Decline in Age at Menarche and Associations with Nutritional Status: Results from Two Representative National Surveys of Israeli Adolescents, 2003 to 2016

Decline in Age at Menarche and Associations with Nutritional Status: Results from Two Representative National Surveys of Israeli Adolescents, 2003 to 2016

Medical & Life Science Event 2022
March 28, 2022 Webinar

Lital Keinan Boker

University of Haifa, Israel

Scientific Tracks Abstracts : Arch Gen Intern Med

Abstract:

The timing of puberty has important clinical, public health and social implications. Globally, there are distinct trends indicating a decline in the age of puberty. However, in the last decade, limited data has been published from the developed world. This study evaluated changes in the age at menarche and associated factors in Israeli girls from 2003 to 2016. Methods: Data from two national representative surveys (MABAT- Israeli Youth Health and Nutrition) were analyzed and compared. Both surveys were cross-sectional, school-based studies, including students in 7th to 12th grade (ages 11-19 years). The first survey was conducted between the years 2003-2004, and the second, from 2015-2016. Kaplan-Meier survival analysis was used to estimate the cumulative probability to reach menarche according to age. Differences by population group (Jews/Arabs) were also determined. Cox proportional hazard models were applied to identify the independent predictive factors of age at menarche. Results: The median age at menarche declined from 13.0 years (IQR: 12.0, 14.0) in 2003-2004 to 12.5 years (IQR: 12.0, 13.0) in 2015-2016. The probability to start menstruation at age ≤12 years increased from 34.1% to 47.2%. Jewish girls reached menarche earlier than Arabs, but no significant differences were found regarding the downward trend in the past decade. In both surveys, higher BMI was associated with a younger age at menarche, with hazard ratio (HR) for one unit of BMI-z score, HR=1.19; p<0.001, in each survey. In the 2003-2004 and the 2015-2016 surveys, the HR was higher in girls categorized as overweight: HR=1.24 (95% CI: 1.11, 1.38, p<0.001); HR=1.22, (95% CI: 1.10, 1.37, p<0.001), and obese: HR=1.36, 95% CI: 1.15, 1.61, p<0.001); HR=1.45, 95% CI: 1.25, 1.69, p<0.001), using normal weight as the reference category. Socioeconomic status did not appear to impact Jewish girls' age at menarche, but a significant association was found in the Arab population. Following a multivariate analysis, including chronological age, population group, BMI and socioeconomic status, age at menarche remained significantly lower over time: HR=1.12 (95% CI: 1.06, 1.19), p<0.001, at 2015-2016 versus 2003-2004. Conclusions: This study confirms the trend toward earlier menarche in Israel. This finding is closely associated to nutritional status and population group but also indicates other environmental factors are likely involved. Key words: Age at Menarche, Early Puberty, Adolescents, Obesity, BMI

Biography:

Prof. Lital Keinan Boker completed her M.D, M.P.H. Hebrew University, Jerusalem and Ph.D. University Medical Center Utrecht, Holand. Her Fields of Research/ Interest are cancer epidemiology, nutrition and cancer, cancer screening, cancer survivorship, firstgeneration Holocaust survivors' long-term chronic health outcomes, second- and third-generation Holocaust survivors' long-term chronic health outcomes.

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