Association between early menarche and endometriosis risk: a systematic
review and meta-analysis
Abstract
Background Early menarche is reported with the risk of endometriosis
(EMS) with varying conclusions. Objective To assess the association
between menarche age and EMS risk. Search strategy PubMed, Medline and
Embase were searched using “endometriosis”, “early menarche” ,
“EMS”, “menarche age”, and “early menstrual characteristics”.
Selection criteria Articles that reported the EMS risk in early menarche
from Jan 2000 to May 2020 were included. Studies without control group,
and lack of data of menarche age were excluded. Data collection and
analysis EMS risks in these articles were collected and analysed through
in random effects meta-analysis. In addition, subgroup analyses and
meta-regressionwere were also performed. Main results A total of 16
studies (8913 EMS cases and 876477 controls) were included in the
meta-analysis. The pooled risk of EMS in early menarche (<12
years) was 1.34 (95% CI: 1.16–1.54), with statistically significant
heterogeneity across the studies (I2 = 72.0%). Stratified analysis
showed that the risks of EMS by earlier menarche was increased in
studies started after 2000, and in developing area, which was further
confirmed by meta-regression analysis. In addition, higher quality in
assessment of the exposure (menarche age) and control of potential
confounders can elimenate heterogeneity. Conclusions The earlier age of
menarche is a major risk factor of EMS, and its risk has an increasing
trend in recent years and in developing countries. Large-scale studies
in different ethnic groups are warranted.