Integrative review links sleep duration and patterns to metabolic syndrome risk.

Due to the use of various methods across different studies, the association between sleep duration, insomnia and sleep pattern with metabolic syndrome (MetS) remains inconsistent. Integrative reviews that thoroughly synthesize data from various study types are therefore required in order to clarify the relationships between particular aspects of sleep and MetS. Therefore, this integrative review aimed to assess and summarize the most recent data regarding the relationship between sleep duration, sleep patterns and insomnia with MetS. Problem identification, literature search, data evaluation, data analysis, and presentation five stage methodology developed by Whitmore and Knaff’s (2005) guided this review. Four databases including; PubMed, Embase, Scopus and Web of Science were utilized. The quality of included studies were assessed by the Mixed Methods Appraisal Tool (2018). Conventional quantitative content analysis method was used to analyze extracted date and the preferred reporting items for systematic reviews and meta analyses checklist guided the reports of this review. Initially a total of 25,472 articles were retrieved, 12 cross-sectional, 5 cohorts, 1 case-control studies were finally included. This study revealed sleep duration, insomnia and specific sleep characteristics such as; long daytime napping > 90 minutes, irregular sleep, social jetlag and early wake-up linked with increased risk of MetS. MetS is a complex problem and could be affected by the interaction of multiple sleep characteristics. Short sleep duration consistently was associated with MetS. However, the association between long sleep duration and insomnia with MetS remained inconsistent.