Association between body mass index, bone bending strength, and BMD in young sedentary women

A Auslander; M T C Liang; J Gavin; E Jo; J Rocha-Rangel; J-H Lin; Y-L Kwoh; S B Arnaud

doi:10.1007/s00198-021-06201-0

Association between body mass index, bone bending strength, and BMD in young sedentary women

Osteoporos Int. 2022 Mar;33(3):673-683. doi: 10.1007/s00198-021-06201-0. Epub 2021 Oct 16.

Authors

A Auslander¹, M T C Liang², J Gavin¹, E Jo¹, J Rocha-Rangel¹, J-H Lin³, Y-L Kwoh¹, S B Arnaud⁴

Affiliations

¹ Musculoskeletal Research Laboratory, Department of Kinesiology and Health Promotion, California State Polytechnic University, 3801 West Temple Avenue, Pomona, CA, 91765, USA.
² Musculoskeletal Research Laboratory, Department of Kinesiology and Health Promotion, California State Polytechnic University, 3801 West Temple Avenue, Pomona, CA, 91765, USA. mtcliang@cpp.edu.
³ Department of Physical Education, National Pingtung University, Pingtung, Taiwan.
⁴ Life Science Division, NASA Ames Research Center, Moffett Field, Santa Clara, CA, USA.

PMID: 34655302
DOI: 10.1007/s00198-021-06201-0

Abstract

The rationale was to determine whether body mass index (BMI) is a predictor of bone bending strength and bone mineral density (BMD) in young sedentary women. Results show that BMI is not a predictor of bone bending strength and that young women with low BMI also have low BMD.

Introduction: The purpose of this study was to determine whether body mass index (BMI) is a predictor of tibial or ulnar bending strength and bone mineral density (BMD) in sedentary women.

Methods: Sedentary women (n = 34), age 19-27 years, with low BMI (LBMI < 18.5 kg/m², n = 16), and normal or high BMI (NHBMI between 18.5 and 29.9 kg/m², n = 18) participated as study subjects. Study outcomes included tibial and ulnar bending strength (EI in Nm²) using a non-invasive mechanical response tissue analyzer (MRTA); BMD and bone mineral content (BMC) of the whole body (WB), femoral neck (FN), total hip (TH), lumbar spine 1-4 (LS1-4), and ulna; and bone turnover biomarkers.

Results: The LBMI group have lower (p < 0.01) body weight [group difference (Δ) = 32.0%], lean mass (LM) (Δ = 23.1%), fat mass (FM) (Δ = 77.2%), and tibial bending strength (Δ = 22.0%), compared to the NHBMI. The LBMI group also have lower (all p < 0.025) BMC in WB (Δ = 19.9%), FN (Δ = 20.1%) and TH (Δ = 19.0%), compared to the NHMBI, not in BMD results. Multivariate regression analysis shows that significant predictors of tibial bending strength are tibia length (adjusted R² = .341), age (adjusted R² = .489), ulna BMD (adjusted R² = .536), and LM (adjusted R² = .580). BMI was positively correlated with tibial EI (p < 0.05), height, weight, FM, LM, body fat% (all p < 0.01), and BMD of WB, FN, TH, and LS 1-4 (p < 0.05 or < 0.01).

Conclusions: Our results show that BMI is not a significant predictor of tibial or ulnar bending strength in young sedentary women.

Keywords: Bone mineral content; Bone turnover biomarkers; Dual-energy X-ray absorptiometry; Fat mass; Lean mass; Mechanical response tissue analyzer.

MeSH terms

Absorptiometry, Photon
Adult
Body Composition*
Body Mass Index
Bone Density*
Female
Femur Neck
Humans
Young Adult