STROBE: The relationship between asthma and early menarche in Korean adolescents.

We explored the relationship between asthma and early menarche in a representative sample of Korean adolescents.Web-based self-reported data collected from 2006 to 2015 by the Korean Youth Risk Behavior Web-based Survey were used. Menarche status was divided into "early" (<12 years of age, n = 69,520) and "not early" (≥12 years of age, n = 234,065).Adolescent girls with early menarche exhibited a higher incidence of asthma (8.1% vs 7.4%, P < .001), more frequent school absences because of asthma (10.8% vs 8.7%), and more frequent ≤4-day stretches of school absence (4.6% vs 2.4%) compared with girls with "not early" menarche (all P < .001). Multivariate analysis performed after adjusting for multiple confounders revealed a 1.04-fold (95% confidence interval [CI] 1.00-1.07) greater likelihood of asthma in the early menarche than not early menarche group. In addition, the odds ratios for missing school due to asthma for 1 to 3 and ≥4 days per year in the early menarche group were 1.00 (95% CI 1.00-1.02) and 1.21 (95% CI 1.01-1.46), respectively.Adolescents with early menarche exhibited increased incidences of asthma and severe asthma.