title: Radiation-associated circulatory disease mortality in a pooled analysis of 77,275 patients from the Massachusetts and Canadian tuberculosis fluoroscopy cohorts.
abstract: High-dose ionising radiation is associated with circulatory disease. Risks associated with lower-dose (<0.5 Gy) exposures remain unclear, with little information on risk modification by age at exposure, years since exposure or dose-rate. Tuberculosis patients in Canada and Massachusetts received multiple diagnostic x-ray fluoroscopic exposures, over a wide range of ages, many at doses <0.5 Gy. We evaluated risks of circulatory-disease mortality associated with <0.5 Gy radiation exposure in a pooled cohort of 63,707 patients in Canada and 13,568 patients in Massachusetts. Under 0.5 Gy there are increasing trends for all circulatory disease (n = 10,209; excess relative risk/Gy = 0.246; 95% CI 0.036, 0.469; p = 0.021) and for ischaemic heart disease (n = 6410; excess relative risk/Gy = 0.267; 95% CI 0.003, 0.552; p = 0.048). All circulatory-disease and ischaemic-heart-disease risk reduces with increasing time since exposure (p < 0.005). Over the entire dose range, there are negative mortality dose trends for all circulatory disease (p = 0.014) and ischaemic heart disease (p = 0.003), possibly due to competing causes of death over this dose interval.These results confirm and extend earlier findings and strengthen the evidence for circulatory-disease mortality radiation risk at doses <0.5 Gy. The limited information on well-known lifestyle/medical risk factors for circulatory disease implies that confounding of the dose trend cannot be entirely excluded.
authors.affiliation: Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA.
authors.forename: Van
authors.initials: V
authors.lastname: Tran
authors.affiliation: Department of Epidemiology and Biostatistics, School of Medicine, University of California San Francisco, San Francisco, CA, USA.
authors.forename: Lydia B
authors.initials: LB
authors.lastname: Zablotska
authors.affiliation: Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA.
authors.forename: Alina V
authors.initials: AV
authors.lastname: Brenner
authors.affiliation: Radiation Epidemiology Branch, National Cancer Institute, Bethesda, MD 20892-9778, USA.
authors.forename: Mark P
authors.initials: MP
authors.lastname: Little
mesh_terms: D000293:Adolescent; D000328:Adult; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005471:Fluoroscopy / Q000009:adverse effects; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000209:etiology / Q000401:mortality*; D011832:Radiation Injuries / Q000209:etiology / Q000401:mortality*; D012307:Risk Factors; D014376:Tuberculosis / Q000000981:diagnostic imaging*