Jhoo JH, Kim KW, Huh Y, Lee SB, Park JH, Lee JJ, Choi EA, Han C, Choo IH, Youn JC, Lee DY, Woo JI. Prevalence of dementia and its subtypes in an elderly urban korean population: results from the Korean Longitudinal Study on Health And Aging (KLoSHA). Dement Geriatr Cogn Disord. 2008;26(3):270-6. Epub 2008 Oct 8.

BACKGROUND/AIMS: We estimated the prevalence of dementia and its major subtypes in an elderly urban Korean population. METHODS: A study population of 1,118 Korean elders was randomly sampled from the residents aged 65 years or older living in Seongnam, Korea. Standardized face-to-face interviews, and neurological and physical examinations were conducted on 714 respondents. Dementia was diagnosed according to the DSM-IV diagnostic criteria, and its subtypes were determined according to the criteria of the NINCDS-ADRDA, the NINDS-AIREN, and the consensus guideline proposed by McKeith et al. [Neurology 1996;47:1113-1124]. RESULTS: The estimated age- and gender-standardized prevalences were 6.3% for dementia (95% CI = 4.5-8.1), 4.8% for Alzheimer's disease (AD; 95% CI = 3.3-6.4), 1.0% for vascular dementia (VD; 95% CI = 0.3-1.8), and 0.4% for dementia with Lewy bodies (DLB; 95% CI = 0.0-0.9). The prevalence of AD consistently increased with age, whereas that of VD peaked at age 75-79 years and decreased thereafter. Of the dementia patients, 72.0% were in the very mild or mild stages of the disease. CONCLUSIONS: The prevalence of dementia in a typical urban area of Korea was estimated to be 6.3%, and AD was the most prevalent subtype. DLB was less prevalent than VD among these community-dwelling Korean elders. Copyright 2008 S. Karger AG, Basel.

Lee JY, Chang SM, Jang HS, Chang JS, Suh GH, Jung HY, Jeon HJ, Cho MJ. Illiteracy and the incidence of Alzheimer's disease in the Yonchon County survey, Korea. Int Psychogeriatr. 2008 Oct;20(5):976-85. Epub 2008 May 1.

BACKGROUND: This study aims to establish the incidence rates of Alzheimer's disease (AD) and to understand the relations between illiteracy and AD in the Korean Yonchon survey cohort. METHODS: A community-based, dementia-free cohort of 966 people aged 65 years and older was followed up for an average of 5.4 +/- 1.60 years to detect incident AD cases using a two-phase procedure. Age-specific incidence rates were calculated using a person-years approach with Poisson distribution confidence intervals. Data were analyzed using the Cox proportional hazards model to find the hazard ratio of illiteracy. RESULTS: The participating percentage of the survivors was 86.4% and 74 subjects were diagnosed with AD. Incidence rates per 1000 person-years were 20.99 (95% CI 16.48 to 26.35) for AD. The hazard ratio of illiteracy was 1.78 (95% CI 1.08 to 2.93) adjusted for age, sex, educational level. AD developed more rapidly with aging in the illiterate group than in the literate group. CONCLUSIONS: Illiteracy is associated with a higher risk of AD and the risk increases with age.

Kim JM, Stewart R, Shin IS, Kim SW, Yang SJ, Yoon JS. Associations between head circumference, leg length and dementia in a Korean population. Int J Geriatr Psychiatry. 2008 Jan;23(1):41-8.

BACKGROUND: Adult leg length is influenced by nutritional intake in childhood. Shorter leg length has been found to be associated with adverse health outcomes in late life, including dementia. Smaller head circumference has also been found to be associated with dementia. The independence of these two potential markers of risk for dementia has not been investigated. METHODS: Community residents aged 65 or over (n = 916) within a defined geographic area of South Korea were screened clinically for dementia and dementia subtypes. Data on anthropometric measures (head circumference and leg length), demographics (age, gender), apolipoprotein E, and early life environment (birth order, number of siblings, parental occupation, area of residence, education) were gathered. Reproductive history was also ascertained in women. RESULTS: Both smaller head circumference and shorter leg length were associated with increased age, rural residence in childhood and lower education. After adjustment for these factors, they were both independently associated with Alzheimer's disease but only in women. CONCLUSIONS: Smaller head size and shorter limb length were associated with lower early-life socio-economic status. Both factors were apparently independent markers of risk for dementia which may indicate risk factors occurring in childhood affecting both brain and skeletal development. Associations were principally present in women. Reasons for gender differences in associations require clarification but, for this population and age group, may include preferential treatment of male children.

