Objectives This study investigated the association between employment status and depression. Methods Data from the Korea Welfare Panel Study (KOWEPS) collected from 2008 to 2011 were used. A total of 7368 subjects were included in this study after exclusion of subjects with missing data and those who were self-employed or could not work. Depression was assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). Employment status, age, sex, region, education, marital status, income, head of household, self-rated health, smoking status, drinking habits, and the current year's and the previous year's CES-D scores were included in the model as independent variables. A generalised linear mixed-effects model for longitudinal binary data was used. Results Compared with those who were permanently employed, individuals who moved from permanent to precarious employment (OR 1.45, 95% CI 1.23 to 1.70) or to unemployment (OR 1.78, 95% CI 1.30 to 2.43) and from precarious employment to unemployment (OR 1.65, 95% CI 1.32 to 2.06) showed a significantly increased the odds of having depression. Continuing precarious employment (OR 1.54, 95% CI 1.30 to 1.83) or unemployment (OR 1.45, 95% CI 1.23 to 1.70) also significantly increased the odds of having depression. These results were particularly identified in men and head of household women. The effects were not significant among non-head of household women. Conclusions Precarious employment and unemployment were clearly associated with having depression. In addition, in view of our findings, policy makers should consider sex and head of household status when developing welfare policies. The inequity between precarious jobs and permanent jobs should be tackled.

Korean Circulation Journal 대한심장학회지 순환기 Noh J, et al. Korean Circ J. 2016 Sep;46(5):672-680. https://doi.org/10.4070/kcj.2016.46.5.672

Considering the effect of sex and head of household responsibilities, this study was designed to evaluate whether precarious employment is associated with the development of new-onset severe depressive symptoms. We followed 2214 male and 1276 female waged workers, ≤59 years of age and without moderate depressive symptom, from the Korean Welfare Panel Study 2007-2013. Their employment status was classified as full-time permanent, precarious, self-employed, or unemployed after baseline. Except for occupation and company size, all variables were treated as time-dependent. Severe depressive symptoms were measured using the 11-item Center for Epidemiologic Studies Depression Scale (CES-D-11). A generalized estimating equation was used to evaluate the effect of employment status on the development of new-onset severe depressive symptoms. After adjusting for initial baseline CES-D-11 score, chronic disease, and other socioeconomic covariates, precarious employment was associated with the development of new-onset severe depressive symptoms among male heads of household [odds ratio (OR) 1.52, 95% confidence interval (95% CI) 1.02-2.25] and female heads of household (OR 4.19, 95% CI 1.70-10.32). In addition, the transition from full-time permanent employment to another employment status was associated with the development of new-onset severe depressive symptoms among both sexes, with an especially strong association among females. The present study suggests that, depending on head of household status and sex, precarious employment is associated with the development of new-onset severe depressive symptoms.

Relationship on new statin use and the risk of hepatocellular carcinoma (HCC) in patients with incident type 2 diabetes mellitus (T2DM), who might be at the risk of developing HCC, is uncertained. A nationwide population–based nested case–control study was conducted within the National Health Insurance Service National Sample Cohort 2002–2013 in Korea. Newly prescribed statin after newly diagnosed T2DM was defined as statin use. Controls were matched to case patients on age, sex, follow–up time, and the date of diabetes diagnosis at a five–to–one ratio. Odds ratios (ORs) for associations of statin use with HCC were calculated using conditional logistic regression. After at least a 5‐year HCC–free period, there were 229 incident HCC cases and 1,145 matched controls from 47,738 patients with incident diabetes. Of these 229 incident HCC cases, 27 (11.8%) were statin users, whereas 378 (33.0%) were statin users among 1,145 controls. Statin use was associated with a reduced risk of HCC development (adjusted OR [AOR]= 0.36, 95% confidence interval [CI] 0.22–0.60) after adjustment for chronic viral hepatitis, liver cirrhosis, alcoholic liver disease, previous cancer, aspirin use, insulin use, sulfonylurea use, metformin use, thiazolidinedione use, history of chronic obstructive pulmonary disease, Charlson comorbidity score, household income level, and residential area. Risk reduction was accentuated with an increase of cumulative defined daily doses (cDDD) compared with non–users (AORs 0.53, 0.36, 0.32, and 0.26 in ≤60, 60–180, 181–365, and >365cDDD, respectively; P for trend <0.0001). The risk reduction was apparent in the presence of liver disease (AOR = 0.27, 95% CI 0.14–0.50), including heterogeneous groups of clinical diagnosis of liver disease, but not significant in the absence of liver disease (AOR = 0.64, 95% CI 0.32–1.29). Among patients with new onset T2DM, statin use before HCC diagnosis may have a beneficial inhibitory effect on HCC development in a dose–dependent manner, especially in individuals with liver disease.

Aspirin has been considered to be beneficial in preventing cardiovascular diseases and cancer. Several pharmaco-epidemiology cohort studies have shown protective effects of aspirin on diseases using various statistical methods, with the Cox regression model being the most commonly used approach. However, there are some inherent limitations to the conventional Cox regression approach such as guarantee-time bias, resulting in an overestimation of the drug effect. To overcome such limitations, alternative approaches, such as the time-dependent Cox model and landmark methods have been proposed. This study aimed to compare the performance of three methods: Cox regression, time-dependent Cox model and landmark method with different landmark times in order to address the problem of guarantee-time bias. Through statistical modeling and simulation studies, the performance of the above three methods were assessed in terms of type I error, bias, power, and mean squared error (MSE). In addition, the three statistical approaches were applied to a real data example from the Korean National Health Insurance Database. Effect of cumulative rosiglitazone dose on the risk of hepatocellular carcinoma was used as an example for illustration. In the simulated data, time-dependent Cox regression outperformed the landmark method in terms of bias and mean squared error but the type I error rates were similar. The results from real-data example showed the same patterns as the simulation findings. While both time-dependent Cox regression model and landmark analysis are useful in resolving the problem of guarantee-time bias, time-dependent Cox regression is the most appropriate method for analyzing cumulative dose effects in pharmaco-epidemiological studies.

This study identified the acceptance of disability’s impact on self-esteem among adults with disabilities in South Korea. This is a four-year follow-up study that obtained data from the Panel Survey of Employment for Persons with Disabilities from 2017 to 2020. In total, 3329 individuals participated. Logistic regression examined the acceptance of disability’s effect on self-esteem. These variables were categorized based on the acceptance of disability (high→high, low→high, high→low, and low→low) and self-esteem (low and not low). Compared to the participants with a consistently high acceptance of disability, those with constantly low acceptance were 2.35 times (95% CI 1.81–3.04) more likely to have low self-esteem. When the acceptance of disability was low→high and high→low, the low self-esteem probability was 1.23 and 1.66 times, respectively. Low self-esteem was prominent for the following: men, 50–64-year olds, married, urban, economic activists, the mid–low household income category, and those with sensory disability. Acceptance of disability can adversely affect self-esteem when it is consistently low or changes from high to low. Among socio-economic factors, there were several risk factors that could make individuals more vulnerable to low self-esteem. Therefore, it is necessary to help people accept their disabilities to maintain healthy self-esteem levels.