Hae-Kwan Cheong

Systematic review of health behavioral risks and cognitive health in older adults

BACKGROUND An increasing body of evidence suggests that health behaviors may protect against cognitive impairment and dementia. The purpose of this study was to summarize the current evidence on health behavioral factors predicting cognitive health through a systematic review of the published literature. METHODS PubMed, Embase, and PsycINFO databases were searched for studies on community representative samples aged 65 and older, with prospective cohort design and multivariate analysis. The outcome--cognitive health--was defined as a continuum of cognitive function ranging from cognitive decline to impairment and dementia, and health behaviors included physical activity, smoking, alcohol drinking, body mass index, and diet and nutrition. RESULTS Of 12,105 abstracts identified, 690 relevant full-texts were reviewed. The final yield amounted to 115 articles of which 37 studies were chosen that met the highest standards of quality. Leisure time physical activity, even of moderate level, showed protective effects against dementia, whereas smoking elevated the risk of Alzheimers disease. Moderate alcohol consumption tended to be protective against cognitive decline and dementia, but nondrinkers and frequent drinkers exhibited a higher risk for dementia and cognitive impairment. Midlife obesity had an adverse effect on cognitive function in later life. Analysis showed vegetable and fish consumption to be of benefit, whereas, persons consuming a diet high in saturated fat had an increased dementia risk. CONCLUSION The review demonstrates accumulating evidence supporting health behavioral effects in reducing the risk of cognitive decline and dementia. Results indicate potential benefits of healthy lifestyles in protecting cognitive health in later life.

Characteristic Profiles of Instrumental Activities of Daily Living in Different Subtypes of Mild Cognitive Impairment

Background/Aims: The purposes of this study were to describe restrictions in instrumental activities of daily living (IADL) in mild cognitive impairment (MCI) and to assess different patterns of IADL in each MCI subtype. Methods: A total of 566 participants, those not cognitively impaired (NCI; n = 311) and MCI patients (n = 255), 60–94 years old (71.25 ± 6.00), were examined. Neuropsychological tests were administered to participants, and each MCI patient was classified into one of four subtypes. They completed the Barthel ADL and Seoul-IADL (S-IADL) for ADL measures. Results: There was a significant difference between NCI and MCI in terms of total S-IADL scores. ANOVA and a post hoc Dunnett analysis revealed that MCI patients performed significantly worse on four out of a total 15 items (i.e. telephone, transportation, finances and household appliances). ANCOVA showed a significant difference in S-IADL-MCI (4 of 15 items) between NCI and amnestic MCI-multiple domains after adjusting for age, gender, education and Geriatric Depression Scale (F = 4.257, d.f. = 1,556, p = 0.002). Conclusion: These findings suggest that scorings of specific IADL items are different in MCI subjects, and these items can possibly help in the identification of MCI subtypes, especially amnestic MCI-multiple domains.

Cortical thinning related to periventricular and deep white matter hyperintensities

Previous studies showed that white matter hyperintensities (WMH) are related to cognitive decline in patients with mild cognitive impairment (MCI) or dementia. Moreover, periventricular WMH (periventricular white matter hyperintensities (PWMH)) and deep WMH (deep white matter hyperintensities (DWMH)) may have different effects on cognition. The purpose of this study is to investigate the contributions of PWMH and DWMH to the topography of cortical thinning and to investigate the relationship among WMH, cortical thinning, and cognitive impairments. Participants included 226 patients with Alzheimers disease or subcortical vascular dementia, and 135 patients with amnestic MCI or subcortical vascular MCI. Cortical thickness was measured using the surface based method. The topography of cortical thinning related to WMH was distributed in the frontal and perisylvian regions, which was similar to that of PWMH. In contrast, there were only small areas of cortical thinning inversely associated with DWMH, which were distributed in medial frontal and lingual gyrus. PWMH, but not DWMH, were associated with the frontal thinning and executive dysfunction; where both PWMH and frontal thinning were independently associated with executive dysfunction. Our results suggest that PWMH are associated with frontal thinning, which is further associated with frontal executive dysfunction.

