Mortality from various diseases of the circulatory system in the Russian Mayak nuclear worker cohort: 1948–2018

Abstract

The paper reports on findings of the study of mortality from diseases of circulatory system (DCS) in Russian nuclear workers of the Mayak Production Association (22,377 individuals with 25.4% of females) who were hired at the facility in 1948–1982 and followed up until end-2018. Using the AMFIT module of EPICURE software, relative risks and excess relative risks per unit absorbed dose (ERR/Gy) for the entire Mayak cohort, the subcohort of workers who were residents of the dormitory town of Ozyorsk and the subcohort of migrants from Ozyorsk were calculated based on maximum likelihood. The mean cumulative liver absorbed gamma-ray dose from external exposure was 0.45 (0.65) Gy (mean (standard deviation) gray) for males and 0.37 (0.56) Gy for females. The mean cumulative liver absorbed alpha dose from internal exposure to incorporated plutonium was 0.18 (0.65) Gy for males and 0.40 (1.92) Gy for females. By the end of the follow-up, 6019 deaths from DCS as the main cause of death were registered among Mayak PA workers (including 3828 deaths in the subcohort of residents and 2191 deaths in the subcohort of migrants) over 890,132 (622,199/267,933) person-years of follow-up. The linear model that took into account non-radiation factors (sex, attained age, calendar period, smoking status and alcohol drinking status) and alpha radiation dose (via adjusting) did not demonstrate significant associations of mortality from DCS, ischemic heart disease (IHD) and cerebrovascular disease (CeVD) with gamma-ray exposure dose in the entire cohort, the resident subcohort and the migrant subcohort (either in males or females). For the subcohort of residents, a significant association with gamma dose was observed for mortality from ischemic stroke in males with ERR/Gy=0.43 (95% CI 0.08; 0.99); there were no significant associations with liver absorbed gamma dose for any other considered outcomes. As for internal exposure, for males no significant associations of mortality from any of the DCS with liver absorbed alpha dose were observed, but for females positive associations were found for DCS (the entire cohort and the resident subcohort) and IHD (the entire cohort) mortality. No significant associations of mortality from various types of DCS with neutron dose were observed either in males or females, although neutron absorbed doses were recorded only in 18% of the workers.

Circulatory disease mortality among male medical radiation workers in South Korea, 1996–2019

“…Our non-significant positive dose-response estimates of CD with occupational radiation doses were generally comparable to those seen amongst medical radiation workers in the United States (12); in the Korean study based on morbidity among 11 500 diagnostic medical radiation workers (11); and amongst Mayak nuclear workers in Russia (20). However, there is considerable variation in the risk estimates from specific studies.…”

“…Literature on radiation epidemiological studies was used to select a few non-radiation risk factors for CD (smoking status, alcohol intake, sleep duration, and shift work) (18)(19)(20). The findings of previously self-reported questionnaires among diagnostic medical radiation workers from 2012-2013 (response rate was 26.5%) (21), were used as the basis to imput these non-radiation risk factors for male workers.…”

Dose rate effect on mortality from ischemic heart disease in the cohort of Russian Mayak Production Association workers

“…The majority of Mayak PA workers (76.1% of the entire cohort and 76.2% of the resident subcohort) received combined (both external and internal) radiation exposures and the rest of the workers received only external exposures to gamma-rays and/or neutrons. As noted earlier 16 , some Mayak workers were internally exposed to radionuclides other than plutonium, but the contribution of plutonium to the alpha dose in the Mayak worker cohort was the largest (> 90%).…”

Ionizing radiation, cerebrovascular disease, and consequent dementia: A review and proposed framework relevant to space radiation exposure

“…For example, in the Russian Mayak Worker Cohort, there was a significant positive ERR for cerebrovascular disease morbidity (ERR/Gy = 0.46, 95% CI: 0.37, 0.57), but not for mortality ( Azizova et al, 2014 ; Moseeva et al, 2014 ). Follow up of the Mayak cohort suggest the most vulnerable to ischemic stroke morbidity were residents of the dormitory town of Ozyorsk ( Azizova et al, 2022 ). Other reports of a positive but not significant ionizing radiation-induced ERR of mortality from cerebrovascular disease include the Sellafield Nuclear Workers from the United Kingdom ( Azizova et al, 2018 ), nuclear industry workers from the 15 Country study ( Vrijheid et al, 2007 ), German uranium miners ( Kreuzer et al, 2013 ), persons exposed to radioactive fallout from nuclear testing in the vicinity of the Semipalatinsk Nuclear Test Site ( Grosche et al, 2011 ), workers at the Los Alamos National Laboratory ( Boice et al, 2021b ), US uranium enrichment workers ( Anderson et al, 2021 ), medical radiation workers in the United States ( Boice et al, 2021a ), medical radiation workers in South Korea ( Cha et al, 2020 ) and tuberculosis fluoroscopy patients with doses less than 0.50 Gy ( Tran et al, 2017 ).…”