Assessment of radiation exposure from cesium-137 contaminated roads for epidemiological studies in Seoul, Korea.

OBJECTIVES: We aimed to assess the radiation exposure for epidemiologic investigation in residents exposed to radiation from roads that were accidentally found to be contaminated with radioactive cesium-137 ((137)Cs) in Seoul. METHODS: Using information regarding the frequency and duration of passing via the (137)Cs contaminated roads or residing/working near the roads from the questionnaires that were obtained from 8875 residents and the measured radiation doses reported by the Nuclear Safety and Security Commission, we calculated the total cumulative dose of radiation exposure for each person. RESULTS: Sixty-three percent of the residents who responded to the questionnaire were considered as ever-exposed and 1% of them had a total cumulative dose of more than 10 mSv. The mean (minimum, maximum) duration of radiation exposure was 4.75 years (0.08, 11.98) and the geometric mean (minimum, maximum) of the total cumulative dose was 0.049 mSv (<0.001, 35.35) in the exposed. CONCLUSIONS: An individual exposure assessment was performed for an epidemiological study to estimate the health risk among residents living in the vicinity of (137)Cs contaminated roads. The average exposure dose in the exposed people was less than 5% of the current guideline.

Prevalence and epidemiological features of moyamoya disease in Korea.

OBJECTIVE: The objectives of the present study were to investigate the annual detection rate of patients with Moyamoya disease (MMD) and to describe the prevalence and epidemiological features of the Moyamoya patients in Korea. MATERIALS AND METHODS: The authors analyzed the epidemiological data of Korean patients taken from the National Health Insurance Corporation in Korea among Moyamoya patients who were treated from 2004 until 2008. RESULTS: Based on 2004 data, 2,539 MMD patients were treated in Korea and the prevalence rate was 5.2 per 100,000 people. There were 2,987 in 2005, 3,429 in 2006, 4,051 in 2007, and 4,517 cases in 2008, and the prevalence rates per 100.000 people were 6.3, 7.0, 8.6, and 9.1, for those respective years. This represents an annual increase of 15% of new cases during this period. In 2008, 466 people were newly diagnosed with MMD, representing an incidence rate of 1 per 100,000 persons. The gender ratio was 1,547 men (34%) and 2,970 women (66%). Women had a higher incidence rate than men (1.94 times). There were two age peaks: teenagers and those in their forties. CONCLUSION: The present study shows that the number of Moyamoya patients in Korea is increasing. This increase could partly be explained by a recent increase in newly diagnosed cases, suggesting that a more careful consideration of the disease and better diagnostic techniques should be promoted among clinicians.

Metabolic syndrome in carbon disulfide-poisoned subjects in Korea: does chemical poisoning induce metabolic syndrome?

OBJECTIVE: Mass carbon disulfide (CS(2)) poisoning was reported at a viscose rayon factory in Korea. We evaluated the association between CS(2) poisoning and the prevalence of metabolic syndrome. METHODS: The cases (n = 170) involved CS(2)-poisoned subjects, who participated in a health examination conducted at a hospital in Korea in 2005. The controls (n = 170) were selected randomly from the participants in the third Korean National Health and Nutrition Examination Survey. Metabolic syndrome was defined as having at least three of following metabolic abnormalities: abdominal obesity, elevated triglyceride, reduced high-density lipoprotein cholesterol, elevated blood pressure, and elevated fasting glucose levels. RESULTS: After adjusting for covariates (age, gender, education, marital status, alcohol consumption, and smoking), CS(2)-poisoned subjects had an increased risk of metabolic syndrome (prevalence ratio 1.57, 95% CI 1.25-1.98). CONCLUSIONS: The findings suggest that CS(2) poisoning may increase the risk of metabolic syndrome.

Assessment of vibration produced by the grinders used in the shipbuilding industry of Korea.

The objective of this study is to estimate the prevalence of finger blanching among the workers in a shipyard of Korea using the dose-response relationship suggested by ISO 5349. The characteristics of vibration exposure produced by six types of grinders were investigated. Vibration measurement was made under the real work conditions. Exposure time was estimated by questionnaire and direct observation. In addition, cold provocation tests were performed, and the results from the tests were compared with the estimated prevalence. As a result, 4 hour-energy-equivalent frequency-weighted accelerations of the finishing grinding (FG) and the prepainting grinding (PG) jobs were 6.23 m/s(2) and 13.39 m/s(2), respectively. The mean exposure time for holding the grinders was 4.64 h per day. Using the ISO 5349 method, it was predicted that after exposure to vibration for 10.79 yr, about a half of the FG workers could develop finger blanching. For the PG workers, the corresponding predicted latency was 5.02 yr. A discrepancy was found between the results from the ISO relationship and those from the cold provocation tests. A linear regression model was suggested employing vibration acceleration and vibration exposure time as explanatory variables for vascular dysfunction.

Heart-rate variability of carbon disulfide-poisoned subjects in Korea.

OBJECTIVES: Mass poisoning by carbon disulfide (CS(2)) occurred in a viscose-rayon factory in Korea. Including 38 who had died, 830 employees were diagnosed as CS(2) poisoned. We evaluated the heart-rate variability (HRV) among CS(2)-poisoned subjects, to discover whether CS(2) may affect HRV and whether its toxic effect persists after exposure has ceased. METHODS: The case group comprised 71 retired male workers with CS(2) poisoning. The control group comprised 127 public officials of the same age-range who had no history of organic-solvent exposure and cardiovascular diseases. Information on individual age, height, weight, cigarette smoking, alcohol drinking, regular exercise, medical and occupational history, and ECG recordings of the two groups were collected through medical examination and self-administered questionnaire. Time (maximum, average, minimum RR interval) and frequency domain measures [low (LF), high (HF), and total power spectrum (TPS)] of the two groups were analyzed. RESULTS: In univariate analysis, time domain measures of the two groups did not differ significantly, while frequency domain measures in the case group was significantly lower than in the control group except for HF power. In multivariate analysis, previous history of CS(2) poisoning was inversely related to all frequency domain measures and significantly affected LF power. CONCLUSIONS: This study suggests that CS(2) may cause heart-rate impairment and its toxic effect persists after exposure has ceased. Based on this study, HRV measurement can be considered as a useful tool to assess toxic effects of CS(2) both in current and retired workers.

Brain MRI findings of carbon disulfide poisoning.

OBJECTIVE: To evaluate the findings of brain MRI in patients with carbon disulfide poisoning. MATERIALS AND METHODS: Ninety-one patients who had suffered carbon disulfide poisoning [male:female=87:4; age, 32-74 (mean 53.3) years] were included in this study. To determine the extent of white matter hyperintensity (Grade 0-V) and lacunar infarction, T2-weighted MR imaging of the brain was performed. RESULTS: T2-weighted images depicted white matter hyperintensity in 70 patients (76.9%) and lacunar infarcts in 27 (29.7%). CONCLUSION: In these patients, the prevalent findings at T2-weighted MR imaging of the brain were white matter hyperintensity and lacunar infarcts. Disturbance of the cardiovascular system by carbon disulfide might account for these results.