Assessment of blood biomarkers in adolescents classified by body mass index and body fat percentage.

The study aimed to compare biomarkers in groups of adolescents classified simultaneously according to body mass index (BMI) and body fat percentage measured by air displacement plethysmography. This was a cross-sectional study with 533 adolescents 18 to 19 years of age in São Luís, Maranhão, Brazil. BMI was classified as adequate (< 25kg/m2) versus excess weight (≥ 25kg/m2). High body fat percentage was defined as ≥ 25% for males and ≥ 30% for females. The adolescents were classified in four groups: "normal weight" (adequate BMI and body fat percentage), "normal weight obese" (adequate BMI with high body fat percentage), "excess weight with adequate body fat percentage", and "excess weight with high body fat percentage". Girls showed higher proportions of "normal weight obesity" (15.6%) and "excess weight with high body fat percentage" (17.1%). "Normal weight obese" adolescents exhibited higher mean values for total cholesterol (172.5mg/dL) and LDL-cholesterol (103.5mg/dL). Those with "excess weight and high body fat percentage" showed lower mean HDL-cholesterol (43.2mg/dL) compared to the other groups, higher mean interleukin-6 (2.7pg/mL) than "normal weight" and "excess weight and adequate body fat percentage" adolescents, and higher median triglycerides (114.0mg/dL) and C-reactive protein (0.14ng/mL) than "normal weight" and "normal weight obese" adolescents. Those with "excess weight and adequate body fat percentage" exhibited the same C-reactive protein levels as those with "excess weight and high body fat percentage". Assessment of nutritional status by BMI alone is limited, since 6.8% of the adolescents presented high body fat percentage despite normal BMI, and those who were "normal weight obese" had two biomarkers that were worse than for adolescents with "excess weight and high body fat percentage".