Editing Radiation hormesis (section)

=== Humans ===

==== Effects of slightly increased radiation level ====

In long-term study of Chernobyl disaster liquidators<ref>{{cite web |url=https://www.rsu.lv/sites/default/files/dissertations/JReste_Promocijas_darba_kopsavilkums_EN.pdf |author=Jeļena Reste |title=THE AGING ASPECTS OF HUMANS PROTRACTEDLY EXPOSED TO IONIZING RADIATION |work=Summary of Doctoral Thesis Speciality. Occupational and Environmental Medicine |publisher=Rīga Stradiņš University |date=2013 |location=Riga}}</ref> was found that: "During current research paradoxically longer telomeres were found among persons, who have received heavier long-term irradiation." and "Mortality due to oncologic diseases was lower than in general population in all age groups that may reflect efficient health care of this group." Though in conclusion interim results were ignored and conclusion followed [[Linear no-threshold model|LNT]] hypothesis: "The signs of premature aging were found in Chernobyl disaster clean-up workers; moreover, aging process developed in heavier form and at younger age in humans, who underwent greater exposure to ionizing radiation."

A study of survivors of the [[Atomic bombings of Hiroshima and Nagasaki|Hirsohima atomic bomb explosion]] yielded similar results.<ref>{{cite journal |last1=Sutou |first1=Shizuyo |title=Black rain in Hiroshima: a critique to the Life Span Study of A-bomb survivors, basis of the linear no-threshold model |journal=Genes and Environment |pages=1 |language=en |doi=10.1186/s41021-019-0141-8 |date=1 January 2020|volume=42 |issue=1 |doi-access=free |pmid=31908690 |bibcode=2020GeneE..42....1S |pmc=6937943 }}</ref>

====Effects of sunlight exposure====
In an Australian study which analyzed the association between solar [[UV]] exposure and DNA damage, the results indicated that although the frequency of cells with [[chromosome]] breakage increased with increasing [[sun exposure]], the misrepair of [[DNA]] strand breaks decreased as sun exposure was heightened.<ref>{{cite journal |doi=10.1093/mutage/ges026 |title=Sunlight and vitamin D affect DNA damage, cell division and cell death in human lymphocytes: A cross-sectional study in South Australia |year=2012 |last1=Nair-Shalliker |first1=V. |last2=Fenech |first2=M. |last3=Forder |first3=P. M. |last4=Clements |first4=M. S. |last5=Armstrong |first5=B. K. |journal=Mutagenesis |volume=27 |issue=5 |pages=609–614 |pmid=22547344 |doi-access= }}</ref>

====Effects of cobalt-60 exposure====
The health of the inhabitants of radioactive apartment buildings in [[Taiwan]] has received prominent attention. In 1982, more than 20,000 tons of steel was accidentally contaminated with [[cobalt-60]], and much of this radioactive steel was used to build apartments and exposed thousands of Taiwanese to gamma radiation levels of up to >1000 times background (average 47.7&nbsp;mSv, maximum 2360&nbsp;mSv excess cumulative dose). The radioactive contamination was discovered in 1992.

A seriously flawed 2004 study compared the building's younger residents with the much older general population of Taiwan and determined that the younger residents were less likely to have been diagnosed with cancer than older people; this was touted as evidence of a radiation hormesis effect.<ref name="Hwang1">{{cite journal |doi=10.1080/09553000601085980 |title=Cancer risks in a population with prolonged low dose-rate γ-radiation exposure in radiocontaminated buildings, 1983–2002 |year=2006 |last1=Hwang |first1=S.-L. |last2=Guo |first2=H.-R. |last3=Hsieh |first3=W.-A. |last4=Hwang |first4=J.-S. |last5=Lee |first5=S.-D. |last6=Tang |first6=J.-L. |last7=Chen |first7=C.-C. |last8=Chang |first8=T.-C. |last9=Wang |first9=J.-D. |last10=Chang |first10=W. P. |journal=International Journal of Radiation Biology |volume=82 |issue=12 |pages=849–858 |pmid=17178625 |s2cid=20545464 }}</ref><ref name="Chen-Age">{{Cite conference
| last = Chen
| first = C. Y.
| author2=Y. J. Chen
| title = The Social Migration Effect Toward Population Aging-The Application of Perston's Rate of Change of a Population's Mean Age Improvement Model in Taiwan
| conference = The 23rd Conference of the European Network for Housing Research
| access-date = 2012-05-09
| year = 2011
| url = http://140.116.240.46/ISAD/files/P28941029-a.pdf
}}</ref> (Older people have much higher cancer rates even in the absence of excess radiation exposure.)

