The relationship between shift work and mental health among electronics workers in South Korea: A cross-sectional study

<div><p>Objective</p><p>To determine the relationship between shift work and mental health, particularly insomnia, depression, and suicidal ideation, among electronics production workers.</p><p>Methods</p><p>A survey was conducted with 14,226 workers from an electronics manufacturer in South Korea. After excluding 112 individuals with incomplete responses, 14,114 respondents were analyzed. As part of a larger project, we collected data on respondents’ general characteristics, work-related characteristics, and health status; however, in this study, we focused on the data related to shift work and mental health. Insomnia, depression, and suicidal ideation were set as dependent variables and working schedule as set as the independent variable. We performed multiple logistic regression analysis with daytime workers as the reference group. The model was adjusted for age, gender, body mass index, workplace, educational level, and marital status with or without children under 6 years of age.</p><p>Results</p><p>Relative to daytime workers, shift workers had 2.35, 1.23, and 1.17 greater odds of insomnia, depression, and suicidal ideation, respectively. Within the shift worker group, we found that the odds of depression and suicidal ideation increased dramatically when respondents had insomnia. The ORs for depression and suicidal ideation were 4.899 and 7.934, respectively.</p><p>Conclusions</p><p>Our findings suggest that shift work is related to an increased risk of mental health problems in production workers, and the sleep disturbance related with shift work is a central mechanism for this relationship. Since these results suggest that proactive management of sleep problems might attenuate their detrimental effects on shift worker’s mental health.</p></div

General characteristics and prevalence mental health outcome of study population.

<p>General characteristics and prevalence mental health outcome of study population.</p

Bisphenol A Exposure and Asthma Development in School-Age Children: A Longitudinal Study

<div><p>Background</p><p>Although the effect of bisphenol A on various health outcomes has been extensively examined, few studies have investigated its effect on asthma.</p><p>Objective</p><p>We hypothesized that exposure to bisphenol A in school-age children was associated with wheezing and asthma.</p><p>Methods</p><p>Participants included 127 children aged 7–8 years without a previous asthma diagnosis in an elementary school in Seoul, Korea. Three surveys were conducted, each 2 years apart. Bisphenol A concentration was measured at the baseline survey, and PC₂₀, which is defined as the methacholine concentration that induces a decrease in FEV₁ of 20% from baseline, was measured at every survey. Associations between bisphenol A concentration at 7–8 years of age and wheezing, asthma, and PC₂₀ at ages up to 11–12 years were examined using generalized estimating equations, a marginal Cox regression model, and a linear mixed model.</p><p>Results</p><p>The log-transformed creatinine-adjusted urinary bisphenol A concentration at 7–8 years was positively associated with wheezing (odds ratio, 2.48; 95% confidence interval, 1.15–5.31; <i>P</i> = .02) and asthma (hazard ratio, 2.13; 95% confidence interval, 1.51–3.00; <i>P</i><.001) at ages up to 11–12 years. Bisphenol A was also negatively associated with PC₂₀ (ß = −2.33; <i>P</i> = .02). When stratified by sex, the association between bisphenol A and asthma remained significant only in girls (hazard ratio, 2.45; 95% confidence interval, 2.18–2.76; <i>P</i><.001).</p><p>Conclusion</p><p>Increased urinary bisphenol A concentrations at 7–8 years old were positively associated with wheezing and asthma and negatively associated with PC₂₀ at ages up to 11–12 years.</p></div

Additional file 1: of Exome-wide association study identifies genetic polymorphisms of C12orf51, MYL2, and ALDH2 associated with blood lead levels in the general Korean population

Results of exome-wide association study for screening of genetic variability for blood lead levels; Table S1. Top 100 single nucleotide polymorphisms most significantly associated with blood lead levels, as identified by the exome-wide association study; Figure S1. Regional association plot of single nucleotide polymorphisms near C12orf51 and ALDH2 genes on chromosome 12q24. (DOCX 139 kb

Overview of study population sampling and follow-up.

<p>Overview of study population sampling and follow-up.</p

Relationship between urinary BPA concentration and PC₂₀.

<p>Penalized regression spline of log-transformed urinary BPA concentrations at 7–8 years on PC₂₀ at ages up to 11–12 years. Solid lines, spline curve; shaded area, 95% confidence intervals. The model is adjusted for gender, parental asthma history, fetal and environmental tobacco smoke exposure, and pet ownership.</p

Association of urinary BPA concentrations (log transformed, µg/g creatinine) at 7–8 years with wheezing and asthma over 11–12 years of age, by longitudinal analyses.

<p>HR, hazard ratio.</p><p>* Number with outcome/total number for analysis.</p>†<p>Generalized estimating equation with a logit link model adjusted for gender, parental asthma history, fetal and environmental tobacco smoke exposure, pet ownership, and grade at enrollment.</p>‡<p>Marginal Cox model considering grade-at-enrollment clustering adjusted for gender, parental asthma history, fetal and environmental tobacco smoke exposure, and pet ownership.</p><p>Association of urinary BPA concentrations (log transformed, µg/g creatinine) at 7–8 years with wheezing and asthma over 11–12 years of age, by longitudinal analyses.</p

Association of urinary BPA concentrations (log transformed, µg BPA/g creatinine) at 7–8 years with wheezing, PC₂₀, and current asthma at 7–8, 9–10, and 11–12 years of age.

<p>*Logistic regression model adjusted for gender, parental asthma history, fetal and environmental tobacco smoke exposure, pet ownership, and grade at enrollment.</p>†<p>Linear regression model adjusted for gender, parental asthma history, fetal and environmental tobacco smoke exposure, pet ownership, and grade at enrollment.</p>‡<p>Number with outcome/total number for analysis.</p>§<p>Total number for analysis.</p><p>Association of urinary BPA concentrations (log transformed, µg BPA/g creatinine) at 7–8 years with wheezing, PC₂₀, and current asthma at 7–8, 9–10, and 11–12 years of age.</p

Additional file 1: Table S1. of The relationship between spontaneous abortion and female workers in the semiconductor industry

Substances causing reproductive toxicity in semiconductor industry. Table S2. Characteristics of 4037 all pregnancies of female workers in the semiconductor industry. Table S3. Characteristics of 2242 first pregnancies of female workers in the semiconductor industry. Table S4. Comparison of the first job and the job held longest. (XLSX 31 kb

Additional file 1: Figure S1. of Persistent asthma phenotype related with late-onset, high atopy, and low socioeconomic status in school-aged Korean children

Tree analysis using latent class analysis in four asthma phenotypes. Definition of abbreviations: BHR methacholine PC20 < 8 mg/ml. (TIF 736 kb