Abstract
BackgroundAssociation between kidney dysfunction and dementia has been studied in western cohorts, but with inconsistent conclusions which may be due to the different measurements of kidney function. We aim to verify the hypothesis that lower levels of kidney function would be associated with increased risk of incident dementia in Chinese elderly.MethodsOne thousand four hundred twelve dementia-free participants aged 60 years or older from the Shanghai Aging Study were enrolled and followed up for 5.3 years on average. Glomerular filtration rate (GFR) was calculated by using combined creatinine–cystatin C CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration) equation. Diagnoses of incident dementia and Alzheimer’s disease (AD) were established using DSM-IV and NINCDS-ADRDA criteria based on medical, neurological, and neuropsychological examinations to each participant. Cox proportional regression was used to analyze the association of baseline GFRcrcys levels with incident dementia/AD, adjusting age, gender, education years, APOE-ε4, diabetes, hypertension, baseline Mini-Mental State Examination score, and proteinuria.ResultsA total of 113 (8%) and 84 (7%) participants developed dementia and AD. Comparing to participants with high GFRcrcys (≥ 80 ml/min/1.73 m2), participants with low (< 67 ml/min/1.73 m2) and moderate GFRcrcys (67 ≤ GFR < 80 ml/min/1.73 m2) had increased risk of incident dementia with hazard ratios (HRs) of 1.87 (95% CI 1.02–3.44) and 2.19 (95% CI 1.21–3.95) after adjustment for confounders, respectively. Low (HR = 2.27 [95%CI 1.10–4.68]) and moderate (HR = 2.14 [95% CI 1.04–4.40]) GFRcrcys at baseline was also independently associated with incident AD after adjustments when comparing to high GFRcrcys. The significant association between GFRcrcys and dementia risk was observed in female but not in male participants.ConclusionsGFRcrcys may be considered as a marker of an individual’s vulnerability to the increased risk of cognitive decline.
Highlights
Association between kidney dysfunction and dementia has been studied in western cohorts, but with inconsistent conclusions which may be due to the different measurements of kidney function
Incidence rate of dementia Dementia incidences were 2.57/100 person-years, 1.50/100 person-years, and 0.56/100 person-years in groups with low, moderate, and high GFRcrcys, respectively, while incidence rates of Alzheimer’s disease (AD) were 1.77/100 person-years, 1.30/100 person-years, and 0.38/100 personyears in groups with low, moderate, and high GFRcrcys, respectively
Association between glomerular filtration rate (GFR) and incident dementia Comparing to participants with high GFRcrcys, participants with moderate (HR = 2.77 [95% confidence interval (CI) 1.53 to 5.05]) and low GFRcrcys (HR = 4.90 [95% CI 2.79 to 8.63]) had increased risks of incident dementia in the unadjusted model
Summary
Association between kidney dysfunction and dementia has been studied in western cohorts, but with inconsistent conclusions which may be due to the different measurements of kidney function. A few large-sampled population-based studies have investigated the relationship between kidney dysfunction and dementia onset but reported inconsistent results [6,7,8,9,10,11]. The major heterogeneity in these studies is the different measurements of kidney function, i.e., inverse of serum creatinine (1/SCr), estimated glomerular filtration rate (GFR) based on creatinine (GFRcr) or cystatin-C (GFRcys). Another might be the different diagnoses of dementia, i.e., DSM criteria or discharge diagnosis. Data from the Asian population, especially Chinese, are still very limited
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