Editing Radiation hormesis (section)

{{Short description|Hypothesis regarding low doses of ionizing radiation on health}}
[[File:Radiations at low doses.gif|294px|thumb|right|Alternative assumptions for the extrapolation of the cancer risk vs. radiation dose to low-dose levels, given a known risk at a high dose: supra-linearity (A), linear (B), linear-quadratic (C) and [[hormesis]] (D).]]
'''Radiation hormesis''' is the [[hypothesis]] that low doses of [[ionizing radiation]] (within the region of and just above [[Background radiation|natural background levels]]) are beneficial, stimulating the activation of [[DNA repair|repair mechanisms]] that protect against [[disease]], that are not activated in absence of ionizing radiation. The reserve repair mechanisms are hypothesized to be sufficiently effective when stimulated as to not only cancel the detrimental effects of ionizing radiation but also inhibit disease not related to radiation exposure (see [[hormesis]]).<ref name="Calabrese">{{cite journal |doi=10.1038/421691a |title=Toxicology rethinks its central belief |year=2003 |last1=Calabrese |first1=Edward J |last2=Baldwin |first2=Linda A |journal=Nature |volume=421 |issue=6924 |pages=691–92 |pmid=12610596|bibcode = 2003Natur.421..691C |s2cid=4419048 }}</ref><ref>{{cite journal |doi=10.1259/bjr/63353075 |title=Evidence for beneficial low level radiation effects and radiation hormesis |year=2005 |last1=Feinendegen |first1=L E |journal=British Journal of Radiology |volume=78 |issue=925 |pages=3–7 |pmid=15673519}}</ref><ref name ="Kaiser">{{cite journal |doi=10.1126/science.302.5644.376 |title=HORMESIS: Sipping from a Poisoned Chalice |year=2003 |last1=Kaiser |first1=J. |journal=Science |volume=302 |issue=5644 |pages=376–79 |pmid=14563981|s2cid=58523840 }}</ref><ref>{{cite journal |doi=10.2307/3433927|pmid=9539019|jstor=3433927|title=The Adaptive Response in Radiobiology: Evolving Insights and Implications|journal=Environmental Health Perspectives|volume=106|pages=277–83|year=1998|last1=Wolff|first1=Sheldon|issue=Suppl 1 |pmc=1533272}}</ref> It has been a mainstream concept since at least 2009.<ref>{{cite book |last=Allison |first=Wade |author-link=Wade Allison |title=Radiation and Reason: The Impact of Science on a Culture of Fear |year=2009 |publisher=York Publishing Services |location=York, England |isbn=978-0-9562756-1-5 |page=2}}</ref>{{Unreliable source?|date=April 2024}}

While the effects of high and acute doses of ionising radiation are easily observed and understood in humans (''e.g.'' [[Atomic bombings of Hiroshima and Nagasaki|Japanese atomic bomb]] survivors), the effects of low-level radiation are very difficult to observe and highly controversial. This is because the baseline cancer rate is already very high and the risk of developing cancer fluctuates 40% because of individual life style and environmental effects,<ref>{{Cite web
| title = WHO Cancer Fact sheet N°297
| access-date = 2011-04-29
| url =https://www.who.int/mediacentre/factsheets/fs297/en/}}</ref><ref name=parkin2011>{{Cite journal |doi=10.1038/bjc.2011.489 |title=16. The fraction of cancer attributable to lifestyle and environmental factors in the UK in 2010 |year=2011 |last1=Parkin |first1=D M |last2=Boyd |first2=L |last3=Walker |first3=L C |journal=British Journal of Cancer |volume=105 |pages=S77–81 |pmid=22158327 |pmc=3252065 |issue=Suppl 2}}</ref> obscuring the subtle effects of low-level radiation. An acute effective dose of 100 [[Sievert|millisieverts]] may increase cancer risk by ~0.8%. However, children are particularly sensitive to radioactivity, with [[childhood leukemia]]s and [[Childhood cancer|other cancers]] increasing even within natural and man-made background radiation levels (under 4&nbsp;mSv cumulative with 1&nbsp;mSv being an average annual dose from terrestrial and cosmic radiation, excluding [[radon]] which primarily doses the lung).<ref>{{cite journal|last1=Kendall|title=A record-based case-control study of natural background radiation and the incidence of childhood leukaemia and other cancers in Great Britain during 1980–2006|journal=Leukemia|date=January 2013|volume=27 |issue=1|pages=3–9|display-authors=etal|doi=10.1038/leu.2012.151|pmid=22766784|pmc=3998763}}</ref><ref>{{cite journal |vauthors=Spycher BD, Lupatsch JE, Zwahlen M, Röösli M, Niggli F, Grotzer MA, Rischewski J, Egger M, Kuehni CE |title=Background ionizing radiation and the risk of childhood cancer: a census-based nationwide cohort study |journal=Environ. Health Perspect. |volume=123 |issue=6 |pages=622–28 |date=June 2015 |pmid=25707026 |pmc=4455589 |doi=10.1289/ehp.1408548 }}</ref> There is limited evidence that exposures around this dose level will cause negative subclinical health impacts to neural development.<ref>{{cite journal|last1=Pasqual|title=Neurodevelopmental effects of low dose ionizing radiation exposure: A systematic review of the epidemiological evidence.|journal=Environment International|year=2020|volume=136|page=105371|doi=10.1016/j.envint.2019.105371|pmid=32007921|display-authors=etal|doi-access=free|bibcode=2020EnInt.13605371P |hdl=10230/46812|hdl-access=free}}</ref> Students born in regions of higher [[Chernobyl disaster|Chernobyl fallout]] performed worse in secondary school, particularly in mathematics. "Damage is accentuated within families (i.e., siblings comparison) and among children born to parents with low education..." who often don't have the resources to overcome this additional health challenge.<ref>{{cite journal|last1=Almond|title=Chernobyl's subclinical legacy: Prenatal exposure to radioactive fallout and school outcomes in Sweden.|journal=Columbia University|date=2007|display-authors=etal|url=http://www.columbia.edu/~le93/Chernobyl.pdf}}</ref>

