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Radon: Is My Family At Risk?Nicklaus Brandehoff, MD and Keith Baker, MDMedical Toxicology FellowsRocky Mountain Poison and Drug CenterDenver, CO

We have no conflicts of interest to report.

Conflicts of Interest

1) Describe radon and where it can be found.

2) Describe known and hypothesized health risks associated with radon exposure.

3) Identify the EPA action level for radon.

4) Examine literature investigating whether there is evidence radon increases the risk of developing lung cancer, leukemia, lymphoma, and CNS malignancies.

5) Apply this information to discussing radon mitigation with patients and with the community.

Objectives

Introduction to Radon

http://www.radontestinginma.com/what-is-radon.html

Introduction to Radon

Ionizing Radiation

What are the types of ionizing radiation?

What are the routes of exposure?

How is radiation and radiation exposure measured?

Ionizing Radiation

Measurements

Disintegrations/ second measured in Becquerels (Bq)

Can also be measured in Picocuries (pCi)

1 pCi = 0.037 Bq

1 pCi/ L = 37 Bq/ m3

Ionizing Radiation

Measurements

Amount of energy of ionizing radiation absorbed by the body or an organ measured in the S.I. unit Grays (Gy)

Different types of different ionizing radiation have different health effects, so a radiation weighting factor (K) is used to convert to a dose equivalent

For alpha K = 20For beta K = 1For gamma K = 1For neutrons K = 5-20

Ionizing Radiation

Measurements

The dose equivalent is then measured using the unit Sieverts (Sv)

1 Gy of alpha radiation = 20 Sv1 Gy of beta radiation = 1 Sv

Exposure to roughly 60 Bq/m3 over the year = exposure to roughly 1 mSv of background radiation

Ionizing Radiation

Radon Mitigation

https://www.youtube.com/watch?v=Mwuev8WTitM

EPA action level for radon is 4 pCi/ L

https://en.wikipedia.org/wiki/Radium_and_radon_in_the_environment

Radon and Lung CancerNicklaus Brandehoff, MD

Meta-analysis of Case Control Studies

1) Lung cancer is leading causing of cancer related deaths world wide.

2) Radon is an IARC1 for lung cancer.

3) Unclear the role of lung cancer for indoor housing exposures.

4) Limitations of epidemiologic studies.

Background

International Agency of Research on Cancer

IARC Background

Group 1 Carcinogenic to humans 120 agents

Group 2A Probably carcinogenic to humans 81

Group 2B Possibly carcinogenic to humans 299

Group 3Not classifiable as to its carcinogenicity to humans

502

Group 4 Probably not carcinogenic to humans 1

Pubmed search of case-control studies

Search terms “radon exposure” and ”lung cancer”

All studies through December 31, 2015

143 total results -> 100 in English language

Inclusion = 100 cases + 100 controls in study + English language

24 papers included in review

Methods

Table 1

Table 2

There is an association between exposure to radon and lung cancer.

Effect is increased in smokers vs non-smokers.

Literature is mixed on the dose response relationship between radon and lung cancer in non-smokers.

Associated lung cancer types include small cell carcinomas, squamous cell carcinomas, and large cell carcinomas.

Results

Heterogeneous study cohort

Variability of “low, medium, high” radon concentrations

Limited studies looking at non-smokers

Limitations

Radon causes lung cancer in all comers

It is unclear the relationship between low exposure to radon and lung cancer in non-smokers

Further studies need to implement further controls to assess the relationship between non-smokers, radon concentrations, and lung cancer

Conclusions

Case Control Study in Low Smoking Population

Lung cancer is leading cause of cancer related deaths in Utah.

Utah has the lowest smoking prevalence in the United States.

80% of population in metropolitan areas/20% in rural areas

30% of homes with radon >[4 pCi/L]- National average is 7%

Background

Surveillance and Epidemiology, and End Results Program (SEER) 1991 - 2010

- Lung cancer cases- Stage of cancer- Age and sex of patient- Population attributes

EPA predicted radon concentrations from 1991 - 2010

Multivariate Poisson regression model

Methods

Low = < 2 pCi/L

Moderate = 2 – 4 pCi/L

High = > 4 pCi/L

Smoking rates determined from previous study

Methods

Results

Results

Non-metropolitan areas- poorer- higher smoking rates- less access to health care

Retrospective review

Large data bases compared

Limitations

• Nonmetropolitan counties have a higher rates of lung cancer

compared to metropolitan counties,

• Opposite of other SEER sites.

• Similar rates between metropolitan and nonmetropolitan

counties with similar radon levels.

• Significantly higher among high radon counties than

moderate radon counties.

Conclusion

Radon and Childhood Leukemia, Lymphoma, and CNS Malignancies

Keith Baker, MD

Radon and Leukemia/CNS Malignancies

1) Radon exposure has clearly been associated with development of lung cancer.

2) What about other cancers?

3) Previous studies have shown conflicting results.

4) Limitations of epidemiologic studies.

Background

Specifically examining risk of leukemia or CNS malignancies

Prospective cohort

Children ages 0-15 years

712,674 children in the Oslo, Norway region

437 leukemia cases, 427 CNS cancer cases

Sub-analyses, etc.

