Association of late bedtime and glycemic control with diabetic retinopathy in adults with diabetes: a population-based study

Background Most epidemiologic studies of sleep and diabetic retinopathy (DR) have focused on sleep duration, sleep quality or sleep apnea. Bedtime timing is less often separated from these sleep measures. We examined whether weekday bedtime timing was associated with DR among adults with diabetes.Methods We used NHANES 2015–2016 and 2017-March 2020 pre-pandemic data. Adults aged 20 years or older with diabetes were included. Weekday bedtime was grouped as normal bedtime, mild late bedtime, and severe late bedtime. We calculated survey-weighted descriptive characteristics and DR prevalence, then fitted survey-weighted logistic regression models to estimate odds ratios and 95% confidence intervals. Primary models adjusted for sociodemographic factors, diabetes duration, sleep duration and HbA1c.Results The analytic sample included 1,981 adults with diagnosed diabetes; 421 had diagnosed DR. Severe late bedtime showed the most pronounced prevalence pattern: DR prevalence was 47.1% in this group versus 18.8% among participants with other bedtimes. In the adjusted bedtime-category model, severe late bedtime was associated with significantly higher odds of DR than normal bedtime (OR 3.77; p = 0.001). The focused contrast for severe late bedtime versus all other bedtimes remained significant after full adjustment (OR 3.92; p = 0.001). Conclusions Severe late bedtime was significantly associated with higher risk of DR.