Neurocognitive impairment in night and shift workers: a meta-analysis of observational studies

Abstract

ObjectiveShift work is an essential element of modern labour, ensuring ideal conditions of service for today’s economy and society. Despite the beneficial properties, its impact on the neurobehavioural performance of exposed subjects remains controversial. This meta-analysis aimed to provide the first summarising effects regarding the association between shift work exposure and different cognitive functions.MethodsA literature search was performed using the databases PubMed, PsyINFO, PsyARTICLES, MedLine, PsycNET and Scopus including eligible studies up to April 2021 that compared shift workers with non-shift workers regarding neurobehavioural performance tests. We carried out a random-effects model using Hedges’ g as a meta-analytical effect size with a restricted likelihood estimator to summarise the mean differences between the exposure group and controls. Positive effect sizes indicate higher performance for non-shift workers. The heterogeneity of effect sizes was addressed by sensitivity analysis using funnel plots, Egger’s tests, p-curve analysis, meta-regressions and subgroup analysis.ResultsWe included 18 studies resulting in a total sample of 18 802 participants and 37 effect sizes concerning six different neurobehavioural outcomes. Our results showed significantly worse performance in shift workers compared with non-shift workers in the following cognitive functions with g (95% CI): processing speed 0.16 (0.02 to 0.30), working memory 0.28 (0.51 to 0.50), psychomotor vigilance 0.21 (0.05 to 0.37), cognitive control 0.86 (0.45 to 1.27) and visual attention 0.19 (0.11 to 0.26).ConclusionsWe provide the first meta-analytical findings that associate shift work with decreased cognitive performance in processing speed, working memory, psychomotor vigilance, cognitive control and visual attention.

Association between medication adherence to chronic diseases and shift-work schedules in the Korean working population

“…Among the four items of the MMAS-4, forgetting to take medication was significantly associated with poor medication adherence among shift workers (SPR 1.23, 95% CI: 1.07–1.38; P = 0.0047). Irregular daily routines and sleep habits in shift workers can be related to decreased alertness and forgetfulness, which may in turn affect poor medication adherence 15 , 21 .…”

“…One of the most prominent and well-known examples of circadian stress in shift workers is the displacement of the sleep-wake cycle 22 . Poor sleep quality and quantity are associated with impaired alertness and decreased cognitive performance 21 , which may result in poor medication adherence. The gastrointestinal system also works via circadian regulation and functions poorly when circadian rhythms are disrupted by sleep displacement and irregular mealtimes 23 .…”

Correspondence on: Neurocognitive impairment in night and shift workers: a meta-analysis of observational studies by Vlasaket al

“…The meta-analysis by Vlasak et al 3 pays little attention to the distinction between acute and chronic affects. Moreover, it seems to conflate the two, switching from a focus on chronic effects in the introduction to acute affects in the discussion.…”

Response to: Correspondence on “Neurocognitive impairment in night and shift workers: a meta-analysis of observational studies” by Tucker

“…We thank Tucker1 for the interest and thoughtful comments on our study ‘Neurocognitive impairment in night and shift workers: a meta-analysis of observational studies’ 2…”

“…As discussed, the meta-analytical results must be interpreted under the assumption of possible moderating effects (eg, reversibility) 3. We recommend further analysis to focus primarily on the identification and quantification of acute and chronic effects of shift work exposure on neurocognitive functions for a deeper understanding of underlying mechanisms 2…”