Background: The objective of this study was to elucidate the relationships musculoskeletal pains with combined vulnerability in terms of age, gender, and employment status Methods: The fifth European Working Conditions Survey (EWCS) in 2010 (43,816 participants aged 15 years and over) analyzed for European employees and the third Korean Working Conditions Survey (KWCS) in 2011 (50,032 participants aged 15 years and older) analyzed for Korean employees. In this study, three well known vulnerable factors to musculoskeletal pains (older age, female gender, and precarious employment status) were combined and defined as combined vulnerability. Associations of musculoskeletal pains with combined vulnerability were assessed with prevalence ratios (PRs) and 95% confidence intervals (CIs) estimated by Poisson regression models with robust estimates of variance. Results: The prevalences of musculoskeletal pains were lower but the absolute and relative differences between combined vulnerabilities were higher among Korean employees compared with the European employees. Furthermore, the increased risk of having musculoskeletal pains according to combined vulnerability was modestly explained by socioeconomic factors and exposure to ergonomic risk factors, especially in Republic of Korea. Conclusions The results of this study showed that the labor market may be more unfavorable for female and elderly workers in Republic of Korea. Any prevention strategies to ward off musculoskeletal pains, therefore, should be found and implemented to mitigate or buffer against the most vulnerable work population, older, female, and precarious employment status, in Republic of Korea.

Background: The objective of this study was to elucidate the relationships musculoskeletal pains with combined vulnerability in terms of age, gender, and employment status Methods: The fifth European Working Conditions Survey (EWCS) in 2010 (43,816 participants aged 15 years and over) analyzed for European employees and the third Korean Working Conditions Survey (KWCS) in 2011 (50,032 participants aged 15 years and older) analyzed for Korean employees. In this study, three well known vulnerable factors to musculoskeletal pains (older age, female gender, and precarious employment status) were combined and defined as combined vulnerability. Associations of musculoskeletal pains with combined vulnerability were assessed with prevalence ratios (PRs) and 95% confidence intervals (CIs) estimated by Poisson regression models with robust estimates of variance. Results: The prevalences of musculoskeletal pains were lower but the absolute and relative differences between combined vulnerabilities were higher among Korean employees compared with the European employees. Furthermore, the increased risk of having musculoskeletal pains according to combined vulnerability was modestly explained by socioeconomic factors and exposure to ergonomic risk factors, especially in Republic of Korea. Conclusions The results of this study showed that the labor market may be more unfavorable for female and elderly workers in Republic of Korea. Any prevention strategies to ward off musculoskeletal pains, therefore, should be found and implemented to mitigate or buffer against the most vulnerable work population, older, female, and precarious employment status, in Republic of Korea.

OBJECTIVES: The objectives of this study were to explore the association between shift work and the bone mineral density in a representative sample of Korean workers. METHODS: He data from the Fourth Korean National Health and Nutrition Examination Survey (2008-2009) was used. The participants were Korean workers aged 16 to 60 years. Logistic regression analysis was applied to determine the association between shift work and the bone mineral density after controlling for covariates using the SAS version 9.3 package program. RESULTS: The blood vitamin D level in shift workers was significantly lower than that of day workers in both males and females. In male shift workers, shift work was significantly associated with a decreased bone mineral density in the femoral neck (odds ratio(OR) 1.42, 95% confidence interval(CI)=1.05~1.92) and lumbar spine (OR 1.53, 95% CI=1.09~2.15) compared to day workers. After controlling for covariates, this association was still significant. In the case of female shift workers, shift work was significantly related to a decreased bone mineral density in the total femur (OR 2.84, 95% CI=1.69~4.79) and lumbar spine (OR 1.58, 95% CI=1.12~2.24). After controlling for covariates, this risk was not statistically significant. CONCLUSIONS: The blood vitamin D level of shift workers was significantly lower than that of day workers. In male shift workers, shift work can decrease the bone mineral density in the femoral neck and lumbar spine. Prospective studies with information on the shift work intensity and duration and exposuredata to explain mechanisms will be needed.
Aged ; Bone Density ; Female ; Femur ; Femur Neck ; Humans ; Logistic Models ; Male ; Nutrition Surveys ; Phenothiazines ; Spine ; Vitamin D ; Work Schedule Tolerance

