Thalamic gray matter volume mediates the association betweenKIBRApolymorphism and olfactory function among older adults: a population-based study

Abstract

The kidney and brain expressed protein (KIBRA) rs17070145 polymorphism is associated with both structure and activation of the olfactory cortex. However, no studies have thus far examined whether KIBRA can be linked with olfactory function and whether brain structure plays any role in the association. We addressed these questions in a population-based cross-sectional study among rural-dwelling older adults. This study included 1087 participants derived from the Multidomain Interventions to Delay Dementia and Disability in Rural China, who underwent the brain MRI scans in August 2018 to October 2020; of these, 1016 took the 16-item Sniffin’ Sticks identification test and 634 (62.40%) were defined with olfactory impairment (OI). Data were analyzed using the voxel-based morphometry analysis and general linear, logistic, and structural equation models. The KIBRA rs17070145 C-allele (CC or CT vs. TT genotype) was significantly associated with greater gray matter volume (GMV) mainly in the bilateral orbitofrontal cortex and left thalamus (P < 0.05) and with the multi-adjusted odds ratio of 0.73 (95% confidence interval 0.56–0.95) for OI. The left thalamic GMV could mediate 8.08% of the KIBRA-olfaction association (P < 0.05). These data suggest that the KIBRA rs17070145 C-allele is associated with a reduced likelihood of OI among older adults, partly mediated through left thalamic GMV.

Prolonged ventricular repolarization associated with mild cognitive impairment and white matter hyperintensities: a cross-sectional study

“…Second, although we have controlled for extensive possible confounders, we cannot rule out the potential impact of residual confounding due to imperfect measurements of some confounders (e.g., self-reported lifestyle factors and health history). Finally, participants in the MRI subsample were younger, healthier, and more educated compared to those in the MIND-China total sample 35 . This should be kept in mind when generalizing these findings to other populations.…”