Insomnia symptoms and risk of bloodstream infections: prospective data from the prospective population-based HUNT Study, Norway

Objective Previous research suggest decreased immune function and increased risk of infections in persons with insomnia. We examined the effect of insomnia symptoms on risk of bloodstream infections (BSI) and BSI-related mortality in a population-based prospective study. Methods A total of 53,536 participants in the Norwegian HUNT2 study (1995–97) were linked to prospective data on clinically relevant BSIs until 2011. In Cox regression, we estimated hazard ratios (HRs) with 95% confidence interval (CI) for a first-time BSI and for BSI related mortality (BSI registered ≤30 days prior to death) associated with insomnia symptoms. Results Compared with participants who reported “no symptoms of insomnia”, participants reporting having “difficulty initiating sleep” often/almost every night had a HR for a first-time BSI of 1.14 (95% CI 0.96–1.34). Participants reporting “difficulties maintaining sleep” often/almost every night had a HR of 1.19 (95% CI 1.01–1.40), whereas those having a “feeling of non-restorative sleep” once a week or more had a HR of 1.23 (95% CI 1.04–1.46). Participants experiencing all three above insomnia symptoms frequently had a HR of 1.39 (1.04–1.87) and being troubled by insomnia to a degree that affected work performance was associated with a HR of 1.41 (95% CI 1.08–1.84). The HRs for BSI related mortality suggest an increased risk with increasing insomnia symptoms, but confidence intervals are wide and inconclusive. Conclusions We found that frequent insomnia symptoms and insomnia symptoms that affected work performance was associated with a weak positive increased risk of BSI. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study was funded by the Norwegian University of Science and Technology. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee of Regional ethical committee for medical research(REK 2018/1819/REKmidt and REK 2012/153) and the Helse Undersokelsen i Nord-Trondelag data access committee gave ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.