Body fat assessment by bioelectrical impedance and its correlation with different anatomical sites used in the measurement of waist circumference in children.

OBJECTIVE: To compare the different anatomical sites used in the measurement of waist circumference, as well as the effectiveness of these landmarks to predict the percentage of body fat by tetrapolar bioelectrical impedance analysis. METHODS: We evaluated 205 children from 6 to 9 years of age of both sexes. Data on weight, height and waist circumference were collected at three different sites: at the lower abdominal curvature, above the navel and at the midpoint between the last rib and the iliac crest. Nutritional status was assessed through the body mass index (BMI)/age as recommended by the World Health Organization. RESULTS: The sample was considered homogeneous in terms of sex, and the mean age was 7.2+/-1.2 years. Regarding nutritional status, 6.3% of the children had low weight, 75.1% were eutrophic, 7.3% were overweight, and 11.2% were obese. Among males, there was no statistical difference between the different sites of measurement; in females, the measurement above the navel was statistically higher. In the correlation analysis, the midpoint measurement showed the best correlation with percentage of body fat, with values of 0.50 in boys and 0.62 in girls. CONCLUSION: Waist circumference measured at the midpoint between the last rib and the iliac crest presented the best correlation with percentage of body fat.