Environmental Tobacco Smoke ......... ................. ....... .......... The Science CD 0\ C> C) BATCo document for Legal Services : Health Canada 22 October 1999 Reader Summary Few issues have generated as much controversy in recent years as the claim that other people's tobacco smoke - often referred to as environmental tobacco smoke or ETS - might affect the health of nonsmokers. The papers that follow summ3rise what is known about ETS and also attempt to place ETS in context, describing the extent to which ETS contributes to the indoor air pollution problems about which people increasingly are complaining. Among the points made are chat (1) ETS has nor been shown to cause disease in nonsmokers or to present a significant health risk to people with pre-exisring medical problems and (2) the keys to good indoor air quality arc adequate ventilation and filtration of the outside air being brought into buildings. 0 1 1-01, CD CD BATCo document for Legal Services : Health Canada 22 October 1999 CONTENTS 1. Introduction page I 2. What is Environmental Tobacco Smoke? page 3 3. To how much ETS are nonsmokers exposed? page S 4. Does ETS affect the health of nonsmokers? page 8 9 Lung cancer among nonsmokers 9 Adult nonsmoker and childhood respiratory health 9 Cardiovascular disease * Other health effects issues S. What about the annoyance sometimes felt with ETS?page 16 9 CD BATCo document for Legal Services : Health Canada 22 October 1999 ............. . . Environmental Tobacco Smoke: A Summary of the Scientific Literature Introduction In a number of countries, discrimination against smokers has increased substantially during the past several years. Much of the discrimination has Come at the hands of government, with some public health officials claiming that tobacco smoke in the air - often referred to as environmental tobacco smoke ('ETS') - presents a health risk to the nonsmoker. The worldwide anti-smoking community, led by the World He2lth Organisation, International Organisation of Consumer Unions and local anti-smoking groups, have joined the ETS debate with enthusiasm, claiming that ETS is responsible for nonsmoker health problems ranging from lung cancer to impotence. Articles appearing in the popular press over the past 10 years would convey the Any study that can be construed, impression that there is little doubt of the health implications of ETS. Any however unreasonably, to indict ETS study that can be construed, however unreasonably, to indict FIFS tends to %*Ids to be covered extensively in be covered extensively in the press. Meanwhile, studies finding no the press while studies finding no association between ETS and association between ETS and nonsmoker health problems are generally nonsmoker health problems are ignored. In a sense, such disparate treatment is nor difficult to understand. A generally ignored. single gunshot may be heard around the world. Bur the war that did nor happen will seldom make either the evening news or the morning newspaper. So, what is the truth about ETS? Has it been shown to be a health hazard? And how should governments and others respond when confronted with demands for smoking bans or severe restrictions- The sections that follow attempt to answer those questions as succinctly as possible. They also attempt to place ETS in context, describing the extent to which ETS contributes to the indoor air problems about which people increasingly are complaining. The first section that follows describes the chemistry and ETS Is not the same, in chemical or physics of ETS. One of the points char emerges from chat discussion is physical properties. as t-%* that ETS is nor the same. in chemical or physical properties, as the mainstr am tobacco smoke to which active .-.k.rs are exposed. mainstream tobacco smoke to which active smokers are exposed. Active smokers and ETS-exposed nonsmokers also differ in the route and manner of exposure and, Conclusions concerning possible even more significantly, in their level of exposure. Consequently, ETS-related health effects cannot be conclusions concerning possible ETS-relared health effects cannot be based an data concerning active :making - requiring instead studies based on data concerning active smoking - requiring instead studies of f nonsmokers exposed to ETS. nonsmokers actually exposed to ETS. The second section summarises the data that are available on A nonsmoker would have to spend the levels of ETS to which nonsmokers are exposed. In sum, the data more than 100 hours is a typical show that a nonsmoker would have to spend more than 100 hours in a environment In which smoking is occurring before being -posed to a typical environment in which smoking is occurring before being exposed luantity of nicotine equivalent to that deli ... ad by the smoking .