Fibromyalgia is a chronic condition that affects millions of people around the world, yet it often goes misunderstood, misdiagnosed, or entirely unrecognized. This is why when asking how common is fibromyalgia, it can be hard to get a definitive answer.
Characterized by widespread pain, fatigue, and cognitive difficulties, fibromyalgia presents unique challenges in diagnosis and management because of its complexity. But understanding the scope of fibromyalgia is a crucial step in improving care, raising awareness, and empowering those affected.
This article aims to provide a comprehensive overview of fibromyalgia’s prevalence across different demographics, explore the intricacies of its diagnosis, and compare its occurrence with other chronic pain and autoimmune conditions.
Understanding Fibromyalgia
Fibromyalgia is a chronic disorder marked by widespread pain, fatigue, and a host of other symptoms, including sleep disturbances and cognitive issues often referred to as “fibro fog.” Fibromyalgia affects approximately 2% to 4% of the global population, or 1 in every 25 people— although the estimated prevalence varies depending on the diagnostic criteria used.¹
Despite its prevalence, fibromyalgia remains a condition that is often misunderstood, partly due to the absence of clinically validated lab tests and the difficulty assessing its symptom activity, which can wax and wane. However, functional MRI (fMRI) studies have shown that brain activity in people with fibromyalgia differs from those who don’t, particularly in pain-related areas. These differences can be observed when fMRI is used to map brain activity when patients are experiencing a painful stimulus.²
In the absence of reliable and accessible lab tests, the American College of Rheumatology has developed criteria to diagnose fibromyalgia: the Widespread Pain Index (WPI) and the Symptom Severity Scale (SSS). These tests are a self-assessment for fibromyalgia that can help patients and providers understand the level of symptom activity and fibromyalgia severity.
Besides the lack of a definitive biomarker or lab test, fibromyalgia can often go undiagnosed, or take patients years to receive a diagnosis. Fibromyalgia may also be diagnosed due to several other factors:
- Lack of Awareness: Both patients and healthcare providers may lack knowledge about fibromyalgia, leading to misdiagnosis or dismissal of symptoms.
- Symptom Overlap: Symptoms common to other conditions can result in misattribution and delayed diagnosis of fibromyalgia, especially with lack of access to lab tests used to rule out other conditions.
- Gender Bias: Men may be underdiagnosed due to the misperception of fibromyalgia as applicable only to women.
Demographic Variations in Fibromyalgia Diagnosis
Fibromyalgia is significantly more prevalent in women than in men. Studies indicate that women are diagnosed at rates 3 to 7 times higher than men, with approximately 80% to 90% of fibromyalgia patients being female.³
This disparity does not mean that men do not have fibromyalgia; in a 2012 Mayo Clinic study, researchers noted that men in particular were likely to meet the diagnostic criteria but still remain undiagnosed. This discrepancy in men diagnosed with fibromyalgia may be attributed to hormonal differences, variations in pain perception, differences in how society expects men and women to respond to pain, physicians believing fibromyalgia is unusual in men, or other potential biases in diagnosis.
While fibromyalgia can affect individuals of all ages, the prevalence tends to increase with age, and the average age of diagnosis varies across studies, ranging from the late 30s to mid-50s.
How Common Is Fibromyalgia vs Other Conditions
Fibromyalgia shares symptoms with various chronic pain and autoimmune conditions, which can also complicate diagnosis, since patients may report overlapping symptoms, or have both fibromyalgia and another condition at the same time.
Osteoarthritis (OA)
Osteoarthritis affects approximately 33 million US adults, making it the most common form of arthritis and the most common rheumatic condition. OA is a degenerative joint disease characterized by the breakdown of cartilage, leading to pain and stiffness, especially in weight-bearing joints.
Unlike fibromyalgia, OA involves structural joint changes observable through imaging, and does not typically involve the fatigue or cognitive symptoms that are hallmarks of fibromyalgia. It is also about three to four times more prevalent than fibromyalgia, affecting approximately 8% of the population.
Rheumatoid Arthritis (RA)
Rheumatoid arthritis is an autoimmune disease that causes chronic inflammation of the joints, leading to pain, swelling, and potential joint deformity. Unlike fibromyalgia, RA results in joint damage that is often visible on imaging studies.
Although people may be more familiar with RA than fibromyalgia, it is actually less common. Approximately 1.3 million US adults are affected by RA, accounting for about 1% of the adult population, compared to 10 million (or about 4% of the US population) with fibromyalgia. Fibromyalgia and RA can occur together, with about 20% of RA patients also having a fibromyalgia diagnosis.⁴
Lupus
Lupus is an autoimmune condition that can affect multiple organ systems, including the joints, skin, kidneys, and nervous system. Its symptoms can mimic those of fibromyalgia, including fatigue.
However, lupus typically involves organ inflammation and damage, making it essential to get thorough clinical evaluation to differentiate among these overlapping disorders. It is also less common than fibromyalgia, affecting an estimated 204,000 Americans,
Chronic Fatigue Syndrome (CFS) / Myalgic Encephalomyelitis (ME)
Myalgic Encephalomyelitis / Chronic Fatigue Syndrome (ME/CFS) is characterized by profound fatigue, sleep disturbances, and cognitive impairments. While it shares symptoms with fibromyalgia, a hallmark of ME/CFS is post-exertional malaise—a worsening of symptoms following physical or mental activity.
Between 836,000 to 3.3 million people in the U.S. are estimated to have ME/CFS. This wide range may stem from reasons familiar to those with fibromyalgia; because there are no specific lab tests or biomarkers that can confirm a diagnosis (and because many of the symptoms can overlap with other conditions) it can be challenging to reach a diagnosis. This leaves many people undiagnosed, and makes understanding the condition’s prevalence difficult.
Summary
Understanding how common fibromyalgia is across demographics, reviewing the diagnostic criteria, and knowing how it differs from other conditions is essential for effective treatment. Increased awareness and education among both healthcare providers and patients can lead to timely diagnosis and appropriate care, with the goal of improving fibromyalgia outcomes for all those affected.
Medically reviewed by Dr. Andrea Chadwick, MD, MSc, FASA
Sources
1. Jones GT, Atzeni F, Beasley M, et al. The prevalence of fibromyalgia in the general population: a comparison of the American College of Rheumatology 1990, 2010, and modified 2010 classification criteria. Arthritis Rheumatol. 2015;67(2):568-575.
2. Staud R. Brain imaging in fibromyalgia syndrome. Clin Exp Rheumatol. 2011 Nov-Dec;29(6 Suppl 69):S109-17. Epub 2012 Jan 3. PMID: 22243558.
3. Wolfe F, Walitt B, Perrot S, Rasker JJ, Häuser W. Fibromyalgia diagnosis and biased assessment: Sex, prevalence and bias. PLoS One. 2018 Sep 13;13(9):e0203755. doi: 10.1371/journal.pone.0203755. PMID: 30212526; PMCID: PMC6136749.
4. Wolfe F, Michaud K, Busch RE, et al. Polysymptomatic Distress in Patients With Rheumatoid Arthritis: Understanding Disproportionate Response and Its Spectrum. Arthritis Care & Research 2014; 66: 1465–71.
