On the conversion of solid cancer excess relative risk into lifetime attributable risk

2001 ◽  
Vol 40 (4) ◽  
pp. 249-257 ◽  
Author(s):  
A. M. Kellerer ◽  
Elke A. Nekolla ◽  
Linda Walsh
2021 ◽  
Vol 14 (1) ◽  
pp. 49-59
Author(s):  
L. Yu. Krestinina ◽  
S. A. Shalaginov ◽  
S. S. Silkin ◽  
S. B. Epifanova ◽  
A. V. Akleyev

The aim of this work is to assess the radiogenic risk of solid cancers incidence in the members of the Urals Childhood Exposure Cohort. The cohort includes people exposed under 20 years of age as a result of two radiation accidents at the Mayak Production Association in the Southern Urals (discharges of radioactive waste into the Techa River and the formation of the East Ural radioactive trace). The number of the cohort for solid cancer incidence analysis is 31,578 individuals. All the members were postnatally exposed and some of them – in-utero. Some of their parents were exposed before conception. 2,018 solid cancers were registered on the incidence catchment area during the period 1956-2018, the total amount of person years was 818,083. The analysis was carried out by the Poisson regression method with a simple parametric excess relative risk model. 95% confidence intervals were estimated with maximum likelihood approach. Only a postnatal dose was used in the first solid cancer incidence analysis of this cohort members with due account for preconception exposure of parents. TRDS-2016 mean postnatal dose accumulated over the entire follow-up period in the stomach of cohort members was 0.047 Gy. The analysis showed linear dependence of solid cancer incidence excess relative risk on postnatal dose. Excess relative risk was 0.66/Gy, р=0.006 with a five-year latency period. While estimating excess relative risk in different age groups at the beginning of exposure, a significant risk was present only in the age group under 1 year and amounted to 2.16/Gy; р<0.02 at the onset of exposure. The present results are in agreement with the results of the solid cancer incidence risk analysis both in the Techa River Cohort of exposed In-Utero where a statistically significant excess relative risk from a postnatal dose was revealed, and with the results of risk analysis in the Japanese cohort of people exposed in-utero and in early childhood.


Author(s):  
V.V. Kashcheev ◽  
◽  
S.Yu. Chekin ◽  
S.V. Karpenko ◽  
M.A. Maksioutov ◽  
...  

The paper considers radiation risks of solid cancer incidence and mortality, as well as risk of leu-kemia incidence (other than chronic lymphocytic leukemia) among Russian Chernobyl cleanup workers (liquidators). The study of the cohort of liquidators carried out at the National Radiation Epidemiological Registry (NRER) was based on the follow-up data collected from 1992 over 2019. The size of the Chernobyl cleanup workers cohort exceeded 65 thousand people, their av-erage age at the time of entering the exclusion zone was 34 years, the average external gamma radiation dose received by liquidators during their cleanup work was about 0.133 Gy. Radiation-induced risks of solid cancer incidence and mortality in the study cohort were statistically signifi-cant, the risk magnitude rose with increasing the follow-up length. For the maximum follow-up period, from 1992 over 2019, the excess relative risk coefficient for solid cancer incidence was ERR/Gy=0.62, 95% CI (0.29; 0.98), and excess relative risk coefficient for solid cancer mortality was ERR/Gy=0.74, 95% CI (0.32; 1.22), the estimated coefficients were in good agreement with similar coefficients calcu-lated for the Russian liquidators with the use of ICRP radiation risk models. Non-parametric esti-mates of relative radiation risk within the same dose intervals for solid cancers and for leukemias in the cohort of liquidators were statistically significant for radiation doses above 0.150 Gy. For radiation doses below 0,150 Гр the linear non-threshold model is conservative, i.e. there was ev-idence for statistically significant radiation risk of leukemia incidence among liquidators during the first 11 years after the accident, from 1986 over 1997, ERR/Gy=4.41, 95% CI (0.24; 14.23). In later years, until 2018 there was no evidence of radiation-related risk of leukemia incidence. Out-comes of future studies will impact on optimization of radiological protection, development of reference levels for Russian general public exposure and improvement of the system for delivery of targeted medical care to people exposed to radiation.


2020 ◽  
Vol 13 (3) ◽  
pp. 6-17
Author(s):  
L. Yu. Krestinina ◽  
S. S. Silkin ◽  
L. D. Mikryukova ◽  
S. B. Epifanova ◽  
A. V. Akleyev

To date, the study of the effects of chronic exposure of the South Ural population has been carried out in two separate cohorts – in the Techa River Cohort and in the East Urals Radioactive Trace Cohort. In 2019, the Ural cohort of accidentally exposed population was formed. It included the population exposed in two radiation situations in the Southern Urals in the 1950s. The number of the combined cohort for the cancer incidence analysis was about 60 thousand people, the follow-up period was extended to 2017, the number of solid cancers was 4537, and the number of person-years was 1283267, which is 3 times more than when analyzing the effects of exposure in each of the two radiation situations separately. In the incidence analysis of all solid cancer types, we used the dose accumulated in the walls of the stomach, which corresponds to the dose accumulated in most organs and tissues with the exception of bone tissue and red bone marrow. The mean dose to the stomach accumulated over the entire follow-up period for cohort members was 38 mGy, the maximum -1.13 Gy. The paper presents the first results of solid cancer incidence risk analysis in the combined cohort, which show a statistically significant dose dependence of the incidence in case of chronic exposure in the range of low and medium doses. The sex and age-averaged excess relative risk value of 0.075/100 mGy (the 95% confidence interval is 0.039–0.113) is comparable to that obtained in the studies of the Japanese cohort of atomic bomb survivors. The statistically significant excess relative risk value of 0.047/100 mGy, obtained separately for men, is in good agreement with that in professional cohorts where men prevail – in the cohort of the Chernobyl NPP accident clean-up workers and in the cohort of professional workers in the three countries (UK, France, USA). The established cohort with a long follow-up period has a great potential for furthermore detailed studies of the effects of radiation and non-radiation factors on public health.


1998 ◽  
Vol 43 (4) ◽  
pp. 411-415 ◽  
Author(s):  
David L Streiner

This article describes various indices of risk, which is the probability that a person will develop a specific outcome. The risk difference is the absolute difference in risks between 2 groups and can be used either to compare the outcome of 2 groups, one of which was exposed to some genetic or environmental factor, or to see how much of an effect a treatment may have. The reciprocal of the risk difference, the number needed to treat, expresses how many patients must receive the intervention in order for 1 person to derive some benefit. Attributable risk reflects the proportion of cases due to some putative cause and indicates the number of cases that can be averted if the cause were removed. Finally, the relative risk and odds ratio reflect the relative differences between groups in achieving some outcome, either good (a cure) or bad (development of a disorder).


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