Relationship between daytime napping with the occurrence and development of diabetes: a systematic review and meta-analysis

OBJECTIVE: To determine the relationship of napping with incident diabetes risk and glycaemic control in people with diabetes. DESIGN: Systematic review and meta-analysis. DATA SOURCES: MEDLINE (PubMed), EMBASE, Web of Science and the Cochrane Library were searched for studies published from database inception to 9 May 2023. ELIGIBILITY CRITERIA: Observational studies reporting the relationship of napping with diabetes or glycaemic control in patients with diabetes in adult populations were included. DATA EXTRACTION AND SYNTHESIS: Two reviewers independently screened the literature, extracted data and assessed the quality of the included studies. The results were reported as ORs and 95% CIs, which were pooled by using fixed and random effects models, and subgroup analyses were performed. The Grading of Recommendations Assessment, Development and Evaluation method was used to assess the quality of the evidence. RESULTS: Forty studies were included in our review. Habitual napping was associated with an increased diabetes risk (OR 1.20, 95% CI 1.14 to 1.27) and poor glycaemic control in patients with diabetes (OR 2.05, 95% CI 1.55 to 2.73). Nap durations less than 30 min were unrelated to diabetes (OR 1.05, 95% CI 0.97 to 1.14). Nap durations of 30–60 min were associated with diabetes risk (OR 1.09, 95% CI 1.02 to 1.17), but there were differences in the subgroup analysis results. Nap durations of more than 60 min significantly increased the risk of diabetes (OR 1.31, 95% CI 1.20 to 1.44). CONCLUSIONS: Napping is associated with increased diabetes risk and poor glycaemic control, and future research will need to confirm whether there are sex and regional differences. Nap durations of more than 60 min significantly increases the risk of diabetes, and the relationship between nap duration and glycaemic control in patients with diabetes needs to be further explored in the future. PROSPERO REGISTRATION NUMBER: CRD42021292103.