[Nutritional status in telarche and menarche in indigenous and non indigenous Chilean adolescents].

A compensatory effect of chronic malnutrition that influences excess of weight has been reported. This effect would be more evident in indigenous populations. The aim of this study was to find out the association between ethnic group (mapuche) and body composition in the telarche and menarche of indigenous and non indigenous adolescents. This was a cross sectional design. At the beginning, a screening of 10,121 girls from 168 schools in the Araucania Region, Chile was done. 230 adolescent in telarche (grade II of the development of the mammary gland): 112 indigenous and 118 non indigenous and 239 in menarche (113 indigenous and 126 non indigenous) were identified. Body mass index (BMI), waist circumference (WC), lean mass (LM) and fat mass (FM) were evaluated. BMI, WC and LM were higher in the indigenous adolescent in telarche. For those with menarche, the differences decreased, reaching with higher values for indigenous girls only in BMI and FM (p=0,04 and 0,02, respectively). Belonging to the indigenous group increased the BMI in 0.37 z scores in telarche (95% CI: 0,17-0,58) and 0,44 in menarche (95% CI:0,18-0,70). Being mapuche was also associated to higher WC: 3.33 cm (CI 1,67 - 4,99) in telarche and 3,17 cm (CI 0,73-5,60) in menarche and to higher lean mass only for those adolescents with telarche (1,3 CI: 0,11-2,43) and to fat mass only for those with menarche (2,4 CI: 1,02-3,77). The body composition indicators in indigenous adolescents are of concern and underscores the importance of programs to promote healthy lifestyles that take into account resources from the indigenous communities.