Association between urinary phthalate metabolites and obesity in adult Korean population: Korean National Environmental Health Survey (KoNEHS), 2012–2014

BACKGROUND: Phthalate is a chemical that is commonly used as a plasticizer in processing plastic products and as a solvent in personal care products. Although previous experimental studies have reported that phthalate metabolites are associated with obesity, epidemiological study results have been inconsistent and insufficient. The objective of the present study was to investigate the association between urinary phthalate metabolites and obesity in adult Korean population. METHODS: The present study selected 4,752 Korean adults aged 19 years or older from the 2012–2014 Korean National Environmental Health Survey data. The concentrations of urinary di-(2-ethyl-5-carboxypentyl) phthalate (DEHP) metabolites—i.e., mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP) and mono-(2-ethyl-5-carboxypentyl) phthalate—mono-benzyl phthalate (MBzP) and mono-n-butyl phthalate (MnBP) were adjusted using the urinary creatinine. We used logistic regression analysis to investigate the association between urinary phthalate metabolite concentration and body mass index (BMI) with respect to sex and age. RESULTS: Among women, urinary MEHHP and DEHP concentrations were found to have statistically significantly positive associations with obesity (Q4 versus Q1; odds ratio (OR): 1.72, 95% confidence interval (CI): 1.19–2.49 for MEHHP and OR: 1.52, 95% CI: 1.04–2.21 for DEHP). Among men, urinary MnBP concentration was found to have statistically significantly negative association with obesity (Q4 versus Q1; OR: 0.71, 95% CI: 0.50–0.99). In the analysis stratified by sex and age, women aged ≥ 50 years showed statistically significantly positive associations between the concentrations of urinary DEHP metabolites, DEHP, MBzP, and obesity (Q4 versus Q1; OR: 1.94, 95% CI: 1.28–2.94 for MEHHP, OR: 1.88, 95% CI: 1.21–2.94 for MEOHP, OR: 2.04, 95% CI: 1.31–3.18 for DEHP, and Q3 versus Q1; OR: 1.45, 95% CI: 1.02–2.05 for MBzP). Meanwhile, men aged ≥ 50 years showed no significant associations between urinary phthalate concentrations and obesity. CONCLUSIONS: In the present study, we found differences in the associations between urinary phthalate metabolites and BMI according to sex and age. However, because the present study was cross-sectional in nature, additional support through prospective studies is needed to estimate the causal associations.

Carbon disulfide exposure estimate and prevalence of chronic diseases after carbon disulfide poisoning-related occupational diseases

BACKGROUND: In Korea, Carbon disulfide (CS2) toxicity was an important social problem from the late 1980s to the early 1990s but there have been few large-scale studies examining the prevalence of diseases after CS2 exposure discontinuance. So we investigated past working exposure to CS2 characteristics from surviving ex-workers of a rayon manufacturing plant including cumulative CS2 exposure index. Furthermore, we studied the prevalence of their chronic diseases recently after many years. METHODS: We interviewed 633 ex-workers identified as CS2 poisoning-related occupational diseases to determine demographic and occupational characteristics and reviewed their medical records. The work environment measurement data from 1992 was used as a reference. Based on the interviews and foreign measurement documents, weights were assigned to the reference concentrations followed by calculation of individual exposure index, the sum of the portion of each time period multiplied by the concentrations of CS2 during that period. RESULTS: The cumulative exposure index was 128.2 ppm on average. Workers from the spinning, electrical equipment repair, and motor repair departments were exposed to high concentrations of ≥10 ppm. Workers from the maintenance of the ejector, manufacturing of CS2, post-process, refining, maintenance and manufacturing of viscose departments were exposed to low concentrations below 10 ppm. The prevalence for hypertension, coronary artery disease, cerebrovascular disease, diabetes, arrhythmia, psychoneurotic disorder, disorders of the nervous system and sensory organ were 69.2%, 13.9%, 24.8%, 24.5%, 1.3%, 65.7%, 72.4% respectively. CONCLUSIONS: We estimated the individual cumulative CS2 exposure based on interviews and foreign measurement documents, and work environment measurement data. Comparing the work environment measurement data from 1992, these values were similar to them. After identified as CS2 poisoning, there are subjects over 70 years of average age with disorders of the nervous system and sensory organs, hypertension, psychoneurotic disorder, cerebrovascular disease, diabetes, coronary artery disease, and arrhythmia. Because among ex-workers of the rayon manufacturing plant, only 633 survivors recognized as CS2 poisoning were studied, the others not identified as CS2 poisoning should also be investigated in the future.

Type and Characters of Agricultural Injury Subjective Burden / 農村醫學 地域保健

OBJECTIVES: In establishing policies for agricultural safety, evaluating injury burdens as well as investigating the rates and characteristics of work injury is important. This study investigated the types and characteristics of agricultural injury subjective burdens. METHODS: By analyzing the injured farmers identified in the 2013 Korean Farmers' Occupational Injury Survey, the burdens caused by injuries were categorized using one direct cost item (medical costs) and five indirect cost items (including productivity decreases and wage increases). Statistical differences among the burden items were analyzed using logistic regression analysis according to the characteristics of the farmers and their farm injuries. RESULTS: Among the subjective burdens indicated by the 457 injured farmers, disruption to work was most common. The major influences on each subjective burden item are as follows: for the item of disruption to work, age, time of injury occurrence, treatment period, and farming machine use were influential; for an increased family member's burden of farm works, the number of family members and treatment period were influential. Regarding cost burden of treatment, the results varied according to whether or not the patient was hospitalized and annual income. CONCLUSION: Subjective burdens induced by indirect costs rather than those induced by direct costs were found to be higher in ratio. In regard to each burden item, the results varied according to the characteristics of the farmers and their farm injuries. To support injured farmer, setting goals to reduce indirect cost burdens and preparing concrete methods is necessary.

