TY - JOUR T1 - Early menarche is associated with increased risk of asthma: Prospective population-study of twins JF - European Respiratory Journal JO - Eur Respir J VL - 42 IS - Suppl 57 SP - 3501 AU - Sofie Lieberoth AU - Elisabeth Gade AU - Kirsten O. Kyvik AU - Vibeke Backer AU - Simon F. Thomsen Y1 - 2013/09/01 UR - http://erj.ersjournals.com/content/42/Suppl_57/3501.abstract N2 - Aim: To examine the association between early menarche and risk of postmenarchal asthma.Methods: Using data from two multidisciplinary questionnaire surveys eight years apart we prospectively studied 10,648 female twins, 12-41 years of age, from the nationwide Danish Twin Registry. Early menarche was defined as menarche before 12 years of age. We performed a cohort analysis and a co-twin control analysis including twin pairs discordant for asthma.Results: Early menarche was observed in 9.3%. The eight-year incidence of asthma was higher in girls with early menarche compared with girls without early menarche (7.4 vs. 4.5%), OR=1.71 (1.30-2.24), p<0.001; also after adjustment for BMI, age, and smoking (p=0.002). The risk of asthma was increased by 8% (0-15%), p=0.041 per year earlier menarche occurred. Among 167 twin pairs discordant for incident asthma, early menarche was more common in the asthmatic twin compared with her non-asthmatic co-twin (12 vs. 9.6%), OR=1.57 (0.61-4.05), p=0.35. The risk of asthma was not uniform in monozygotic and dizygotic twins.Conclusion: Early menarche is associated with postmenarchal asthma among Danish female twins independently of BMI, age, and smoking. Results indicate a complex relationship possibly mediated through genetic and environmental effects. ER -