OBJECTIVES: The effect of mercury on the cardiovascular system has recently been reported on, but the mechanisms as well as its nature of this effect still need to be confirmed. In this study, the mercury in the hair of a community population was analyzed in relation to the cardiac autonomic activity. METHODS: A hair sample was obtained from the occiput area and the mercury in the hair was analyzed by using a Direct Mercury Analyzer. We measured the cardiovascular risk factors, including total cholesterol, triglyceride, blood pressure, and the body mass index (BMI). Heart rate variability was assessed for 5 minutes, in the time and frequency domain, by using SA-3000P from the Medi-core(R). company. The association between the mercury in the hair and heart rate variability was assessed after controlling for the other cardiovascular risk factors. RESULTS: The mean age of the 671 total subjects was 36 years. The geometric mean of the hair mercury was 0.90 ppm. The hair mercury level was elevated in males, adults, smokers and drinkers. Hair mercury and age, the systolic and diastolic blood pressure, total cholesterol, triglyceride, LDL cholesterol and BMI were all positively correlated. However, hair mercury and heart rate, HDL cholesterol, standard deviation of the NN intervals (SDNN), total power (TP), low-frequency (LF), high- frequency (HF) were negatively correlated. In the higher mercury group, heart rate, SDNN, LF and HF indices were significantly lower compared with those of the lower mercury group. Heart rate was decreased 2.6 beats/min, Ln (HF) was decreased 0.131 msec2 and HF norm was decreased 2.550 with a 1 ppm increase of Ln (Hg), according to multiple linear regression analysis after controlling for age, gender and other cardiovascular risk factors. CONCLUSION: This cross-sectional study showed that mercury may affect the cardiac autonomic activity through parasympathetic dysfunction.
Adult ; Autonomic Nervous System ; Blood Pressure ; Body Mass Index ; Cardiovascular System ; Cholesterol ; Cholesterol, HDL ; Cholesterol, LDL ; Cross-Sectional Studies ; Hair ; Heart ; Heart Rate ; Humans ; Linear Models ; Male ; Risk Factors

BACKGROUND: This study is aimed at finding out the relationship between long working hours, one of major job stress elements, and hearing impairment in unexposed workers to occupational and environmental noise. METHODS: This study was performed on 1628 regular, full-time wage workers between the age of 25-64 who indicated in the survey of having no experience of exposure to noise, normal otoscopic findings, and not suffering from diabetes based on the data from the fifth Korea National Health and Nutrition Examination Survey (KNHANES 2010–2012). The average working hours per week was categorized into 40 h and lower group, more than 40 to 48 h group, more than 48 to 60 h group, and more than 60 h group. The groups were defined as suffering from low or high frequencies hearing impairment if the average hearing threshold for 0.5, 1, 2 kHz or 3, 4, 6 kHz in both ears exceeds 25 dB based on the pure tone audiometry. The association between average weekly working hours and hearing impairment was analyzed using logistic regression after gender stratification. RESULTS: The prevalences of low and high frequencies hearing impairment in male workers were 4.3 and 28.6 %, respectively, which were much higher than female’s prevalence of 2.7 and 11.1 %. For male workers, no significant association was found between average weekly working hours and low and high frequencies hearing impairment. For female workers, odds ratios (OR) of low and high frequencies hearing impairment were 4.22 (95 % confidence interval (CI) 1.09–16.27) and 4.49 (95 % CI 1.73–11.67), respectively, after controlling for several related factors, such as, age, Body Mass Index (BMI), socio-economic status, health-related behavioral, and occupational characteristics variables, in the final model in the group working more than 60 h compared to the group working 40 h and lower. In addition, a dose-response relationship was observed that ORs of low and high frequencies hearing impairment were increased according to increasing average weekly working hours. CONCLUSIONS: The association between long working hours and hearing impairment in both low and high frequencies was significant in Korean female workers with a dose-response relationship. Therefore, the law to change the culture of long working hours should be enacted in order to protect the workers’ health and improve the quality of life in Korean workers.
Audiometry ; Body Mass Index ; Ear ; Female ; Hearing Loss* ; Hearing* ; Humans ; Jurisprudence ; Korea* ; Logistic Models ; Male ; Noise* ; Nutrition Surveys* ; Odds Ratio ; Prevalence ; Quality of Life ; Salaries and Fringe Benefits

