Perfluoroalkyl substances (PFAS) are widely used in industry and daily life due to their useful properties. They have a long half-life, accumulate in the body, and there is evidence that they are associated with biomarkers of lipid metabolism and liver damage. This may suggest non-alcoholic fatty liver disease (NAFLD) caused by PFAS. However, since there has been no study analyzing the relationship between PFAS and NAFLD in the entire population in Korea. We sought to confirm the relationship between serum PFAS concentration and NAFLD prevalence in Korean adults using the Korean National Environmental Health Survey (KoNEHS) cycle 4.

The study was conducted on 2,529 subjects in 2018–2019 among KoNEHS participants. For the diagnosis of NAFLD, the hepatic steatosis index (HSI) was used, and the geometric mean and concentration distribution of serum PFAS were presented. Logistic regression was performed to confirm the increase in the risk of NAFLD due to changes in PFAS concentration, and the odds ratio and 95% confidence interval (CI) were calculated.

In both adjusted and unadjusted models, an increased odds ratio was observed with increasing serum concentrations of total PFAS and perfluorooctane sulfonate (PFOS) in the non-obese group. In the adjusted model, the odds ratios for serum total PFAS and PFOS were 6.401 (95% CI: 1.883–21.758) and 7.018 (95% CI: 2.688–18.319).

In this study, a higher risk of NAFLD based on HSI was associated with serum total PFAS, PFOS in non-obese group. Further research based on radiological or histological evidence for NAFLD diagnosis and long-term prospective studies are necessary. Accordingly, it is necessary to find ways to reduce exposure to PFAS in industry and daily life.

As unpredictable work schedule (UWS) has increased worldwide, various studies have been conducted on the resulting health effects on workers. However, research on the effect of UWS on workers' well-being in Korea is still insufficient. This study aimed to investigate the relationship between UWS and work-family conflict (WFC) using 6th Korean Working Conditions Survey (KWCS).

Both UWS and WFC were measured using self-reported questionnaires, using data from the 6th KWCS conducted between 2020 and 2021, including 31,859 participants. UWS was measured by questions regarding the frequency of changes in work schedules and limited advanced notice. WFC was measured by questions regarding work to family and family to work conflicts. Logistic regression analysis was conducted to investigate the association between UWS and WFC.

The prevalence of UWS was higher among men, those under 40 years old, service and sales workers and blue-collar workers, and those with higher salaries. Workplace size also influenced UWS prevalence, with smaller workplaces (less than 50 employees) showing a higher prevalence. The odds ratio (OR) for WFC was significantly higher in workers with UWS compared to workers without UWS after adjusting for gender, age, marital status, occupation, salary, education, weekly working hours, shift work, company size, and having a child under the age of 18 years, employment status (OR: 3.71; 95% confidence interval: 3.23–4.25).

The analysis of nationwide data revealed that UWS interferes with workers’ performance of family roles, which can lead to WFC. Our findings suggest that it is crucial to implement policies to address unfair work schedule management, promoting a healthier work-life balance and fostering a conducive environment for family responsibilities.