Association between segmental body composition and bone mineral density in US adults: results from the NHANES (2011-2018)

OBJECTIVE

The association between segmental body composition and bone mineral density (BMD) remains uncertain. The primary aim of this cross-sectional investigation was to elucidate the connection between segmental body composition and BMD within the United States adult population.

METHODS

We selected a cohort of 10,096 individuals from the National Health and Nutrition Examination Survey (NHANES) database, with a mean age of 39 years and a mean BMI of 28.5 kg/m². The parameter of segmental body composition was achieved by quantifying body fat and lean mass percentages across various anatomical regions, including the torso, Android, Gynoid, arms and legs. We conducted a weighted multivariate linear regression analysis to investigate the association between segmental body composition and total BMD. Additionally, subgroup analysis was performed based on age and gender.

RESULTS

We found an inverse association between fat proportion in each anatomical region and total BMD, with the arm and leg regions demonstrating the most significant negative correlation. Conversely, a positive correlation was observed between lean mass and BMD across all anatomical regions. These associations remained consistent in subgroup analyses.

CONCLUSION

Our investigation revealed a negative association between adipose levels in various anatomical regions and BMD among Americans aged 20 to 59. Importantly, higher fat proportion in the extremities exerted the most deleterious impact on BMD. Furthermore, an increase in lean mass within each anatomical region was ascertained to confer a positive effect on bone health. Consequently, the evaluation of segmental body composition is well-positioned to predict bone health status.

Segmental body composition estimated by specific BIVA and dual-energy X-ray absorptiometry

AIMS

The aim of this study was to analyse the association between specific bioelectric impedance vector analysis (BIVA) and dual-energy X-ray absorptiometry (DXA) to assess segmental body composition using DXA as the reference technique.

METHODS

The sample comprised 50 young active students who practised or played different sports (25 men, age: 24.37 ± 4.79 y; 25 women, age: 24.32 ± 4.43 y) from the National Institute of Physical Education of Catalonia (INEFC). Anthropometric data (height, weight, arm, waist, and calf circumferences) and bioelectrical measurements (R, ohm; Xc, ohm) were recorded. Body composition was analysed with specific BIVA. DXA was used as the reference method to assess body composition of the whole-body, the trunk, and the limbs. The percentage of fat mass (%FM_DXA) and fat-free mass index (FFMI_DXA = FFM/length²) were calculated. The agreement between specific BIVA and DXA was evaluated by a depth-depth analysis, two-way ANOVA, and Pearson's correlations.

RESULTS

The depth-depth analysis showed a good agreement between DXA and BIVA (F = 14.89, p < 0.001) in both sexes and all body segments. Specific vector length (Zsp; i.e. indicative of %FM) was correlated with %FM_DXA in the whole body and all body segments, and the phase angle was correlated with FFMI_DXA, with he trunk in women as the only exception. Specific BIVA demonstrated to balance the effect of body size on bioelectrical measurements in both whole and segmental approaches.

CONCLUSIONS

Segmental specific BIVA and DXA provided a consistent evaluation of body composition in both sexes, of the whole body and each body segment. The indices %FM and FFMI obtained with DXA were correlated to vector length and phase angle in each segment, respectively. Specific BIVA represents a promising technique for monitoring segmental body composition changes in sport science and clinical applications.