[Apolipoprotein e polymorphism and cognitive function change of the elderly in a rural area, Korea].

OBJECTIVES: The aim of this study is to examine the cognitive function change related to aging, the incidence of cognitive impairment, and the association between apolipoprotein E polymorphism and cognitive impairment through a follow-up of the elderly with normal cognitive ability at baseline. METHODS: Two hundred and fifteen subjects aged 65 and over were surveyed in February, 1998 (baseline survey), and their cognitive function was assessed again in 2003 (1st follow-up) and the once again in 2006 (2nd follow-up). Ninety one subjects completed all surveys up through the 2nd follow-up and their cognitive function scores using MMSE-K (Korean Version of the Mini-Mental State Examination) and the distribution of apolipoprotein E allele were analyzed. RESULTS: The cognitive function scores decreased with aging and the difference between baseline and the 2nd follow-up scores of the study increased with the age group. The incidence rate of cognitive impairment through an 8-year follow-up was 38.5% and higher in older age groups. Age was the only significant factor for incidence of cognitive impairment, but there was no significant association between apolipoprotein E genotype and incidence of cognitive impairment. CONCLUSIONS: The cognition of the elderly decreased with aging and the association of apolipoprotein E genotype with incidence of cognitive impairment was not significant in this study. To confirm the association between apolipoprotein E polymorphism and incidence of cognitive impairment further studies will be needed.

[Change of cognitive function and associated factors among the rural elderly: a 5-year follow-up study].

OBJECTIVES: This prospective population-based cohort study was conducted to evaluate the risk factors of cognitive impairment and the degree of cognitive function change through a 5-year follow-up. METHODS: The baseline and follow-up surveys were conducted in 1998 and 2003, respectively. Among 176 subjects who had normal cognitive function in the baseline study, 136 were followed up for 5 years. The cognitive function was investigated using the Korean version of the Mini-Mental State Examination (MMSE-K). The collected data were analyzed using SPSS and Stata. RESULTS: Of the 136 subjects analyzed, 25 (18.4%) were cognitively impaired. Old age and low social support in the baseline survey were risk factors for cognitive impairment after 5 years. In the generalized estimating equation for 128 subjects except severe cognitive impairment about the contributing factors of cognitive function change, the interval of 5 years decreased MMSE-K score by 1.02 and the cognitive function was adversely affected with increasing age, decreasing education and decreasing social support. CONCLUSIONS: Although the study population was small, it was considered that the study results can be used to develop a community-based prevention system for cognitive impairment.

Evaluation of reliability of traditional and computerized neurobehavioral tests.

Most Korean blue-collar workers are taking government-mandated medical screening periodically. The periodic neurobehavioral test provides a great chance to evaluate the functional change of the central nervous system. To utilize periodic neurobehavioral tests effectively, the reliability of currently used neurobehavioral tests needs to be evaluated. Test-retest of neurobehavioral tests were conducted to evaluate the reliability of neurobehavioral tests that are commonly used for Korean workers. The test-retest of five computerized tests, simple reaction time, additions, symbol digit, digit span, and finger tapping speed, and five traditional tests, Benton visual retention, digit symbol, digit span, pursuit aiming, and pegboard, were administered to 85 college students and 35 hospital workers over a 1 month interval. Computerized additions was found to have the highest test-retest reliability coefficient (r=0.90), followed by finger tapping speed (nondominant hand, r=0.89; dominant hand, r=0.85), symbol digit (r=0.82), and digit span (r=0.74). However, only two traditional tests, digit symbol (r=0.86) and pursuit aiming (r=0.72), showed a reliability coefficient greater than 0.70. These results suggest that the computerized additions, symbol digit, finger tapping speed, and traditional digit symbol are more satisfactory for periodical evaluation of the central nervous system of workers exposed to neurotoxic substances in Korea.

[Effects of the personal stereo system on hearing in adolescents].

