Summary:
Insomnia is a common issue affecting 20% of U.S. adults, but only 10% experience chronic (long-term) insomnia. While insomnia has been linked to a higher risk of death, it’s unclear if this applies to both persistent and occasional insomnia. This study aimed to find out whether long-term insomnia increases mortality risk, independent of factors like sedative use, sleep deprivation, and other health conditions. This study followed 1,409 adults for 38 years and found that persistent insomnia was linked to higher mortality, especially from heart and lung diseases. Researchers also examined inflammation (CRP levels), since poor sleep is associated with increased inflammation, which in turn raises the risk of heart disease and death. Participants with persistent insomnia had higher CRP levels, but this did not fully explain their increased mortality risk, suggesting other factors are involved. In short, long-term insomnia is a serious health risk, independent of other factors.
Abstract:
Background: Insomnia has been associated with mortality risk, but whether this association is different in subjects with persistent vs intermittent insomnia is unclear. Additionally, the role of systemic inflammation in such an association is unknown. Methods: We used data from a community-based cohort to determine whether persistent or intermittent insomnia, defined based on persistence of symptoms over a 6-year period, was associated with death during the following 20 years of follow-up. We also determined whether changes in serum C-reactive protein (CRP) levels measured over 2 decades between study initiation and insomnia determination were different for the persistent, intermittent, and never insomnia groups. The results were adjusted for confounders such as age, sex, body mass index, smoking, physical activity, alcohol, and sedatives. Results: Of the 1409 adult participants, 249 (18%) had intermittent and 128 (9%) had persistent insomnia. During a 20-year follow-up period, 318 participants died (118 due to cardiopulmonary disease). In adjusted Cox proportional-hazards models, participants with persistent insomnia (adjusted hazards ratio [HR] 1.58; 95% confidence interval [CI], 1.02-2.45) but not intermittent insomnia (HR 1.22; 95% CI, 0.86-1.74) were more likely to die than participants without insomnia. Serum CRP levels were higher and increased at a steeper rate in subjects with persistent insomnia as compared with intermittent (P = .04) or never (P = .004) insomnia. Although CRP levels were themselves associated with increased mortality (adjusted HR 1.36; 95% CI, 1.01-1.82; P = .04), adjustment for CRP levels did not notably change the association between persistent insomnia and mortality. Conclusions: In a population-based cohort, persistent, and not intermittent, insomnia was associated with increased risk for all-cause and cardiopulmonary mortality and was associated with a steeper increase in inflammation.
Article Publication Date: 14/10/2014
DOI: 10.1016/j.amjmed.2014.10.015
