Factors Associated with Occupational Injuries of Ship-building Supply Workers in Busan / 대한산업의학회지

OBJECTIVE: This study was conducted to evaluate both personal and work-related factors associated with occupational injuries of ship-building supply workers in Busan, Korea. METHODS: A self-administered, questionnaire survey, asking both personal and work-related factors associated with occupational injuries, was administered to 1,651 workers from 64 different ship-building supply companies in Busan, Korea. All occupational injuries had occurred within the previous 5 years. The workers were divided into three sub-groups: Group I, under 4 day-sick leave, Group II, 4 day-sick leave and over, and Group III, which consisted of both Groups I and II. The statistical significance of the factors associated with occupational injuries underwent cross tabulation analysis for each group. Afterwards, the relationships between the factors which had statistical significance and the occurrence of occupational injuries were analyzed through multiple logistic regression by using the SPSS 12.0 K program. RESULTS: The prevalence of occupational injuries was 4.30% in Group II and 7.57% in Group III. The work activities which had the most frequent occupational injuries were 'Fit-up' and 'Welding', and 30.0% of injured workers were covered by workers' compensation in Group II. According to the multiple logistic regression analysis results, the factors which had statistical significance in occupational injury occurrence were education level above college (OR 2.78) and high level of fatigue (OR 2.18) in Group I, sleeping less than 5 hours per day (OR 3.47), high level of fatigue (OR 2.79) and working over 56 hours per week (OR 1.53) in Group II, and education level above college (OR 1.78), sleeping less than 5 hours per day (OR 2.98), poor sleep quality (OR 1.65) and high level of fatigue (OR 2.58) in Group III. CONCLUSION: This study demonstrated that several factors of ship-building supply workers such as sleep hours, sleep quality, fatigue, working hours, and educational level exerted a statistical effect on the occurrence of occupational injuries. In association with occupational injuries occurrence, these factors need to be controlled by proper methods such as effective safety education, work condition modification, and life style management.

Factors Associated with Occupational Injuries of Ship-building Supply Workers in Busan / 대한산업의학회지

OBJECTIVE: This study was conducted to evaluate both personal and work-related factors associated with occupational injuries of ship-building supply workers in Busan, Korea. METHODS: A self-administered, questionnaire survey, asking both personal and work-related factors associated with occupational injuries, was administered to 1,651 workers from 64 different ship-building supply companies in Busan, Korea. All occupational injuries had occurred within the previous 5 years. The workers were divided into three sub-groups: Group I, under 4 day-sick leave, Group II, 4 day-sick leave and over, and Group III, which consisted of both Groups I and II. The statistical significance of the factors associated with occupational injuries underwent cross tabulation analysis for each group. Afterwards, the relationships between the factors which had statistical significance and the occurrence of occupational injuries were analyzed through multiple logistic regression by using the SPSS 12.0 K program. RESULTS: The prevalence of occupational injuries was 4.30% in Group II and 7.57% in Group III. The work activities which had the most frequent occupational injuries were 'Fit-up' and 'Welding', and 30.0% of injured workers were covered by workers' compensation in Group II. According to the multiple logistic regression analysis results, the factors which had statistical significance in occupational injury occurrence were education level above college (OR 2.78) and high level of fatigue (OR 2.18) in Group I, sleeping less than 5 hours per day (OR 3.47), high level of fatigue (OR 2.79) and working over 56 hours per week (OR 1.53) in Group II, and education level above college (OR 1.78), sleeping less than 5 hours per day (OR 2.98), poor sleep quality (OR 1.65) and high level of fatigue (OR 2.58) in Group III. CONCLUSION: This study demonstrated that several factors of ship-building supply workers such as sleep hours, sleep quality, fatigue, working hours, and educational level exerted a statistical effect on the occurrence of occupational injuries. In association with occupational injuries occurrence, these factors need to be controlled by proper methods such as effective safety education, work condition modification, and life style management.

Lifestyle and Work related Factors Associated with Serum PFOA among Workers at Manufacturing Companies / 대한산업의학회지

