RESUMEN
OBJECTIVES: To identify trends in percentage body fat (PBF) in adolescents to determine gender-specific classification thresholds for being overweight and obese. METHODS: A cross-sectional study of 899 adolescents (11 to 14.5 years) from Hanoi and Nam Dinh was conducted in Vietnam. PBF, subcutaneous fat and percentage of lean mass were measured directly using OMRON HBF 375 scales to measure bioelectrical impedance. RESULTS: PBF decreased in boys with increasing age (p < 0.001). The difference in PBF between boys and girls, significantly increased with age after 12.5 years (p < 0.001). There was a stronger correlation between PBF and fat content (Pearson's r = 0.860, p < 0.0001) than that between (BMI) and fat content (Pearson's r = 0.521, p < 0.0001). The prevalence of being overweight or obese in girls was similar when determined by PBF or BMI. Hanoi had higher rates of adolescents being overweight or obese compared with Nam Dinh. CONCLUSION: PBF provides a more accurate body assessment for being overweight or obese in adolescents compared with BMI.