Sleep as a predictive factor for the onset and resolution of multi-site pain : A 5-year prospective study

BACKGROUND: Disturbed sleep and pain often co-exist and the relationship between the two conditions is complex and likely reciprocal. This 5-year prospective study examines whether disturbed sleep can predict the onset of multi-site pain, and whether non-disturbed sleep can predict the resolution of multi-site pain. METHODS: The cohort (n = 1599) was stratified by the number of self-reported pain sites: no pain, pain from 1-2 sites and multi-site pain (≥3 pain sites). Sleep was categorized by self-reported sleep disturbance: sleep A (best sleep), sleep B and sleep C (worst sleep). In the no-pain and pain-from-1-2 sites strata, the association between sleep (A, B and C) and multi-site pain 5 years later was analysed. Further, the prognostic value of sleep for the resolution of multi-site pain at follow-up was calculated for the stratum with multi-site pain at baseline. In the analyses, gender, age, body mass index, smoking, physical activity and work-related exposures were treated as potential confounders. RESULTS: For individuals with no pain at baseline, a significantly higher odds ratio for multi-site pain 5 years later was seen for the tertile reporting worst sleep [odds ratio (OR) 4.55; 95% confidence interval (CI) 1.28-16.12]. Non-disturbed (or less disturbed) sleep had a significant effect when predicting the resolution of multi-site pain (to no pain) (OR 3.96; 95% CI 1.69-9.31). CONCLUSION: In conclusion, sleep could be relevant for predicting both the onset and the resolution of multi-site pain. It seems to be a significant factor to include in research on multi-site pain and when conducting or evaluating intervention programmes for pain.