OBJECTIVES: The objective of this study was to determine serum perfluorooctanoic acid (PFOA) concentrations and to investigate the relationship of lifestyle, health status and work-related factors among workers at manufacturing companies with possible occupational exposure to PFOA. METHODS: The study subjects were 315 workers (male 203, female 112) of manufacturing companies with possible exposure to PFOA from August to December, 2007. A questionnaire was administered to investigate lifestyle and work-related factors. Serum PFOA concentrations were analyzed by LCMS/ MS, and liver function and total cholesterol were also tested. RESULTS: Serum PFOA concentrations ranged from 1.0 to 40.9 ng/mL (mean 8.0 ng/mL). Serum PFOA concentrations increased with age. Male workers had higher PFOA concentration than female workers (male 9.0 ng/mL; female 6.3 ng/mL). According to stepwise multiple regression analysis, factors significantly associated with PFOA concentration were male, being older, higher total cholesterol, and lower body mass index. Adjusted for age and gender by logistic regression, dyeing and finishing textiles had significantly higher odds ratio (OR) of 6.16, and moulding patterns, moulds and industrial patterns (OR=4.84), sections for ships (OR=3.87), and plastics synthetic leather (OR=10.05) had marginally significantly high odds ratios. CONCLUSIONS: This study demonstrated the factors affecting serum PFOA concentration of workers at manufacturing companies. Further study is needed to ensure the effect of occupational exposure on serum PFOA concentration.

Gene Expression Analysis in Basal Ganglia of Manganese-Exposed Rat Based on cDNA Array / 대한산업의학회지

OBJECTIVES: This study investigated the gene expression profile in basal ganglia of manganese-exposed rats based on cDNA array analysis. METHODS: For cDNA array, 25 male Sprague-Dawley rats (250+/-25 g) were intraperitoneally injected with 25 mg/kg B.W./day of MnCl2 (0.3 ml) for 10 days. For dose-related gene expression analysis, rats were intraperitoneally injected with 0.2, 1.0, and 5.0 mg/kg B.W/day of MnCl2 for 10 days. Control rats were injected with an equal volume of saline. RNA samples were extracted from brain tissue and reversetranscribed in the presence of [alpha32P]-dATP. Membrane sets of the Atlas Rat 1.2 array II and Toxicology array 1.2 kit (Clontech, Palo Alto, CA) were hybridized with cDNA probe sets. Northern blot hybridization method was employed to assess the dose-related gene expression. RESULTS: Fifty-two genes showed significant changes in expression of more than two-fold. Twentyeight were up-regulated and 24 were down-regulated in the manganese-exposed group compared to the control. Among the 52 genes, 28 genes including nuclear factor I-X1 (NF1-X1), neuroligin 2 and 3, mitochondrial stress-70 protein (MTHSP70), neurodegeneration-associated protein 1 (Neurodap1), multidrug resistance protein (MDR), and endoplasmic reticulum stress protein 72 (ERP72), were reported for the first time related to the manganese-induced neurotoxic-metabolism in the rat basal ganglia. According to the dose-related gene expression analyses, MTHSP70, Neurodap1 and ERP72 genes were up-regulated compared to the control even in the group exposed to low manganese dose (0.2 mg/kg B.W./day). CONCLUSIONS: Twenty-eight genes detected for the first time in this study were closely related to the manganese-induced neurotoxic-metabolism in the rat basal ganglia and further study of these genes can give some more useful information about the manganese metabolism.

Effects of Cadmium on Placental Function and Reproduction in Rats / 대한산업의학회지

OBJECTIVES: This study investigated the toxic effects of cadmium on placental function and reproduction in rats. For this study, the mRNA levels of the placental prolactin-growth hormone (PRL-GH) gene family, placental trophoblast cell frequemcy and reproductive data were analyzed. METHODS: Pregnant F344 Fisher rats (200 g+/-23 g) were intraperitoneally injected with 0, 0.5, and 5.0 mg/kg B.W/day of cadmium (CdCl2) dissolved in saline from days 7-11 or 16-20 of pregnancy, and were sacrificed at days 11 or 20, respectively. The mRNA levels were analyzed by Northern blot hybridization and reverse transcription-polymerase chain reaction. The hormone concentration was analyzed by radioimmunoassay and the frequemcy of the placental trophoblast cells was observed by histochemical study. Reproductive data were surveyed at day 20 of the pregnancy and after the births. Statistical analysis was carried out using the SAS program (version 8.1). RESULTS: The mRNA levels of the PRL-GH gene family were reduced dose dependently by cadmium. The mRNA levels of Pit-1a and -b isotype genes were also reduced by cadmium. The hormone concentration of PL-Iv and -II was decreased by cadmium. During the second half of pregnancy (days 11-21), a high dose of cadmium exposure significantly reduced the frequency of spongiotrophoblast and trophoblast giant cells that secrete the PRL-GH hormones. In the last stage of pregnancy (day 20), a high dose of cadmium exposure induced the apoptosis of spon-giotrophoblast cells in the junctional zone of the placenta. Reproductive data such as placental and infant weight, number of live fetuses were decreased, and number of resorptions and dead fetuses, post-implantation loss were increased significantly in the cadmium exposed group compared with the control. CONCLUSIONS: Cadmium disrupts the functions of the placenta and these effects leads to reproductive disorders in rats.

