Meta-analysis of differences in sleep quality based on actigraphs between day and night shift workers and the moderating effect of age

OBJECTIVES: This study was to conduct a meta-analysis of studies that used actigraphs to compare the influence of day and night shifts on the sleep quality of workers as well as examine the moderating effect of age. METHODS: Databases including PubMed, CINAHL, the Cochrane Library, MEDLINE, and EBSCOhost were searched for relevant studies published in English between January 1st, 2000 and April 30st, 2021. Our main targets were studies that used actigraphs to assess the sleep quality of night shift workers. This meta-analysis included 12 papers and was performed using Comprehensive Meta-Analysis (CMA) Version 3.0. Effect sizes were displayed in a forest plot using standardized mean difference (SMD) and 95% confidence intervals (CI). RESULTS: Among the sleep quality indices of the day and night shift workers, no significant difference existed in terms of sleep efficiency (SE) (SMD = 0.27, 95% CI: -0.03-0.57), whereas night shift workers presented longer sleep-onset latency (SOL) (SMD = 0.62, 95% CI: 0.15-1.08), greater wake after sleep onset (WASO) (SMD = 0.41, 95% CI: 0.12-0.70), and longer total sleep time (TST) (SMD = 0.85, 95% CI: 0.32-1.39) than did day shift workers. The differences between the day and night shift workers in SOL, WASO, and TST did not vary with age. CONCLUSIONS: Among the sleep quality indices, night shift workers presented longer SOL and greater WASO than did day shift workers. However, night shift workers could regulate their rest time and had adequate TST; thus, their SE was not different from that of day shift workers.