Abstract
BACKGROUND: Multiple sclerosis (MS) is an autoimmune disease with complex aetiology involving genetic, environmental and lifestyle factors. Shift work disrupts circadian rhythms and is a potential occupational risk factor for MS, with exposure before age 20 thought to be of additional risk.</p>
OBJECTIVE: To investigate associations between retrospective lifetime shift work exposure and MS diagnosis and between prospective shift work exposure and incident MS over 13 years of follow-up in the UK Biobank cohort.</p>
METHODS: Participants that were in work and free of MS at baseline were followed up for 13 years, and lifetime exposure to night, day and mixed shift work was assessed in a subset of participants. Logistic regression and Cox proportional hazard models were applied to test associations between shift work and MS diagnosis, controlling for demographic and lifestyle confounders.</p>
RESULTS: Lifetime exposure to mixed, day or night shift work was not associated with an increased risk of MS diagnosis. No significant associations were observed for early-life shift work exposure or in prospective analysis of those reporting shift work at baseline. Factors such as female sex, smoking, childhood obesity and reduced sunlight exposure were consistently associated with higher MS risk.</p>
CONCLUSIONS: There was no evidence for an association between shift work and the risk of MS diagnosis in this cohort, in retrospective analysis of lifetime exposure or in prospective studies of shift work at baseline following 13 years of follow-up. Further research is needed to elucidate mechanisms and latitudinal variations in shift work-related MS risk.</p>