Effects of Toluene on the Expression of Placental PRL-GH Family Genes and Reproduction in the Rat / 대한산업의학회지

OBJECTIVES: The purpose of this experimental study was to investigate the toxic effects of toluene on the placental functions and reproductionin the rat. In this study, the expression of placental prolactin-growth hormone (PRL-GH) and Pit-1 genes, the frequency of placental trophoblast cells, and the reproductive data were analyzed. METHODS: The pregnancy of the Sprague-Dawley rats (250+/-25 g) was determined by verifying the presence of the copulatory plug or sperm in the vaginal smear and the day on which this was observed was defined as pregnancy day 0. The pregnant rats were divided into three groups. The control group was intraperitoneally (ip) injected with sesame oil, and the other two groups were given either 150 or 750 mg/kg BW/day of toluene resuspended in sesame oil during pregnancy days 7-11 and 16-20. The rats from the three experimental groups were sacrificed on pregnancy days 11 and 20, respectively. The mRNA levels of the PRL-GH, Pit-1a and b isotype genes were analyzed by Northern blot hybridization and Reverse transcription-polymerase chain reaction (RT-PCR), respectively. The hormonal concentration was analyzed by Radioimmunoassay. The frequency of the placental trophoblast cells was determined by means of a histochemical study. Reproductive data, such as the placenta and infnat weight, pregnancy period and litter size were surveyed at pregnancy day 20 and after birth. Statistical analysis was carried out by means of the SAS program (version 8.1). RESULTS: The mRNA levels of the PRL-GH family genes were reduced in a linear fashion by exposure to toluene. The mRNA levels of the Pit-1a and b isotype genes, which induce the expression of the PRL-GH family genes, were also reduced by exposure to toluene. The placental lactogen Iv and II concentrations in the rat placenta, fetus and maternal blood were also decreased by exposure to toluene. During the last stage of gestation, exposure to a high dose of toluene reduced the frequency of the spongiotrophoblast cells that secrete the PRL-GH hormones. Reproductive data such as the placenta and infant weight, and litter size were reduced, and the pregnancy period was extended in the toluene exposed group as compared with the control group. CONCLUSIONS: Toluene disrupts the PRL-GH hormone metabolism in the rat placenta and this leads to reproductive disorder.

An Epidemiologic Study on Death Caused by Cancer in Pusan / 예방의학회지

This study surveyed and measured the level and structure of cancer deaths and their trends over time for offering the fundamental data of the cancer prevention and control in Pusan city in the future. Authors conducted the study of descriptive epidemiology using materials derived from the computerized data of total 3,722 certified cancer deaths in Pusan city from January 1 to December 31, 1993 registered on the National Statistical Office, the Republic of Korea. The obtained results were as follows: 1. According to the total registered cases of deaths(16,331 cases) in Pusan city during 1993, cancer(3,722 cases) and cerebrovascular disease(2,718 cases) were the first and second cause of deaths as 23.1% and 16.9%, respectively. These pattern showed the change between cancer(14.7%) and cerebrovascular disease(18.5%) in order of frequency in comparison to 1982. Also, the total number of cancer deaths was increased in comparison to 1982. The rate of death certification by physicians was 87.1% of all registered deaths, which was increased to 6.8% in comparison to 1982(80.3%). 2. Crude death rate and cancer specific death rate was 4.06 per 1,000 populations and 93.8 per 100,000 populations(male:117.8, female:70.0), respectively. The former was similar to that of 1982, but the latter was increased to 1.6 times as that of 1982. 3. Age-adjusted cancer specific death rate by standardization with whole country population was 111.9(male:141.5, female:106.7) per 100,000 populations, higher than not age-adjusted cancer specific death rate(93.8), and the sex difference was statistically significant with male predominance(p<0.05). 4. Cancer specific death rate by age was generally increased with age and most of cancer deaths(male:91.8%, female:88.5%) occurred since 40 years old. 5. The major cancer(cancer specific death rate per 100,000 populations) in male was liver(30.6) followed by stomach(25.6), lung(21.9), and GB and EHBD(5.7), in female stomach(15.7), liver(9.9), lung(7.3), and uterus(6.9). The relative frequency of the leading three cancer among total cancer deaths marked 66.3% in male and 47.1% in female, and decreased in comparison to 1982(male:72.2%, female:54.5%). 6. The total ratio of male to female cancer specific death rate showed 1.68 to 1 with male predominance. And the ratio was above 2.0 in larynx, oral cavity & pharynx, esophagus, liver, lung, bladder cancer and the ratio was 1.0~1.9 in stomach, pancreas, gall bladder and EHBD, brain, rectum and anus cancer, leukemia, but the ratio was reversed in thyroid and colon cancer. In conclusion, cancer was the first cause of deaths. The proportion of lung cancer was increased, that of stomach & uterine cancer was decreased relatively, and liver cancer was constantly higher proportion. In the future, it is necessary to conduct the further investigations on the cancer risk factors considering areal specificity.

