Tobacco Documents Online

O C T 2- tLi 1990 TIIF. UNIVERSITY HEALTH CENTER AT TYLFR Lkp.nmeet d Lledklse P.O. bos 200). TTler. TX 75710 P4onr (214) t77•)4f 1 September 28, 1990 The Project Officer for Environmental Tobacco Smoke (ETS) Office of Health and Environmental Assessment (RD-689) United States Environmental Protection Agency Room 3703-MALL 401 M Street S.W. Washington, D.C. 20460 Dear EPA Project Officer, I am a Professor of Medicine at the University of Texas. My branch of the university has a mission dedicated exclusively to pulmonary diseases and my own academic career has been devoted almost entirely to the study of pulmonary medicine, including extensive research on tobacco and health. I have read and carefully examined the EPA Review Draft entitled, "Health Effects of Passive Smoking: Assessment of Lung Cancer in Adults and Respiratory Disorders in Children," hereafter referred to as "EPA Review Draft." My qualifications for commenting on this document are appended to the enclosed document. For the past year, I have spent a good portion of my time reviewing virtually all of the literature on environmental tobacco smoke and related issues. This review was conducted with computer-assisted analyses, including an assessments of several thousand more articles than were cited in the EPA Review Draft; all of the seminal publications have been critiqued carefully. This project will be published as a scientific textbook in 1991, with Professor Robert J. Pandina, Ph.D., of Rutgers University. There are three main issues that I have tried to address in the enclosed commentary. First, I am concerned that the cited ETS literature database on which the EPA Review Draft is based is selective and is not complete. The reasons for this selection and restriction are not clear. No criteria are offered in the EPA Review Draft to explain or justify why so many important scientific publications have been excluded from analysis. When evaluated within the context of a more comprehensive literature database, many of the conclusions reported in the EPA Review Draft would take on a substantially different meaning. Because the EPA Review Draft was based on an incomDlete and skewed sampling of the literature, erroneous conclusions were drawn and a loss of scientific objectivity occurred. Science is objective. When objectivity in (p.1 pqaWwry/AIIbw.M.r ANfw fan/aie. I

a work is lost, it is no longer science. Of all of the agencies in our government that we as citizens must depend on, the EPA hopefully would be above distortion of science and loss of scientific objectivity. Second, I am concerned by the manner in which the physical, chemical, and biological properties of ETS were addressed in the EPA Review Draft. This is a rapidly changing field, and the information presented in the EPA Review Draft is now outdated. From the development of my own publications, I personally can appreciate the difficulty_of this problem. Nevertheless, the concepts in the EPA Review Draft are presented in a way that loses scientific credibility. Environmental tobacco smoke is o~t sidestream smoke or some fraction of mainstream smoke, although it has been incorrectly treated as such. ETS is really not smoke at all, in the conventional sense. What humans passively inhale upon exposure to an active smoker are a few residual constituents of sidestream and mainstream tobacco smoke. These residual constituents, which appear on clear chemical identification to be perhaps 50 to at most 100 in number, are highly diluted by a factor of 100 to 1,000 or more relative to mainstream tobacco smoke, which contains at least 4000 to 5000 clearly identifiable constituents and several thousand more trace constituents. The residual constituents of ETS are present in environmental air in only very low concentrations. As individual entities, they have their own behavior characteristics. Thus, implications that are based on analyses of mainstream or sidestream smoke have no meaning whatsoever for ETS. For these reasons, dose-related linear extrapolations from active smokers to passive smokers simply cannot be made. We all have made that mistake in the past, but that is not the scientific fact of the present. The EPA should set the standard for analyses of real exposure levels, not distorted theoretical or calculated levels based on what now has become fallacious reasoning. As an extension of this second concern, reliable surrogate markers for exposure to ETS do not exist. The EPA Review Draft places considerable emphasis on nicotine and/or cotinine measured in the blood, saliva, or urine of nonsmokers passively exposed to active smokers. Such measurements have come to be accepted, without adequate questioning, as reliable indicators of ETS exposure. They are not. Viewed in the present knowledge that is available, blood, salivary, or urinary nicotine or cotinine levels reflect an exposure to some residual nicotine in the environment of the nonsmoker. This nicotine probably is derived predominantly as a gas-phase residual constituent, but even that is not certain. There are small residual amounts of nicotine in respirable suspended particulates and nicotine is adsorbed ubiquitously to almost every surface within a closed environment where there are smokers, from which it may re-enter environmental air over hours to days. Each constituent of ETS has its own residual time and behavior in the environment, and there are, at

this time, no acceptable or reliable biometric markers of exposure other than for the actual measurement of each residual constituent. In that context, each such residual constituent of ETS has its own environmental toxicology and its own established environmentally acceptable level for exposure. Third, I am concerned that the risk assessments for infants and children passively exposed to smokers developed in the EPA Review Draft are not scientifically supportable. There surely is nothing of greater medical importance than the area of concern for the health of the very young. Unfortunately, this is the most difficult area of all of the ETS questions to address. The risk ratios for disease in infants and children exposed passively to the smoke of others are very weak, even in those studies that report a positive risk relationship. This matter is complicated further because there are overall as many or more negative studies published as there are positive studies, even though, in general, negative studies do not get published. The negative studies, however, are there, although they generally tend not to surface on computerized literature retrieval searches because they are not coded as such. In addition, there are fifty or more confounding variables that affect the outcome results in these studies on infants and children, and very few of these confounding influences have been controlled in the reported studies. The EPA Review Draft does mention this consideration, but almost only in passing. This is a very important concern that cannot be ignored, excluded, or treated as insignificant. The most important confounding variables include genetic susceptibility to childhood respiratory illnesses, cross-infection among family members within the home, socioeconomic status, number of household members, demographic characteristics of the study population, birth weight, nursing practices, infant nutritional status, growth rates, psychological factors, age, prevalence of parental respiratory symptoms, damp housing, outdoor air pollution, father's occupation, infections acquired in day care centers, nutrition, family health habits, parental lifestyle, and other factors that are discussed in the appended text. The EPA Review Draft excludes a vast body of important literature in this area and in so doing introduces, by the process of neglect, substantial bias in its conclusions. Again, this is not science, and credibility is sacrificed. In summary, there exists a major need to update the information that is available on the health effects of the residual constituents of environmental tobacco smoke. Such a review needs to be, above all, scientifically objective. By losing scientific objectivity, the current EPA Review Draft has lost credibility. In years past, this EPA Review Draft might have passed as scientifically acceptable, based on the best scientific information available. But, this is not the past, and far better

and more extensive research results are available now than were included in this review. By excluding so much valuable information, the EPA Review Draft takes on an unusual air of bias. That may well meet someone's political agenda, but it should not be called science. Those who depend on the Environmental Protection Agency for honesty and credibility deserve something better. The attached materials are in response to the opportunity to comment on the EPA Review Draft. If I can be of any further service I would be glad to offer help in any way possible. Sincerely, (~, (I - 5 t ./[,. L., '0 3 Gary L. Huber, M.D. Professor of Medicine