Association between body fat distribution and age at menarche: a two sample Mendelian randomization study

Area of Science:

• Reproductive Endocrinology
• Human Genetics
• Obesity Research

Background:

• Traditional obesity metrics like BMI are commonly linked to age at menarche (AAM).
• Limited research exists on body fat distribution's impact on AAM.
• Few Mendelian randomization (MR) studies have explored this relationship.

Purpose of the Study:

• To investigate the causal effects of eight body fat distribution indicators on AAM using MR.
• To identify specific body fat distribution patterns influencing AAM.
• To enhance understanding of pubertal development through body measurements.

Main Methods:

• A two-sample Mendelian randomization (MR) study was conducted.
• Inverse variance weighted (IVW) method was primary; MR-Egger and weighted median were supplementary.
• MR Bayesian model averaging (MR-BMA) addressed high exposure correlation and identified dominant factors.

Main Results:

• Whole body fat mass, left leg fat percentage/mass, and left arm fat percentage/mass were associated with decreased AAM.
• Consistent trends were observed across MR evaluation methods.
• MR-BMA confirmed left arm fat percentage as a dominant factor influencing AAM.

Conclusions:

• Body fat distribution significantly impacts age at menarche (AAM).
• Left arm fat percentage plays a crucial role in AAM.
• Further investigation into body measurements can improve understanding of pubertal development.