BACKGROUND: Previous studies on the association between shift or night work and weight change have been focused on finding the risk of weight gain caused by shift or night work. In this study, we aimed to reveal the risk of weight gain and weight loss associated with night work by using a nationwide representative data. METHODS: This study was performed on 1605 full-time wage workers between the age of 20 and 69 based on the fifth Korea National Health and Nutrition Examination Survey (KNHANES 2010–2012). The association between night work and involuntary weight change in the previous year was divided into the categories of weight gain and weight loss and studied with modifications in socio-demographic variables, health behavior-related variables, and occupational characteristic variables. RESULTS: The participants working in night work accounted for 10.6 % of total study participants (male; 11.9 %, female 7.4 %). Workers who worked more than 48 hours per week on average accounted for 41.6 % of the total study participants (male; 46.3 %, female 29.1 %). Odds ratio (OR) of weight loss associated with night work in male workers was 0.34 (95 % confidence interval (CI) 0.16–0.76) after controlling for several related factors. OR of weight loss associated with night work in female workers with long working hours was 1.95 (95 % CI 0.47–80.86) and that of weight gain was 2.83 (95 % CI 0.12–69.83) after adjusting associated factors. CONCLUSIONS: In this cross-sectional study with national representative sample, night work may lower the risk of weight loss in male workers and induce weight change (weight loss or weight gain) in female workers with long working hours. Therefore, future studies with cohort study design for night workers are needed to reveal the mechanisms and health effects of weight change associated with night work and establish proper management solutions with health and labor policies for Korean night workers.
Cohort Studies ; Cross-Sectional Studies ; Female ; Humans ; Korea* ; Male ; Nutrition Surveys* ; Odds Ratio ; Salaries and Fringe Benefits ; Weight Gain ; Weight Loss

BACKGROUND: This study was aimed at finding out the exposure level of bisphenol A (BPA), a well-known endocrine disruptor, in relation to dietary factors using a data representing the Korean general population. METHODS: This study was performed on 5402 adults aged 19 years and older based on the Second Korean National Environmental Health Survey (KoNEHS 2012–2014). The data analyzed urinary BPA concentration in relation to socio-demographic variables, health behavior-related variables, and dietary factor-related variables. Odds ratio (OR) was calculated through a logistic regression analysis after dividing the participants into high BPA exposure group and low BPA exposure group based on the top 75 percentile concentration. The logistic regression analysis was carried out considering the appropriate sample weight, stratification, and clustering of the second KoNEHS sample design. RESULTS: The group drinking bottled water at home and the group using zip-top bags/plastic bags showed significantly higher urinary BPA concentration in female. OR tends to increase as the intake frequency of frozen food increased and OR of frozen food consumption of more than once a week was 1.48 (95% confidence interval (CI) 1.02–2.24) for male and the group drinking bottled water showed significantly higher OR of 1.45 (95% CI 1.06–2.17) after adjusting the related factors for female. CONCLUSIONS: BPA levels were high in female using bottled water and in male consuming frozen food, and therefore bottled water and frozen food need to be avoided to reduce BPA levels.
Adult ; Drinking ; Drinking Water ; Environmental Health* ; Female ; Frozen Foods ; Humans ; Logistic Models ; Male ; Odds Ratio

