Asthma mortality in male workers of the dye industry in Korea

Workers in the dye industry are exposed to various chemicals, of which reactive dye is a well-known occupational asthmagen. This study examined the relationship between asthma mortality and occupational exposure in the dye industry. The cohort comprised 66,089 male workers, including 904 workers in the dye industry, who underwent medical examinations from 1995 to 2003 at a medical service institute located in Incheon, Korea. Deaths were also observed during the 1995 to 2003 period. The mortality was analyzed using the standardized mortality ratio (SMR) compared to the Korean general population, and the mortalities from asthma in dye manufacturing workers and other workers were compared using the standardized rate ratio (SRR). The all-cause mortality in dye industry workers was significantly lower than in the general population (SMR=0.40, 95% CI 0.24-0.63), while the asthma mortality (SMR=9.03, 95% CI 1.86-26.39) was significantly higher. Deaths from non-malignant respiratory diseases were higher in dye industry workers, but were not statistically significant (SMR=2.0, 95% CI 0.41-5.86). In the internal comparison, the all-cause mortality was the same in both groups, while the mortalities from non-malignant respiratory diseases (SRR=6.04, 95% CI 4.00-9.44) and asthma (SRR=23.29, 95% CI 11.05-58.83) were higher in dye industry workers than in workers in other industries. Because asthma is a life-threatening disease, special consideration and preventive measures must be taken for workers in the dye industry.