Epidemiology and Health

Volume 21 (2); December 1999

Original Articles

Occupational Cancer Surveillance System Using Data Linkage Analysis in Korea.: Sang Yun Lee, Jaiyong Kim, Seongwoo Choi, Hyungjun Im, Kijung Yoon, Ho Jang Kwon, Soo Hun Cho, Daehee Kang; Korean J Epidemiol. 1999;21(2):276-282.

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To develop the occupational cancer surveillance system in Korea, data linkage analysis was performed on the subjects of Health-monitoring-pocketbook (the list of subjects who were exposed to selected occupational carcinogens) and the retired workers of a cokes manufacturing factory using the Korean medical insurance data, Korean death certificate data and Korean cancer registry data. Study subjects comprised the 822 retired subjects and the 3101 present-post subjects of Health-monitoring-pocketbook and the 182 retired workers of a cokes manufacturing factory. The incidence of cancer of these study subjects was ascertained by linkage of Korean medical insurance data of year 1995-6, Korean death certificate data of year 1992-8 and Korean cancer registry data of year 1993-5. In the study subjects, Eighty seven percent were males and mean age was 39.3+/-8.9 year-old, Average work duration was 8.0+/-5.5 years. Chrome, asbestos and cokes were the most frequent exposed agents. In the study subjects, total 13 cancer cases were ascertained by data linkage analysis. In the ascertained cancer cases, 8 cases were male and 5 cases were female, and 7 cases were aged 40-49 yr, 5 cases were aged 50-59 yr and 1 cases were aged 30-39 yr. The commonest exposure agent in the ascertained cancer cases was asbestos and cokes. By the site of cancer, 3 stomach cancer cases, 2 hematopoietic cancer cases and 2 biliary tract cancer cases were ascertained. The occupational cancer surveillance system using data linkage analysis on the workers exposed to hazardous agents was the most feasible and efficient method in Korea. And to do this, establishment of occupational history information in several disease registry database is needed with the effort of estimating the proper size of workers exposed hazardous agents.; Summary

The Usefulness of the Secondary Database for Occupational Asthma Surveillance System in Korea.: Hyungjune Im, Sungwoo Choi, Jaiyong Kim, Sang Yun Lee, Kijung Yoon, Youngju Lee, Ho Jang Kwon, Daehee Kang, Soo Hun Cho; Korean J Epidemiol. 1999;21(2):266-275.

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Occupational asthma is defined as a disease that is characterized by airway narrowing and bronchial hyperresponsiveness caused by specific working environment. It is estimated that occupational asthma cases in Korea have been underreported. This study, using Korean Medical Insurance Data(KMID), examined the distribution of asthma patients' occupations and the frequency of high risk occupations for occupational asthma in Seoul, Korea to evaluate the usefulness of the KMID data as a database for active occupational asthma surveillance system. Six hundreds and forty two(30.7%) of 2093 patients who were finally chosen as a study population by using 1995-year KMID, were contacted by telephone. 296 persons(47.4%) of 642 patients replied that they were diagnosed as asthma. The occupations of 296 asthma patients were classified by Korean standardized industrial classfication (KSIC). The most common occupations included Wholesale and Retail trade(19.5%), Real estate, Renting and Business activities(14.9%), Construction(14.9%), Manufacturing(12.3%). Forty(13.5%) of 296 patients who could be classified by KSIC were working at high risk jobs for occupational asthma. KMID could be used as a useful data for occupational asthma surveillance system if the limitations of KMID, which is the accuracy of diagnosis, data accessibility, difficulty of following up study subjects, would be solved. The prevalence of occupational asthma could be estimated if the follow-up study diagnosing occupational asthma for asthma patients working in high risk jobs would be held.; Summary

Obesity and Physical Activity Related to Colorectal Adenoma by Anatomic Sites in Korea.: Mi Kyung Kim, Won Chul Lee, Kyu Yong Choi, Se Young Lee, Sukil Kim, Yang Cha Lee-Kim, Kwang Ho Meng; Korean J Epidemiol. 1999;21(2):254-265.

