Sleep problems and risk of fibromyalgia: longitudinal data on an adult female population in Norway.

OBJECTIVE Sleep problems are common among patients with fibromyalgia (FM). However, it is not known whether poor sleep is a contributing factor in FM or a consequence of the illness. The aim of the current study was to prospectively investigate the association between self-reported sleep problems and risk of FM among adult women. METHODS We longitudinally studied 12,350 women who did not have FM, musculoskeletal pain, or physical impairments at baseline (1984-1986). A generalized linear model was used to calculate the adjusted relative risk (RR) of FM at followup in 1995-1997. RESULTS Incident FM was reported by 327 women at followup. A dose-dependent association was found between sleep problems and risk of FM (P for trend<0.001), with an adjusted RR of 3.43 (95% confidence interval [95% CI] 2.26-5.19) among women who reported having sleep problems often or always, compared to women who never experienced sleep problems. Age-stratified analysis showed that women age≥45 years who reported having sleep problems often or always had an adjusted RR of 5.41 (95% CI 2.65-11.05), whereas the corresponding RR for women ages 20-44 years who reported having sleep problems often or always was 2.98 (95% CI 1.76-5.05). CONCLUSION These prospective data indicate a strong dose-dependent association between sleep problems and risk of FM. The association is somewhat, although not significantly, stronger in middle-aged and older women than in younger women.