Public Health Briefs
last menstrual period. J Epidemiol Community neonatal mortality in Belgium and the United lum Kristensen FB, Chen JH, Masuy
Health. 1984;38:79-80. States. Paediatr Perinat Epidemiol. 1995; Stroobant G. A comparison of prenatal care
22. Buekens P, Wilcox AJ, Kiely J, Masuy- 9:273-280. utilization in the United States and in Europe.
Stroobant G. Birthweight, preterm births and 23. Buekens P, Kotelchuck M, Blondel B, Bor- Am JPublic Health. 1993;83:31-36.
~;w'S_l:~U1 ~ ~.:'*S
Effects of Radon Mitigation
vs Smoking Cessation in Reducing
Radon-Related Risk of Lung Cancer
.. , ^ .. ,s , _ ^. 4, ....~~~~~~~~~~~~~~~~~~~~~~~..
.. ... ..
David Mendez, PhD, Kenneth E. Warner, PhD, and Paul N. Courant, PhD
Introduction estimate the effects on risk reduction of
radon mitigation alone, smoking cessation
The Environmental Protection Agency alone, or both together. We assumed that
(EPA) considers radon a major cause of lung mitigation means reducing all elevated
cancer that is responsible for 7000 to 30 000 radon exposures to 2 pCi/L, the level that
deaths in the United States annually.' The EPA believes can be attained on average.' If
.t'K' .......,....:- agency has urged Americans to test their individuals were to remediate one home
homes and remediate those in which radon and then move to another high-radon home,
readings exceed 4 pCi/L.2 we assumed that they would remediate that
EPA distinguishes the risks of radon home as well.
exposure for smokers and never smokers in To compute the risk reduction attribut-
its A Citizen s Guide to Radon.3 The risks able to quitting smoking, we assumed that
are dramatically higher for smokers, reflect- background lung cancer risk declines lin-
ing an interaction effect between radon and early from levels for current smokers to the
cigarette smoking.3-5 Although the guide average for former smokers in 15 years. This
recommends quitting smoking, along with was an extremely conservative approach
remediating homes with high radon read- that, for 2 reasons, considerably underesti-
ings, no publication has compared the risk mates risk reduction: (1) it treats the average
reduction attainable by radon mitigation, risk for former smokers as the risk attained
smoking cessation, or the two combined. 15 years following cessation, although the
average former smoker has been abstinent
: only a few years, and (2) empirical evidence
Methods on lung cancer risk reduction after cessation
of smoking indicates a rate of decline more
In our analysis, we used the standard rapid than linear.'0
*' ' .t.'''"' .'.' radon lung cancer risk model used by EPA, As with EPA's results, our findings
T" , "
f4 , ';
' 'iKj BEIR [V,4 linked with 2 other models, one represent averages for both sexes. In actual-
describing the distribution of radon in homes ity, risks will be higher for men, and risk
in the United States6'7 and one characterizing reductions greater, because men have
Americans' patterns of moving to new higher background lung cancer rates."
9,...S.:....~ ~ ~
~~ ~ I'. -
~ ~~~~~~~~~~~~~~~~~~ (averaging 10 or:11 moves through-
s '' *;
homes8 . ......e.
~ ~ ~ ~ ~ ~ ~*
i.. .... Z. s
..os.ed-. out their lives9). Introducing realistic pat-
tems of residential mobility greatly reduces David Mendez and Kenneth E. Warner are with
estimates of the individual risk confronted the Department of Health Management and Policy,
by people currently residing in high-radon
School of Public Health, University of Michigan,
homes, simply because they will spend most Ann Arbor. Paul N. Courant is with the Depart-
of their lives in lower-radon homes.5'8 The ment of Economics and School of Public Policy,
models and the analytical process have been University of Michigan.
described elsewhere '8 (a technical appendix Requests for reprints should be sent to David
Mendez, PhD, Department of Health Management
is available from the authors). and Policy, School of Public Health, University of
In using the BEIR IV model, we Michigan, 109 S Observatory St, Ann Arbor, MI
assumed a multiplicative relationship 48 109-2029.
between smoking and radon exposure to This paper was accepted October 17, 1997.
American Journal of Public Health 811
Public Health Briefs
lung cancer. However, they will not change
TABLE 1-Lifetime Risk of Radon-Related Lung Cancer: 40-Year-Old Living in our qualitative finding that smoking cessa-
Current Home for 10 Years More tion is more effective than mitigation in
Radon Exposure: Current Home reducing radon-related lung cancer risk.
4 pCVL 10 pCVL The radon-related health benefits of
Does Not Mitigates Does Not Mitigates
quitting smoking pale in comparison with its
Mitigate Now Mitigate Now other contributions to health." The principal
health motivation for quitting smoking,
Smoker who does not quit smoking, % 1.69 1.35 3.00 1.83 therefore, is not to solve a radon problem.
