Body mass index, waist circumference and triceps skinfold for prediction of lipid abnormalities in children

Abstract

Introduction: Investigation of lipid levels is carried out by laboratory analyses, however there are anthropometric methods (noninvasive and of low cost) such as body mass index (BMI), waist circumference (Wcir) and triceps skin fold (TR) that can be used as markers of dyslipidemia. Objective: To suggest cutoff points for these anthropometric measurements and to test whether the reference values recommended by the International Obesity Task Force (IOTF) and Conde and Monteiro (C&M) can be used to screen schoolchildren aged 10 to 12 years for lipid abnormalities. Methodology: The BMI, Wcir and TR were determined for 374 schoolchildren from the public education system of Santa Maria, RS, Brazil. Subjects were selected by stratification by public or private school and by sex. Laboratory analysis (gold standard) was used to determine Total Cholesterol (TC), Low Density Lipoprotein (LDL-C), High Density Lipoprotein (HDL-C) and Triglycerides (TG). Analysis employed descriptive statistics, calculations of sensitivity, specificity and negative and positive predictive values, and area under the ROC curve with a 95% confidence interval. Results: The prevalence rates of overweight calculated by the two different methods were statistically different, IOTF (24.7%) and C&M (28.6%). Sensitivity (33% - 83%) and specificity (62% - 80%) varied widely between the cutoff points employed to indicate dyslipidemia. The anthropometric variables only exhibited diagnostic capacity for TG among the girls and for CT and LDL-C for the boys. Conclusions: The cutoff points proposed by the IOTF and by C&M can be used to screen for elevated CT and LDL-C among males. Either the IOTF or the C&M cutoffs can be used to identify people without dyslipidemia, since both have high specificity. A BMI of 19.3kg.m-2 is a diagnostic value for abnormal TG levels in females and for abnormal CT and LDL-C among males. Elevated concentrations of CT and LDL-C can also bediagnosed in boys using cut-off values of WCir > 65.7 cm and TSF> 21.0mm.