Relevance of body mass index and bioelectrical impedance analysis vs. deuterium dilution technique to assess excess of fat among young adults

Our study aimed to assess the nutritional status by using body composition among young Tunisian adults through three measurement methods: body mass index (BMI), bioelectrical impedance analysis (BIA) and deuterium oxide dilution technique ((H2O)-H-2) and to determine the accuracy of BMI and BIA in order to evaluate the overweight and obesity among young adults in Tunisia. Our study involved 144 young adults. Anthropometric parameters were measured. The fat mass percentage (%FM) was determined by (H2O)-H-2 and BIA techniques. The analysis of deuterium enrichment was performed using a Fourier transform infrared spectrophotometer (FTIR). According to BMI, 26.4% of subjects were overweight and 5.5% were obese. The mean of %FM estimated by BIA was significantly higher than that determined by (H2O)-H-2 (29.7 +/- 7.7 vs. 26.3 +/- 10.6, p < .0001). Consequently, the prevalence of overweight and obesity assessed by BIA was significantly higher than by (H2O)-H-2 (51.4% vs. 34%, p < .0001). Using BMI, the prevalence of overweight and obesity was similar to that estimated by (H2O)-H-2 (31.9% vs. 34%, p = 0.544). Compared to (H2O)-H-2, BIA overestimates the prevalence of overweight and obesity in young adults. On the other hand, the BMI showed an interesting correlation with the %FM determined by (H2O)-H-2.