title: Age of menarche and nutritional status of indigenous and non-indigenous adolescents in the Araucanía Region of Chile.
abstract: BACKGROUND
  Early onset of menarche has been linked to prevalence of obesity; however, this may differ for indigenous females.
  
  
  OBJECTIVE
  To analyse the relationship between age of menarche and nutritional status among indigenous and non-indigenous girls.
  
  
  METHODS
  The design of this study was cross-sectional. Date of menarche was determined through interviews, and all responses were confirmed by the girls' mothers. A total of 8504 adolescents were screened for recent menarche. One hundred and thirty-one girls of Mapuche (indigenous) and 143 girls of Chilean-Spanish background were identified and evaluated by anthropometric measurements.
  
  
  RESULTS
  Median age of menarche was 150 months, interquartile range (IR) 143-157 in indigenous, and 145.5 months, IR 139-153 in non-indigenous girls (p = 0.04). The indigenous females showed a higher prevalence of overweight (36.4% vs 23.1%), although the frequency of obesity was similar (16.8% vs 16.3%). For indigenous girls, age of menarche was delayed by 2.69 months (confidence intervals (CI) -0.38 to 5.77). It was observed that girls with overweight experienced age of menarche 7.59 months earlier than those with normal weight, CI -10.78 to -4.41. In the analysis of obesity, the effect on age of menarche was similar, with onset 7.53 months earlier than for the normal weight, CI -11.34 to -3.72.
  
  
  CONCLUSIONS
  Age of menarche is younger than has been previously reported and occurs earlier in girls with overweight and obesity, while being indigenous was not related.
authors.affiliation: Department of Nutrition, Faculty of Medicine, University of Chile, Santiago, Chile. hamigo@med.uchile.cl
authors.forename: Hugo
authors.initials: H
authors.lastname: Amigo
authors.forename: Patricia
authors.initials: P
authors.lastname: Bustos
authors.forename: Santiago
authors.initials: S
authors.lastname: Muzzo
authors.forename: Ana María
authors.initials: AM
authors.lastname: Alarcón
authors.forename: Sergio
authors.initials: S
authors.lastname: Muñoz
mesh_terms: D000293:Adolescent; D000375:Aging / Q000502:physiology*; D002648:Child; D002677:Chile; D004522:Educational Status; D005260:Female; D006801:Humans; D008572:Menarche / Q000502:physiology*; D009765:Obesity / Q000503:physiopathology; D044382:Population Groups