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 Alzheimers 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.

Clinical features and outcome of community-onset bloodstream infections caused by extended-spectrum β-lactamase-producing Escherichia coli

This study was conducted to evaluate the epidemiology and clinical features of bloodstream infections caused by extended-spectrum β-lactamase-producing E. coli (ESBL-EC) in community-onset bacteremia. Of 929 episodes of community-onset E. coli bacteremia, 4.1% (38/929) had bacteremia with ESBL producers. Of these, 63.2% (24/38) were further classified as healthcare-associated infections. Although most patients had risk factors for infection due to ESBL producers, three patients with urinary tract infection, four patients with cholangitis, and one patient with a liver abscess had no identified predisposing risk factors. The 30-day mortality was 21.1% (8/38). ESBL-EC is a significant cause of bloodstream infection, even in patients with community-onset infection.

A new classification system for ischemia using a combination of deep and periventricular white matter hyperintensities.

The Clinical Research Center for Dementia of South Korea (CREDOS) group developed a new classification system for ischemia using a combination of deep and periventricular white matter hyperintensities (WMHs). In this study, we aimed to evaluate the validity of the CREDOS ischemia classification system. A total of 352 patients with cognitive impairments were included. Their WMH scores were rated using the CREDOS WMH visual rating scale. These patients were divided into 3 groups according to the CREDOS ischemia classification system. The volume of WMH was also automatically measured. The number of lacunes and microbleeds (MBs) were counted. The CREDOS ischemia classification system was revised with factor analysis using vascular risk factors and cerebrovascular disease (CVD) markers (WMH volume, lacunes, and MBs). External validation was performed in another group of patients with cognitive impairment using multinomial logistic regression analysis. The CREDOS WMH visual rating scale showed excellent correlation with the automatically measured volume of WMH. The factor analysis showed that the severe group was expanded to D3P1 and D3P2 in the revised CREDOS ischemia classification system. In the validation group, the presence of vascular risk factors and the severity of CVD markers could be distinguished according to the revised CREDOS ischemia classification. We validated a newly developed classification system for ischemia. This simple visual classification system was capable of providing information on vascular risk factors and CVD markers by simply rating WMH on magnetic resonance imaging.

Impact of white matter changes on activities of daily living in mild to moderate dementia.

The association between white matter changes and activities of daily living (ADL) in a large, well-defined cohort of patients with mild-to-moderate dementia (either Alzheimer’s disease or subcortical vascular dementia) were investigated. A total of 289 patients were divided into three groups (140 mild, 99 moderate, and 50 severe) depending on the degree of white matter changes as indicated on brain magnetic resonance image scans. Further, we analyzed the three groups’ performances on basic and instrumental ADL. The degree of white matter changes was associated with greater age, hypertension, previous history of stroke, higher Hachinski Ischemic Score, worse global cognitive and functional status, and an increased impairment of basic ADL and instrumental ADL. The increased impairment with regard to the severe group’s performance on both the basic and instrumental ADL remained significant after adjustment for age and hypertension. Tasks involving physical activities were most significant. This was the first study investigating the association between white matter changes and ADL in a large, well-defined dementia cohort. The present study suggests that severe white matter changes may be associated with higher impairment on both basic and instrumental ADL.

Cardiovascular risk factors cause cortical thinning in cognitively impaired patients: relationships among cardiovascular risk factors, white matter hyperintensities, and cortical atrophy.

