Background: It is well known that specific occupations can cause harm in developing malignant neoplasms. Chemical exposure is particularly high in the manufacturing industry and workers in this sector may face a higher occupational risk for cancer. We aimed to estimate inequalities in the risk of cancers related to occupational chemical exposure in various manufacturing categories.
Methods: Using nationwide clinical inpatient data (1984-2017) in Japan, we undertook a multicenter, case-control study with regard to risks of developing cancers among various manufacturing industry categories. Using the food manufacturing industry as the reference group, odds ratios and 95% confidence intervals for each industry were estimated by conditional logistic regression, adjusted for sex, age, admission period, and the admitting hospital. Medical record summaries accounting for 89% of industrial categories with high odds ratios were collected to confirm diagnoses made on the basis of histology. We estimated industrial hazards based on the Pollutant Release and Transfer Register.
Results: A reduced risk for some of common cancers was observed among lumber and wood products industries. Leather tanning, leather products and fur tended to show a higher risk: 2.36 (95% CI 1.15-4.83) for pancreatic cancer, 2.85 (95% CI 1.26-6.47) for liver cancer and 2.00 (95% CI 1.01-3.99) for lung cancer. For the electronics category, observations of high risk ranged from 2.09 (95%CI 1.18-3.70) for ureter cancer, to 2.49 (95% CI 1.79-3.55) for kidney cancer.
Conclusions: This study revealed industry risk inequalities in manufacturing categories were present with regard to the risk of common cancers in Japan.
Keywords: Cancer risk; Case control study; manufacturing industry; occupational hazard.