Association of chronic kidney disease with cognitive impairment risk in middle-aged and older adults: the first longitudinal evidence from CHARLS.

Previous studies have yielded inconsistent results regarding the association between chronic kidney disease (CKD) and the risk of cognitive impairment (CI). This study aimed to investigate the longitudinal association of CKD with CI risk in the Chinese middle-aged and older population. A total of 16,515 CI-free participants 45 years of age or older including 15,595 without CKD and 920 with CKD were followed from 2011 until 2018 (median [interquartile range]: 7 [5.5-7]) to detect incident CI. Over the follow-up, 648 participants developed CI. Data were analyzed using multi-adjusted Cox proportional hazard regression and Laplace regression. The incidence rate (IR) of CI was significantly higher in individuals with CKD at 11.46 per 1,000 person-years (95% confidence interval [CI], 8.90 to 14.76) than in those without CKD at 6.38 per 1,000 person-years (95% CI, 5.89 to 6.92). Compared to those without CKD, the hazard ratios of those with CKD was 1.56 (95% CI, 1.19 to 2.04) for CI. Participants with CKD in the middle-aged group (45-54 years) exhibited a heightened risk of CI in age-stratified analyses. CKD accelerated the onset of CI by 1.24 years (10th percentile difference [PD]; 95% CI, -2.03 to -0.43, p < 0.01). The findings from this study revealed a significantly increased risk of CI in individuals with CKD, especially in middle-aged population, where the risk appeared to be more pronounced. This observation underscores the importance of early detection and intervention strategies to alleviate the potential cognitive decline associated with CKD.