The impact of sleep duration, sleep debt and insomnia symptoms on infection risk: a longitudinal cohort study with 1-year follow-up.

Abstract

To study whether sleep duration, sleep debt (difference between sleep need and duration), and insomnia severity at baseline would predict increased prevalence of infections 1 year later. In total, 861 participants recruited from the Norwegian Primary Care Research Network completed a baseline survey about sleep and were invited for follow-up 1 year later. The response rate at follow-up was 60.5%, rendering 521 patients eligible for analyses. At baseline the participants completed questions about sleep habits and insomnia symptoms (insomnia severity index), and at follow-up they responded to whether they had experienced various infections during the last 3 months and whether they experience more infections than peers. Participants with normal sleep duration, no sleep debt and no insomnia at baseline reported the lowest prevalences of infections at 1-year follow-up. In the adjusted analyses, long sleep duration (>9 h, present only in 11 participants) increased the odds of influenza-like illness, gastrointestinal infection, and experiencing more infections than peers by about four times, whereas short sleep duration (<6 h) doubled the odds of skin infection. Compared to no sleep debt, ≤2 h sleep debt doubled the odds of skin infection and >2 h sleep debt tripled the odds of experiencing more infections than peers. Insomnia doubled the odds of any type of infection and influenza-like illness, and more than tripled the odds of gastrointestinal infection and experiencing more infections than peers. This longitudinal study supports the notion that people who have insufficient sleep are at increased risk of infections.