Association between self-reported napping and risk of cardiovascular disease and all-cause mortality: A meta-analysis of cohort studies

Objectives: To assess the association between adult nap duration and risks of all-cause mortality and cardiovascular diseases (CVD). Methods: PubMed, Cochrane Library, Embase and Web of Science were searched without language restriction. Study quality was assessed using the Newcastle-Ottawa Scale. Random-effects meta-analyses (Stata 14.0) pooled hazard ratios (HRs) with 95% confidence intervals (CIs); publication bias was assessed with funnel plots and Egger's test. Results: Twenty-one cohort studies involving 371,306 participants were included. Daytime napping vs. no napping was associated with higher all-cause mortality (HR 1.28, 95% CI 1.18–1.38; I²=38.8%) and higher CVD risk (HR 1.18, 95% CI 1.02–1.38; I²=87.9%). Nap duration modified risk: naps <1 hour showed no significant association with mortality (HR 1.00, 95% CI 0.90–1.11; I²=62.6%) or CVD (HR 1.03, 95% CI 0.87–1.12; I²=86.4%); naps ≥1 hour were associated with increased mortality (HR 1.22, 95% CI 1.12–1.33; I²=40.0%) and increased CVD risk (HR 1.37, 95% CI 1.09–1.71; I²=68.3%).

Meng Wang, Xin Xiang, Zhengyan Zhao, Yu liu, Yang Cao, Weiwei Guo, Linlin Hou, Qiuhuan Jiang