Long nighttime sleep duration and risk of renal tubular damage: evidence from rural China and a Mendelian randomization analysis

Abstract

Objective: Renal tubular damage, a pivotal pathological feature of chronic kidney disease (CKD), predicts disease progression. While extreme nighttime sleep duration is linked to glomerular injury by prior studies, its impact on tubular damage remains unclear. Given that 7–9 h of sleep per night is widely recommended for maintaining overall health, this study aimed to assess whether long nighttime sleep duration is associated with renal tubular damage using both observational and genetic evidence. Methods: We analyzed 2,683 adults in rural China to assess the link between nighttime sleep duration and renal tubular damage (measured by retinol-binding protein and β2-microglobulin). Mendelian randomization (MR) analysis was performed to assess the causal relationship between prolonged nighttime sleep duration and elevated kidney injury molecule-1 (KIM-1) levels. Results: Multivariate logistic regression indicated that sleeping more than 9 h per night was associated with a 1.38-fold increased risk of renal tubular damage (95% CI: 1.11–1.71) compared to 7–9 h of sleep, with particularly pronounced effects observed in elderly individuals and women. MR analysis further supported a causal relationship between genetically predicted long nighttime sleep duration and elevated KIM-1 levels (β: 0.994, 95% CI: 0.282–1.707), suggesting a genetic predisposition linking prolonged sleep duration with renal tubular damage. Conclusions: Our findings provide observational and genetic evidence linking prolonged nighttime sleep to increased renal tubular damage risk. Given that 7–9 h of sleep per night is the widely accepted recommendation for maintaining overall health, our results emphasize the potential risks of excessive sleep duration exceeding 9 h.