Papers of the Week

Although sleep quantity and quality appear to be interrelated, most previous studies have considered sleep duration and insomnia symptoms as distinct entities. We therefore examined whether there is a joint effect of sleep duration and long-term changes in insomnia symptoms on the risk of recurrent chronic spinal pain. We performed a prospective study of 8,788 participants who participated in three surveys over ∼22 years and reported chronic spinal pain at the first, second, or both surveys. Adjusted risk ratios (RRs) were calculated for the risk of recurrent spinal pain at the last survey associated with self-reported sleep duration at the first survey and changes in insomnia symptoms between the two first surveys. Compared to participants with normal sleep duration (7-9 h) and no insomnia symptoms at the two first surveys, participants with insomnia symptoms over the same period had RRs of spinal pain of 1.33 (95% CI 1.26-1.41) in the last survey if they reported normal sleep duration and 1.50 (95% CI 1.34-1.67) if they reported short sleep (≤6 h). The corresponding RRs for spinal pain for participants who improved their sleep symptoms were 1.09 (95% CI 1.00-1.19) for those with normal sleep and 1.13 (95% CI 0.88-1.45) for those with short sleep. In conclusion, people who reported insomnia symptoms over ∼10 years in combination with short sleep had a particularly increased risk of recurrent spinal pain. Improvement in insomnia symptoms was associated with a favorable prognosis.