Shah A, Ellanchenny N, Suh GH. A comparative study of behavioral and psychological symptoms of dementia in patients with Alzheimer's disease and vascular dementia referred to psychogeriatric services in Korea and the U.K. Int Psychogeriatr. 2005 Jun;17(2):207-19.

BACKGROUND: There is a paucity of cross-cultural studies of behavioral and psychological symptoms of dementia (BPSD). METHOD: BPSD were examined in consecutive series of referrals to a psychogeriatric service in Korea and the U.K. using the Behavioral Pathology in Alzheimer's Disease (BEHAVE-AD) rating scale and the Cornell Scale for Depression in Dementia (CSDD). Results were analyzed separately for Alzheimer's disease and vascular dementia. RESULTS: Koreans in both diagnostic groups had lower Mini-mental State Examination (MMSE) scores and higher BEHAVE-AD total and subscale scores for most subscales. In both countries, for both diagnostic groups, the total BEHAVE-AD score and several subscale scores were negatively correlated with the MMSE scores. Logistic regression analysis for Alzheimer's disease revealed that BEHAVE-AD total and most subscale scores independently predicted the country of origin in addition to the MMSE scores predicting the same. CONCLUSIONS: These differences in BPSD are most likely explained by the lower MMSE scores in the Korean sample. However, genuine differences in BPSD between the two countries can only be critically examined in a cross-cultural population-based epidemiological study for both diagnostic categories using validated instruments to measure BPSD and controlling for the influence of MMSE score.

Suh GH, Kim JK, Cho MJ. Community study of dementia in the older Korean rural population. Aust N Z J Psychiatry. 2003 Oct;37(5):606-12.

OBJECTIVE: This study aims to estimate the prevalence of all dementias, including Alzheimer's disease (AD) and vascular dementia (VaD) in a population of Korean elderly and to identify possible risk factors which correlated with specific types of dementia. METHOD: A two-phase survey, based on a door-to-door survey, was conducted. Initially, the Korean version of the Psychogeriatric Assessment Scale (PAS-K) was administered to all 1037 participants aged 65 years and older. Three hundred and seventy people sampled from the case groups (n = 320) of PAS-K subscales and the non-case group (n = 50) entered the second phase for clinical evaluation. Dementia was defined using the DSM-III-R, NINCDS-ADRDA and NINDS-AIREN criteria. RESULTS: Among 1037 elderly people aged 65-94 years who completed the interview, 74 cases of dementia were detected, giving an overall age-standardized prevalence (95% CI) of 6.8% (6.1-7.5) (male 6.3%[5.3-7.4]; female 7.1%[6.1-8.0]). The prevalence (95% CI) of AD was 4.2% (3.6-4.7) (male 2.4%[2.0-2.8]; female 5.3%[4.5-6.1]), and it increased with age. The prevalence (95% CI) of VaD was 2.4% (2.0-2.8) (male 3.5%[2.7-4.3]; female 1.6%[1.2-2.1]). Smoking for longer than 30 pack-years significantly increased the risk of VaD (OR = 11.5 [2.8-44,6]). CONCLUSION: Long-term smoking, much more prevalent in men, may be closely related to higher risk of cerebrovascular disease that leads to vascular dementia.

Woo JI, Lee JH, Yoo KY, Kim CY, Kim YI, Shin YS. Prevalence estimation of dementia in a rural area of Korea. J Am Geriatr Soc. 1998 Aug;46(8):983-7.

OBJECTIVES: A cross-sectional survey was conducted to estimate prevalence of dementia and to determine factors related to dementia among residents in a rural area, Yonchon county, Korea, in 1993. PARTICIPANTS: Of the study population more than 65 years of age (n = 2171), 1674 persons participated in the cross-sectional survey using the Korean version of the Mini-Mental State Examination (MMSE-K). DESIGN: Subjects were defined as having dementia according to NINCDS-ADRDA criteria through direct interview by psychiatrists. A total of 436 subjects were selected randomly according to MMSE-K scores, and cases were confirmed as having either Alzheimer's or vascular dementia. RESULTS: The adjusted prevalence of dementia was estimated at 9.5%. The prevalence of total dementia was 8.8% for men and 9.9% for women. The prevalence of Alzheimer's disease was 3.2% for men and 5.3% for women and that of vascular dementia 3.1% and 2.1%, respectively. Age-standardized prevalence of Alzheimer's disease was 4.5%, whereas that of vascular dementia was 2.5%. Using DSM-III-R criteria to stratify dementia patients according to severity showed the prevalence of mild, moderate, and severe Alzheimer's disease was 3.4%, 0.7%, and 0.5%, respectively. CONCLUSION: These results showed that the prevalence of dementia in Korea was similar to its presence in Western countries but different from that previously reported in other Asian countries, e.g., China and Japan.