Abstract
Previous studies have suggested that in addition to respiratory system cancers, exposure to external airborne agents (EAAs) may also affect the risk of digestive tract cancer. However, previous epidemiological studies have been limited. To clarify this relationship, we conducted a Workers' Korea National Health Insurance Service cohort study. The EAA exposure group comprised participants who had ever visited a hospital as an inpatient for 'lung diseases due to external agents'. The reference population comprised men from the general working population. The EAA exposure group and reference group included a total of 98,666 and 79,959,286 person-years, respectively. Age-adjusted standardized incident rates (SIRs) with 95% confidence intervals (95%CI) were calculated for each 5-year age stratum. The SIR (95% CI) of EAA exposure was 1.30 (1.19-1.38) for all digestive tract cancers. The highest risk associated with EAA exposure was observed for oral cancer, followed by esophageal and stomach cancers [SIRs (95%CI): 3.96 (3.02-4.78), 3.47(2.60-4.25), and 1.34(1.17-1.47), respectively.] These statistically significant associations did not be attenuated in a subgroup analysis using logistic regression adjusted for age, smoking and alcohol consumption. Our findings suggest that EAA exposure should address risk reduction of both digestive tract and respiratory system cancers.