( a to a quantity of nicotine equivalent to that delivered in smoking a single single cigarette. cigarette. The data summarised in the second section also provide Qn CD 01% r**j BATCo document for Legal Services : Health Canada 22 October 1999 0.11' 1 ..... . ....... I ..................................................... valuable insights concerning the effects of ventilation on ETS levels in occupied spaces as well as some of the problems chat can arise when ventilation is inadequate or a building's ventilation system is inadequately maintained. The section char follows discusses the major health effects issues that have been The health *ffects section concludes ' raised with respect to ETS, beginning with the claim that ETS can cause that ETS has not been shown to lung cancer among nonsmokers, In addition to focusing on studies of cause disease in nonsmokers or to present a significant health risk to adults and children, the health effects section examines the special people with pro-*xiscing medical concerns that have been raised with respect to individuals with medical problorns. impairments such as heart disease, asrhma or emphysema. In sum, the health effects section concludes that ETS has not been shown to cause disease in nonsmokers or to present a significant health risk to nonsmokers with pre-existing medical problems. The concluding section in the series deals with the issue of nuisance or annoyance. ETS can be, of course, an annoyance - to smokers as well as nonsmokers A si"iti.-minded fus an ETS ha. - if it is allowed to accumulate indoors to excessive levels. That fact proven repeatedly to be both short- occasionally has prompted calls for smoking bans or severe restrictions. sighted and ineffective. The key to a One of the points made in the concluding section is that a single-minded safe and comfortable indoor environment is proper ventilation. focus on ETS has proven repeatedly to be both short-sighted and ineffective. The key to a comfortable indoor environment is adequate ventilation, which Can reduce the level of all substances that will accumulate if the air is not constantly replenished with appropriately filtered air or when a building's ventilation system has not been maintained in accordance with established standards. The reader will find at the end of each of the sections that follow a list of suggested readings. The suggested readings address the issues char have been raised with respect to ETS in much more detail than would be possible or appropriate here. Those wanting to pursue any of the issues covered here could profitably begin with the suggested readings, and then proceed from there to the primary source materials cited in the suggested readings. 0 Ln CD CD ON r%J C> .4…. BATCo document for Legal Services : Health Canada 22 October 1999 ... ......... I ..... . - I What is Environmental Tobacco Smoke? Environmental tobacco smoke ('ETS') is produced when tobacco products are smoked. ETS is a combination of exhaled mainstream smoke (the smoke that is exhaled after a puff is taken) and sidestream smoke (the smoke that comes off the burning end of the cigarette between puffs). Before exposure occurs, both forms of smoke undergo a variety of changes - often referred to as 'aging.' Even more significantly, ETS is progressively diluted with room air until it leaves the particular environment by ventilation or is adsorbed on room surfaces. The major =Qmilcal components of Like all other forms of smoke, ETS is comprised of gases and particles. ETS are wiser and carbon dioxide. The major chemical components of ETS are water and carbon dioxide Most athecmmicals found in ETS (which is a substance that people exhale with normal breaching). Most are at minuscule levels. other chemicals found in ETS are at minuscule levels. A number of articles have been published in the scientific literature comparing the ratio of certain chemicals in sidestream and mainstream tobacco smoke. Although such analyses have some academic interest, they do nor tell us much about ETS. ETS is nor sidestream tobacco smoke, even though sidesrream smoke is one of the sources of ETS. As it leaves the cigarette, sidesrrearn smoke cools, undergoes a variety of chemical and physical transformations and is substantially diluted before becoming part of ETS. Similarly, ETS is not mainstream tobacco smoke, the smoke to which the active smoker is exposed. Mainstream smoke is inhaled almost immediately by the smoker, without significant intervening transformations occurring. As a consequence, scientists have been able to develop a rather precise profile of mainstream smoke. Much less is known about the composition of ETS than of mainstream smoke, principally because of ETS's dynamic and variable nature - the result of There are important differences the ageing process mentioned above. We do know, however, that there be,.... mainstream tobacco smoke are important differences between mainstream tobacco smoke and ETS. and ETS. These include differences in the phase distribution (particle versus vapour) of the components as well as differences in particle size, with ETS particles being smaller than mainstream smoke particles. A number of scientists have