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Although the etiology of colorectal adenoma is not yet clear, numerous epidemiologic studies of colorectal adenoma(precursors of cancer) have shown a positive association with obesity and an inverse association with physical activity. The difference of the possible association of colorectal adenoma with body mass index(BMI= wt(kg)/ht2(m2) and physical activity(kcal/day) according to anatomic sites and gender was investigated in this case-control study. Between July 1994 and october 1998, 345 cases of patients(male 181, female 164) with pathologically confirmed incident colorectal adenoma and 1655 control subjects(male 598, female 1,057) were collected from Our Lady of Mercy Hospital, The Catholic University of Korea. After colonoscopy, self-reported weight and height, together with measures of intensity and time of exercise and lifetime job activity was obtained by the interviewers. Site- and gender-specific odds ratios relative to the lowest tertile of BMI and physical activity were determined using unconditional logistic regression after adjusting for potential confounders. Compared with subjects in the lowest terile of body mass index, multivariate-adjusted odds ratio of right colon for male and female in highest tertile were 1.49(95% CI:0.74-3.01) and 1.96(95% CI:0.93-4.15), respectively. Compared with subjects in the lowest tertile of physical activity, multivariate-adjusted odds ratio of right colon for male and female in highest tertile were 0.66(95% CI:0.35-1.26) and 0.83(95% CI:0.50-1.39), respectively. These results support a positive association between body mass index and occurrence or progression of adenoma in left colon and physical activity is associated with an elevated risk of right colon.; Summary

A Review Study on Confounding Effect: Case-control Study.: Seonwoo Kim, Minji Kim, Soon Young Lee; Korean J Epidemiol. 1999;21(2):248-253.

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Confounding is the distortion of a disease/exposure association brought about by other factors which are not considered in the study design or the data analysis. These factors are called confounding factors. We should be cautious in data analysis of observational study of association of disease/exposure, since confounding often occurred in observational study. This study examines confounding effect according to data pattern (the ratio of controls to cases, the ratio of exposures to non-exposures for each level of confounding factor), criteria for treating a variable as a confounding variable, and some notes for the analysis in case-control study.; Summary

A Population-Based Case-Control Study on the Risk Factors of Congenital Heart Malformations.: Soon Ho Soh, Byung Chul Chun, Soon Duck Kim, Bae Jung Yoon, Yong Tae Yum; Korean J Epidemiol. 1999;21(2):234-247.

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The multifactorial hypothesis is proposed as a working hypothesis which encompass both the genetic and environmental factors known to participate in the etiology of congenital heart malformations. So, it is believed that avoidance of suspected environmental factors in early pregnancy is the most certain preventive measure of congenital heart malformations. This study has been undertaken in order to find the possible environmental risk factors for congenital heart malformations in Korea. A total of 114 mothers of first graders of the elementary schools with congenital heart malformations confirmed through the screening program in Kyonggi Province from 1992 to 1995 were included as cases. And 206 mothers of healthy students matched by sex and elementary schools comprised the control group. Environmental risk factors including drug use during the first trimester of pregnancy, and other confounders were collected by telephone interview using standardized questionnaires by well trained interviewers. The result of multivariate logistic regression analysis showed that congenital heart malformation were associated with family history of congenital heart malformations(OR=2.94, 95% CI: 1.08, 7.96), the order of birth(OR=0.49, 95% CI: 0.31, 0.79). And the coffee consumption over 14 cups/week during early pregnancy showed marginal significance(OR=3.52, 95%CI: 0.98, 12.62). The mother's age at the subject birth and father's smoking at home were significant in linear trend test(p<0.05). It is recommended that the genetic counselling and the avoidance of known environmental risk factors in early pregnancy were needed to prevent congenital heart malformations.; Summary

Characteristics of Shigella sonnei Isolated in Kyungsangbuk-do in 1998: Biochemical Characteristics, Biotyping, Antibiotic Resistance Pattern, and Plasmid Profile.: Chang Kyu Sohn, Wan Huh, Doo Young Lee, Si Kyu Lim, Je Wook Lee, Byung Chun Kim, Wan Park; Korean J Epidemiol. 1999;21(2):227-233.

