Dependence between Age at Menarche, Body Composition and Selected Somatic Indices

Area of Science:

• Human Physiology
• Pediatric Endocrinology
• Nutritional Science

Background:

• Menarche onset is influenced by various factors, including body composition and somatic indices.
• Understanding these associations is crucial for assessing pubertal development in adolescent girls.
• Previous studies suggest a link between body fat and menarche, but data from Tanzanian girls requires specific analysis.

Purpose of the Study:

• To analyze the age at menarche in Tanzanian girls.
• To investigate associations between menarcheal age and body composition (body H2O, fat, muscle).
• To examine relationships with somatic indices like Body Mass Index (BMI), Waist-to-Hip Ratio (WHR), and Waist-to-Height Ratio (WHtR).

Main Methods:

• Cross-sectional study involving 97 Tanzanian girls (71 post-menarche, 26 pre-menarche).
• Measurements included height, weight, waist, and hip circumferences.
• Body composition analyzed for H2O, fat, and muscle percentages; BMI, WHR, and WHtR calculated.

Main Results:

• Average age at menarche was 14.29 years (recall) and 15.92 years (calendar age).
• Post-menarcheal girls had a lower prevalence of body weight below 48kg (32.39%) compared to pre-menarcheal girls (57.69%).
• Higher body fat percentage (≥22%) was observed in 97.18% of post-menarcheal girls versus 88.46% of pre-menarcheal girls; BMI indicated healthy weight in most girls across both groups.

Conclusions:

• Menarche onset in Tanzanian girls does not appear to be strictly dependent on reaching a critical threshold of body weight or specific body composition.
• While body fat percentage was higher in post-menarcheal girls, significant differences in BMI, WHR, and WHtR were not observed, suggesting complex regulatory mechanisms.
• Further research is needed to explore other contributing factors to menarcheal timing in this population.