Little is known about long-term cancer risks following in utero radiation exposure. We evaluated the association between in utero radiation exposure and risk of solid cancer and leukemia mortality among 8,000 offspring, born from 1948-1988, of female workers at the Mayak Nuclear Facility in Ozyorsk, Russia. Mother's cumulative gamma radiation uterine dose during pregnancy served as a surrogate for fetal dose. We used Poisson regression methods to estimate relative risks (RRs) and 95% confidence intervals (CIs) of solid cancer and leukemia mortality associated with in utero radiation exposure and to quantify excess relative risks (ERRs) as a function of dose. Using currently available dosimetry information, 3,226 (40%) offspring were exposed in utero (mean dose = 54.5 mGy). Based on 75 deaths from solid cancers (28 exposed) and 12 (6 exposed) deaths from leukemia, in utero exposure status was not significantly associated with solid cancer: RR = 0.94, 95% CI 0.58 to 1.49; ERR/Gy = -0.1 (95% CI
Cites: Radiat Environ Biophys. 2002 Mar;41(1):29-3112014404
Cites: J Natl Cancer Inst. 2008 Mar 19;100(6):428-3618334707
Cites: Radiat Res. 2003 Jun;159(6):787-9812751962
Cites: Int J Radiat Biol. 2003 May;79(5):293-30912943238
Cites: Ann ICRP. 2003;33(1-2):5-20612963090
Cites: Br J Cancer. 1975 Mar;31(3):271-871156514
Cites: Radiat Res. 1997 Mar;147(3):385-959052687
Cites: Br J Radiol. 1997 Feb;70:130-99135438
Cites: Health Phys. 2007 Sep;93(3):190-20617693770
Cites: Health Phys. 2000 Jul;79(1):72-610855780
Cites: Radiat Environ Biophys. 2002 Mar;41(1):23-812014403
Cites: Radiat Environ Biophys. 2008 Jul;47(3):301-1218528700
Cites: Int J Cancer. 2008 Aug 15;123(4):905-1118528867
Cites: Br J Cancer. 2008 Aug 5;99(3):545-5018665174
Cites: Environ Health Perspect. 2008 Dec;116(12):1731-419079728
The Sverdlovsk region of the Russian Federation is characterised by its abundance of natural resources and industries. Located in this region, Asbest city is situated next to one of the largest open-pit chrysotile asbestos mines currently operational; many city residents are employed in activities related to mining and processing of chrysotile. We compared mortality rates from 1997 to 2010 in Asbest city to the remaining Sverdlovsk region, with additional analyses conducted for site-specific cancer mortality.
Population and mortality data for Asbest city and Sverdlovsk region were used to estimate crude and age-specific rates by gender for the entire period and for each calendar year. Age-standardized mortality rates were also calculated for the adult population (20+) and Poisson regression was used to estimate standardized mortality ratios, overall and by gender.
During the period of 1997 to 2010, there were similar mortality rates overall in Asbest and the Sverdlovsk region. However, there were higher rates of cancer mortality (18 % males; 21 % females) and digestive diseases (21 % males; 40 % females) in Asbest and lower rates of unknown/ill-defined in Asbest (60 % males; 47 % females). Circulatory disease mortality was slightly lower in Asbest. Cancer mortality was higher for men in Asbest from oesophageal, urinary tract and lung cancers compared to the Sverdlovsk region. In women, cancer mortality was higher for women in Asbest from stomach, colon, lung and breast cancers compared to the Sverdlovsk region.
This large population-based analysis indicates interesting differences but studies with individual exposure information are needed to understand the underlying factors.