Methods

Methods

Radon exposure assessment

Exposures measured in Bq/m3

EPA action level is 4 pCi/L

For the purpose of this presentation I have converted results from Bq/ m3 to pCi/ L to help make sense of the results in light of EPA recommendations.

Methods

Radon exposure divided into tertiles which were rounded.

1) < 1.4 pCi/L (< 50 Bq/m3)

2) 1.4 – 2.7 pCi/L (50-100 Bq/m3)

3) > 2.7 pCi/L (> 100 Bq/m3)

Methods

Further exposure grouping

1) < 2.7 pCi/L (< 100 Bq/m3)

2) 2.7 – 5.4 pCi/L (100-200 Bq/m3)

3) > 5.4 pCi/L (> 200 Bq/m3)

Also analyzed as continuous variable grouped into 5 groups by increments of 2.7 pCi/L (100 Bq/m3)

Methods

Mean (pCi/L) Median (pCi/L)

Cohort 2.5 2.0

CNS Malignancy 2.7 2.1

Leukemia 2.4 2.0

Radon Exposure

Table 2

1) Results of tertiles without subanalyses showed a few small differences

2) Results of tertiles with subanalyses did not show any statistically significant differences

Results

No association was observed when radon exposure was classified into the exposure categories:

1) < 2.7 pCi/L

2) 2.7 – 5.4 pCi/L

3) > 5.4 pCi/L

Results

Results

Results

Strengths and limitations

https://clipartxtras.com

Discussion of Results

What can we take from these results?

How does this affect our patients/ our communities?

http://he.memegenerator.net/instance/66439261/linda-richman-mike-myers-coffee-talk-discuss-amongst-yourselves

Radon and Lymphoma

1) Radon exposure has clearly been associated with development of lung cancer.

2) What about other cancers?

3) Previous studies have shown conflicting results.

4) Limitations of epidemiologic studies.

Background

Specifically examining risk of radon exposure and development of lymphoma

Lymphoma divided into subtypes

Study population estimate 6,523,632 children in Texas

2147 total lymphoma cases further divided into subtype

Sub-analyses, etc.

Methods

Methods

Radon exposure assessment

Exposures measured in Bq/m3

EPA action level is 4 pCi/L

For the purpose of this presentation I have converted results from Bq/m3 to pCi/L to help make sense of the results in light of EPA recommendations.

Methods

Regional mean radon concentrations assessed by quartile

Cut points based on the distribution across the state

Methods

Results

Arithmetic Mean: 1.24 pCi/LGeometric Mean (95% CI): 1.02 pCi/L (0.68 – 1.53 pCi/L)

Minimum: 0.25 pCi/LMaximum: 3.30 pCi/L

Percentile25th 0.70 pCi/L50th 1.10 pCi/L75th 1.30 pCi/L90th 2.60 pCi/L99th 3.30 pCi/L

Results

Results

Results

Strengths and limitations

https://fitlabs.ru/ne-rastut/

Discussion of Results

What can we take from these results?

How does this affect our patients/ our communities?

http://children-learningreading.info/kwrbinfo-boardroom-suggestion.htm

Baseline lymphoma rate 23 per million

DLBCL in this study made up 14.67% of cases so we can extrapolate rate to about 3.4 per million

aIRR of 73% for high exposure group increases rate to 5.9 per million

This would mean an addition of 2.5 cases per million or 1 per 400,000

Prevention/NNT

Assuming approximately 2 children per household this would mean 200,000 homes would need mitigation to prevent 1 case of DLBCL.

Average cost of mitigation is about $1200

200,000 X $1200 = $240,000,000

So we can estimate that to prevent 1 case of DLBCL in the high radon exposure group (in this study), almost a quarter of a billion dollars would have to be spent on mitigation.

Prevention/NNT

Conclusion

What do I tell the public about the risks associated with radon?

Who should have radon mitigation?

What recommendations should I make to my patients and my community?

ACKNOWLEDGEMENTS

Thanks to:

Christopher Hoyte, MDMichael Kosnett, MDMelinda Malamaco, MS

This was supported, in part, by the American College of Medical Toxicology (ACMT) and funded (in part) by the cooperative agreement award number 1 U61TS000238-04 from the Agency for Toxic Substances and Disease Registry (ATSDR).

The U.S. Environmental Protection Agency (EPA) supports the PEHSU by providing partial funding to ATSDR under Inter-Agency Agreement number DW-75-92301301-9. Neither EPA nor ATSDR endorse the purchase of any commercial products or services mentioned in PEHSU publications.

www.pehsu.net/nationalclassroom.html

Webinars

Series of scientific webinars that provide a forum for discourse on scientific

issues.

Live and On-Demand

Case Conferences Journal ClubsGrand Rounds

CE Available

Online Courses

Interactive and Self-Paced

Evidence-based online courses on a variety of

children's environmental health topics.

CE Available

Resource Catalog

Fact sheets, journal publications, reports, and

other resources for parents, community members,

patients and healthcare professionals

Topics included: Air Quality, Pesticides, Natural

Disasters, BPA, Mold, Lead, Mercury