title: Thyroid cancer incidence in the vicinity of nuclear sites in Belgium, 2000-2008.
abstract: BACKGROUND
  Public health concern about nuclear activities have existed since the 1980s. Most studies on this subject investigated childhood leukemia. Thyroid cancer may be another health outcome of interest, because some nuclear installations are a potential source of radioactive iodine isotopes in the environment and because thyroid cancer is known to occur after exposure to these isotopes.
  
  
  METHODS
  This study describes an ecological study investigating whether there is excessive thyroid cancer incidence among residents living in the vicinity of nuclear sites. Single-site analyses using indirect standardization (standardized incidence ratios [SIRs]) and Poisson regression modeling (rate ratios [RRs]) were conducted. The proximity area is typically defined as a circular zone with a radius of 20 km centered on the site. However, the choice of the size of this area is somewhat arbitrary. Therefore, a sensitivity analysis was carried out to investigate whether the results vary with radii of increasing proximity.
  
  
  RESULTS
  No increased thyroid cancer incidence was found within the 20 km proximity area around the nuclear power plants of Doel (SIR=0.74 [95% confidence interval (CI)=0.64; 0.84] and RR=0.72 [95% CI=0.63; 0.83]) and Tihange (SIR=0.86 [95% CI=0.70; 1.01] and RR=0.85 [95% CI=0.70; 1.02]). For the sites of Mol-Dessel and Fleurus, where a combination of nuclear research and industrial activities are located, the incidences of thyroid cancer within the 20 km proximity area were higher than expected (Mol-Dessel: SIR=1.19 [95% CI=1.01; 1.36] and RR=1.19 [95% CI=1.02; 1.38]; Fleurus: SIR=1.15 [95% CI=1.02; 1.28] and RR=1.17 [95% CI=1.04; 1.33]). For Chooz, a French nuclear power plant close to the Belgian border, the results were unstable as a result of the small population denominator. For all Belgian nuclear sites, the results were generally insensitive to the choice of the proximity area.
  
  
  CONCLUSIONS
  No evidence for excessive thyroid cancer incidence around the Belgian nuclear power plants was found. On the other hand, an increased incidence of thyroid cancer was observed around the sites with other nuclear activities. Further research is recommended to verify whether the observed increases could be related to the site-specific nuclear activities.
authors.affiliation: 1 Scientific Institute of Public Health, Operational Direction Surveillance and Public Health , Brussels, Belgium .
authors.forename: Kaatje
authors.initials: K
authors.lastname: Bollaerts
authors.forename: Sébastien
authors.initials: S
authors.lastname: Fierens
authors.forename: Lodewijk
authors.initials: L
authors.lastname: Van Bladel
authors.forename: Koen
authors.initials: K
authors.lastname: Simons
authors.forename: Michel
authors.initials: M
authors.lastname: Sonck
authors.forename: André
authors.initials: A
authors.lastname: Poffijn
authors.forename: David
authors.initials: D
authors.lastname: Geraets
authors.forename: Pol
authors.initials: P
authors.lastname: Gosselin
authors.forename: Herman
authors.initials: H
authors.lastname: Van Oyen
authors.forename: Julie
authors.initials: J
authors.lastname: Francart
authors.forename: An
authors.initials: A
authors.lastname: Van Nieuwenhuyse
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001530:Belgium / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology*; D055848:Nuclear Power Plants; D009688:Nuclear Reactors; D062486:Public Health Surveillance; D011848:Radioactive Pollutants / Q000633:toxicity*; D012042:Registries; D018570:Risk Assessment; D012737:Sex Factors; D062211:Spatio-Temporal Analysis; D013961:Thyroid Gland / Q000528:radiation effects*; D013964:Thyroid Neoplasms / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D011848:Radioactive Pollutants