Use of factor analysis to model relationships between bone mass and physical, dietary, and metabolic factors in frail and pre-frail older adults

Esteves, Gabriel P, Swinton, Paul, Sale, Craig ORCID: https://orcid.org/0000-0002-5816-4169, Gualano, Bruno, Roschel, Hamilton and Dolan, Eimear (2023) Use of factor analysis to model relationships between bone mass and physical, dietary, and metabolic factors in frail and pre-frail older adults. Journal of Applied Physiology, 135 (1). pp. 146-153. ISSN 8750-7587

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Abstract

Bone mass and quality declines with age, and can culminate in osteoporosis and increased fracture risk. This investigation modelled associations between bone and physical, dietary, and metabolic factors in a group of 200 pre-frail/frail older adults using factor analysis and structural equation modelling (SEM). Exploratory (EFA) and confirmatory factor analysis (CFA) were conducted to compose factors and to assess their robustness. SEM was used to quantify associations between bone and the other factors. Factors arising from EFA and CFA were: Bone (whole body, lumbar and femur bone mineral density and trabecular bone score; good fit), Body composition-lean (lean mass, body mass, vastus lateralis and femoral cross-sectional area; good fit), Body composition-fat (total fat mass, gynoid, android and visceral fat; acceptable fit), Strength (bench and leg press, handgrip and knee extension peak torque; good fit), Dietary intake (kilocalories, carbohydrate, protein and fat; acceptable fit), and metabolic status (cortisol, IGF1, GH and free testosterone; poor fit). SEM using isolated factors showed that body composition (lean) (β=0.66, p<0.001), body composition (fat) (β=0.36, p<0.001) and strength (β=0.74, p<0.001) positively associated with bone. Dietary intake relative to body mass negatively associated with bone (β=-0.28, p=0.001), whereas in absolute terms it showed no association (β=0.01, p=0.911). In a multivariable model, only strength (β=0.38, p=0.023) and body composition (lean) (β=0.34, p=0.045) associated with bone. Resistance training programs that focus on improving lean mass and strength in older individuals may benefit bone in this population.