Relationship of age at menarche and serum leptin with the metabolically unhealthy phenotype in adolescents.

Objective: to analyze the relationship of age at menarche and leptin with the metabolically healthy (MH) and metabolically unhealthy (MUH) phenotypes in adolescent girls in different body mass index (BMI) categories. Method: an observational and cross-sectional study consisting of 139 female adolescents attended to at the Adolescent Reference Center in Macaé, Rio de Janeiro. Menarche was classified as early (EM) when the first menstruation occurred at or before 11 years of age; normal menarche (NM) was categorized at ages 12 to 14; menarche was considered late (LM) when it occurred at age 15 or older. The factors required to ascertain the subjects' phenotype, as well as their leptin levels, weight, and height, were measured and their BMIs were calculated. The girls were classified as MH or MUH based on the NCEP-ATP III criteria as adapted for children and adolescents. Results: 82 % (n = 114) of the girls were classified as MH and 18 % (n = 25) as MUH. Mean age at menarche was 11.79 ± 1.39 years. There was a higher prevalence of MUH amongst the girls who had EM (p = 0.04). A higher inadequacy of serum leptin concentrations was found in girls who had EM (p = 0.05) and in those classified as MUH (p = 0.01). The adolescents who were severely obese exhibited inadequate leptin levels (p < 0.01) and had gone through EM (p = 0.02). A total of 8.1 % (n = 7) of the normal-weight girls were classified as MUH, and 29.4 % (n = 5) of those who were severely obese were classified as MH (p < 0.01). Conclusion: early menarche and high serum leptin concentrations are related with the MUH phenotype in adolescent girls in different BMI categories.