Fibromyalgia: Associations Between Fat Infiltration, Physical Capacity, and Clinical Variables

Björn Gerdle; Olof Dahlqvist Leinhard; Eva Lund; Ann Bengtsson; Peter Lundberg; Bijar Ghafouri; Mikael Fredrik Forsgren

doi:10.2147/JPR.S376590

Fibromyalgia: Associations Between Fat Infiltration, Physical Capacity, and Clinical Variables

J Pain Res. 2022 Aug 27:15:2517-2535. doi: 10.2147/JPR.S376590. eCollection 2022.

Authors

Björn Gerdle^{1

2}, Olof Dahlqvist Leinhard^{2

3

4}, Eva Lund³, Ann Bengtsson¹, Peter Lundberg^{2

3}, Bijar Ghafouri¹, Mikael Fredrik Forsgren^{2

3

4}

Affiliations

¹ Pain and Rehabilitation Centre, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, SE 581 83, Sweden.
² Centre for Medical Image Science and Visualization (CMIV), Linköping, SE 581 83, Sweden.
³ Department of Radiation Physics, and Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, SE 581 83, Sweden.
⁴ AMRA Medical AB, Linköping, Sweden.

Abstract

Background: Obesity is a risk factor for the development of fibromyalgia (FM) and generally most studies report increased Body Mass Index (BMI) in FM. Obesity in FM is associated with a worse clinical presentation. FM patients have low physical conditioning and obesity further exacerbates these aspects. Hitherto studies of FM have focused upon a surrogate for overall measure of fat content, ie, BMI. This study is motivated by that ectopic fat and adipose tissues are rarely investigated in FM including their relationships to physical capacity variables. Moreover, their relationships to clinical variables including are not known. Aims were to 1) compare body composition between FM and healthy controls and 2) investigate if significant associations exist between body composition and physical capacity aspects and important clinical variables.

Methods: FM patients (n = 32) and healthy controls (CON; n = 30) underwent a clinical examination that included pressure pain thresholds and physical tests. They completed a health questionnaire and participated in whole-body magnetic resonance imaging (MRI) to determine body composition aspects.

Results: Abdominal adipose tissues, muscle fat, and BMI were significantly higher in FM, whereas muscle volumes of quadriceps were smaller. Physical capacity variables correlated negatively with body composition variables in FM. Both body composition and physical capacity variables were significant regressors of group belonging; the physical capacity variables alone showed stronger relationships with group membership. A mix of body composition variables and physical capacity variables were significant regressors of pain intensity and impact in FM. Body composition variables were the strongest regressors of blood pressures, which were increased in FM.

Conclusion: Obesity has a negative influence on FM symptomatology and increases the risk for other serious conditions. Hence, obesity, dietary habits, and physical activity should be considered when developing clinical management plans for patients with FM.

Keywords: body composition; body mass index; chronic pain; fat; fibromyalgia; magnetic resonance imaging; muscle; physical fitness.

Grants and funding

This research was funded by grants from the Swedish Research Council (grant number: 2018-02470).