Differences in Cancer Mortality Rate Depending on Occupational Class among Japanese Women, 1995-2015

Although it is known that cancer mortality rate varies depending on occupations in Japan, differences in female cancer mortality rate depending on occupational classes have not been analyzed using the Vital Statistics in Japan. In this study, we analyzed the Vital Statistics data in Japan from 1995 to 2015, and revealed differences in cancer mortality rate depending on occupational classes among Japanese women.

The Vital Statistics data by occupations from 1995 to 2015 were obtained from the "Report of Vital Statistics : Occupational and Industrial Aspects" in Japan, and data on mortality for cancer in all sites, colorectal cancer, liver cancer, gallbladder and extrahepatic bile duct cancer, pancreatic cancer, lung cancer, breast cancer, and uterine cancer were used. We classified main occupation categories into non-manual workers and manual workers, and calculated age-standardized mortality rate for each of the occupational class, year, age group, and type of cancer and its annual percent change.

Age-standardized mortality rates for non-manual workers (222.0 per 100,000 persons in 1995 and 143.8 per 100,000 persons in 2015) were higher in cancer in all sites than those for manual workers (127.6 per 100,000 persons in 1995 and 103.7 per 100,000 persons in 2015) throughout the years. However, age-standardized mortality rates showed a significant decreasing trend between 1995 and 2015 for non-manual workers, and the absolute value of annual percent change was higher in non-manual workers than in manual workers. As a result, a difference in age-standardized mortality rates for cancer in all sites between the two types of occupational classes decreased throughout the years.

A further study investigating differences in physical or behavioral characteristics of female non-manual and manual workers is needed in order to understand the key factors for the higher cancer mortality rate in non-manual workers.