Anthropometric indices and bioimpedance body composition as ontogenetic indicators to describe risk of obesity

The body mass index does not distinguish body fat mass from fat-free mass and does not capture changes in these parameters. The aim of this study was to establish an association between anthropometric indexes and bioimpedance indicators with age-specific obesity on the example of male population in the Magadan oblast. To achieve it, we examined 586 males who lived in the Magadan oblast by using conventional methods for assessment of physical development. The ROC analysis was performed and the area under the ROC curve (AUC) was measured.

The analysis of the obtained research data established a significant decrease in FFMI values with age (from young males to elderly ones) together with growing FMI, FMI/FFMI ratio, total body fat and the waist-to-hip ratio. To determine an optimal BMI value as an indicator eligible to diagnose obesity, a ROC-curve was built to describe a relationship between BMI and FMI/FFMI value < 0.4 cu. It showed that when BMI ranged between 22 kg/m2 and 25.0 kg/m2 in young males, bioimpedance values corresponded to the physiological norm; in the early maturity group, the optimal BMI cut-off point for diagnosing obesity was 26.5 kg/m2; the optimal BMI range in the 2nd maturity group was 24.0–27.5 kg/m2. It is noteworthy that the ROC-analysis turned out to have no predictive significance among elderly men; this indicates that BMI is hardly eligible for being used as an indicator of obesity risk in this period of ontogenesis.

Classical BMI ranges cannot be considered a clear indicator to diagnose obesity among males in the Magadan oblast whereas indicators obtained by bioimpedance analysis (FMI/FFMI ratios) can be used as relevant indicators when assessing risks of obesity and sarcopenia in the analyzed population.