Body mass index and leptin levels in three Chilean aboriginal populations

Background: Although there is a clear relationship between body mass index aid leptin levels, few authors have addressed the possible influence ce of ethnic factors on these levels. Aim: To measure serum leptin in three diffe rent Chilean aboriginal populations. Subjects and methods: Fasting serum le ptin and insulin levels were measured radioimmunoassay in 345 rural mapuche individuals, 247 rural aymara subjects and 162 urban mapuche subjects. A b ody mass index of 27.5 kg/m(2) was used as cutoff point to classify study s ubjects. Results: Among the three ethnic groups, women had serum leptin lev els three times higher than men. Bz all three ethnic groups, there was a si gnificant association between leptin levels, body mass index and gender (r( 2) = 0.32 and 0.5 P <0.001, in rural mapuche, r(2) = 0.32 and 0.5 P <0.001, in aymara and r(2) = 0.24 and 0.49, P <0.001 in urban mapuche populations) . No differences in leptin levels were observed for the interaction between age and insulin. The increments per quartile ii leptin levels were lower a mong mapuche than aymara individuals. Conclusions: Rural mapuche individual s have a high frequency of obesity. However their leptin levels are lower t han those of aymara or urban mapuche populations. The higher leptin levels observed in urban mapuche subjects could be due to environment influences.