Occupational exposure to ionizing radiation and electromagnetic fields in relation to the risk of thyroid cancer in Sweden

Occupation and thyroid cancer

“…Jeong et al 52 observed a significantly increased risk of thyroid cancer among 8429 male Korean nuclear power workers (SIR=5.93, 95% CI 2.84 to 10.9). In this study, risk increased with increasing radiation exposure based on dosimetry metrics, with an 18-fold increased RR among the two cases exposed to more than 100 milliSievert (mSv) of radiation as part of their job (RR=18.51; 95% CI 1.7 to 204.3, p-trend=0.03) and an elevated but not statistically significant excess RR per Sievert (ERR 45.2, 95% CI <−12.1 to 97.4) 48. An increased risk of thyroid cancer was also observed by Zielinski et al 55 among a cohort of Canadian medical workers who were identified using the National Dose Registry of radiation workers when compared to the Canadian general population (SIR 1.74; 90% CI 1.40 to 2.14).…”

“…47 48 57–60. More generic characterisations of healthcare occupations, such as laboratory workers that may or may not have radiation exposure, were often, but not consistently, associated with thyroid cancer risk.…”

“…The occupational evidence was observed primarily from large cohort studies of radiation-exposed workers51 52 55 or workers with direct interaction with X-ray technology47 48 57–60 and from population-based studies that examined risk in relation to X-ray work47 or ionising radiation48 rather than more general healthcare occupations. Radiation is a biologically plausible risk factor that is supported by strong and consistent epidemiologic evidence from studies of childhood exposure to radiotherapy, and fallout from atomic bombings 8.…”

Occupational exposure to chemicals and risk of thyroid cancer in Sweden

“…Our risk estimators were adjusted for age, period and geographical area, since TC incidence varies among the diVerent Swedish counties, being highest in certain regions lying in the centre and south of the country (Jensen et al 1988) but evincing no great diVerences between rural and urban areas (Pettersson et al 1996). The only fully established risk factor, however, is exposure to ionising radiation, and, while the eVect of this physical agent was conWrmed in this same cohort by using an ionising-radiation-speciWc JEM (Lope et al 2006), adjustment for such exposure nonetheless resulted in no change to the estimators obtained for the chemicals studied in this paper.…”

“…Furthermore, in view of the fact that ionising radiation is the best-established TC risk factor, the possible confounding eVect of occupational exposure to this radiation was also assessed for all subjects in the cohort, using a common JEM for both sexes which had been used to evaluate risk of TC in a previous study (Lope et al 2006).…”