Hormesis remains largely unknown to the public. Government and regulatory bodies disagree on the existence of radiation hormesis and research points to the "severe problems and limitations" with the use of hormesis in general as the "principal dose-response default assumption in a risk assessment process charged with
ensuring public health protection."<ref>{{cite journal |vauthors=Kitchin KT, Drane JW |title=A critique of the use of hormesis in risk assessment |journal=Hum Exp Toxicol |volume=24 |issue=5 |pages=249–53 |date=May 2005 |pmid=16004188 |doi=10.1191/0960327105ht520oa |bibcode=2005HETox..24..249K |s2cid=9105845 |url=https://zenodo.org/record/894716 }}</ref>

Quoting results from a literature database research, the Académie des Sciences – Académie nationale de Médecine ([[French Academy of Sciences]] – [[French Academy of Medicine|National Academy of Medicine]]) stated in their 2005 report concerning the effects of low-level radiation that many laboratory studies have observed radiation hormesis.<ref name = "Calabrese2">{{cite journal |doi=10.1016/j.taap.2004.02.007 |title=Hormesis: From marginalization to mainstream |year=2004 |last1=Calabrese |first1=Edward J |journal=Toxicology and Applied Pharmacology |volume=197 |issue=2 |pages=125–36 |pmid=15163548}}</ref><ref name = "Duport">{{cite journal |doi=10.1504/IJLR.2003.003488 |title=A database of cancer induction by low-dose radiation in mammals: Overview and initial observations |year=2003 |last1=Duport |first1=P. |journal=International Journal of Low Radiation |volume=1 |pages=120–31}}</ref> However, they cautioned that it is not yet known if radiation hormesis occurs outside the laboratory, or in humans.<ref name="Aurengo">{{Cite journal
| author = Aurengo
| title = Dose-effect relationships and estimation of the carcinogenic effects of low doses of ionizing radiation
| publisher = Académie des Sciences & Académie nationale de Médecine
| date = 2005-03-30
| citeseerx = 10.1.1.126.1681
}}</ref>

Reports by the [[United States National Research Council]] and the [[National Council on Radiation Protection and Measurements]] and the [[United Nations Scientific Committee on the Effects of Atomic Radiation]] (UNSCEAR) argue<ref>UNSCEAR 2000 Report Vol. II: Sources and Effects of Ionizing Radiation: [http://www.unscear.org/docs/reports/annexg.pdf Annex G: Biological effects at low radiation doses].</ref> that there is no evidence for hormesis in humans and in the case of the National Research Council hormesis is outright rejected as a possibility.<ref name=BEIR_VII>{{harvnb|BEIR VII Phase 2|2006}}</ref> Therefore, estimating [[linear no-threshold model]] (LNT) continues to be the model generally used by regulatory agencies for human radiation exposure.