Cites: Int J Cancer. 1967 May 15;2(3):269-796041994
Cites: BMJ. 2003 Oct 25;327(7421):96414576248
Cites: BMJ. 2003 Jun 7;326(7401):1240-212791737
Cites: Cancer Epidemiol. 2013 Aug;37(4):440-523608525
Cites: J Natl Cancer Inst. 2011 Dec 21;103(24):1827-3922158127
Workers at the Mayak nuclear facility in the Russian Federation offer a unique opportunity to evaluate health risks from exposure to inhaled plutonium. Risks of mortality from lung cancer, the most serious carcinogenic effect of plutonium, were evaluated in 14,621 Mayak workers who were hired in the period from 1948-1982, followed for at least 5 years, and either monitored for plutonium or never worked with plutonium. Over the follow-up period from 1953-2008, there were 486 deaths from lung cancer, 446 of them in men. In analyses that were adjusted for external radiation dose and smoking, the plutonium excess relative risk (ERR) per Gy declined with attained age and was higher for females than for males. The ERR per Gy for males at age 60 was 7.4 (95% CI: 5.0-11) while that for females was 24 (95% CI: 11-56). When analyses were restricted to plutonium doses
Cites: Health Phys. 2002 Dec;83(6):833-4612467291
Cites: Radiat Res. 2003 Jun;159(6):787-9812751962
Cites: Radiat Environ Biophys. 2003 Jul;42(2):129-3512851829
Cites: Ann ICRP. 2003;33(4):1-11714614921
Cites: Am J Epidemiol. 2004 Jul 15;160(2):163-7215234938
Cites: Radiat Res. 2004 Oct;162(4):377-8915447045
Cites: Health Phys. 1994 Dec;67(6):577-887960779
Cites: J Natl Cancer Inst. 1995 Jun 7;87(11):817-277791231
In 2008, the worldwide estimated age-standardised incidence rates for thyroid cancer incidence were 4.7 and 1.5 per 100,000 women and men, respectively. Thyroid cancer's overall contribution to the worldwide cancer burden is relatively small, but incidence rates have increased over the last three decades throughout the world. This trend has been hypothesised to reflect a combination of technological advances enabling increased detection, but also changes in environmental factors, including population exposure to ionising radiation from fallout, diagnostic tests and treatment for benign and malignant conditions. Studies of the atomic bomb survivors and populations treated with radiotherapy have established radiation as a risk factor for thyroid cancer, particularly from early life exposure. About 0.62 mSv (20%) of the global annual per caput effective radiation dose comes from diagnostic medical and dental radiation for the period of 1997-2007, increased from 0.4 mSv for the years 1991-1996. This international trend of increasing population exposure to medical diagnostic sources of radiation, attributed in large part to the growing use of computed tomography scans, but also interventional radiology procedures, has raised concerns about exposure to radiosensitive organs such as the thyroid. Worldwide, medical and dental X-rays constitute the most common type of diagnostic medical exposures, but their contribution to the cumulative effective dose is relatively low, whereas computed tomography scans account for 7.9% of diagnostic radiology examinations but 47% of the collective effective dose from diagnostic radiation procedures in parts of the world. Although the radiation exposure from computed tomography scans is substantially lower than that from radiotherapy, multiple computed tomography scans could result in non-trivial cumulative doses to the thyroid. Studies are currently underway to assess the incidence of cancer in large cohorts of children who received computed tomography scans. National and international efforts have been developed to raise awareness and to standardise procedures for use of computed tomography and interventional radiology procedures in paediatric and general populations.
Chrysotile, a serpentine asbestos fibre, is the only type of asbestos produced and consumed in the world today. It is an established human carcinogen. We have begun fieldwork on a retrospective cohort study of employees of one of the world's largest chrysotile mine and mills, situated in Asbest, Russia. The primary aim of the study is to better characterize and quantify the risk of cancer mortality in terms of (i) the dose-response relationship of exposure with risk; (ii) the range of cancer sites affected, including female-specific cancers; and (iii) effects of duration of exposure and latency periods. This information will expand our understanding of the scale of the impending cancer burden due to chrysotile, including if chrysotile use ceased worldwide forthwith. Herein we describe the scientific rationale for conducting this study and the main features of its study design.
