Ye BJ, et al. Ann Occup Environ Med. 2016 Jan;28(1):5. https://doi.org/10.1186/s40557-015-0086-8

Kim HC, et al. Ann Occup Environ Med. 2015 Dec;27(1):30. https://doi.org/10.1186/s40557-015-0085-9

Objectives: This study aimed to investigate the relationship between working hours and lifestyle behaviors using data from a large nationally representative panel survey. Methods: We used the Korea Health Panel Study (KHPS) data from 2011 to 2014. Weekly working hours and lifestyle risk factors were assessed by questionnaires. Comparing to the reference group, the weekly working hours were 40 h per week, odds ratios and 95% confidence intervals for smoking status, alcohol consumption status, and regular exercise status of other weekly working hours groups (52) were calculated, using generalized estimating equation models considering repeated measures. Results: Our findings clearly showed a relationship between long working hours and unhealthy lifestyles, such as cigarette smoking, alcohol consumption, physical inactivity, and insufficient sleep. Additionally, weekly working hours are positively associated with the amount of smoking and drinking, and inversely associated with sleep duration among those who worked 40 h or more per week. Conclusion: Long working hours are associated with unhealthy lifestyles, such as cigarette smoking, alcohol consumption, physical inactivity, and insufficient sleep.

Purpose: Sleep disturbances are prevalent in firefighters, but the relationship between patterns of shift work and sleep disturbances has not yet been investigated. Here, this relationship has been evaluated in Korean firefighters. Methods: A cross-sectional study was conducted using an online questionnaire, which captured demographic, psychosocial and work-related characteristics. Sleep disturbance was assessed using the insomnia severity index (ISI). The relationship between insomnia and work-related factors (including type of shift work and the frequency of emergency events and off-duty work which means overtime work on off days) was analyzed. Results: A total of 9810 firefighters completed the survey, representing approximately 21.5% of all Korean firefighters; data from 9738 subjects were included in the analysis. All firefighter roles were significantly associated with insomnia; the odds ratio (OR) was 2.456 (95% confidence interval [CI] 1.461–4.128) for fire suppression and 1.871 (95% CI 1.105–3.167) for the emergency medical services and rescue. However, the pattern of shift work did not show a statistically significant relationship. The OR increased along with the frequency of emergency events and off-duty work (p value for trend < 0.05). Conclusions: This study found a significant association between the frequency of emergency and off-duty work and insomnia in Korean firefighters, whereas the pattern of shift work showed no significant relationship. Therefore, measures to reduce the frequency of emergency and off-duty work are required to prevent sleep disturbances in firefighters.

Background: Socioeconomic status plays an important role in pain coping strategy. Its influence on migraine and tension-type headache may differ by gender. This study aimed to evaluate how socioeconomic status affects the prevalence of migraine and tension-type headache by gender. Methods: We used data from the Korean Headache Survey, a population-based sample of Koreans aged 19–69 years. Education level, district size, and household income were evaluated as socioeconomic variables. Results: Among 1507 participants, the 1-year prevalence rates of migraine and tension-type headache were 8.7% [95% confidence interval (CI) 1.9-4.6%] and 29.1% (95% CI 25.7-32.5%) in women and 3.2% (95% CI 1.9-4.6%) and 32.5% (95% CI 29.1-35.9%) in men, respectively. In women, multiple regression analysis found that living in rural areas was related to higher prevalence of migraine [odds ratio (OR) 4.52, 95% CI 1.85-11.02] and lower prevalence of tension-type headache (OR 0.29, 95% CI 0.15–0.58) and college-level education was related to lower prevalence of tension-type headache (OR 0.37, 95% CI 0.18–0.74). In men, multiple regression analysis failed to reveal significant influences of any socioeconomic variable on the prevalence of migraine or tension-type headache. Conclusions: The influence of socioeconomic status on migraine and tension-type headache differs by gender, with women being more susceptible to socioeconomic influence.

Non-occupational heavy metals are considered risk factors for coronary heart disease (CHD). Several recent epidemiologic studies have evaluated the relationship between non-occupational cadmium exposure and risk factors for cardiovascular disease (CVD). This study was designed to investigate the relationship between non-occupational cadmium exposure and risk factors for CHD using the Framingham estimate of 10 year CHD risk. The heavy metal dataset of the Korean National Health and Nutrition Examination Survey for 2008 through 2010, a cross-sectional survey of a representative sample of 4,668 non-institutionalized Koreans, was analyzed. Subjects were stratified into seven age groups to minimize the effects of age. The log-transformed blood cadmium concentrations were compared with the Framingham estimate of 10 year CHD risk in each age stratum. The Framingham estimate of 10 year CHD risk was significantly associated with the log-transformed blood cadmium concentrations (p<0.05) in all age groups of Korean men, with the lowest regression coefficient (0.254) for men aged 20 to <35 years and the highest (3.354) for men aged 55 to <60 years; similar results, however, were not observed in Korean women. After adjusting for survey year, age, and urinary cotinine concentration, the log-transformed blood cadmium levels among men aged 20 to <35, 40 to <45, 50 to <55, and 60 to <65 years were significantly associated with systolic blood pressure (p<0.05), but not with total and high density lipoprotein (HDL) cholesterol concentrations. Cadmium exposure, even at non-occupational levels, may be associated with CHD risk in men. Despite the declines in non-occupational cadmium exposure over the past several decades, more efforts are needed.