ets exposure, lung cancer - Legacy Tobacco Documents Library

General's Report, the 1986 U .S . National Research Council Reporr,
and the 1992 U .S . Environmental Protection Agency Report) to the
effect that ETS exposure is associated with a 15 - 30 % increas~d
risk of lung cancer are based upon such meta-analyses, the
justification for pooling the data from the various studies intcp
a single statistical analysis and, thus, the validity of sur.h a
conclusion, is a matter of considerable and heated debate .
Another area of co7troversy relates to the surrogate used
for ETS exposure, spousal smoking status . Usually, this-index f
exposure, which is based upon the response to a questionnaire,
lacks verification by a biologic marker, such as a specific
tobacco constituent in a body fluid (e .g ., urine, plasma, or
saliva levels of nicotine or its metabolite, cotinine) .
Furthermore, spousal smoking has been shown to be an inaccurata
estimate, both qualitatively and quantitatively, of such exposuTe
for the following reasons : 1) it usually fails to differentiat
between spousal smoking in and out of the home ; 2) it does not ~
take into consideration ETS exposure from ot'er sources (e .g .,
social or work exposures) ; and 3) it is subject to
misclassification of smoking status of subjects .
With regard to ~ smoking statu~
misclassification, individuals married to smokers have been
demonstrated to have an increased likelihood of being smokers
themselves . This pher.omenon, called "marital concordance" or
"marital aggregation", is recognized to be a potential source o~
inflation of the odds ratio in studies of lung cancer associateti
with spousal smoking. ' ^