OBJECTIVES: The present study was designed to determine the characteristics of shift work and the relationship between shift work and the level of self-rated health using the Korean Labor and Income Panel Study (KLIPS) data, which represents urban households in Korea. METHODS: Using the 9th wave of KLIPS, this study analyzed 2,087 male workers aged 25 to 64 years; participants missing data were excluded from analysis. To determine the impact of shift work on the level of self-rated health, logistic regression analysis was applied that controlled for socio-demographic characteristics, labor environment, and health-related behaviors. RESULTS: Shift workers comprised 13.4% of study subjects overall. The majority(69.2%) of participants were in 2-teams and in 2-shifts. Week 1 shift cycle changes were the highest, 56.3%. The risk of poor self-rated health was not significantly higher among shift workers compared to non-shift workers (OR=1.08, 95% CI=0.79~1.48). When divided by tenure, shift workers with more than 10-years experience (OR=1.79, 95% CI=0.91~3.50) tended to show greater risk than non-shift workers at marginal significance. CONCLUSIONS: In the present study, a significantly higher risk of self-rated poor health among shift workers was not observed. However, shift workers with more than 10-years experience tended to show increased health risk compared to non-shift workers. Further studies are required to determine time-series data and to consider both healthy worker effect and information bias.
Aged ; Bias (Epidemiology) ; Family Characteristics ; Healthy Worker Effect ; Humans ; Korea ; Logistic Models ; Male

BACKGROUND: This study aimed to analyze environmental tobacco smoking exposure in female nonsmokers by public transportation mode using representative data of Koreans. METHODS: Data from the Second Korean National Environmental Health Survey (2012–2014) were analyzed. Urine cotinine was analyzed by public transport behavior, secondhand smoke exposure, socioeconomic factors, and health-related factors. Participants were 1322 adult females; those with the top 75% urine cotinine concentrations were assigned to the high exposure group. A logistic regression analysis was performed considering appropriate weights and stratification according to the sample design of the Second Korean National Environmental Health Survey. RESULTS: The geometric mean of urine cotinine concentrations differed according to public transportation modes: subway (1.66 μg/g creatinine) bus (1.77 μg/g creatinine), and taxi (1.94 μg/g creatinine). The odds ratio [OR] was calculated for the high exposure group. The OR of the taxi (2.39; 95% confidence interval, 1.00–5.69) was statistically significantly higher than the subway value (reference), and marginally significant after adjusted with life style, sociodemographic factors and involuntary smoking frequency (2.42, 95% confidence interval, 0.97–6.04). CONCLUSIONS: The odds ratio of passengers who mainly used taxis was marginally significantly higher than those of passengers who used subways and buses after adjusted with life style and sociodemographic factors. Implementation of supplementary measures and further studies on exposure to environmental tobacco smoking in taxis are warranted.
Adult ; Cotinine ; Environmental Health ; Female ; Humans ; Life Style ; Logistic Models ; Motor Vehicles ; Odds Ratio ; Railroads ; Smoking ; Socioeconomic Factors ; Tobacco Smoke Pollution ; Tobacco ; Transportation ; Weights and Measures

BACKGROUND: We aimed to find the exposure level of triclosan (TCS), a known endocrine disruptor, related to the use of personal care products using a nationally representative data of the general population in Korea. METHODS: This study included data of 6288 adults aged 19 years and older (2692 men, 3596 women), based on the Second Korean National Environmental Health Survey (KoNEHS 2012–2014). The data were divided according to gender. The frequency and proportion of each variable were determined by dividing participants into two groups based on the top 75th percentile concentration of urinary TCS (male: 1.096 μg/g creatinine, female: 1.329 μg/g creatinine). Odds ratios (ORs) were calculated using logistic regression analysis for the high TCS exposure and low TCS exposure groups. RESULTS: Overall, the proportion of participants using personal care products was higher in women than in men. There was a significantly higher proportion of participants in the high TCS exposure group with younger age, higher education and income levels and with more frequent use of fragrance products, hair care products, body cleansers, cosmetics, and antimicrobial agents. In both men and women, ORs tended to increase with increased frequency of use of hair care products, body cleansers, and cosmetics before and after adjustment. CONCLUSIONS: Our findings demonstrate that as the frequency of use of personal care products increases, urine TCS concentration increases. Because TCS is a well-known endocrine disruptor, further studies are needed and explore other health effects with exposure to TCS in general population in Korea. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s40557-019-0283-y) contains supplementary material, which is available to authorized users.
Adult ; Anti-Infective Agents ; Creatinine ; Education ; Environmental Health ; Female ; Hair ; Humans ; Korea ; Logistic Models ; Male ; Odds Ratio ; Triclosan