Editing Radon (section)

==== Inhalation and smoking ====
Results from epidemiological studies indicate that the risk of lung cancer increases with exposure to residential radon. A well known example of source of error is smoking, the main risk factor for lung cancer. In the US, cigarette smoking is estimated to cause 80% to 90% of all lung cancers.<ref>{{cite web |title=What Are the Risk Factors for Lung Cancer? |url=https://www.cdc.gov/cancer/lung/basic_info/risk_factors.htm |website=Centers for Disease Control and Prevention |access-date=3 May 2020 |date=18 September 2019}}</ref>

According to the EPA, the risk of lung cancer for smokers is significant due to [[Synergy|synergistic]] effects of radon and smoking. For this population about 62 people in a total of 1,000 will die of lung cancer compared to 7 people in a total of 1,000 for people who have never smoked.<ref name="epa" /> It cannot be excluded that the risk of non-smokers should be primarily explained by an effect of radon.

Radon, like other known or suspected external risk factors for lung cancer, is a threat for smokers and former smokers. This was demonstrated by the European pooling study.<ref name="bmj38308">{{cite journal |doi=10.1136/bmj.38308.477650.63 |pmid=15613366 |pmc=546066 |title=Radon in homes and risk of lung cancer: Collaborative analysis of individual data from 13 European case-control studies |journal=BMJ |volume=330 |issue=7485 |pages=223 |year=2005 |last1=Darby |first1=S. |last2=Hill |first2=D. |last3=Auvinen |first3=A. |last4=Barros-Dios |first4=J. M. |last5=Baysson |first5=H. |last6=Bochicchio |first6=F. |last7=Deo |first7=H. |last8=Falk |first8=R. |last9=Forastiere |first9=F. |last10=Hakama |first10=M. |last11=Heid |first11=I. |last12=Kreienbrock |first12=L. |last13=Kreuzer |first13=M. |last14=Lagarde |first14=F. |last15=Mäkeläinen |first15=I. |last16=Muirhead |first16=C. |last17=Oberaigner |first17=W. |last18=Pershagen |first18=G. |last19=Ruano-Ravina |first19=A. |last20=Ruosteenoja |first20=E. |last21=Rosario |first21=A. Schaffrath |last22=Tirmarche |first22=M. |last23=Tomášek |first23=L. |last24=Whitley |first24=E. |last25=Wichmann |first25=H.-E. |last26=Doll |first26=R. }}</ref> A commentary<ref name="bmj38308" /> to the pooling study stated: "it is not appropriate to talk simply of a risk from radon in homes. The risk is from smoking, compounded by a synergistic effect of radon for smokers. Without smoking, the effect seems to be so small as to be insignificant."

According to the European pooling study, there is a difference in risk for the [[Histology|histological]] subtypes of lung cancer and radon exposure. [[Small-cell lung carcinoma]], which has a high correlation with smoking, has a higher risk after radon exposure. For other histological subtypes such as [[adenocarcinoma]], the type that primarily affects non-smokers, the risk from radon appears to be lower.<ref name="bmj38308" /><ref>{{cite web |first=R. William |last=Field |location=Charleston, South Carolina |url=https://www.aarst.org/images/PCPanelRadonTest.pdf |title=President's Cancer Panel, Environmental Factors in Cancer: Radon |date=December 4, 2008 |url-status=dead |archive-url=https://web.archive.org/web/20130829005508/http://www.aarst.org/images/PCPanelRadonTest.pdf |archive-date=August 29, 2013 |publisher=The American Association of Radon Scientists and Technologists (AARST)}}</ref>

A study of radiation from post-[[mastectomy]] [[radiotherapy]] shows that the simple models previously used to assess the combined and separate risks from radiation and smoking need to be developed.<ref>{{cite journal |last1=Kaufman |first1=E. L. |last2=Jacobson |first2=J. S. |last3=Hershman |first3=D. L. |last4=Desai |first4=M. |last5=Neugut |first5=A. I. |date=2008 |title=Effect of breast cancer radiotherapy and cigarette smoking on risk of second primary lung cancer |journal=[[Journal of Clinical Oncology]] |volume=26 |issue=3 |pages=392–398 |doi=10.1200/JCO.2007.13.3033 |pmid=18202415|doi-access=free }}</ref> This is also supported by new discussion about the calculation method, the [[linear no-threshold model]], which routinely has been used.<ref>{{cite journal |doi=10.1093/rpd/ncq141 |title=Review and evaluation of updated research on the health effects associated with low-dose ionising radiation |date=2010 |last1=Dauer |first1=L. T. |last2=Brooks |first2=A. L. |last3=Hoel |first3=D. G. |last4=Morgan |first4=W. F. |last5=Stram |first5=D. |last6=Tran |first6=P. |journal=[[Radiation Protection Dosimetry]] |volume=140 |issue=2 |pages=103–136 |pmid=20413418}}</ref>

A study from 2001, which included 436 non-smokers with lung cancer and a control group of 1649 non-smokers without lung cancer, showed that exposure to radon increased the risk of lung cancer in non-smokers. The group that had been exposed to tobacco smoke in the home appeared to have a much higher risk, while those who were not exposed to passive smoking did not show any increased risk with increasing radon exposure.<ref>{{cite journal |last1=Lagarde |first1=F. |last2=Axelsson |first2=G. |last3=Damber |first3=L. |last4=Mellander |first4=H. |last5=Nyberg |first5=F. |last6=Pershagen |first6=G. |date=2001 |title=Residential radon and lung cancer among never-smokers in Sweden |journal=Epidemiology |volume=12 |issue=4 |pages=396–404 |doi=10.1097/00001648-200107000-00009 |jstor=3703373 |pmid=11416777|s2cid=25719502 |doi-access=free }}</ref>