Abstract and Introduction
Aim: The aim of this study was to determine the frequency of increasing body mass index (BMI) in fibromyalgia (FM) and to understand the impact of increasing BMI on FM.
Methods: Patients with FM were divided into 3 BMI classifications: normal weight, overweight, and obese. We then sought relationships of increasing BMI to core process FM variables and symptoms and disability, as well as medical comorbidities and demographic, socioeconomic, psychiatric, and treatment data.
Results: Of 224 patients, 0.4% were underweight; 25.9%, normal weight; 29.9%, overweight; 43.8%, obese. We found no differences within groups with regard to age, gender, demographics, FM symptoms, FM impact questionnaire scores, and meeting the American College of Rheumatology 1990 criteria and FM survey criteria. Patients with FM who are obese, compared with normal-weight patients, have higher depression scores measured by Patient Health Questionnaire 9 (13.2 [6.6] vs 10.5 , P = 0.03), report increased disability by Health Assessment Questionnaire Disability Index scores (1.3 [0.6] vs 0.9 [0.6], P < 0.001), exercise less (8.4% vs 25.4%, P = 0.003), have more medical comorbidities (1.5 [1.3] vs 0.7 [0.9], P < 0.001), take more medications for FM (3.5 [2.2] vs 2.1 [1.8], P < 0.001), and report higher prevalence of abuse (48% vs 33.9%, P = 0.016) and sexual abuse (17.3% vs 6.8%, P = 0.01).
Conclusions: Compared with normal-weight patients, obese FM patients are more disabled, report more medical comorbidities, exercise less, have a higher incidence of abuse, report increased depressive symptoms, and take more medications for FM. Bivariate analysis showed association of increasing BMI with the Health Assessment Questionnaire Disability Index (not FM impact questionnaire) and depression. We confirm that the prevalence of overweight and obesity is high in FM and believe that physicians treating FM should be aware of our bivariate linear correlations and discuss weight loss with their FM patients. Even if increasing BMI is not intrinsic to FM, it contributes to poor mood and functional outcome and should be a treatment goal.
Fibromyalgia (FM) is a biopsychosocial disorder affecting between 2% and 5% of the US population, characterized by widespread pain, fatigue, poor sleep, memory and concentration impairment, and strong association with depression and other mood disorders.[1,2] High body mass index (BMI), measured as weight in kilograms divided by height in meters squared, has been associated with increased prevalence of widespread musculoskeletal pain.[4,5]
Being overwheight or obese was associated with increased risk of FM, especially among women with low levels of physical exercise. Several studies have reported high rates of obesity in FM patients[7–9] and found BMI to be associated with pain, function, fatigue, and FM impact questionnaire (FIQ) scores.[8–13] Weight loss in obese FM patients results in significant reduction in pain, tender point counts, and sensitivity, decrease in FIQ compared with baseline, and in some cases even loss of FM phenotype.[14–17] These studies imply that BMI may be a core process factor for FM.
While many studies of obesity in FM included measures of pain, fatigue, and sleep, as well as depression, anxiety, and function, very little is known about the relationship of obesity to other symptoms related to FM, such as bipolar disorder symptoms, number, and kinds of medications, comorbidities, stress, and history of abuse. Our study had the following goals: (1) to determine the prevalence of obesity in a tertiary-care center naturalistic cohort of FM patients enrolled consecutively; (2) to establish the relationships of BMI to symptoms, comorbidities, and function and mood disorders; and (3) to determine if BMI was associated with core process FM symptoms and measures.
J Clin Rheumatol. 2015;21(6):289-295. © 2015 Lippincott Williams & Wilkins