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Thirty nine strains and 109 strains of Shigella sonnei were isolated from the outbreaks of Youngchun and Kyungju, respectively, while 15 strains were isolated from sporadic cases of eight regions in Kyungbuk province from September to November in 1998. We investigated the relationship among the S. sonnei strains by using biochemical characteristics, biotyping, antibiotic resistance pattern, and plasmid profile. Among the isolates, seven strains of S. sonnei isolated in Youngchun showed gelatin hydrolyase positive but the others showed gelatin hydrolyase negative. One hundred and fifty two strains were a type, while eleven among thirty nine strains isolated in Youngchun were g type. Antibiotics resistance patterns of S. sonnei strains isolated in Youngchun and Kyungju were significantly different. Thirty nine strains of S. sonnei isolated in Youngchun were resistant to SM, TE, and TMP/SMX, while eighty six of S. sonnei among one hundred and nine strains isolated in Kyungju were resistant to AM, CB, K, SM, TE, and TMP/SMX. Antibiotics resistance patterns of residual twenty three isolates were similar to those of eighty six strains. The Plasmid profiles of strains of S. sonnei isolated from the Kyungju were different from those of S. sonnei strains isolated in Youngchun. The Plasmid profiles of S. sonnei strains isolated from Youngchun were identical to those of a S. sonnei strains randomly selected from the outbreak in Daegu in 1998. The Plasmid profiles of S. sonnei strains isolated from Kyungju were identical to those of two strains of S. sonnei randomly selected from the outbreaks of Kanglung and Wonju in 1998. From the above results, it is considered that the strains of S. sonnei isolated from Kyungju and Youngchun region are not identical clone.; Summary

Isolation and Identification of Respiratory Disease Virus in Pusan, 1998-1999.: Kyung Soon Cho, Myung Ju Jung; Korean J Epidemiol. 1999;21(2):220-226.

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This study was performed to monitor the causative agent of patient with respiratory disease in Pusan, 1998-1999. The results obtained were as follows. Among 1,320 cases of specimens from throat swab, influenzavirus infections were detected 232(89.6%), adenovirus infections were in 14(5.4%), coxsackievirus infections were in 11(4.2%), and echovirus infections were in 2(0.8%). The 222 strains out of 232 strains of influenzavirus showed A-type and the rest of them represented B-type. The distribution for sex- and age-groups is as follows. The male distribution was similar to the female distribution: male distribution, 47.1% and female distribution, 52.9%. Most of the patients was less than 10 years old. The monthly influenza distribution was consistent from Dec. 1998 to Apr. 1999. The 113 strains from the A-type isolates was A/Sydney/05/97(H3N2)-like, the 109 strains A/Beijing/262/95(H1N1)-like, and all of the 10 B-type isolates B/Harbin/07/94-like. Electron micrograph of negative-stained showed about 95 nm and about 71 nm with influenzavirus and adenovirus, respectively. Coxsackievirus and echovirus showed non-enveloped, isometric particle of about 30 nm diameter.; Summary

Preventive Efficacy of Influenza Vaccination against to Influenza-like Illness among Eldery.: Byung Chul Chun, Heung Jeong Woo, Seung Chul Park; Korean J Epidemiol. 1999;21(2):205-219.

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BACKGROUND
Influenza is a highly infectious viral illness. The epidemics of influenza occur from the late fall to the early spring nearly every year and are responsible for several hundred thousand death per year all over the world. Influenza vaccine is the primary method for preventing influenza and its more severe complications. The efficacy of influenza vaccination have been well known in developed countries. The influenza vaccination has been recommended as one of the tentative immunization schedule for indicated persons since 1997 in Korea. But there are still no available data about them, even though nearly 5 - 8 million doses of influenza vaccine were used in a winter season. PURPOSE: To assess the clinical efficacy of influenza vaccine against influenza-like illness(ILI) among Korean elderly(age over 65).
METHODS
Primary study design - a prospective field trial. Study subjects and method - We prospectively observed the 1,488 vaccinee and 1,425 non-vaccinee in a community(Nonsan city) from November 1 1998 to March 31 1999. The vaccinee were those who randomly selected 100-200 per 13 sub-region(Myon) in Nonsan city, and the non-vaccinee were those who had not vaccinated until January 1999 among the Nonsan city elderly cohort. This cohort was consisted of 5,787 elderly(over 1/3 of total elderly population) who had ever visited the community health center or 13 public health offices in Nonsan city in 1998. We followed up these two groups two times-in January and April 1999 - by telephone survey. The questionnaire included the questions about the health behaviors, medical history, socioeconomic condition, medical security type, physical function status, medical facility utilization in the season, symptom and signs of influenza-like illness, number and type of the flu, hospitalization or not. We did throat swap to isolate the virus of 490 patient who had influenza -like symptoms in the same period.
RESULTS
Influenza vaccination was significantly reduced the incidence of influenza -like illness(fever or chilling sensation and cough or sore throat) in the vaccinated. The preventive effect of influenza-like illness among influenza risk group was about 32%(95% CI, 20%-44%). The illness duration of main symptoms of influenza-like illness(fever, cough) was significantly shorter in the vaccinee. The consistency of the survey was noted quite high from the analysis of the result of test-retest(104 person).
CONCLUSION
Influenza vaccination significantly reduced the incidence of influenza-like illness(32%) among elderly.; Summary