In the years shortly after exposure, the total number cancer cases have been reported to be either lower than the society-wide average or slightly elevated.<ref name=":0">{{Cite book |title=Casarett & Doull's essentials of toxicology |date=2021 |author1=Curtis D. Klaassen |author2=John B. Watkins, III |isbn=978-1-260-45229-7 |edition=4th |publisher=McGraw-Hill Education |location=New York |page=459 |oclc=1159605376}}</ref><ref>{{Cite book |title=Environmental pollutant exposures and public health |date=2021 |publisher=CPI Group |isbn=978-1-83916-043-1 |editor-last=Harrison |editor-first=Roy M. |location=London |page=50 |oclc=1204222461 |quote=Cancer incidence in a cohort of ~6250 people has been studied, and marginally raised levels of cancer in relation to assessed doses have been reported, although there are a number of uncertainties in the student, including lack of control for confounding factors such as smoking}}</ref> Leukaemia and thyroid cancer were substantially elevated.<ref name="Hwang1" /><ref name=":0" /> When a lower rate of "all cancers" was found, it was thought to be due to the exposed residents having a higher [[socioeconomic status]], and thus overall healthier lifestyle.<ref name="Hwang1" /><ref name=":0" /> Additionally, Hwang, et al. cautioned in 2006 that [[leukaemia]] was the first cancer type found to be elevated amongst the survivors of the Hiroshima and Nagasaki bombings, so it could be decades before any increase in more common cancer types is seen.<ref name="Hwang1" />

Besides the excess risks of leukaemia and thyroid cancer, a later publication notes various DNA anomalies and other health effects among the exposed population:<ref name="Hwang2008">{{cite journal |doi=10.1667/RR0732.1 |title=Estimates of Relative Risks for Cancers in a Population after Prolonged Low-Dose-Rate Radiation Exposure: A Follow-up Assessment from 1983 to 2005 |year=2008 |last1=Hwang |first1=Su-Lun |last2=Hwang |first2=Jing-Shiang |last3=Yang |first3=Yi-Ta |last4=Hsieh |first4=Wanhua A. |last5=Chang |first5=Tien-Chun |last6=Guo |first6=How-Ran |last7=Tsai |first7=Mong-Hsun |last8=Tang |first8=Jih-Luh |last9=Lin |first9=I-Feng |last10=Chang |first10=Wushou Peter |journal=Radiation Research |volume=170 |issue=2 |pages=143–148 |pmid=18666807 |bibcode=2008RadR..170..143H |s2cid=41512364 |url=http://ntur.lib.ntu.edu.tw/bitstream/246246/246866/-1/index.html }}</ref>
<blockquote>
There have been several reports concerning the radiation effects on the exposed population, including cytogenetic analysis that showed increased micronucleus frequencies in peripheral lymphocytes in the exposed population, increases in acentromeric and single or multiple centromeric cytogenetic damages, and higher frequencies of chromosomal translocations, rings and dicentrics. Other analyses have shown persistent depression of peripheral leucocytes and neutrophils, increased eosinophils, altered distributions of lymphocyte subpopulations, increased frequencies of lens opacities, delays in physical development among exposed children, increased risk of thyroid abnormalities, and late consequences in hematopoietic adaptation in children.
</blockquote>
People living in these buildings also experienced infertility.<ref>{{Cite journal |last1=Lin |first1=C.-M. |last2=Chang |first2=W. P. |last3=Doyle |first3=P. |last4=Wang |first4=J.-D. |last5=Lee |first5=L.-T. |last6=Lee |first6=C. L. |last7=Chen |first7=P.-C. |date=March 2010 |title=Prolonged time to pregnancy in residents exposed to ionising radiation in cobalt-60-contaminated buildings |journal=Occupational and Environmental Medicine |volume=67 |issue=3 |pages=187–195 |doi=10.1136/oem.2008.045260 |issn=1470-7926 |pmid=19773284|s2cid=40448903 }}</ref>

==== Radon therapy ====
{{Further|Health effects of radon#Bathing}}
Intentional exposure to water and air containing increased amounts of [[radon]] is perceived as therapeutic, and "radon spas" can be found in United States, Czechia, Poland, Germany, Austria and other countries.