Health Risks of Ionizing Radiation: - Clark University
Health Risks of Ionizing Radiation: - Clark University
Health Risks of Ionizing Radiation: - Clark University
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Site-specific risks were all compatible with a<br />
linear dose-response model (see Table 4-1). Genderspecific<br />
risks were significantly different for skin<br />
cancer and cancers <strong>of</strong> the digestive, respiratory,<br />
and excretory (kidney and bladder) systems; in all<br />
cases the ERR estimates for females were 2- to 4fold<br />
higher than for males 7 . Age at exposure was<br />
a significant factor in the risks <strong>of</strong> skin, breast, and<br />
thyroid cancer and cancers <strong>of</strong> the digestive system<br />
and central nervous system (Figure 4-6). Land et<br />
al. (2003) reanalyzed the breast cancer incidence<br />
in depth and reaffirmed that risk was higher with<br />
exposure before age 20 8 .<br />
Skin cancer risk was further explored by Ron<br />
et al. (1998). This study found an overall ERR <strong>of</strong><br />
0.62/Sv (90% CI 0.23-1.3) for non-melanoma skin<br />
cancer. The risk <strong>of</strong> basal cell carcinoma, a subtype<br />
<strong>of</strong> skin cancer, was higher (ERR 1.9/Sv) and was<br />
found to depend significantly on age at exposure.<br />
Atomic Bomb Survivors 49<br />
The risk <strong>of</strong> basal cell carcinoma after exposure at<br />
ages 0-9, for example, had an ERR <strong>of</strong> 21/Sv (4-73).<br />
The liver cancer risk estimate was improved with<br />
better pathology review by Cologne et al. (1999).<br />
This study found an ERR <strong>of</strong> 0.81/Sv (0.32-1.43)<br />
and this was similar for males and females. Risk<br />
appeared to be higher after exposure at ages 10-30.<br />
Sharp et al. (2003) demonstrated that liver cancer<br />
risk was increased dramatically with combined risk<br />
factors <strong>of</strong> radiation and the hepatitis C virus 9 .<br />
4.4.2 Incidence <strong>of</strong> leukemia and related cancers<br />
Preston et al. (1994) analyzed the incidence <strong>of</strong> cancers<br />
<strong>of</strong> the blood and lymph through 1987. These include<br />
leukemias, lymphomas, and multiple myeloma,<br />
a cancer that originates in the liquid part <strong>of</strong> blood<br />
and lymph and infiltrates bone marrow. Leukemia<br />
was subdivided into subtypes: acute lymphocytic<br />
Figure 4-6. Incidence ERR by age at exposure for selected cancer sites (based on data from Thompson et al. 1994).<br />
7 Estimates <strong>of</strong> ERR/Sv (females/males) were 1.4/0.4 (nonmelanoma skin), 0.5/0.3 (digestive system), 1.7/0.4<br />
(respiratory system), and 2.3/0.7 (kidney and urinary organs)<br />
8 ERR estimates were 3.9, 2.8, 2.7, 1.3 and 0.5/Sv after exposure at ages 0-4, 5-14, 15-19, 20-39, and 40+,<br />
respectively.<br />
9 The ERR estimate was 58/Sv (2.0-∞) for HCV-positive, cirrhosis-free hepatocellular carcinoma.