Abstract
A cohort population of 7,271 people, who received low dose-rate γ-irradiation for about 10 years as a result of occupying buildings containing 60Co-contaminated steel and with 103,225 person-years of follow-up, was assessed for their cancer risks via standardized incidence ratios (SIRs), as compared with those populations with the same temporal and geographic characteristics in Taiwan. The association of risks with excess cumulative exposure, 47.7 mSv in average, was further evaluated for hazard ratios (HR) by the Cox regression analyses.
The risks in SIRs were significantly higher for all leukemia combined and acute lymphocytic leukemia in men, and marginally significant for thyroid cancers in women. All cancers combined, all solid cancers, and a combination of leukemia and thyroid/breast cancers were further shown with exposure-dependent increased HRs in those received initial exposure before 30 years old.
Via the Cox proportional hazard models, significant higher Excess Relative Risks (ERR1Sv) were observed in all cancers combined, breast cancers, and leukemia (except chronic lymphocytic leukemia), while marginally significant higher ERR1Sv were shown in solid cancers (except thyroid cancers), all solid cancers combined, stomach cancers, and lung cancers.
Prolonged low dose-rate radiation exposure appeared to increase the risks of developing certain cancers in this population in Taiwan.
