Bioimpedance assessment of the Heath-Carter somatotype: updated formulas and software

Introduction. In our recent publications, we have established the possibility of using bioimpedance measurements to assess the Heath-Carter somatotype in different age groups. We aimed to develop unified formulas for calculating the somatotype in children and adults, evaluate their accuracy based on age and body mass index, and improve the somatotyping protocol in bioimpedance analyzer software. Materials and methods. Data from our previous studies on comprehensive anthropometry and related BIA measurements were considered. The main group consisted of ethnic Russians aged 7-59, who were examined in Moscow, Arkhangelsk, Arkhangelsk Region, Elista, and Samara (N=4,296). The comparison group 1 included ethnic Russians aged 16-86 from the Krasnoyarsk Region (N=3,954). The comparison group 2 consisted of ethnic Kalmyks aged 8-25 from Elista (N=940). Using the data of the main group, bioimpedance predictive formulas for Endomorphy (ENDOBIA) and Mesomorphy (MESOBIA) ratings were obtained. We evaluated their accuracy in different subgroups of the main group and the comparison groups. Results. The obtained formulas were as follows: ENDOBIA = -3,411.8/R50 + 0.942´BMI – 0.00938´BMI2 – 0.0235´Ht – 0.28´Sex + 0.034´Age – 2.69 (N=4,296; R2=0.84; SEE=0.76); MESOBIA = 1,531.8/R50 + 0.302´BMI – 0.0529´Ht + 0.57´Sex – 0.032´Age + 4.52 (N=4,296; R2=0.87; SEE=0.48). These were relatively accurate for the age range 7-40 years for males and 7-59 years for females, but less accurate outside these age ranges or at high BMI values. Based on this, we also suggested formulas for obese people: ENDOBIA = -2,569/R50 + 0.854´BMI – 0.0087´BMI2 – 0.0263´Ht – 0.032´Sex + 0.018´Age – 1.60 (N=296; R2=0.69; SEE=0.87); MESOBIA = 1,567/R50 + 0.55´BMI – 0.00512´BMI2 – 0.0524´Ht + 0.42´Sex – 0.035´Age + 1.66 (N=296; R2=0.62; SEE=0.64). The formulas were integrated into the ABC-02 'Medas' (SRC Medas, Russia) BIA instrument software. Conclusions. Our findings expand the possibilities for assessing the somatotype and studying its variability. Using uniform calculation formulas for children and adults will help improve comparability of estimates and validity of comparisons. © 2025. This work is licensed under a CC BY 4.0 license