Cardiovascular risk factors are associated with cognitive impairments. However, the effects of cardiovascular risk factors on the topography of cortical thinning have not yet been studied in patients with mild cognitive impairment (MCI) or dementia. Thus, we aimed to evaluate the topography of cortical thinning related to cardiovascular risk factors and the relationships among cardiovascular risk factors, white matter hyperintensities (WMH), and cortical atrophy. Participants included 226 patients with Alzheimer disease or subcortical vascular dementia and 135 patients with amnestic MCI or subcortical vascular MCI. We automatically measured the volume of WMH and cortical thickness. Hypertension was associated with cortical thinning in the frontal and perisylvian regions, and cortical thinning related to diabetes mellitus (DM) occurred in the frontal region. In path analyses, hypertension accounted for 0.04 of the frontal thinning with the mediation of WMH and 0.16 without the mediation of WMH. In case of DM, it accounted for 0.02 of the frontal thinning with the mediation of WMH and 0.13 without the mediation of WMH. Hypertension and DM predominantly affected frontal thinning both with and without the mediation of WMH, where the effects without the mediation of WMH were greater than those with the mediation of WMH.

Effects of Medial Temporal Atrophy and White Matter Hyperintensities on the Cognitive Functions in Patients with Alzheimer’s Disease

Aims: We conducted this study to investigate the independent association of medial temporal atrophy (MTA) and white matter hyperintensities (WMH) with cognitive impairments of Alzheimer’s disease (AD) patients and the interaction between MTA and WMH. Methods: From 13 centers, a total of 216 AD patients were consecutively recruited and their MTA and WMH were visually rated. We evaluated the association of MTA and WMH with the various cognitive domains, and the interaction between MTA and WMH. Results: MTA independently correlated with scores of the Mini-Mental State Examination (MMSE), Clinical Dementia Rating scale (CDR), delayed recalls of the Seoul Verbal Learning Test (SVLT), the Boston Naming Test (BNT), and Word Fluency. WMH independently correlated with MMSE, CDR, Digit Span, and Stroop word reading, but not with delayed recall. There were interactions of WMH and MTA on CDR (p = 0.004), SVLT (p = 0.023), BNT (p = 0.002) and the semantic Word Fluency (p = 0.007). Conclusion: MTA and WMH independently affected cognitive deficits in AD patients, with somewhat different patterns where MTA was associated mostly with memory and language, while WMH were associated with attention and frontal executive functions. This study also showed interactions between MTA and WMH on some cognitive deficits and dementia severity, suggesting that they synergistically contribute to cognitive impairment in AD.

Urinary metabolites before and after cleanup and subjective symptoms in volunteer participants in cleanup of the Hebei Spirit oil spill.

BACKGROUND On December 7th, 2007, the Hong Kong tanker Hebei Spirit (HS) (146,848 tons) was crushed by a crane ship near the shore of Taean, Korea. More than 12,547 kl of crude oil spilled into the sea and contaminated the western coastline of the Korean peninsula. For a period of six months after the accident, approximately 1,000,000 volunteers participated in the cleanup. Our goal in this study was to examine the exposure status and acute health effects on volunteers that participated in the oil spill cleanup. METHODS A survey questionnaire was filled out by 565 volunteers, requesting information regarding physical symptoms. Out of the total number of participants, urine samples from 105 university student volunteers were collected before and after the cleanup work, and metabolite levels of volatile organic compounds and polycyclic aromatic hydrocarbons were analyzed. RESULTS Volunteers that participated for longer cleanup work reported an increase in physical symptoms including visual disturbance, nasal and bronchus irritation, headaches, heart palpitations, fatigue and fever, memory and cognitive disturbance, and abdominal pain. The levels of t,t-muconic acid, mandelic acid, and 1-hydroxypyrene were significantly higher in samples after cleanup than those measured before participation (p<0.05). Other than the associated risk of dermal irritation with the difference in the t,t-muconic acid level between the post- to pre-cleanup levels, no other physical symptoms demonstrated a significant association with changes observed in the levels of urinary metabolites. CONCLUSIONS Based on the significant increase of subjective symptoms in volunteers participating in the study, monitoring of the long term health effects, focusing on those with longer exposure, is warranted.