The effect of aircraft noise on sleep disturbance among the residents near a civilian airport: a cross-sectional study

BACKGROUND: Aircraft noise is a major environmental noise problem. This study was conducted in order to investigate the relationship between sleep disturbance and exposure to aircraft noise on the residents who are living near an airport. METHODS: There were 3308 residents (1403 in the high exposure group, 1428 in the low exposure group, and 477 in the non-exposure group) selected as the subjects for this study. The Insomnia severity Index (ISI) and Epworth Sleepiness Scale (ESS) questionnaires were used to evaluate sleep disturbance. RESULTS: The mean ISI and ESS scores were 6.9 ± 6.4 and 5.5 ± 3.7, respectively, and the average scores were significantly greater in the aircraft noise exposure group, as compared to the non-exposure group. The percentage of the abnormal subjects, which were classified according to the results of the ISI and ESS, was also significantly greater in the noise exposure group, as compared to the control group. The odd ratios for insomnia and daytime hypersomnia were approximately 3 times higher in the noise exposure group, as compared to the control group. CONCLUSIONS: The prevalence of insomnia and daytime hypersomnia was higher in the aircraft noise exposure group, as compared to the control group. Further study is deemed necessary in order to clarify the causal relationship.

Risk factors for lesions of the knee menisci among workers in South Korea’s national parks

BACKGROUND: This study was designed to investigate the prevalence of the menisci lesions in national park workers and work factors affecting this prevalence. METHODS: The study subjects were 698 workers who worked in 20 Korean national parks in 2014. An orthopedist visited each national park and performed physical examinations. Knee MRI was performed if the McMurray test or Apley test was positive and there was a complaint of pain in knee area. An orthopedist and a radiologist respectively read these images of the menisci using a grading system based on the MRI signals. To calculate the cumulative intensity of trekking of the workers, the mean trail distance, the difficulty of the trail, the tenure at each national parks, and the number of treks per month for each worker from the start of work until the present were investigated. Chi-square tests was performed to see if there were differences in the menisci lesions grade according to the variables. The variables used in the Chi-square test were evaluated using simple logistic regression analysis to get crude odds ratios, and adjusted odds ratios and 95 % confidence intervals were calculated using multivariate logistic regression analysis after establishing three different models according to the adjusted variables. RESULTS: According to the MRI signal grades of menisci, 29 % were grade 0, 11.3 % were grade 1, 46.0 % were grade 2, and 13.7 % were grade 3. The differences in the MRI signal grades of menisci according to age and the intensity of trekking as calculated by the three different methods were statistically significant. Multiple logistic regression analysis was performed for three models. In model 1, there was no statistically significant factor affecting the menisci lesions. In model 2, among the factors affecting the menisci lesions, the OR of a high cumulative intensity of trekking was 4.08 (95 % CI 1.00–16.61), and in model 3, the OR of a high cumulative intensity of trekking was 5.84 (95 % CI 1.09–31.26). CONCLUSION: The factor that most affected the menisci lesions among the workers in Korean national park was a high cumulative intensity of trekking.

Estimated rate of agricultural injury: the Korean Farmers' Occupational Disease and Injury Survey

OBJECTIVES: This study estimated the rate of agricultural injury using a nationwide survey and identified factors associated with these injuries. METHODS: The first Korean Farmers' Occupational Disease and Injury Survey (KFODIS) was conducted by the Rural Development Administration in 2009. Data from 9,630 adults were collected through a household survey about agricultural injuries suffered in 2008. We estimated the injury rates among those whose injury required an absence of more than 4 days. Logistic regression was performed to identify the relationship between the prevalence of agricultural injuries and the general characteristics of the study population. RESULTS: We estimated that 3.2% (+/-0.00) of Korean farmers suffered agricultural injuries that required an absence of more than 4 days. The injury rates among orchard farmers (5.4 +/- 0.00) were higher those of all non-orchard farmers. The odds ratio (OR) for agricultural injuries was significantly lower in females (OR: 0.45, 95% CI = 0.45-0.45) compared to males. However, the odds of injury among farmers aged 50-59 (OR: 1.53, 95% CI = 1.46-1.60), 60-69 (OR: 1.45, 95% CI = 1.39-1.51), and > or =70 (OR: 1.94, 95% CI = 1.86-2.02) were significantly higher compared to those younger than 50. In addition, the total number of years farmed, average number of months per year of farming, and average hours per day of farming were significantly associated with agricultural injuries. CONCLUSIONS: Agricultural injury rates in this study were higher than rates reported by the existing compensation insurance data. Males and older farmers were at a greater risk of agriculture injuries; therefore, the prevention and management of agricultural injuries in this population is required.