Prevalence of fibromyalgia and chronic widespread pain

Objective - To explore the prevalence of fibromyalgia and chronic widespread musculoskeletal pain In a general population using the criteria of the American College of Rheumatology from 1990. Design - Structured interview and clinical examination, including tender-point count and pain threshold measured with a dolorimeter, of subjects with suspected chronic widespread musculoskeletal pain. Setting - The general population in south-west Sweden 1995-1996. Subjects - 303 individuals with suspected chronic widespread pain were identified in a previously defined cohort containing 2425 men and women aged 20-74 years. 202 individuals were invited and 147 agreed to participate. Main outcome measures - Tenderpoint count, pain threshold and prevalence of chronic widespread pain and fibromyalgia. Results - The prevalence of fibromyalgia was estimated to 1.3% (95% CI 0.8-1.7; n = 2425) and that of all chronic widespread pain to 4.2% (95% CI 3.4-5.0; n=2425). The mean pain threshold measured with a dolorimeter was lower in subjects with chronic widespread pain (p < 0.01) and correlated with the number of tender points (r = - 0.59, p < 0.01) but could not be used to distinguish the subjects with fibromyalgia. Conclusion - Compared to other studies, fibromyalgia and chronic widespread musculoskeletal pain seemed to be relatively rare conditions in the south-west of Sweden.