Age at Menarche and Time Spent in Education: A Mendelian Randomization Study

Area of Science:

• Human genetics
• Reproductive health
• Educational attainment

Background:

• Menarche marks female puberty onset and influences self-identity.
• The relationship between early puberty and educational duration is unclear due to confounding environmental factors in observational studies.

Purpose of the Study:

• To investigate the causal effect of age at menarche on time spent in education using a Mendelian randomization approach.

Main Methods:

• Utilized Mendelian randomization (MR) with genetic variants (SNPs) as instrumental variables.
• Employed Genome-Wide Association Study (GWAS) meta-analyses from large cohorts (182,416 women for menarche, 118,443 women for education).

Main Results:

• A statistically significant causal effect was found: each one-year delay in menarche was associated with an average increase of 0.14 years (approximately 53 days) in time spent in education.
• Sensitivity analyses confirmed the robustness of this causal effect.

Conclusions:

• Delayed age at menarche has a positive causal impact on educational duration in women.
• Findings contribute to understanding the broader social implications of pubertal timing in females.