Evidence map›Paper›PMID 40988126›Full record

ArticleHeadache2025

The acute effect of night work-related circadian misalignment on headache episodes: Results from the 1001 nights-cohort.

Rikke Harmsen, Jakob Møller Hansen, Dagfinn Matre, Anne Emily Saunte Fiehn Arup, Anne Helene Garde, Kirsten Nabe-Nielsen

Abstract read
In one paragraph

Article in Headache, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 6 papers, 1 of them a synthesis that pooled it.

0numbers the graph read from it
0cells of the map it votes in
6citing papers in PubMed, 1 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

6 citing papers in PubMed, 1 synthesis or guideline pooled it.

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4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Rikke HarmsenThe National Research Centre for the Working Environment, Copenhagen, Denmark.ORCID 0009-0008-5658-2851
Jakob Møller HansenNeurology Practice, Slagelse, Region Zealand, Denmark.ORCID 0000-0002-9417-2481
Dagfinn MatreNational Institute of Occupational Health (STAMI), Oslo, Norway.ORCID 0000-0003-0042-6389
Anne Emily Saunte Fiehn ArupThe National Research Centre for the Working Environment, Copenhagen, Denmark.ORCID 0009-0005-8394-8351
Anne Helene GardeThe National Research Centre for the Working Environment, Copenhagen, Denmark.ORCID 0000-0002-1553-2291
Kirsten Nabe-NielsenThe National Research Centre for the Working Environment, Copenhagen, Denmark.ORCID 0000-0002-4298-1420

Funding

European Union 874703The Danish Working Environment Research Fund 19-2022-09The Danish Working Environment Research Fund 26-2020-09The Health Foundation B-0452The National Research Centre for the Working Environment
6 · The paper itself

Abstract

objectivesWe aimed to investigate the prevalence of headaches on days with night shifts compared with days with day shifts within the same individuals, accounting for work-related psychosocial stressors, physical job demands, and sleep duration and quality. This approach allowed us to isolate the impact of circadian misalignment due to night work from other potential headache triggers.

backgroundNight work has been suggested to increase the risk of headaches, primarily due to circadian misalignment and disturbed sleep. Most previous studies compare night workers with day workers, but differences in job characteristics and tasks between these groups may introduce bias. To minimize this potential bias, we examined headache occurrence under different working conditions (night vs. day shifts) within the same individuals.

methodsWe used data from 14 days of repeated measurements in the 1001 nights-cohort, which includes female employees from the Danish hospital sector. Data were collected from September 2022 to April 2024. Participants completed diaries for 14 consecutive days, providing daily information on working hours, sleep, work-related psychosocial stressors, physical job demands, and headache occurrence (yes/no). Participants with data from at least one day shift and at least one night shift were eligible for inclusion in the analyses. In total, 522 participants contributed 3348 measurement days (1926 day shifts and 1422 night shifts). We estimated prevalence ratios (PRs) for headache occurrence while accounting for repeated measures within individuals and with adjustment for possible confounders (adjusted prevalence ratio [aPR]).

resultsHeadache was reported on 21.5% of measurement days with day shifts and on 27.9% of measurement days with night shifts. Working a night shift was associated with a significantly higher headache prevalence (aPR, 1.31; 95% confidence interval, 1.13-1.52) compared with day shifts when adjusting for work-related psychosocial stressors, physical job demands, and sleep duration and quality. For consecutive night shifts, the similarly adjusted headache prevalence was highest on the measurement day with the second night shift (aPR, 1.20; 95% confidence interval, 1.02-1.42), using the first night shift as a reference.

conclusionThis study is the first to investigate the headache prevalence when working night shifts compared with day shifts while accounting for work-related psychosocial stressors and physical job demands. Neither these factors, nor shorter sleep duration or lower sleep quality, explained the increased headache prevalence observed when participants worked night shifts. Thus, other (cascading) effects and underlying mechanisms of night work-related circadian misalignment may be the primary drivers of headache in night shift workers.

Indexed as

Circadian RhythmHeadacheOccupational StressShift Work ScheduleSleep Disorders, Circadian RhythmWork Schedule ToleranceAdultCohort StudiesDenmarkFemaleHumansMiddle AgedPrevalencehealthcaremigraineoccupationrotating shiftsshift work

Identifiers

PMID40988126
PMCPMC12497931

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.