Risk of Hematologic Malignancies in the Offspring of Female Workers of the Mayak Nuclear Facility in the Southern Urals, Russian Federation

Abstract

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.

Health Impacts of Low-Dose Ionizing Radiation: Current Scientific Debates and Regulatory Issues

“…A dose–response relationship between α-radiation exposure and incidence of various cancerous and noncancerous disorders was observed in nuclear workers chronically exposed by inhalation to plutonium ( 239 Pu) in the Mayak Nuclear Enterprise (Chelyabinsk region, Russia). 98 - 120 For instance, the incidence of lung cancer corrected for smoking was 0.56, 0.59, and 0.83 at body burdens of 343, 1180, and 4200 Bq, respectively, in 500 nuclear workers relative to internal controls. Of note, the lung cancer incidence was linearly associated with cigarette smoking, with 2-fold risk of lung cancer in those workers who smoked 1 pack of cigarettes per day for at least 5 years.…”

“…113 The solid cancer incidence in the same offspring cohort (n ¼ 8466) also did not differ from that in the general population 114 ; there was also no consistent association demonstrated between the risk of hematologic malignancies and plutonium exposure. 115 In a more recent study aimed to analyze cancer risk in a cohort of patients exposed in utero due to releases of nuclear waste into the Techa River in the Southern Urals (n ¼ 10 482 for solid cancers, and n ¼ 11 070 for hematological cancers), no association between in utero exposure and risk for both solid and hematological cancer was found. 116 In the pooled analyses of 2 offspring cohorts of Mayak female workers and female residents of contaminated areas near Techa River, a tendency toward both decreased solid cancer incidence and mortality was observed in this large pooled cohort (mortality analysis, n ¼ 16 821; incidence analysis, n ¼ 15 813).…”

In utero exposure to radiation and haematological malignancies: pooled analysis of Southern Urals cohorts

“…The MWOC comprised all individuals born alive in the town of Ozyorsk between January 1948 and December 1988 to mothers who were members of the Mayak worker cohort that comprised workers employed by the Mayak Production Association (a large nuclear facility) for any period of time between January 1948 and December 1982 at one of the nuclear reactors, the plutonium production plant, the radiochemical plant, the water treatment plant, or the mechanical repair plant (Deltour et al , 2016). Because of the differences in inclusion criteria between the two cohorts, many members of the MWOC had an estimated zero radiation dose despite the potential of in utero exposure, whereas the TRCIU by definition comprised only individuals who had a non-zero dose (with few exceptions).…”

“…Dose rates were adjusted as appropriate for pregnancies that occurred very close together. The mothers of MWOC members may also have been exposed to plutonium; exposure to internal radiation was modelled for the MWOC-specific analysis but not used in the pooled analysis (Deltour et al , 2016). For MWOC members who later became Mayak workers themselves (and therefore members of the Mayak worker cohort), estimates of postnatal occupational exposure to γ- radiation (red bone marrow dose) were extracted from the Mayak Worker Dosimetry System 2008.…”

“…The two cohorts have been analysed separately for both incidence and mortality of haematological malignancies. Based on 32 incident cases, analysis of the Mayak female worker offspring cohort (MWOC) has revealed some weak indications of increased risk (Deltour et al , 2016), whereas analysis based on 26 incident cases in the Techa River in utero exposed cohort (TRCIU) has not shown an increase (Kharyuzov et al , 2015). …”