, and maternal age at birth became significant (positive association, P <0.001). Conclusion: Age at menarche was influenced by both pre- and post-natal factors, and these factors may affect breast cancer risk through this route.