Correlation between sleep duration and hypertension: a dose-response meta-analysis

To deeply investigate the correlation between sleep duration and hypertension. The electronic databases Cochrane Library, Pubmed and Embase updated to December 2017 were retrieved, and manual searching for paper-based documents was also performed. After studies were selected according to the predefined screening criteria, their qualities were assessed using Newcastle-Ottawa Scale. Based on R 3.43 software, the association between sleep duration and hypertension was analyzed by dose-response meta-analysis, using relative risk (RR) and 95% confidence interval (95% CI) as effect indexes. Furthermore, publication bias of the eligible studies was evaluated using Egger's test. In addition, sensitivity analysis was conducted through ignoring one study per time and then observing its influences on the pooled results. A total of 9 studies (involving 48525 objects) were included in this dose-response meta-analysis, which had high qualities. The differences in <= 5 h vs. 7 h, 6 h vs. 7 h, and 9 h vs. 7 h groups had statistical significances, suggesting that hypertension risk was higher for shorter sleep duration (P < 0.05). There was no significant difference in >9 h vs. 7 h group. No publication bias was found for the eligible studies, indicating that our results were highly credible (t = 0.030, P = 0.9766). However, the pooled results were reversed after ignoring each included study per time. Dose-response meta-analysis showed that the hypertension risk reduced for 0.3207% when the sleep duration increased by 1 h. Shorter sleep duration contributes to the increase of hypertension risk.