The association of KIBRA rs17070145 polymorphism with dementia and cognitive function among older adults in China: A population‐based cross‐sectional study

Abstract

AbstractBackgroundKIBRA, as a ligand protein, is mainly expressed in kidney and brain. A genome‐wide association study in 2006 revealed that KIBRA rs17070145 was associated with impairment in episodic memory. Since then, several studies that investigate the association of this SNP and cognitive function have yielded mixed results. This study aims to explore the association of KIBRA rs17070145 with dementia and cognitive function among rural‐dwelling older adults in China.MethodThis population‐based cross‐sectional study included 4700 participants from the Multidomain Interventions to Delay Dementia and Disability in Rural China (MIND‐CHINA), who were aged ≥65 years (mean 71.7 years; 57.2% women). Data on demographic features and cognitive function were collected through face‐to‐face interviews, clinical examinations, and laboratory tests. SNPs were detected by multiplex PCR assay. Global cognitive function was assessed with the Mini‐Mental State Examination (MMSE). Diagnoses of dementia Alzheimer’s disease (AD), and vascular dementia (VaD) were reached according to the DSM‐IV, NIA‐AA, and NINDS‐AIREN criteria, respectively. Data were analyzed using multiple logistic regression and general linear regression models.ResultOf all participants, 2689(57.2%) carried the KIBRA rs17070145 TT polymorphism in intron 9, 1719(36.6%) carried CT polymorphism, and 292(6.2%) were homozygous CC carriers. The multi‐adjusted odds ratio (95% CI) of dementia associated with C allele and genotype CC was 1.27 (1.02‐1.58) and 1.78 (1.07‐2.97), respectively. The association of KIBRA genotype CC with VaD was significantly, but not with AD. However, the association of genotype CC with VaD was reduced and became non‐significant when further adjusting for cerebrovascular diseases.ConclusionKIBRA rs17070145 genotype CC is associated with an increased likelihood of dementia among rural‐dwelling Chinese older adults, driven largely by the association with VaD. Cerebrovascular disease may partly explain the association of genotype CC with VaD.