From BMI to TMI: revisiting adiposity and fitness assessment in young active adults through a historical and contemporary lens.

TMI showed a stronger positive correlation with body fat percentage than BMI in physically active young adults.

• TMI correlation with body fat percentage: r = 0.50, p < 0.001
• BMI correlation with body fat percentage: r = 0.38, p = 0.003
• Body fat percentage was derived from whole-body bioimpedance analysis
• Sample consisted of 59 participants (male = 37, female = 22; age 22.63 ± 2.29 years)

BMI was positively correlated with hemoglobin and hematocrit in physically active young adults.

• BMI correlation with hemoglobin (HGB): r = 0.32, p = 0.013
• BMI correlation with hematocrit (HCT): r = 0.26, p = 0.046
• These associations were not observed for TMI
• Blood markers were obtained via venous blood sampling

Both BMI and TMI were negatively correlated with neutrophil-to-lymphocyte ratio (NLR).

• BMI correlation with NLR: ρ = -0.27, p = 0.041
• TMI correlation with NLR: ρ = -0.27, p = 0.039
• BMI was also negatively correlated with platelet-to-lymphocyte ratio (PLR): r = -0.30, p = 0.022
• TMI did not show a significant correlation with PLR

In the multivariable regression model, hematocrit was a significant negative predictor of body fat percentage, while TMI showed a positive but marginally non-significant association.

• HCT was a significant negative predictor of adiposity: β = -0.34, p = 0.021
• TMI showed a positive but marginally non-significant association with adiposity: β = 0.25, p = 0.073
• Predictors in the model included BMI, TMI, HGB, HCT, NLR, and PLR
• Assumptions of the regression model and multicollinearity were reported as acceptable

The study employed a cross-sectional design with physically active young adults meeting WHO/ACSM physical activity guidelines.

• Physical activity status defined as ≥150 min·week⁻¹ of moderate-to-vigorous activity per WHO/ACSM guidelines
• Sample size was n = 59 (37 males, 22 females), mean age 22.63 ± 2.29 years
• Participants underwent anthropometry, whole-body bioimpedance analysis, and venous blood sampling
• Statistical significance threshold was set at α = 0.05; normality assumptions were checked before selecting correlations and regression approaches

Traditional BMI may misclassify physically active individuals with high lean mass, motivating examination of the triponderal mass index (TMI) as an alternative adiposity measure.

• TMI has emerged as a potentially more accurate alternative to BMI for adiposity assessment
• Evidence for TMI's utility in physically active populations was described as limited prior to this study
• The concern with BMI is that it does not distinguish between fat mass and lean mass
• This historical and contemporary review framing was central to the study's rationale