Night shift work and indicators of cardiovascular risk: a systematic review and meta-analysis

Cardiovascular disease (CVD) is a leading cause of death worldwide, and shift workers have an increased risk of CVD. This comprehensive systematic review and meta-analysis aimed to assess the association between night shift work and cardiovascular risk indicators. A systematic literature search was performed according to the PRISMA 2020 guidelines using Medline, Embase, and Web of Science databases from inception through May 2024. Original manuscripts reporting relevant cardiovascular risk indicators and biomarkers in night shift workers were included. Risk of bias was assessed using the JBI's critical appraisal tools. When applicable, random-effect meta-analyses were performed. If suitable data were not available, a narrative synthesis was performed by combining p-values or vote-counting. Meta-regression analyses were performed to assess the contribution of sex, body mass index, and age as possible modifiers of effect. Evidence was weighed using an adapted GRADE. This study is registered in PROSPERO (CRD42022337285). Of the 8,387 studies identified, 81 were included in the synthesis, comprising 14 cohort and 67 cross-sectional studies. Moderate-confidence evidence was presented demonstrating increased inflammation, dyslipidaemia and impaired cardiac excitability among night shift workers. Dose-dependent effects were reported for these cardiovascular risk indicators, suggesting that the intensity and duration of night shift work contribute to risk of CVD. Furthermore, no association between night shift work and indicators of vascular dysfunction, deregulation of the autonomic nervous system, or altered homeostasis was observed. Considering this, regulatory and preventative initiatives are essential to reduce the cardiovascular risk among night shift workers.