Ionising radiation and cardiovascular disease: systematic review and meta-analysis.

OBJECTIVE: To systematically review and perform a meta-analysis of radiation associated risks of cardiovascular disease in all groups exposed to radiation with individual radiation dose estimates. DESIGN: Systematic review and meta-analysis. MAIN OUTCOME MEASURES: Excess relative risk per unit dose (Gy), estimated by restricted maximum likelihood methods. DATA SOURCES: PubMed and Medline, Embase, Scopus, Web of Science Core collection databases. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Databases were searched on 6 October 2022, with no limits on date of publication or language. Animal studies and studies without an abstract were excluded. RESULTS: The meta-analysis yielded 93 relevant studies. Relative risk per Gy increased for all cardiovascular disease (excess relative risk per Gy of 0.11 (95% confidence interval 0.08 to 0.14)) and for the four major subtypes of cardiovascular disease (ischaemic heart disease, other heart disease, cerebrovascular disease, all other cardiovascular disease). However, interstudy heterogeneity was noted (P<0.05 for all endpoints except for other heart disease), possibly resulting from interstudy variation in unmeasured confounders or effect modifiers, which is markedly reduced if attention is restricted to higher quality studies or those at moderate doses (<0.5 Gy) or low dose rates (<5 mGy/h). For ischaemic heart disease and all cardiovascular disease, risks were larger per unit dose for lower dose (inverse dose effect) and for fractionated exposures (inverse dose fractionation effect). Population based excess absolute risks are estimated for a number of national populations (Canada, England and Wales, France, Germany, Japan, USA) and range from 2.33% per Gy (95% confidence interval 1.69% to 2.98%) for England and Wales to 3.66% per Gy (2.65% to 4.68%) for Germany, largely reflecting the underlying rates of cardiovascular disease mortality in these populations. Estimated risk of mortality from cardiovascular disease are generally dominated by cerebrovascular disease (around 0.94-1.26% per Gy), with the next largest contribution from ischaemic heart disease (around 0.30-1.20% per Gy). CONCLUSIONS: Results provide evidence supporting a causal association between radiation exposure and cardiovascular disease at high dose, and to a lesser extent at low dose, with some indications of differences in risk between acute and chronic exposures, which require further investigation. The observed heterogeneity complicates a causal interpretation of these findings, although this heterogeneity is much reduced if only higher quality studies or those at moderate doses or low dose rates are considered. Studies are needed to assess in more detail modifications of radiation effect by lifestyle and medical risk factors. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020202036.

Methodology for estimating cancer risks of diagnostic medical exposure: with an example of the risks associated with computed tomography.

Because of fast growing medical radiation use, estimating possible late health effects of radiation, including potential cancer risk, is an issue of substantial interest. Since physicians make the decision to order or perform a radiological procedure, it is very important to provide them with objective information about possible radiation-associated risks. Methodology for estimating cancer risks based on recommendations of ICRP Publication 103 is presented in the paper. Organ doses, age, and gender are used as basic parameters. An example of the evaluation of radiation-associated risks from computed tomography examination is presented.

Lessons from Chernobyl and prognosis for Fukushima: radiological consequences.

The following are considered: results of large-scale radiation epidemiological studies of the health effects of the Chernobyl accident, radiation risks for emergency workers and the affected population; and verification of ICRP risk models taking into account data on the Chernobyl accident and preliminary prognostic estimates of potential radiological consequences of the Fukushima disaster.

Estimation of individualized radiation risk from chronic occupational exposure in Russia.

Internationally, the upper limit of acceptable individualized risk from occupational exposure for nuclear industry workers is determined by the death probability 10(-3) y(-1). The same risk value of 10(-3) y(-1) is established by the radiation safety standards currently in force in Russia. The United Nations Scientific Committee on the Effects of Atomic Radiation has proposed the formulas for estimating individualized risk of developing cancer with allowance for radiation dose, age at exposure, attained age, and sex. This methodology is first applied to estimate individualized radiation risk for Russian nuclear industry workers (49,900 persons) who were monitored for radiation exposure through the use of personal dosimeters. The estimates show that in 2006 the threshold of 10(-3) y(-1) for individualized risk is exceeded for 755 persons, which is 1.6% of all workers covered by personal dose monitoring. The excess absolute risk (EAR) and attributable risk (AR) were estimated for all cancers, solid cancers, and leukemias.

Latent period in induction of radiogenic solid tumors in the cohort of emergency workers.

The paper presents estimates for the latent period of the induction of radiogenic solid cancers among Chernobyl emergency workers (males) living in six central regions of Russia. The analysis is based on medical and dosimetry data gathered by the National Radiation and Epidemiological Registry over the time period from 1986 to 2005. The cohort includes 59,770 persons who stayed in the exposure zone (30-km zone around the Chernobyl nuclear power plant) in 1986-1987. There were 2,718 cases of solid tumors identified during the follow-up time in this cohort. The mean radiation dose in the cohort is 0.13 Gy. The radiation risk and latent period were estimated using the method of maximum likelihood. The excess relative risk per unit dose was found to be 0.96 (95% confidence interval (CI): 0.3-1.7) and the minimum latent period for induction of solid tumors is 4.0 years (95% CI: 3.3-4.9).

