Age at menarche and chronological age as explanatory factors of BMI: a cross-sectional study among Peruvian...

Age at menarche has been associated with various indicators of adolescent health, including body mass index (BMI). However, its specific contribution to BMI across different geographical contexts remains largely unexplored.

To analyze whether chronological age and age at menarche act as explanatory factors of BMI in a sample of Peruvian adolescents.

This was an explanatory study. A non-probabilistic sample of 423 adolescents from Lambayeque, Peru, was included. A structured data collection sheet was used to assess age at menarche, as well as weight and height.

The multiple regression model identified age at menarche and chronological age as significant predictors of BMI. Model 2 demonstrated a better fit (BIC = 1658 vs. BIC = 1669 in Model 1) and explained 31% of the variability in BMI (adjusted R² = 0.310, F = 96.018, p < 0.001). A negative effect of age at menarche on BMI was observed (β = -0.161, p < 0.001), indicating that earlier menarche is associated with higher BMI. Similarly, chronological age had a significant positive effect (β = 0.516, p < 0.001) and was the variable with the greatest impact on BMI.

Chronological age and age at menarche are important explanatory factors of BMI in adolescents. Earlier menarche is associated with higher BMI, underscoring the importance of considering pubertal development when evaluating nutritional status during this stage of life.