Night shift work is associated with an increased risk of asthma

Thorax. 2021 Jan;76(1):53-60. doi: 10.1136/thoraxjnl-2020-215218. Epub 2020 Nov 16.

Abstract

Introduction: Shift work causes misalignment between internal circadian time and the external light/dark cycle and is associated with metabolic disorders and cancer. Approximately 20% of the working population in industrialised countries work permanent or rotating night shifts, exposing this large population to the risk of circadian misalignment-driven disease. Analysis of the impact of shift work on chronic inflammatory diseases is lacking. We investigated the association between shift work and asthma.

Methods: We describe the cross-sectional relationship between shift work and prevalent asthma in >280000 UK Biobank participants, making adjustments for major confounding factors (smoking history, ethnicity, socioeconomic status, physical activity, body mass index). We also investigated chronotype.

Results: Compared with day workers, 'permanent' night shift workers had a higher likelihood of moderate-severe asthma (OR 1.36 (95% CI 1.03 to 1.8)) and all asthma (OR 1.23 (95% CI 1.03 to 1.46)). Individuals doing any type of shift work had higher adjusted odds of wheeze/whistling in the chest. Shift workers who never or rarely worked on nights and people working permanent nights had a higher adjusted likelihood of having reduced lung function (FEV1 <80% predicted). We found an increase in the risk of moderate-severe asthma in morning chronotypes working irregular shifts, including nights (OR 1.55 (95% CI 1.06 to 2.27)).

Conclusions: The public health implications of these findings are far-reaching due to the high prevalence and co-occurrence of both asthma and shift work. Future longitudinal follow-up studies are needed to determine if modifying shift work schedules to take into account chronotype might present a public health measure to reduce the risk of developing inflammatory diseases such as asthma.

Keywords: asthma; asthma epidemiology.

Publication types

  • Multicenter Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Asthma / epidemiology*
  • Asthma / etiology
  • Asthma / physiopathology
  • Circadian Rhythm
  • Cross-Sectional Studies
  • Female
  • Humans
  • Male
  • Middle Aged
  • Prevalence
  • Risk Assessment / methods*
  • Risk Factors
  • Shift Work Schedule / adverse effects*
  • Sleep / physiology*
  • Surveys and Questionnaires
  • Time Factors
  • United Kingdom / epidemiology