PP122 - MUSCLE-TO-BONE RATIO AND STRENGTH IN YOUTH: A CROSS-SECTIONAL ANALYSIS FROM NHANES 2011-2014.

PP122

MUSCLE-TO-BONE RATIO AND STRENGTH IN YOUTH: A CROSS-SECTIONAL ANALYSIS FROM NHANES 2011-2014.

M. Truchon^1,*, S. Lefevre¹, J. Smit¹, L. Duval¹, S. Eftekhariranjbar^2,3, L. M. Donini³, E. Poggiogalle³, P. Noirez¹

¹Faculty of Sport Sciences, Laboratory Performance, Santé, Métrologie, Société (PSMS), Université de Reims Champagne-Ardenne, Reims, France, ²Department of Medicine and Aging Sciences, University “G.D’Annunzio” of Chieti-Pescara, Chieti, ³Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy

Rationale: Muscle-to-Bone ratio (MtB), defined as the lean mass (LM) to bone mineral content (BMC) ratio measured by dual-energy X-ray absorptiometry (DXA), is an emerging indicator of the muscle-bone relationship. Relative Handgrip Strength (RHS), defined as handgrip strength (HS) normalised to MtB, may index muscle quality. This study examined arm and leg MtB, HS and RHS.

Methods: This cross-sectional study used NHANES 2011-2014 data (n=5146; 2704 males, 2442 females; mean age=16.2±6.0 years, range: 8-29 years) with complete DXA scans. MtB was calculated as LM/BMC. Participants were categorised by BMI and %BF using age- and sex-specific thresholds. Kruskal-Wallis tests with Dunn’s post hoc, two-way ANOVAs, and univariate and multivariate odds ratios (OR) were performed. 

Results: Males had higher MtB than females for both arms (18.9±2.4 vs 16.2±2.8; p<.0001) and legs (19.5±2.5 vs 18.3±2.6; p<.0001), with 5.8-fold higher odds of elevated arm MtB (OR=5.8[5.1-6.5]; p<0.0001). A non-linear age-MtB trajectory by sex was observed (arms: R²=.41; p<.0001; legs: R²=.07; p<.0001). BMI-Obesity was associated with higher MtB (arms: OR=4.6[3.8-5.5]; legs: OR=12.9[10.7-15.6]; p<.0001), attenuated by %BF (arms: OR=1.7[1.4-1.9]; p<0.001; legs: OR=2.7[2.4-3.2]; p<.0001). Males showed higher RHS than females (1.87±0.86 vs 1.59±0.59; p<.0001). RHS increased with age (8-12yrs: 0.97±0.32; 13-19yrs: 1.99±0.52; 20-29yrs: 2.36±0.59; all p<.0001). BMI groups showed higher RHS in overweight/obese vs normal; %BF showed an inverse gradient (Normal > Overweight > Obese; all p<.0001).

Conclusion: As reported by Czeck et al. (2023), obesity was associated with higher MtB, suggesting BMI partially reflects LM rather than adiposity. RHS increased with age and differed by sex. %BF provided finer discrimination for MtB and RHS, supporting %BF-MtB combined assessment during growth.

References: Czeck, M. A. et al. (2023). https://doi.org/10.1016/j.jocd.2023.02.001

Disclosure of Interest: None declared