Since the 1980s, restructuring, which includes downsizing, closures, mergers, and privatization, has expanded worldwide, and various studies have investigated its effect on health. However, previous studies have mainly focused on restructuring accompanied by massive lay-offs, and the effect of a merger on workers’ health is still controversial. This study aims to investigate changes in worker depression and job stress after a merger without downsizing, which is unusual in Korea.

Repeated surveys were done in April 2014, April 2015, and April 2016 involving the participation of 209 subjects. Participants were divided into two groups, which were comprised of blue-collar workers (104) and white-collar workers (105). Sociodemographic characteristics, including age, education level, job tenure, gender, marital status, smoking status, and alcohol consumption, were measured via a survey. To determine the level of depression, the Korean version of the Center for Epidemiologic Studies Depression Scale (CES-D) was employed, and to investigate job stress, the Korean Occupational Stress Scale-Short Form (KOSS-SF) was used. For statistical analyses, Pearson’s chi-square test, the Student’s t-test, and repeated measure analysis of variance (ANOVA) were performed.

The results showed that depression (CES-D, F[2, 400] = 0.466, p = 0.628) was changed but without significance and job stress (KOSS-SF, F[1.899, 379.831] = 3.192, p = 0.045) were significantly different. The between-group difference in the CES-D score between the blue- and white-collar workers by survey administration time was not statistically significant (F = 0.316, p = 0.574). The interaction between the survey time and occupational group was also not statistically significant (F = 0.967, p = 0.381). The between-group difference in the KOSS-SF total score was not statistically significant (F = 1.132, p = 0.289), and the interaction between the survey administration time and occupational group was also not significant (F = 0.817, p = 0.437). In the job stress subgroup analyses Job insecurity and Lack of reward showed a significant difference by survey administration time.

This study showed that a merger without massive downsizing can cause negative health effects such as an changes in depression and increase in job stress. To improve the health of workers, both the immediate negative effects on health, and the long-term effects or their resolution over time should be considered prior to the merger.