OBJECTIVES: This study was conducted to evaluate the effects of the personal stereo system on the hearing in adolescents. METHODS: A total of 68 adolescents (age: 13-18 years) who visited the ENT Department at a University Hospital in Daegu were personally interviewed. The questionnaires were about general characteristics of the subjects, the time of personal stereo system use (year, hour) and place. Cumulative exposure to the personal stereo system was calculated by the product of the total years and the daily hours of their use. Pure tone audiometry was performed and the hearing threshold was measured at 500, 1000, 2000, 4000 and 8000 Hz. RESULTS: The average time of using a personal stereo system a day was about 3 hours and 75% of the subjects used a personal stereo system for 2-5 years. The elevation of threshold was more prominent in the subjects who used personal stereo systems for 4 years and more compared with those subjects who used them for 3 years and under. The elevation of hearing threshold was also more prominent in the subjects who used personal stereo systems for 4 hours and more a day compared with those subjects who used personal stereo systems for 3 hours and under a day. The elevation of hearing threshold was more prominent in the subjects who used personal stereo systems for 13 hour x years and more compared to the subjects who used them 12 hour x years and under. CONCLUSIONS: These results suggest that the elevation of hearing threshold can happen to adolescents who used personal stereo systems for a long time. In order to prevent hearing loss, we need to teach adolescents appropriate usage of the personal stereo system and hearing tests should be included in the periodic school-based physical examination for the adolescents.

[Helicobacter pylori reinfection rate and its related factors after successful eradication: 4-year follow-up in a Korean rural community].

BACKGROUND/AIMS: Recurrence of peptic ulcer after successful eradication of Helicobacter pylori is closely associated with reinfection. The aim of this study was to measure the rate and related factors of H. pylori reinfection through a 4-year follow-up excluding recrudescence. METHODS: Triple therapy was administered to H. pylori-positive 204 people in April 1998 in Gyeongju, Korea. The urea breath test was performed in April 1999. Eighty-seven subjects were regarded as negative for H. pylori, and they were followed up for 4 years to analyze the trends of reinfection rate and its related factors. Sixty-seven subjects completed the 4-year follow-up. During the follow-up period the urea breath test and questionnaire surveys were performed in April 2000, October 2001, and April 2003. RESULTS: The cumulative reinfection rate was 16.4% for 4 years, and the yearly reinfection rate was 4.1%. The reinfection rate of subjects having postprandial fullness and epigastric bloating was significantly high (p<0.05), and that of the subjects with high dyspepsia symptom scores (4 or 5) was also significantly higher than those with low dyspepsia symptom scores (3 or below)(p=0.016). According to the multiple logistic regression analysis to predict the factors related with H. pylori reinfection, the dyspepsia symptom score was the only significant variable with the odds ratio of 1.688. CONCLUSIONS: The cumulative reinfection rate for 4 years was 16.4% in a Korean rural community. The dyspepsia symptom score can be used to predict H. pylori reinfection in community population.

Cross-cultural comparison of neurobehavioral performance in Asian workers.

Widely-used neurobehavioral tests have been developed and standardized on Western populations, but studies on subject factors for Asian populations have been very limited. For the effective application and interpretation of neurobehavioral tests in Asian populations, an evaluation of the effects of subject factors, including cultural background, is necessary. A cross-cultural study was conducted to evaluate the effects of cultural background and the interaction between cultural background and education on neurobehavioral tests in Asian populations. The Korean version of the Swedish Performance Evaluation System (Simple Reaction Time, Symbol Digit, and Finger Tapping Speed) and a pegboard test were administered to 537 workers who were not exposed to chemicals at work from Fareast (Korea and Chinese), Central (Uzbekistan and Tajikistan), and South Asia (Sri Lanka and Indonesia). The Fareast Asian group exhibited better performance in adjusted test scores than other Asian groups, achieving significance for Symbol Digit and Finger Tapping Speed in both genders. The magnitude of the effect of cultural background on Symbol Digit was comparable to the effect of about 10 years of education. Cultural background did not modify the relation between years of education and Symbol Digit in either males or females. This study may provide the first evidence that cultural background has a large impact on neurobehavioral test performance, even within Asian populations, and suggests that cultural background is a critical confounding factor that must be controlled in epidemiologic studies which include Asian populations in the sample.