Long-term effects of in utero exposure to ionizing radiation remain poorly quantified in humans. In this study, the risk of hematologic malignancies was investigated in offspring of female workers of the Mayak Production Association, a large Russian nuclear facility. Excess relative risks (ERR) for exposure to gamma radiation and plutonium were estimated in a cohort of 8,466 offspring who were born between January 1, 1948 and December 31, 1988 and followed until 2009. An unstable linear ERR of 1.12 (95% CI 0.11-3.44) per 100 mGy gamma exposure in utero was estimated based on 32 incident hematologic malignancies in 277,002 person-years under risk. The ERR was increased in the dose category 20-79 mGy gamma exposure in utero (1.75, 95% CI 0.04; 5.63), while the other dose categories showed decreased or unstable estimates. Leukemia showed an ERR of 1.76 (95% CI 0.01-8.33) per 100 mGy based on 13 cases. There was no consistent association with plutonium exposure. While an increased risk of hematologic malignancies after gamma exposure in utero was suggested, the small numbers prevented more definitive conclusions.
Studies of cancer risk following in utero exposure to ionizing radiation are limited in number, particularly for adult-onset cancers, and the evidence is unclear. In the present study, the risk of solid cancer incidence following in utero radiation exposure is examined among 8466 offspring of female nuclear workers at one of the largest nuclear facilities (Mayak Production Association) in the Russian Federation. Poisson regression methods were used to estimate excess relative risks (ERRs) per Gray (Gy). Mother's uterine gamma dose served as a surrogate for fetal gamma dose. During 277,002 person-years of follow-up (1948-2009), there were 177 first primary solid cancers excluding non-melanoma skin cancers. Estimated in utero gamma and plutonium doses exceeded zero for 41 and 23 % of offspring, respectively. Of the 177 solid cancers, 66 occurred among individuals with some in utero exposure to gamma radiation and 53 among those with estimated plutonium exposures. There was no indication of a statistically significantly increased risk of solid cancer incidence from in utero gamma exposure (linear ERR/Gy -1.0; upper 95 % confidence limit 0.5). This result was unchanged after accounting for subsequent occupational exposure. Plutonium doses were estimated but were too low to obtain meaningful risk estimates. Thus, in this cohort in utero radiation exposure was not associated with solid cancer risk. This is consistent with an earlier report of mortality in the cohort, but is based on twice as many cases and less susceptible to biases inherent in mortality analyses. Given the relatively young age of the cohort with respect to cancer, continued follow-up should be done as the number of cancer cases increases.
Our understanding of cancer risk from ionizing radiation is largely based on studies of populations exposed at high dose and high dose rates. Less certain is the magnitude of cancer risk from protracted, low-dose and low-dose-rate radiation exposure. We estimated the dose-response relationship for solid cancer mortality in a cohort of 29,730 individuals who lived along the Techa River between 1950 and 1960. This population was exposed to both external ? radiation and internal (90)Sr, (137)Cs and other radionuclides after the release of radioactive waste into the river by the Mayak Radiochemical Plant. The analysis utilized the latest individualized doses from the Techa River Dosimetry System (TRDS) 2009. We estimated excess relative risks (ERRs) per Gy for solid cancer mortality using Poisson regression methods with 95% confidence intervals (CIs) and P values based on likelihood ratio tests. Between 1950 and 2007, there were 2,303 solid cancer deaths. The linear ERR/Gy = 0.61 (95%; CI 0.04-1.27), P = 0.03. It is estimated that approximately 2% (49.7) of solid cancers deaths were associated with the radiation exposure. Our results, based on 2,303 solid cancer deaths and more than 50 years of follow-up, support an increased risk of solid cancer mortality following protracted radiation exposure from the Techa River contamination. The wide confidence interval of our estimate reflects the challenges of quantifying and describing the shape of the dose-response relationship in the low dose range. Nevertheless, the risk estimates provide important information concerning health risks from whole-body radiation exposure that can occur from accidents that result in wide-scale environmental contamination.