Browsing by Author "Kim, Ki-Woong"

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    APOE Promoter Polymorphism-219T/G is an Effect Modifier of the Influence of APOE ε4 on Alzheimer's Disease Risk in a Multiracial Sample
    (MDPI, 2019-08-16) Choi, Kyu Yeong; Lee, Jang Jae; Gunasekaran, Tamil Iniyan; Kang, Sarang; Lee, Wooje; Jeong, Jangho; Lim, Ho Jae; Zhang, Xiaoling; Zhu, Congcong; Won, So-Yoon; Choi, Yu Yong; Seo, Eun Hyun; Lee, Seok Cheol; Gim, Jungsoo; Chung, Ji Yeon; Chong, Ari; Byun, Min Soo; Seo, Sujin; Ko, Pan-Woo; Han, Ji-Won; McLean, Catriona; Farrell, John; Lunetta, Kathryn L.; Miyashita, Akinori; Hara, Norikazu; Won, Sungho; Choi, Seong-Min; Ha, Jung-Min; Jeong, Jee Hyang; Kuwano, Ryozo; Song, Min Kyung; An, Seong Soo A.; Lee, Young Min; Park, Kyung Won; Lee, Ho-Won; Choi, Seong Hye; Rhee, Sangmyung; Song, Woo Keun; Lee, Jung Sup; Mayeux, Richard; Haines, Jonathan L.; Pericak-Vance, Margaret A.; Choo, IL Han; Nho, Kwangsik; Kim, Ki-Woong; Lee, Dong Young; Kim, SangYun; Kim, Byeong C.; Kim, Hoowon; Jun, Gyungah R.; Schellenberg, Gerard D.; Ikeuchi, Takeshi; Farrer, Lindsay A.; Lee, Kun Ho; Radiology and Imaging Sciences, School of Medicine
    Variants in the APOE gene region may explain ethnic differences in the association of Alzheimer's disease (AD) with ε4. Ethnic differences in allele frequencies for three APOE region SNPs (single nucleotide polymorphisms) were identified and tested for association in 19,398 East Asians (EastA), including Koreans and Japanese, 15,836 European ancestry (EuroA) individuals, and 4985 African Americans, and with brain imaging measures of cortical atrophy in sub-samples of Koreans and EuroAs. Among ε4/ε4 individuals, AD risk increased substantially in a dose-dependent manner with the number of APOE promoter SNP rs405509 T alleles in EastAs (TT: OR (odds ratio) = 27.02, p = 8.80 × 10-94; GT: OR = 15.87, p = 2.62 × 10-9) and EuroAs (TT: OR = 18.13, p = 2.69 × 10-108; GT: OR = 12.63, p = 3.44 × 10-64), and rs405509-T homozygotes had a younger onset and more severe cortical atrophy than those with G-allele. Functional experiments using APOE promoter fragments demonstrated that TT lowered APOE expression in human brain and serum. The modifying effect of rs405509 genotype explained much of the ethnic variability in the AD/ε4 association, and increasing APOE expression might lower AD risk among ε4 homozygotes.
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    Correlates of Gait Speed Among Older Adults From 6 Countries: Findings From the COSMIC Collaboration
    (Oxford University Press, 2023) Sprague, Briana N.; Zhu, Xiaonan; Rosso, Andrea L.; Verghese, Joe; Delbaere, Kim; Lipnicki, Darren M.; Sachdev, Perminder S.; Ng, Tze Pin; Gwee, Xinyi; Yap, Keng Bee; Kim, Ki-Woong; Han, Ji Won; Oh, Dae Jong; Narazaki, Kenji; Chen, Tao; Chen, Sanmei; Brodaty, Henry; Numbers, Katya; Kochan, Nicole A.; Walker, Richard W.; Paddick, Stella-Maria; Gureje, Oye; Ojagbemi, Akin; Bello, Toyin; Rosano, Caterina; COSMIC Consortium; Medicine, School of Medicine
    Background: Few studies have compared gait speed and its correlates among different ethnogeographic regions. The goals of this study were to describe usual and rapid gait speed, and identify their correlates across Australian, Asian, and African countries. Methods: We used data from 6 population-based cohorts of adults aged 65+ from 6 countries and 3 continents (N = 6 472), with samples ranging from 231 to 1 913. All cohorts are members of the Cohort Studies of Memory in an International Consortium collaboration. We investigated whether clinical (body mass index [BMI], hypertension, stroke, apolipoprotein status), psychological (cognition, mood, general health), and behavioral factors (smoking, drinking, physical activity) correlated with usual (N = 4 cohorts) and rapid gait speed (N = 3 cohorts) similarly across cohorts. Regression models were controlled for age, sex, and education, and were sex-stratified. Results: Age- and sex-standardized usual gait speed means ranged from 0.61 to 1.06 m/s and rapid gait speed means ranged from 1.16 to 1.64 m/s. Lower BMI and better cognitive function consistently correlated with faster gait speed in all cohorts. Less consistently, not having hypertension and greater physical activity engagement were associated with faster gait speed. Associations with mood, smoking, and drinking were largely nonsignificant. These patterns were not attenuated by demographics. There was limited evidence that the associations differed by sex, except physical activity, where the greater intensity was associated with usual gait among men but not women. Conclusions: This study is among the first to describe the usual and rapid gait speeds across older adults in Africa, Asia, and Australia.