Chronic Kidney Disease: a Risk Factor for Dementia Onset: a Population-based Study. The Osaki-Tajiri Project

Objectives: To examine the relationship between the incidence of dementia and chronic kidney disease (CKD).

Design: Longitudinal data analyses.

Setting: Baseline data and follow-up data from the Osaki-Tajiri Project.

Participants: The Tajiri Project dementia prevalence study in 1998 involved 497 community-dwelling, older men and women (346 with Clinical Dementia Rating score (CDR) of 0 (healthy), 119 with a CDR of 0.5 (questionable dementia), and 32 with a CDR of 1 or greater (dementia)). Two hundred fifty-four participants with CDR of 0 and 0.5 who were reclassified as converters (n=28) or nonconverters (n=230) to dementia in the incidence study in 2003 were followed.

Measurements: The prevalence of CKD and the onset of dementia were retrospectively analyzed, and the effects of other vascular risk factors on converters and CKD were analyzed.

Results: Weighted logistic regression showed CKD to be significantly associated with incident dementia after adjustment for age, sex, education, hypertension, diabetes mellitus, dyslipidemia, ischemic heart disease, and anemia. The odds ratio for conversion to dementia for those with CKD compared to those without was 5.3 (95% confidence interval=1.7, 16.2). Apart from dyslipidemia, there were no associations between dementia and the other vascular risk factors.

Conclusion: CKD was strongly associated with the incidence of dementia independent of age, sex, education, and other vascular risk factors.