National trends in chronic kidney disease prevalence by sleep duration in South Korea, 2007 to 2022: A nationwide cross-sectional study.

Despite growing evidence linking sleep duration to chronic kidney disease (CKD), long-term trend analyses specific to the Korean population remain limited, and most previous studies have relied on broad intermediate sleep categories. This study analyzed trends in CKD prevalence by self-reported sleep duration among Korean adults. We included 87,246 Korean adults aged ≥19 years from the Korea National Health and Nutrition Examination Survey, 2007 to 2022. CKD was defined as an estimated glomerular filtration rate <60 mL/minutes/1.73 m2. Sleep duration was categorized into 5 groups (<6, 6-7, 7-8, 8-9, and ≥9 hours), with 7 to 8 hours as the reference. Weighted linear and logistic regression models provided β-coefficients and weighted odds ratios with 95% confidence intervals, sequentially adjusted for age, sex, body mass index, region, household income, education, smoking status, physician-diagnosed diabetes mellitus, hypertension, and dyslipidemia, and perceived stress. CKD prevalence declined across all 5 categories from 2007 to 2009 to 2020 to 2022 (<6 hours, 5.13% [95% confidence intervals, 4.12-6.13]-3.53% [2.74-4.33]; 7 to 8 hours, 2.37% [1.82-2.93]-1.52% [1.16-1.89]; ≥9 hours, 4.33% [3.17-5.48]-2.95% [2.18-3.72]). A U-shaped association was observed: relative to 7 to 8 hours, the fully adjusted odds of CKD were higher for <6 hours (weighted odds ratios 2.34 [2.04-2.69]) and ≥9 hours (2.07 [1.77-2.41]), with smaller elevations for 6 to 7 hours (1.18 [1.03-1.36]) and 8 to 9 hours (1.20 [1.05-1.37]). These estimates were essentially unchanged after adjustment for cardiometabolic comorbidity and perceived stress, and the pattern was present both among participants without and with each of these conditions. Short sleep was more strongly associated with CKD among females, whereas among adults aged ≥65 years the association was confined to long sleep. Trend slopes did not differ significantly before versus during the coronavirus disease 2019 pandemic in any category (all P > .05). In conclusion, CKD prevalence showed a U-shaped association with sleep duration that persisted after adjustment for cardiometabolic comorbidity and perceived stress. The absence of a significant change across the pandemic threshold should be interpreted in light of the short observation window relative to the natural history of CKD.