Background: Menarche is the endpoint of a complex sequence of maturational events but is the unique marker of female puberty. Timing of menarche is a strongly heritable trait. However, secular trends suggest that lifestyle and/or environmental factors are important.
Objective: To assess the trend in age at menarche (AAM) in Istanbul over the last 12 years, and compare the patterns according to socioeconomic status (SES), education and body mass index (BMI).
Method: A cross-sectional study carried out between March 2022 and April 2022 on schoolgirls aged 9-18 years. A predesigned, pretested, structured and self-administered questionnaire was filled anonymously by the students. The data of AAM was included in the statistical analysis if the time of AAM is remembered precisely for months and years. A probit model was used to calculate the median AAM. The effect of the pandemics on AAM was assessed by comparing menarcheal age among the girls born before and after 2021. The findings were compared with those from the study performed 12 years ago at the same region of Istanbul.
Results: 1211 schoolgirls out of 7000 gave consent and filled the survey. The mean age was 13.8±1.7 years (median 14.2). The AAM was reported in 929 girls. The median AAM was 11.72 years (95% CI 11.41-11.91). The median AMM was reported 12.01 years (95% CI 11.92-12.11, n=679) and 12.03 years (95% CI 11.88-12.19, n=250) among girls attaining menarche before and after 2021 (P=0.02). The AMM was positively correlated with maternal AAM (P<0.0001) and negatively correlated with BMI-SDS, maternal and paternal education status (P<0.0001, 0.002, 0.009; respectively). The girls with BMI-SDS≥1.5 (n=86) had earlier menarche than the ones with BMI-SDS<1.5 (n=843) (mean 11.44 vs 12.1 years, P<0.0001). AAM was not significantly different among girls born with low birthweight (n=91) than the others (n=838) (median 11.99 vs 12.02 years, P=0.65). Among mother-girl pairs who reported AAM data (n=812), girls had a mean of 0.88 years (median 0.93) earlier menarche than their mothers. AAM was lower than that reported 12 years ago as 12.74 years (P<0.0001).
Conclusion: The present study denotes a significant downward trend in the menarcheal age of the girls living in Istanbul over the last decade. Although our findings suggest a strong contribution of genetic factors and BMI on AAM, but they do not support the influence of pandemics on AAM.
15 Sep 2022 - 17 Sep 2022