The Dose-response Relationship between Amount of Cigarette Smoking and Blood Lipids and Sugar.: Kang Sook Lee, Hyun Sook Hong, Jin Sook Jeong; Korean J Epidemiol. 1999;21(2):195-204.

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PURPOSE
To explore the dose-response relationship between amount of cigarette smoking and blood lipids and sugar METHODS: In this cross-sectional study, we gathered the smoking history by self-administered questionnaire between 1994 and 1998 among 2888 men who visited the Health Promotion Center at St. Mary's Hospital, Seoul.
RESULTS
Adjusted for age, body mass index, the odds ratio of hypercholesterolemia (> or =240 mg/dl) were 2.06 (95% Confident Interval, 1.44-2.94), 2.03(95% CI 1.31-3.11), higher LDL-cholesterol(> or =160 mg/dl) were 2.06(95% CI 1.43-2.98), 2.25(95% CI 1.45-3.45) among group of men who smoked 21-30, over 30 cigarettes per day respectively compared with nonsmokers group. And adjusted for age, body mass index, the odds ratio of lower HDL-cholesterol(<35 mg/dl) were 1.76(95% CI 1.34-2.33), 1.98(95% CI 1.39-2.81), 2.35(95% CI 1.54-3.54), hypertriglyceridemia(> or =200 mg/dl) were 1.93(95% CI 1.47-2.55), 2.57(95% CI 1.82-3.62), 2.80(95% CI 1.86-4.21) among group of men who smoked 11-20, 21-30, over 30 cigarettes per day respectively compared with nonsmokers group. The adjusted odds ratio of diabetes(FBS> or =126 mg/dl) was 1.86(95% CI 1.10-3.06) only among who smoked more than 30 cigarettes compared with nonsmokers.
CONCLUSION
This study showed that there were dose-response relationships betwen amount of cigarette smoking and total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride and sugar. It suggested that health promotion program including quitting and decrease of cigarette smoking would be necessary to prevent cardiovascular disease in Korean men.; Summary

An Epidemiologic Investigation on the Mode of Transmission of the Lethal Salmonellosis Outbreak in Hamyang County.: Jang Rak Kim, Sang Won Lee, Hong Bin Kim, Jin Cha, Kwang Hyun Lee, Kang Woo Bae; Korean J Epidemiol. 1999;21(2):185-194.

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An outbreak of Salmonella enteritidis epidemic involving about 200 inpatients of gastroenteritis and 1 death occurred among about 750 participants from Hamyang County who attended 4 wedding lunch parties at one buffet restaurant on April 25, 1999. There were also many patients including 1 death among about 500 participants outside Hamyang County who attended same parties. Person to person interviews made to 155 inpatients revealed that distribution of incubation periods was between 1 to 34 hours with median time, 13-14 hours. A retrospective cohort study was conducted to investigate the mode of transmission. Telephone interviews were made to party participants (except 61 inpatients who already had been interviewed personally) on symptoms and on which they had eaten among 40 served foods including water at the parties and data among 288 persons were available for the analyses. One hundred and ninety one interviewees had more than two symptoms among symptoms of diarrhea(more than 3 times), abdominal pain, and fever, which gave an attack rate of 66.3%(191/288). The relative short incubation period and high attack rate suggested the presence of higher infecting dose in this epidemic. Logistic regression analysis revealed that the probable infective foods were boiled cockle, gamju, boiled midodok, fried rices, eomook, and boiled pig's trotter. Salmonella enteritidis were identified in the specimens of boiled cockle, cooked beef, and uncooked beef. Only boiled cockle was both an epidemiological and microbiological infective food. There might be cross-contaminations between several served foods, which meant presence of many contaminated foods by Salmonella enteritidis with different stage of their multiplications. Efforts to inspect food service areas and educate foodhandlers in good personal hygiene and proper foodhandling practices should be strengthened to reduce the incidences of salmonellosis in Korea.; Summary