Smoker who quits smoking now, % 0.81 0.65 1.45 0.90 Still, we find it intriguing that mastering
Never smoker, % 0.09 0.07 0.16 0.10 America's premier cause of preventable pre-
mature mortality, cigarette smoking, domi-
nates strategies to deal with the problem
To illustrate model results, we consider risk reduction than does quitting smoking posed by indoor radon as well. O
here two representative 40-year-olds who after having mitigated the radon problem.
have smoked since 20 years of age, one in a (The never smoker confronts a lifetime risk
home with a radon reading of4 pCi/L and the of 0.16%, which mitigation would lower by Acknowledgment
other in a home with a reading of 10 pCi/L, a nearly 40%.) This paper was supported by grant ROI CA57691
very high level reached or exceeded in only Not shown are results associated with from the National Cancer Institute.
0.7% of residences. We assumed that these varying the age of the individual or the
individuals would live in their current homes minimum length of continued residence in
for 10 more years and thereafter move the same home. These results would not References
according to the residential mobility model. qualitatively alter the findings. Varying the 1. Technical Support Document for the 1992
age at which one quits smoking would Citizen's Guide to Radon. Washington, DC:
influence the findings in obvious ways. For US Environmental Protection Agency; 1992.
EPA publication 400-R-92-01 1.
Results example, mitigation undertaken at 40 years 2. Cole LA. Element of Risk: The Politics of
of age reduces risk to a greater extent than Radon. Washington, DC: AAAS Press; 1993.
Table 1 presents the 2 hypothetical does smoking cessation at 70 years of age. 3. A Citizen's Guide to Radon. The Guide to
40-year-olds' lifetime percentage risks of (However, quitting smoking at age 60 Protecting Yourself and Your Family from
contracting radon-related lung cancer, with affords risk reduction comparable to that Radon. 2nd ed. Washington, DC: US Envi-
the risks of a never smoker of the same age achieved with mitigation at age 40.) ronmental Protection Agency; 1992. EPA
presented for comparison. publication ANR-464.
4. Committee on the Biological Effects of Ioniz-
For the smoker living in a home with a ing Radiation, National Research Council.
radon reading of 4 pCi/L (columns 1 and Discussion Health Risks of Radon and Other Internally
2), doing nothing produces a 1.69% lifetime Deposited Alpha-Emitters. BEIR IV. Wash-
chance of radon-related lung cancer. Miti- The striking finding of this analysis is ington, DC: National Academy Press; 1988.
gating the radon problem but not quitting that quitting smoking will reduce the risk of 5. Warner KE, Mendez D, Courant PN. Toward a
smoking would decrease risk by a fifti, to radon-related lung cancer more than will more realistic appraisal of the lung cancer risk
from radon: the effects of residential mobility.
1.35%. Quitting smoking but not mitigating directly addressing the home's radon prob- Am JPublic Health. 1996;86:1222-1227.
radon would decrease risk by more than lem itself. This is true even at unusually 6. The National Residential Radon Survey.
half, to 0.81%. Both mitigating radon and high levels of radon and despite modeling Washington, DC: US Environmental Protec-
quitting smoking reduces risk by just over assumptions that clearly underestimate the tion Agency; 1993.
60%, to 0.65%. The incremental gain of risk reduction benefits of quitting smoking. 7. The EPA/State Residential Radon Surveys.
mitigation, once one has quit smoking, is Of course, to maximize risk reduction, Washington, DC: US Environmental Protec-
tion Agency; 1993.
small relative to the incremental gain of smokers in high-radon homes should both 8. Warner KE, Courant PN, Mendez D. Effects
quitting smoking, given that one has miti- quit smoking and remediate the home. In of residential mobility on individual vs popu-
gated. (The never smoker who does not most situations, however, the latter will pro- lation risk of radon-related lung cancer. Envi-
mitigate has less than 0.1% chance of con- duce only a relatively small marginal gain ron Health Perspect. 1995;103:1144-1149.
tracting radon-related lung cancer.) once the former has been achieved. 9. Long LE. Changing residence: comparative
For the smoker living in a home with a Our specific findings depend critically perspectives on its relationship to age, sex, and
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radon reading of 10 pCi/L (columns 3 and 10. Halpem MT, Gillespie BW, Warner KE. Pat-
4), doing nothing translates into a 3% life- smoking and radon in producing radon- terns of absolute risk of lung cancer mortality
time chance of radon-related lung cancer. related lung cancer. We used the same risk in former smokers. J Natl Cancer Inst.
Mitigating the radon problem while contin- model used by EPA (and widely accepted 1993;85:457-464.
uing to smoke reduces risk by nearly 40%, elsewhere as well). This model posits a 11. Reducing the Health Consequences ofSmoking:
to 1.83%. Quitting smoking but not mitigat- multiplicative relationship between smok- 25 Years of Progress. A Report of the Surgeon
ing and radon exposure.' Alternative mod- General. Washington, DC: US Dept of Health
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1.45%. Combining mitigation and quitting els, consistent with the existing data, that trol; 1989. DHHS publication CDC 89-8411.
smoking reduces risk by fully 70%, to specify a submultiplicative relationship'2 12. Lubin JH, Steindorf K. Cigarette use and the
0.9%. As before, mitigating after having might imply that quitting smoking has a estimation of lung cancer attributable to radon in
quit smoking creates a smaller incremental lesser impact in reducing radon-induced the United States. RadiatRes. 1995;141:79-85.
812 American Journal of Public Health May 1998, Vol. 88, No. 5