A large cohort study on the effect of low dose protracted radiation on the leukemia in Chernobyl cleanup workers

It has not been elucidated clearly yet that chronic low dose radiation could cause leukemia. The following report from NIEHS seems to definately confirm that hypothesis. Those leukemic cases who have started treatment 2 years prior to this study won't agree with it as the authors said. It must be further studied in the future. Even if they are included in the study, it gives the same result.

IAEA etc has confirmed only thyroid cancer of childhood in relation with the radiation in Chernobyl. They should correct their lack of understanding about carcinogenesis, or at least leukemogenesis, of radiation other than this thyroid cancer in such a nuclear power plant accident. The event in Fukushima is not, of course, exceptional for this problem. This teaches us an important lesson for those irradiated in Fukushima due to the nuclear power plant accident. We should follow and back up those people in a long perspective. Especially, those who have had accumulated radiation in protracted course should be closely followed by proper medical facilities.

The summary and the URL of the paper are given as follows;

Background: Risks of most types of leukemia from exposure to acute high doses of ionizing
radiation are well known, but risks associated with protracted exposures, and associations
between radiation and chronic lymphocytic leukemia (CLL) are not clear

Objectives: To estimate relative risks of CLL and non-CLL from protracted exposures to lowdose
ionizing radiation.

Method: A nested case-control study was conducted in a cohort of 110,645 Ukrainian cleanup
workers of the 1986 Chornobyl nuclear power plant accident. Cases of incident leukemia
diagnosed in 1986-2006 were confirmed by a panel of expert hematologists/hematopathologists.
Controls were matched to cases on place of residence and year of birth. Individual bone marrow
radiation doses were estimated by the Realistic Analytical Dose Reconstruction with Uncertainty
Estimation (RADRUE) method. A conditional logistic regression model was used to estimate
excess relative risk of leukemia per gray (ERR/Gy) of radiation dose.

Results: A significant linear dose-response was found for all leukemia (137 cases, ERR/Gy=1.26
(95% confidence interval 0.03, 3.58))
. There were non-significant positive dose-responses for
both CLL and non-CLL (ERR/Gy=0.76 and 1.87, respectively). In our primary analysis
excluding 20 cases with direct in-person interviews <2 years from start of chemotherapy with an
anomalous finding of ERR/Gy=-0.47 (<-0.47, 1.02), the ERR/Gy for the remaining 117 cases
was 2.38 (0.49, 5.87). For CLL the ERR/Gy was 2.58 (0.02, 8.43) and for non-CLL ERR/Gy
was 2.21 (0.05, 7.61). Altogether, 16% of leukemia cases (15% of non-CLL, 18% of CLL) were
attributed to radiation exposure.

Conclusions: Exposure to low doses and low dose-rates of radiation from post-Chornobyl
cleanup work was associated with a significant increase in risk of leukemia
, which was
statistically consistent with estimates for the Japanese atomic bomb survivors. Based on the
primary analysis, we conclude that CLL and non-CLL are both radiosensitive.


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