Age at Menarche and Asthma Onset Among US Girls and Women: Findings from NHANES, 2001-2018

Abstract Background: Findings on the association between early menarche and asthma onset remain inconsistent and the evidence in the US is lacking. Furthermore, there was no clear separation of childhood- and adult-onset asthma in previous studies. Therefore, we aim at quantitatively estimating the association of age at menarche with risk of childhood- and adult-onset asthma separately in US girls and women.Methods: We conducted a retrospective cohort study of 24,282 US girls and women aged less than 80 years by using continuous NHANES data in 2001-2018. Weighted Cox proportional-hazards regression models with censoring ages of 19 and 79 were used to separately estimate hazard ratios of childhood- and adult-onset asthma associated with age at menarche. Results: Each one-year increase of age at menarche was significantly associated with a 17% (HR [95%CI]: 0.83 [0.77, 0.90]) decrease in the risk of childhood-onset asthma. Compared with age at menarche of 12-14, we observed a 60% (HR [95%CI]: 1.60 [1.22, 2.09]) increased risk of childhood-onset asthma for early menarche (age at menarche <12 years) and 41% (HR [95%CI]: 0.59 [0.32, 1.08]) decreased risk for late menarche (age at menarche ≥15 years). Race, family income, education and family history of asthma did not modify these associations. No significant association between age at menarche and adult-onset asthma.Conclusions: In this US nationally representative study, we found that early menarche was associated with increased risk of childhood-onset asthma, but not adult-onset asthma. These findings help demonstrate early menarche may be a risk factor for childhood-onset asthma in US, indicating timely and effective management of special individuals with early menarche for preventing asthma.