Polymorphisms of DNA damage response genes in radiation-related and sporadic papillary thyroid carcinoma.

Papillary thyroid carcinoma (PTC) etiologically occurs as a radiation-induced or sporadic malignancy. Genetic factors contributing to the susceptibility to either form remain unknown. In this retrospective case-control study, we evaluated possible associations between single-nucleotide polymorphisms (SNPs) in the candidate DNA damage response genes (ATM, XRCC1, TP53, XRCC3, MTF1) and risk of radiation-induced and sporadic PTC. A total of 255 PTC cases (123 Chernobyl radiation-induced and 132 sporadic, all in Caucasians) and 596 healthy controls (198 residents of Chernobyl areas and 398 subjects without history of radiation exposure, all Caucasians) were genotyped. The risk of PTC and SNPs interactions with radiation exposure were assessed by logistic regressions. The ATM G5557A and XRCC1 Arg399Gln polymorphisms, regardless of radiation exposure, associated with a decreased risk of PTC according to the multiplicative and dominant models of inheritance (odds ratio (OR) = 0.69, 95% confidence interval (CI) 0.45-0.86 and OR = 0.70, 95% CI 0.59-0.93 respectively). The ATM IVS22-77 T > C and TP53 Arg72Pro SNPs interacted with radiation (P = 0.04 and P = 0.01 respectively). ATM IVS22-77 associated with the increased risk of sporadic PTC (OR = 1.84, 95% CI 1.10-3.24) whereas TP53 Arg72Pro correlated with the higher risk of radiogenic PTC (OR = 1.80, 95% CI 1.06-2.36). In the analyses of ATM/TP53 (rs1801516/rs664677/rs609429/rs1042522) combinations, the GG/TC/CG/GC genotype strongly associated with radiation-induced PTC (OR = 2.10, 95% CI 1.17-3.78). The GG/CC/GG/GG genotype displayed a significantly increased risk for sporadic PTC (OR = 3.32, 95% CI 1.57-6.99). The results indicate that polymorphisms of DNA damage response genes may be potential risk modifiers of ionizing radiation-induced or sporadic PTCs.

Late cancer and noncancer risks among Chernobyl emergency workers of Russia.

The presented work summarizes data on estimated radiation risks among Chernobyl emergency workers of the Russian Federation. In 1991-1998, the excess relative risk (ERR) of death from malignant neoplasm was statistically significant: excess relative risk per 1 Gy (ERR/Gy)=2.11 with 95% confidence interval (CI) (1.31-2.92). In 1991-2001, the ERR estimation for incident solid cancers gives a positive, but statistically insignificant value: ERR/Gy=0.34 with 95% CI (-0.39; 1.22). In 1986-2003, radiation risk for leukemia incidence was investigated. During the first 10 y after the Chernobyl accident (1986-1996) the relative risk (RR) of leukemia (excluding chronic lymphocytic leukemia) was statistically significant: RR=2.2 with 95% CI (1.3-3.8) for emergency workers with doses>0.15 Gy in comparison with less exposed workers. In 1986-2000, a statistically significant dose response was observed for incident cerebrovascular diseases: ERR/Gy=0.39, 95% CI=(0.004; 0.77). For doses>0.15 Gy a statistically significant risk of cerebrovascular diseases as a function of mean daily dose was observed: ERR per 0.1 Gy d(-1)=2.17 with 95% CI=(0.64; 3.69). Different but overlapping cohorts of Russian emergency workers were used for these estimations. No adjustments were made for recognized risk factors for cerebrovascular diseases. All results should be considered as preliminary.

Non-cancer thyroid diseases among children in the Kaluga and Bryansk regions of the Russian Federation exposed to radiation following the Chernobyl accident.

This paper presents results of estimated radiation risks of non-cancer thyroid diseases in the people from Kaluga and Bryansk regions of the Russian Federation exposed in their childhood to radioiodine as a result of the Chernobyl accident. This work was carried out under the Joint Medical Research Project on non-cancer thyroid diseases conducted by Sasakawa Memorial Health Foundation and the Medical Radiological Research Center of the Russian Academy of Medical Sciences. The subjects were 2,457 people who underwent health examinations from 1997 to the end of 1999 who had individual radiometric thyroid data obtained between May and June 1986 and were aged 10 y or less at the time of exposure. The thyroid absorbed doses from incorporated 131I were estimated on the basis of measurements of exposure dose rate in the vicinity of the subject's thyroid and liver. A compartment model accounting for 131I metabolism in humans and cows was used. The estimated dose varied from 0 to 6 Gy, and its distribution was approximately lognormal with a mean of 0.132 Gy and standard deviation of 0.45 Gy. The prevalence of diffuse goiter in males showed a significant dose-response (p = 0.03) with an estimated odds ratio 1.36 at 1 Gy.