Urinary Metabolites and Neurobehavioral Test on Styrene Exposure Workers / 예방의학회지

In order to prepare the fundamental data for the health promotion by assessing the exposure level of styrene, the author determined the concentration of mandelic acid and phenylglyoxylic acid in urine of 42 workers who were exposed to styrene by high performance liquid chromatography and surveyed 16 symptoms, by questionnaire and also tested neurobehavioral test(digit symbol, benton visual retention) in 2 FRP plants of Kyung Nam area from July to September, 1995. Control was sampled by age sex matching method. The concentration of styrene in air was determined by gas chromatography. The results were as follows; 1. Geometric mean concentration of styrene in air was 17.4ppm, geometric mean concentration of mandelic acid(MA) in urine were 404.3mg/g creatinine for exposure group, 46.4mg/g creatinine for control group, geometric mean concentration of phenylglyoxylic acid(PGA) in urine were 57.5mg/g creatinine for exposure group, 9.5mg/g creatinine for control group. Mean concentration of MA and PGA showed statistically significant difference between exposure group and control group(p<0.01). 2. Number of symptom were 2.9 for exposure group, 3.3 for control group, number of digit symbol were 24.1 for exposure group, 32.5 for control group, number of Benton visual retention test were 6.1 for exposure group, 6.0 for control group, respectively. As result of adjusting the education year, number of Benton visual retention test showed statistically significant difference between exposure group and control group(p<0.05). 3. Excellent correlation were observed between environmental styrene exposure and urinary MA(r=0.80), PGA(r=0.73), and MA+PGA(r=0.81).

Risk Factors of Hypertension and The Effect of These Factors on Blood Pressure / 한국역학회지

This study was conducted to find out the risk factors of hypertension and the effect of thesefactors on blood pressure. The eighteen factors were collected on the subjects of 932 from November 1994 to January 1995 through questionnaire and laboratory test - those were age, sex, education level, body mass index(BMI), family history of hypertension (FHH), triglyceride (TG), blood sugar and lactate dehydrogenase(LDH), etc. The status of blood pressure was classified by the classification of hypertension proposed by Joint National Committee of hypertension, USA. The prevalence of diastolic hypertension was 17.7% and the prevalence of systolic hypertension was 11.6 %. In the frequency analysis on the status of blood pressure, by age, education level, smoking habit, RM, BMI, FBS, LDH, TG, the prevalences were significantly different for both diastolic and systolic hypertension(p(0. 05). By stepwise logistic regression with dichotemization of blood pressure, the following odds ratios were significantly high (p, 0.05) - for diastolic hypertension, age 1.973, BMI 2. 106, FHH 2, 102, LDH 2. 773, TG 1.715, and for systolic hypertension, age 4.414, BMI 1.563, FHH 2.125, RM 0.487, LDH 3.814, TG 2. 707. By multiple regression analysis with blood pressure as dependent variable and these factors as independent variables, the regression equationswere diastolic hypertension =51.07+0.20.age+0.07 BMI+0.02.TG+0.02.LDH+3.22.FHH, and systolic hypertension = 88. 59+0.23.age+0.06.BMI+5.46.FHH-2.62.RM+0.03.LDH+0,03.TG By this study, the significant risk factors of hypertension were age, BMI, TG, family history of hypertension, LDH, and efficient control of hypertension would be expected through control of these factors.

Neuroendocrine Effects in Occupational Solvents Exposure / 대한산업의학회지

Long term occupational exposure to solvent mixtures may cause adverse effects to the central nervous system with neurobehavioral symptoms. And some organic solvents have been suggested to cause impairment of tuberoinfundibular dopaminergic activity and neurochemical mechanisms controlling pituitary secretion. For the purpose of assessing neuroendocrine effects in occupational solvents exposure, hormonal study settings (shoes-manufacturing industry & fishing products industry) and compared with nonexposed controls (33men, 85women). Male workers exposed to solvent mixtures had significantly lower plasma level of follicle-stimulating hormone (FSH) than nonexposed male controls. While female workers exposed to solvent mixtures had significantly lower plasma levels of growth hormone (GH), and thyroid-stimulating hormone (TSH) than nonexposed female controls. The results of significant decrease in plasma concentrations of pituitary hormones (FSH, GH, and TSH) in workers exposed solvent mixtures indicate that occupational exposure to solvent mixtures may induce neuroendocrine effects through an effect on hypothalamic pituitary axis.