Menarche and critical weight hypothesis revisted in Sagamu, Southwest Nigeria
Background: Menarche is the age at first menstruation in a girl child. Values vary globally, influenced by factors that included gene, race, industrialization, and nutrition. Attainment of a critical weight before menarche had been hypothesized and found applicable in studies from different countries, Nigeria inclusive.
Objective: To re-evaluate age of menarche in our practice using the prospective method of evaluation and establish if the critical weight hypothesis is applicable in our setting
Design: Cohort of 63 secondary schoolgirls were longitudinally followed up for twenty-four months to obtain accurate age, weight and height at point of menarche.
Results: Mean age at menarche in this study was 13.65(±1.26) years and the range was between 10 and 16 years. Similarly, the means and ranges for weight and height were 45.9(±0.90) [43.8-48.1] kilograms and 156.16(±1.77) [149-161]. Using logistic regression correlation, while accounting for other variables, demonstrated stronger correlation between age at menarche and weight than menarche and height.
Conclusion: Study demonstrated leveling off of menarche at between 13 and 14 years in our practice and agreed with hypothesis of critical weight of between 45 and 46kg. The heights of our girls at menarche compared with global average of 155 and 156cm.