Background: Subjects with chronic musculoskeletal pain or sleep disturbances have been shown to have a poor healthstatus as measured by the SF-36 health survey. Fatigue is commonly reported by subjects with chronic musculoskeletal pain and sleep disturbances. There is little known about the temporal relationship between chronic pain, sleep disturbances and changes of vitality.

Objectives: The aim of this study was to evaluate the predictive value of chronic musculoskeletal pain and sleep disturbances with regard to changes in vitality as measured by SF-36 over an eight year period.

Method: An eight year follow up of 2 425 subjects aged 20-74 from the general population that in 1995 answered the same postal questionnaire. The questionnaire assessed chronic musculoskeletal pain, sleep disturbances, and included the SF-36 health survey. Pain was considered "chronic" if persistent for three months or more. Sleep disturbances assessed were difficulty in falling asleep, frequent awakenings, early awakenings and not feeling rested. Main outcome measure was change of vitality as measured by SF-36 in those that at baseline reported vitality over the median value. Statistical analyses were done with use of logistic regression. Besides the studied variables, the logistic regression analyses also controlled for gender, age, socio-economic group, and the use of analgesics and sleeping pills.

Results: At baseline 1212 subjects reported a vitality score on SF-36 above the median score of 75. There were 943 subjects (78%) responding at the eight-year follow up. Chronic pain at baseline predicted (OR=1,64, 95% CI 1,14-2,36%, p=0,01) worsening of vitality over time. Loss of vitality was also predicted by moderate problems with falling asleep (OR=2,17, 95% CI 1,31-3,60%, p<0,01), and problems with not feeling rested (moderate problems OR=2,08, 95% CI 1,23-3,50%, p=0,01, and major problems OR=4,76, 95% CI 1,53-14,78%, p=0,01).

Conclusion: Loss of vitality in SF-36 over an eight-year period was predicted by chronic musculoskeletal pain, problems with falling asleep and problems with not feeling rested. Problems with frequent awakenings and early awakenings did not predict lower value of vitality over an eight-year period. It could thus be important to attend to sleeping problems and especially the feeling of not being rested in subjects with chronic musculoskeletal pain.