Interaction of white matter hyperintensities (WMHs) and apolipoprotein E (APOE) genotypes on cognition in patients with amnestic mild cognitive impairment (aMCI).

The clinical implications of WMHs in aMCI are inconclusive. Moreover, clinical interactions between APOE genotypes and WMHs remain unclear. This study was conducted to investigate the relationship between WMHs and cognitive functions and how this relationship interacted with APOE genotype in people with aMCI. This study included a total of 1472 patients with aMCI from the Clinical Research Center for Dementia of South Korea (CREDOS) and divided them into 3 groups according to the severity of WMHs as assessed by visual ratings of brain magnetic resonance images. The associations of WMHs with the various cognitive domains and with APOE epsilon 4 (ɛ4) status were evaluated. After multivariable adjustments, the severity of WMHs was independently associated with semantic/phonemic verbal fluency and Stroop test-color reading, while APOE ɛ4 status was associated with verbal and visual memory-immediate, delayed recall, and recognition. Moreover, there were interaction between WMHs and APOE ɛ4 status in semantic verbal fluency (animal, P=0.033; supermarket, P=0.047)/Stroop test-color reading (P=0.024). WMHs independently deleteriously affected frontal executive functions in aMCI patients, regardless of APOE ɛ4 presence. Furthermore, APOE ɛ4 possession caused a rapid decline in frontal executive functions with the increase in the WMHs severity (vs. absence), suggesting that WMHs and APOE ɛ4 genotypes synergistically contribute to frontal executive dysfunctions in aMCI.

Clinical characteristics of a nationwide hospital-based registry of mild-to-moderate Alzheimer's disease patients in Korea: a CREDOS (Clinical Research Center for Dementia of South Korea) study.

With rapid population aging, the socioeconomic burden caused by dementia care is snowballing. Although a few community-based studies of Alzheimer's disease (AD) have been performed in Korea, there has never been a nationwide hospital-based study thereof. We aimed to identify the demographics and clinical characteristics of mild-to-moderate AD patients from the Clinical Research Center for Dementia of Korea (CREDOS) registry. A total of 1,786 patients were consecutively included from September 2005 to June 2010. Each patient underwent comprehensive neurological examination, interview for caregivers, laboratory investigations, neuropsychological tests, and brain MRI. The mean age was 74.0 yr and the female percentage 67.0%. The mean period of education was 7.1 yr and the frequency of early-onset AD (< 65 yr old) was 18.8%. Among the vascular risk factors, hypertension (48.9%) and diabetes mellitus (22.3%) were the most frequent. The mean score of the Korean version of Mini-Mental State Examination (K-MMSE) was 19.2 and the mean sum of box scores of Clinical Dementia Rating (CDR-SB) 5.1. Based on the well-structured, nationwide, and hospital-based registry, this study provides the unique clinical characteristics of AD and emphasizes the importance of vascular factors in AD in Korea.