TY - JOUR

T1 - Age at Menarche and Risk of Multiple Sclerosis

T2 - A Prospective Cohort Study Based on the Danish National Birth Cohort

AU - Nielsen, Nete Munk

AU - Harpsøe, Maria

AU - Simonsen, Jacob

AU - Stenager, Egon

AU - Magyari, Melinda

AU - Koch-Henriksen, Nils

AU - Baker, Jennifer L

AU - Hjalgrim, Henrik

AU - Frisch, Morten

AU - Bager, Peter

N1 - © The Author 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

PY - 2017/4/15

Y1 - 2017/4/15

N2 - Few studies have addressed the possible association between age at menarche and multiple sclerosis (MS), and results are conflicting. We studied this issue in a large prospective cohort study. The study cohort comprised 77,330 women included in the Danish National Birth Cohort (1996-2002). Information on menarcheal age was ascertained at the first interview, which took place in the 16th week of pregnancy. Women were followed for MS from the first interview to December 31, 2011. Associations between age at menarche and risk of MS were evaluated with hazard ratios and 95% confidence intervals using Cox proportional hazards regression models. Overall, 226 women developed MS during an average follow-up period of 11.7 years. Age at menarche among women with MS was generally lower than that among women without MS (Wilcoxon rank-sum test; P = 0.002). We observed an inverse association between age at menarche and MS risk. For each 1-year increase in age at menarche, risk of MS was reduced by 13% (hazard ratio = 0.87, 95% confidence interval: 0.79, 0.96). Early age at menarche appears to be associated with an increased risk of MS. The mechanisms behind this association remain to be established.

AB - Few studies have addressed the possible association between age at menarche and multiple sclerosis (MS), and results are conflicting. We studied this issue in a large prospective cohort study. The study cohort comprised 77,330 women included in the Danish National Birth Cohort (1996-2002). Information on menarcheal age was ascertained at the first interview, which took place in the 16th week of pregnancy. Women were followed for MS from the first interview to December 31, 2011. Associations between age at menarche and risk of MS were evaluated with hazard ratios and 95% confidence intervals using Cox proportional hazards regression models. Overall, 226 women developed MS during an average follow-up period of 11.7 years. Age at menarche among women with MS was generally lower than that among women without MS (Wilcoxon rank-sum test; P = 0.002). We observed an inverse association between age at menarche and MS risk. For each 1-year increase in age at menarche, risk of MS was reduced by 13% (hazard ratio = 0.87, 95% confidence interval: 0.79, 0.96). Early age at menarche appears to be associated with an increased risk of MS. The mechanisms behind this association remain to be established.

KW - Adolescent

KW - Adult

KW - Age Factors

KW - Child

KW - Denmark

KW - Female

KW - Humans

KW - Interviews as Topic

KW - Menarche

KW - Multiple Sclerosis

KW - Proportional Hazards Models

KW - Prospective Studies

KW - Registries

KW - Risk Factors

KW - Young Adult

KW - Journal Article

U2 - 10.1093/aje/kww160

DO - 10.1093/aje/kww160

M3 - Journal article

C2 - 28369233

VL - 185

SP - 712

EP - 719

JO - American Journal of Epidemiology

JF - American Journal of Epidemiology

SN - 0002-9262

IS - 8

ER -