Age at Menarche and Its Association with Excess Weight and Body Fat Percentage in Girls in the Southwestern Region of the Brazilian Amazon

Study Objective: To analyze age at menarche and its association with excess weight and body fat percentage. Design: School-based cross-sectional survey. Setting: Southwestern region of the Brazilian Amazon. Participants: The sample was made up of 727 girls, in the 8- to 16-year age range, divided into 3 groups: early, normal, and late menarche, from public and private schools, selected through proportional stratified random sampling. Interventions and Main Outcome Measures: Bioimpedance was used to measure body fat percentage and body mass index, applying the Global School-Based Student Health Survey questionnaire to categorize behavior variables. Age at menarche was determined using the status quo method. Sexual maturity was assessed through self-assessment according to criteria described by Tanner. Results: Overall age at menarche was 11.52 (+/- 1.35), early 10.48 (+/- 0.78), normal 12.39 (+/- 0.50) and late 14.27 (+/- 0.51) years. Prevalence of excess weight and body fat was 28.3% (206/727) and 443% (322/727), among those with menarche. There was a positive association between excess weight and body fat with age at early menarche (P = .000 and .015). Conclusion: Age at menarche among girls from the Amazon region is similar to that of industrialized countries. Prevalence of excess weight and body fat was high, and there was evidence of an association between age with early menarche and excess weight. Trends in age at menarche and stage of sexual maturation should be monitored with related factors, to adopt obesity control strategies from an early age.