Why do we need an Asian brain template in clinical trials of Alzheimer's disease? A comparative study of brain structures between Asian vs Caucasian brains

Abstract

AbstractBackgroundThere is a recognized need for the creation of ethnic‐specific brain templates of cognitively normal older adults for the purpose of evaluating structural and functional brain imaging data in the normal aging process and neurodegenerative disease including Alzheimer’s disease. However, previous studies of racial difference in cortical thickness of cognitively normal older adults have been restricted to small sample size and have not adequately controlled biases. We aimed to compare cerebral cortical thickness between cognitively normal older adults of East Asians and of Caucasians adjusting for age, gender, education.MethodWe evaluated the brain cortical thickness by using FreeSurfer on standard T1‐weighted images of cognitively normal older adults in East Asians [n= 321 (60’s = 166, 70’s = 155)] and Caucasians [n= 282 (60’s = 111, 70’s = 171)], and examined the difference in cortical thickness between two races by whole brain analysis (ANCOVA adjusting age, education, MMSE scores, corrected p < 0.05, FDR correction).ResultEast Asians were shown to have a higher cortical thickness in bilateral superior frontal, lateral and medial orbitofrontal, middle temporal, left superior parietal, right inferior parietal, and inferior temporal cortex and lower cortical thickness in bilateral parahippocampus, postcentral, lateral occipital, left transverse temporal, lingual, precuneus, right superior temporal, fusiform cortex than Caucasians. Additionally, interactions between age and race had an impact on cortical thickness in right superior frontal cortex.ConclusionThe findings indicated that there was a significant difference in cortical thickness between cognitively healthy elderly in East Asians and in Caucasians according to the brain regions. The findings could contribute to a better understanding of the race‐specific structural change in the normal aging and provide an importance of an ethnic‐specific template for evaluating the structural and functional brain imaging in the healthy aging and neurodegenerative disease including Alzheimer’s disease.