Work

Skeletal Muscle Fat and Its Association With Physical Function in Rheumatoid Arthritis

Year: 2017

Type: article

Abstract: Objective To characterize skeletal muscle fat (SMF), intermuscular adipose tissue (IMAT), and subcutaneous adipose tissue (SAT) in individuals with rheumatoid arthritis (RA), and assess the associations between these fat depots and physical function and physical activity. Methods In a cross‐sectional analysis from an RA cohort, SMF, IMAT, and SAT were measured using computed tomography imaging of the midthigh cross‐sectional region. Physical function was measured using the Health Assessment Questionnaire (HAQ) and a battery of performance‐based tests that included quadriceps muscle strength, gait speed, repeated chair‐stands, stair ascent, and single‐leg stance. Physical activity was assessed using an activity monitor. Associations between SMF, IMAT, and SAT and physical function and activity were assessed by multiple linear regression models adjusted for potential confounders such as age, sex, body mass index (BMI), muscle area, and muscle strength. Results Sixty subjects with RA (82% female, mean ± SD age 59 ± 10 years, mean ± SD BMI 31.79 ± 7.16 kg/m2) were included. In the adjusted models, lower SMF was associated with greater gait speed, single‐leg stance, quadriceps strength, and physical activity, and less disability (R2Δ range 0.06–0.25; P < 0.05), whereas IMAT was not associated with physical function or physical activity and SAT was negatively associated with disability (HAQ) (R2Δ = 0.13; P < 0.05) and weakly but positively associated with muscle strength (R2Δ = 0.023; P < 0.05). Conclusion Fat infiltration within the muscle seems to independently contribute to low physical function and physical activity, contrary to IMAT or SAT accumulation. Longitudinal studies are necessary to confirm the impact of SMF on disability and health promotion in persons with RA.

Source: Arthritis Care & Research

DOI: 10.1002/acr.23278

Authors: Samannaaz S. Khoja, Charity G. Moore, Bret H. Goodpaster, Anthony Delitto, Sara R. Piva

Institutions: University of Pittsburgh, Carolinas Healthcare System, Translational Research Institute for Metabolism and Diabetes

Language: English

Topic: Rheumatoid Arthritis Research and Therapies

Subfield: Rheumatology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: green

Funders: University of Pittsburgh, National Institutes of Health, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Center for Medical Rehabilitation Research