{
  "abstract": "Objective To investigate the prevalence of headaches on days with night shifts compared with day shifts within the same individuals, accounting for work-related psychosocial stressors, physical job demands, and sleep duration and quality. This approach aimed to isolate the impact of circadian misalignment due to night work from other potential headache triggers.Material and Methods We used data from the 1001 nights-cohort, comprising female employees from the Danish hospital sector. Participants completed 14-day diaries, providing daily information on working hours, sleep, emotional job demands, quantitative job demands, physical job demands, and headache occurrence (yes/no). Participants with data from at least one day shift and one night shift were included. In total, 522 participants contributed 3,348 measurement days (1,926 day shifts and 1,422 night shifts). We estimated prevalence ratios (PRs) for headache occurrence, accounting for repeated measures within individuals.Results Headaches were reported on 21.5% of days with day shifts and 27.9% of days with night shifts. Night shifts were associated with a significantly higher headache prevalence (PR: 1.32; 95% CI: 1.15–1.51) compared with day shifts, independent of work-related psychosocial stressors, physical job demands, or sleep characteristics. Among consecutive night shifts, the second night showed the highest headache prevalence (PR: 1.20; 95% CI: 1.03–1.40), using the first night as the reference.Conclusion This is the first study to assess headache occurrence on days with night shifts versus day shifts while accounting for both job-related and sleep-related factors. Neither work-related psychosocial stressors, physical job demands, nor sleep parameters explained the higher headache prevalence. These findings suggest that other mechanisms related to night work-induced circadian misalignment may be key drivers of headache risk in night shift workers.Funding The present study was funded by the Danish Working Environment Research Fund.",
  "authors": [
    {
      "affiliations": [
        "The National Research Centre for the Working Environment, Copenhagen, Denmark. Neurology Practice, Slagelse, Region Zealand, Denmark. National Institute of Occupational Health (STAMI), Oslo, Norway. University of Copenhagen, Department of Public Health Science, Copenhagen, Denmark"
      ],
      "name": "Kirsten Nabe-Nielsen"
    },
    {
      "affiliations": [
        "The National Research Centre for the Working Environment, Copenhagen, Denmark. Neurology Practice, Slagelse, Region Zealand, Denmark. National Institute of Occupational Health (STAMI), Oslo, Norway. University of Copenhagen, Department of Public Health Science, Copenhagen, Denmark"
      ],
      "name": "Rikke Harmsen"
    },
    {
      "affiliations": [
        "The National Research Centre for the Working Environment, Copenhagen, Denmark. Neurology Practice, Slagelse, Region Zealand, Denmark. National Institute of Occupational Health (STAMI), Oslo, Norway. University of Copenhagen, Department of Public Health Science, Copenhagen, Denmark"
      ],
      "name": "Jakob Møller Hansen"
    },
    {
      "affiliations": [
        "The National Research Centre for the Working Environment, Copenhagen, Denmark. Neurology Practice, Slagelse, Region Zealand, Denmark. National Institute of Occupational Health (STAMI), Oslo, Norway. University of Copenhagen, Department of Public Health Science, Copenhagen, Denmark"
      ],
      "name": "Dagfinn Matre"
    },
    {
      "affiliations": [
        "The National Research Centre for the Working Environment, Copenhagen, Denmark. Neurology Practice, Slagelse, Region Zealand, Denmark. National Institute of Occupational Health (STAMI), Oslo, Norway. University of Copenhagen, Department of Public Health Science, Copenhagen, Denmark"
      ],
      "name": "Anne Emily Saunte Fiehn Arup"
    },
    {
      "affiliations": [
        "The National Research Centre for the Working Environment, Copenhagen, Denmark. Neurology Practice, Slagelse, Region Zealand, Denmark. National Institute of Occupational Health (STAMI), Oslo, Norway. University of Copenhagen, Department of Public Health Science, Copenhagen, Denmark"
      ],
      "name": "Anne Helene Garde"
    }
  ],
  "title": "8239437 The acute effect of night work-related circadian misalignment on headache episodes: results from the 1001 nights-cohort",
  "uid": "8dde722f-8f32-5984-9edf-91de5a0702db"
}