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.