AIMS: To explore the link between daytime napping and the risk of major adverse cardiovascular events (MACE) and mortality in individuals with type 2 diabetes. METHODS: This prospective study included 21,129 participants with diabetes from the UK Biobank, all of whom were free of MACE and cancer at baseline. Data on habitual daytime napping and sleep duration were collected via a baseline questionnaire. Cox proportional hazards regression models were employed to assess the relationship between daytime napping and MACE, all-cause mortality, and cardiovascular disease (CVD) specific mortality. MACE was defined as a composite of myocardial infarction, heart failure, and stroke. RESULTS: Over an average 11.9-year follow-up, 5,611 MACE cases, 3,854 all-cause deaths, and 1,839 CVD deaths were identified. Compared to those who never/rarely napped, the multivariable-adjusted hazard ratios for usually napping were: 1.39 (1.08, 1.65) for MACE
1.44 (1.01, 1.92) for myocardial infarction
1.33 (1.07, 1.64) for heart failure
1.57 (1.06, 2.33) for stroke
1.28 (1.01, 1.60) for all-cause mortality
1.33 (0.97, 1.94) for CVD mortality. CONCLUSIONS: Frequent daytime napping is significantly associated with an increased risk of MACE and mortality among individuals with diabetes, particularly those who have extended sleep durations of more than 10 h and severe diabetes.