Association Between Social Jetlag and Components of Metabolic Syndrome: A Systematic Review and Meta-Analysis.

Background: A mismatch between biological and social time, often referred to as social jetlag (SJL), can lead to inadequate sleep and activities or taking meals at times that do not align with our biological rhythms, increasing the risk of metabolic abnormalities. Although the association between sleep and metabolic syndrome (MetS) is well established, the effects of SJL on MetS and the components of MetS in adults remain unclear.

Purpose: This study was designed to explore the relationship between SJL and MetS components in adults.

Methods: A systematic review and meta-analysis was conducted on studies registered in PubMed, Cochrane, Web of Science, and Embase between the inception of each database until November 15, 2023. We focused on studies designed to evaluate the relationship between SJL and either MetS or its components. Only studies using cross-sectional, prospective, or retrospective designs were considered for inclusion. The relationship between SJL and MetS was depicted as an odds ratio with a corresponding 95% confidence interval (CI). We determined the mean differences and 95% CIs to estimate the associations between SJL and MetS components. The Joanna Briggs Institute Critical Appraisal Checklist was used to evaluate the methodological rigor of the selected studies. Data were analyzed using RevMan software Version 5.4.

Results: The systematic review included 16 studies, with five analyzed via a meta-analysis covering four outcomes, each based on two to three studies. When comparing SJL of less than 1 hour with SJL of 2 hours or more, the latter showed a higher likelihood of MetS (pooled odds ratio: 1.52). Although a significant decrease in systolic blood pressure (pooled mean differences = -3.52 mmHg, 95% CI [-6.41, -0.64]) and a significant increase in waist circumference (pooled mean differences = 2.17 cm, 95% CI [0.61, 3.73]) were observed, the correlation between SJL and diastolic blood pressure failed to reach statistical significance.

Conclusions/implications for practice: The meta-analysis conducted in this study found an association between SJL and MetS. Healthcare practitioners should prioritize the management of sleep quality and duration, especially for individuals exhibiting substantial SJL. Improving sleep can aid in controlling blood pressure and managing weight and should form part of MetS management strategies.