Early menarche and current nutritional status of the adolescents from a birth cohort.

Objective: To assess the association between early menarche and the nutritional status of the adolescents from the RPS - Brazilian Birth Cohorts Consortium (Ribeirão Preto, Pelotas and São Luís) birth cohort in São Luís, Maranhão.

Methods: A longitudinal study with data from the first and third follow-up of the cohort was conducted. A total of 1,225 adolescents aged 18 to 19 years were surveyed and analyzed for age at menarche, defined as early if <12 years old, and for the variable body mass index (BMI) for age, classified into z-scores by sex, as underweight (z-score <-2), adequate weight (z-score ≥-2 and ≤+1), and excess weight (z-score >+1). Directed acyclic graphs were constructed using the DAGitty^® program to select confounding variables for adjustment. Multinomial logistic regression adjusted for confounding variables such as parental obesity (yes or no), skin color (white or non-white), and birth weight (low birth weight, adequate birth weight, and high birth weight) was used to assess the association between early menarche and nutritional status. Statistical analyses were performed using STATA 15.0 software.

Results: Out of the 1,225 adolescents investigated, 32.6% experienced early menarche, and the majority had a BMI appropriate for their age (75.2%). Among adolescents with early menarche, 28.3% were classified as excess weight for their age. Multinomial logistic regression revealed an association between early menarche and excess weight (OR = 1.80; 95% CI = 1.21-2.69; p-value = 0.004).

Conclusion: Thus, the results indicate an association between the occurrence of early menarche and excess weight in the investigated adolescents.