A Study of Major Gene Dominant Family for Factor VII Concentration: Segregation Analysis.: Sun Ha Jee, Kyung Sooon Song, Won Heum Shim, Il Suh, Hyun Kyung Kim, Young Sup Yoon, Eunna Go, Jung Yong Park, Miyang Kim, Sujeong Kim; Korean J Epidemiol. 1999;21(2):176-184.

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Elevated plasma level of factor VII is a risk factor for coronary artery disease. We investigated environmental, familial, and genetic influences on factor VII levels. We used maximum likelihood segregation analysis to fit several genetic and nongenetic modes of inheritance to the data to determine whether Mendelian inheritance of a major gene could best explain the familial distribution of factor VII. The study population included 414 family members of 67 subjects who had undergone elective coronary arteriography. The factor VII level was adjusted for age, gender, body mass index, smoking and alcohol drinking (R2=20.6%). Factor VII levels revealed strong familial aggregation with estimated correlation spouse of 0.12, parent-offspring of 0.31, and siblings of 0.40. Regressive models were used to examine inter-individual variation in adjusted factor VII levels in these 67 families. This analysis strongly favored a major gene model with codominant transmission. Genotypic means were 111.6, 123.2, and 184.3% with relative frequencies of 59.4%, 35.4%, and 5.2%. This putative major gene explains 39.9% of the total variance of factor VII. Likelihood was used to search for etiologic heterogeneity by sorting pedigrees into groups that favor one model over another. Compared to pedigrees less favoring Mendelian models, pedigrees favoring Mendelian codominant models have almost 8 times earlier onset of coronary heart disease. These family data suggest that there are strong familial and genetic effects on the factor VII activity in these high risk families. Therefore, linkage studies in these families may be worthwhile to clarify the molecular basis of factor VII levels.; Summary

Development of Lipoma among Residents Exposed to Glass Fiber Waste.: Hyun Sul Lim, Hae Kwan Cheong, Ji Yong Kim, Jung Ran Kim, Kiyoshi Sakai, Naomi Hisanaga; Korean J Epidemiol. 1999;21(2):159-175.

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This study was conducted to determine the relationship between exposure to glass fiber waste from an insulator factory and the development of cluster of lipomas among local residents in suburb Incheon, Korea. Authors surveyed 152 residents(71 males and 81 females) living near an insulator factory with a questionnaire and physical examination. Unused and disposed fiberglass from the waste site, along with ground water samples were examined under light and polarizing microscope and scanning electron microscope(SEM). Subcutaneous tumors excised from three of the residents were also examined under light and polarizing microscope, SEM with energy dispersive X-ray analysis(EDX), and transmission electron microscope(TEM). Analysis of elemental composition of the fibers and fiber concentration was done by with EDX under SEM and TEM after low temperature ashing. Twelve(7.9%) had subcutaneous tumors among the 152 residents. Tumors were surgically excised from 3 of them and they were all lipomas, consisting of mature fat tissue. These lipomas contained abundant birefringent fibers and particles under polarizing microscope. The concentrations of the fibers were 6.7, 71.8 and 499.2 million fibers per gram dry tissue, respectively. The birefringent fibers were composed of needle shaped particles with rectangular fractured ends up to 17 micrometer in length and 0.5 micrometer in diameter. EDX and x-ray diffraction analysis of the fibers showed that 71 to 100% of the fibers were magnesium silicate, talc. Magnesium silicate fibers were also found in the glass fiber sampled from the waste site. Glass fibers and magnesium silicate fibers were also identified in the ground water. Based on the fact that the magnesium silicate fibers found in the lipomas were similar in morphology and elemental composition to those found in the ground water and those from the waste site, these particles are likely to be introduced into the gastrointestinal tract through consumption of the contaminated ground water. It is suggested that fibrous magnesium silicate, talc, a component of fiberglass waste, may be associated with the development of lipomas.; Summary

Factors Related to Health Behaviors of the People in an Urban Community: Based on the Health Belief Model.: Byung Mann Cho; Korean J Epidemiol. 1999;21(2):151-158.

