Adipokines, Leptin/Adiponectin Ratio and C-Reactive Protein Levels in a Population with High Prevalence of Diabetes – the Brazilian Xavante Indians

The aim of this study was to evaluate serum levels of C-reactive protein (CRP), adiponectin and leptin and their relationship with categories of glucose tolerance and body mass index (BMI) in a population with high prevalence of diabetes, the Brazilian Xavante Indians. A cross-sectional study was conducted among 938 Xavante Indians aged 20 years or more, from the Sangradouro and São Marcos reservations, Mato Grosso state, Brazil. Individuals were classified into three groups according to their BMI: eutrophic (BMI < 25 kg/m2, n=138); overweight (BMI 25-29.9 kg/m2, n=323) and obese (BMI ≥ 30 kg/m2, n=477). Using the 75g oral glucose tolerance test, individuals were classified, according to the WHO 1999 criteria, as normal glucose tolerance (NGT), impaired glucose tolerance (IGT) or diabetes (DM). Prevalence rates of DM were 25.4% in the eutrophic group, 26.6% in the overweight group and 25.4% in the obese group. Geometric means with their 95% confidence intervals for C-reactive protein, adiponectin and leptin serum levels were calculated among groups according to gender, glucose tolerance and BMI. Two-way ANOVA with logarithmic transformation of data was used to test geometric mean differences among groups. Levels of CRP in the NGT group were lower in overweight women. Among the women, those with obesity and IGT or DM had higher CRP levels than those in the eutrophic or overweight groups. For all glucose tolerance categories and for both genders, adiponectin levels were lower in obese individuals, with the differences being significant for men in the NGT and IGT groups and for women in the IGT group. Leptin levels were higher in overweight and obese individuals of both genders and of all glucose tolerance categories, with the differences being significant for all, except the women in the diabetic group. Leptin/adiponectin ratios were higher in overweight and obese individuals of both genders, independent of the glucose tolerance category. These data support the fact that metabolic changes promoted by being overweight/obese and glucose tolerance abnormalities induce alterations in inflammatory mediators and hormones. The higher leptin/adiponectin ratios detected in overweight and obese Xavante Indians of both genders in the NGT group deserve further attention, in this population with high risk for diabetes, since these adipokines are significant factors in b-cell failure and the low-grade inflammation process, characteristic of obesity.