Occupational inequalities in mortality in Korea: an analysis using nationally representative mortality follow-up data from the late 2000s and after

Abstract

Many Korean and international studies have found higher mortality rates and poorer health conditions among manual workers than among non-manual workers. However, a recent study using unlinked data argued that since the economic crisis in Korea in the late 2000s, the mortality estimates of male Korean non-manual workers have been higher than those of manual workers. Our work using individually linked data from the late 2000s and after aimed to examine mortality inequality by occupational class. We analyzed Korea National Health and Nutrition Examination Survey data that were individually linked to cause-of-death data. Cox regression analysis was used to identify the hazard ratios for mortality by occupational class. Of 11,766 males aged between 35 and 64, 397 died between 2007 and 2018: 142 died from cancer, 68 from cardiovascular disease, 88 from external causes, and 99 from other causes. After controlling for age, the mortality estimates for manual workers were 1.85 times higher than those for upper non-manual workers (p<0.05). We observed no evidence of reversed mortality inequality among occupational classes in Korea since the 2000s; this previously reported finding might have been due to numerator-denominator bias arising from the use of unlinked data.

Mortality of Suicide and Cerebro-Cardiovascular Diseases by Occupation in Korea, 1997–2020

“…Over the 24-year period, SMR of suicide and CCVD were highest in SFF and MNG among males and females, respectively ( Appendix A ). Appendix B displays the result of analyzing the SMR of male suicide and CCVD in 2007–2018 by period and four occupation groups, simila r to the recent linked data study [ 20 ]. As a result of sorting them into four occupational groups, the SMR of upper non-manual workers (MNG and PRF) was lower than that of other groups.…”

“…In contrast, the results of studies on occupational mortality in Korea are inconsistent. Some studies using unlinked data showed that male mortality of upper non-manual workers (MNG and PRF) turned out to be higher than that of manual workers in the mid-2010s, unlike in the late 1990s [ 9 , 19 ], whereas others reported that the mortality of manual workers remained the highest after the late 2000s [ 20 , 21 ].…”

“…However, studies using the same unlinked data showed different results for suicide mortality rates, especially for managers [ 9 , 21 ]. Furthermore, although suicide and CCVD may seem heterogeneous, some similarities regarding mortality can be inferred from previous studies [ 9 , 15 , 18 , 19 , 20 ]. However, few studies have analyzed the mortality trend of suicide and CCVD over time using long-term data in Korea.…”

“…However, Japan is known to be a representative country with higher mortality for upper non-manual workers (managers and professionals) after the economic bubble burst [ 18 , 19 ], whereas the results for Korea are conflicting. In recent years, studies have reported that the mortality of upper non-manual workers was higher than that of manual workers [ 9 , 19 ], whereas others found it to be lower [ 20 , 21 ]. The discrepancy may be because of a numerator–denominator bias due to differences in the use of unlinked data [ 20 ].…”

“…In recent years, studies have reported that the mortality of upper non-manual workers was higher than that of manual workers [ 9 , 19 ], whereas others found it to be lower [ 20 , 21 ]. The discrepancy may be because of a numerator–denominator bias due to differences in the use of unlinked data [ 20 ]. However, studies using the same unlinked data showed different results for suicide mortality rates, especially for managers [ 9 , 21 ].…”