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Variables derived from the health belief model were studied in relation to practices of health behavior, which was measured in terms of thoroughness. Data were collected from the sample of 984 adults living in A-Gu of Pusan, during in-home interviews using structured questionnaires. Women practiced more health behaviors than men. The significant negative relationship was found between perceived barriers to health behavior and practices of health behavior in men and women. In addition, emotional support in men and perceived benefits of health behavior in women were also significant predictors of health behaviors. These findings suggest that in the study population, perceived barriers is the most powerful predictor for practices of health behavior and social support is also important for facilitating positive health behaviors.; Summary

Incorrect Disease Coding in Medical Insurance Claims and the Effect of Official Intervention: Based on Medical Insurance Claims of 6 Notifiable Acute Communicable Diseases.: Yong Mun Park, Kwang Ho Meng, Euichul Shin, Kidong Park, Won Chul Lee, Sukil Kim, Jung Hee Jang; Korean J Epidemiol. 1999;21(2):142-150.

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Abstract PDF: Abstract
BACKGROUND
Because of their large size and excellent computerized records of illness and services rendered, the importance of national insurance program is getting much attentions from the public health researchers and the national and local health authorities. In reality, however, most health records from medical insurance program suffer very much from inaccurate disease coding, and therefore, they are practically in no use.
METHODS
Pattern of incorrect disease coding of 6 Notifiable Acute Communicable Diseases that believed not to have been occurred in Korea lately was reviewed. The reasons of such incorrect codings in different level of medical institutions were studied. This study also attempted to see how an official intervention asking the medical institutions to correct their coding behavior works by comparing the frequencies of incorrect disease coding before and after the intervention.
RESULTS
Study results showed that more incorrect disease codings came from clinics than hospitals, and non-physician personnel in clinics and hospitals seemed to be responsible for most of the incorrect disease codings. Most frequent diseases coded incorrectly such as cholera and poliomyelitis were the ones that physicians and non-physician personnel in the clinics and hospitals had been familiar with for a long time period.
CONCLUSION
Even a simple official intervention asking the clinics and hospitals to correct their coding behavior was very effective : total number of incorrect disease codings before intervention (398 cases from 144 institutions) dramatically decreased (14 cases from 8 institutions) after intervention. Significant decrease in incorrect disease coding was found more in small institutions such as clinics and public health facilities than large institutions.; Summary

The Epidemiological Characteristics of a Shigellosis Outbreak (1998) in Wonju City, Kangwon-Do.: Jong Ku Park, Chun Bae Kim, Won Seok Seok, Kee Ho Park, Seungjun Wang; Korean J Epidemiol. 1999;21(2):131-141.

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From September 8-28 1998, 55 cases of shigellosis, characterized by watery diarrhea, high fever, abdominal cramps and headache were reported at K elementary school in Wonju City. The isolated serotype was Shigella sonnei (group D). We collected bacteriologic specimens from high-risk populations, disinfected epidemic areas, and monitored all the medical facilities in Wonju City. Through these efforts, we found 168 cases of shigellosis, and of these, 117 were culture-confirmed and 51 were diagnosed by symptoms. The incidence rate per 10,000 population in Wonju City was 1.00 in males and 1.19 in females. The secondary attack rate was 13.6%. The mode of transmission at K elementary school was most often caused by the common epidemic source of single exposure. The source of infection was believed to be the foods distributed on September 7. However, epidemiologic evidence suggested that the sources of infection were scattered over many places within the city. The reasons included: i) shigellosis is an endemic disease in Korea; ii) there were shigellosis-like patients at J primary school in Wonju City in late August; and iii) there was a shigellosis outbreak at Chongil Myun, Hoeng Seong Gun, which was located near Wonju City, in early August.; Summary

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