pointed our that one cannot reach valid conclusions concerning the possible health effects of ETS from reports about the health effects of smoking on the smoker. In part, that is because of the differences in chemical and physical properties between Mainstream tobacco smoke and ETS as well as the very different quantities of smoke involved. In addition, smokers draw mainstream smoke into their mouth and lungs and typically hold the smoke there for a second or two before exhaling. Nonsmoker exposure to ETS, in contrast, occurs primarily through the nose and is 0" caenot reach valid conclusions accompanied by the shallow breaths characteristic of normal breathing. concerning she possible health effects These factors, in combination, have led most scientists studying possible of ETS from resovta about the health ETS health effects to focus on ETS itself rather than any surrogate - and effect* of savokax on the smoker. to conduct studies on nonsmokers exposed to ETS rather than relying on data relating to smokers. kil CD (D Ln BATCo document for Legal Services : Health Canada 22 October 1999 . . While perhaps something of a digression, it may be worth noting here that the phrase 'passive smoking' - which often is used by anti-smoking activists when talking about The sara" 'passive smokInS' Is nonsmoker exposure to ETS - is misleading. Products of combustion are tni.iradifts. found, at trace or higher levels, in almost every environment, and the chemicals produced in that manner also find their way into air from many noncombustion sources. Yet, it would never occur to anyone to characrerise someone walking along a street with passing vehicles or cooking dinner as a 'passive smoker.' Indeed, it The phrue lp"si.* smoking' would seems clear that the phrase 'passive smoking' would never have been no,*, have been coined by the ntanised and-5making community coined by the organised anti-smoking community were it nor for the *were It not for the phewe's phrase's emotional content. synotional content. The section that follows will describe what is known about the amount of ETS ro which nonsmokers may be exposed. Suffice it to say here that very few chemicals in any natural environment can be traced reliably to ETS. The primary reason is that, with Smozzol adds few chemicals to an o-visiou one that are not already few exceptions, the chemicals in ETS are ubiquitous having a variety of -them sources, both natural and man-made- In fact, smoking adds few chemicals to an environment that are not already there. In addition, ETS is far from the predominant source for most of ETS is far from the predominant the chemicals found in indoor air. Consequently, banning smoking will source (or most of the chemicals eliminate few chemicals from any environment and may nor significantly found In indoor air. alrer the level of most chemicals. Unless people are prepared to live in stainless steel enclosures without furniture or any of the other accoutrements of modern society - thus Imprortoll in a mitaningful way the being protected from motor vehicle exhausts, common household and quality it the air indoor% typically office dusts, fumes from photocopiers, gases from processed woods and requires enhanced ventilation and carpers, erc. - improving in a meaningful way the quality of the air proper iltration. indoors typically requires enhanced ventilation and proper filtration. SUCGESTED READING "99PLA indm=0A.C. no Ongin, and PropernesoiEnvironenenrad Tobacco Stooke, Enwitt,notcar Internatimal. vol lb_pZ31-24; i t9901. FATouGK 0 L ff A The Chconwal Charactensation oi Eavitonmenfal Tobacm Smoke. in En-co,all rbacco sook. procredip .4 the L.-Ation.1 5-posivao M.Gill Voi-sky 1519, Lc,u.St- Booka. pp 1.39,19901. GOAL 4 and K&MM KNUinurrann and Enviroarpentai Tab- 5-ke. Revolocey T.,ticolcipy and M-avolly. -114. -p SS-105 (19911. GLOM M it. . al. The Chenimy of E-ime-tal Thsoco 5-ket C~pmki- "dAks.-coot. L- Pob6hM.I"!1. ASASOIL M and WILL J, AlMling Upesum to Environeornral T~b- S..k,. 1, 1, Valid To F- A- S-ki.tt?. jo-ol of Snakiog-Related Ditoctim. -12. pp 111-12' 119%11. RoultrioK r. Indoor.Air Pollutiom- Sauter& Effeen andMitiganno SmtMm in Tob.- S k. N-volot" f.h. I.-tion.1 Syntpoei- ., MGill Vtti~iy 9989. L-,.V- Book~ pp 333-355,19901. (XI CD N) BATCo document for Legal Services: Health Canada 22 October 1999 To how much ETS are nonsmokers exposed? Intuitively, one might expect this to be a rather easy question to answer. It is not, in part because of the factors discussed in the preceding paper in this series. As noted there, ETS is a dynamic mixture that changes continuously as it ages and is diluted with room air. Almost -11 o( the channicais found in In addition, almost all of the chemicals found in ETS have a variety of ETS have a variety of other sources other sources indoors. Consequently, simply measuring the levels of indoors. individual chemicals in the air will not necessarily provide much insight concerming the contribution made by ETS. A number of scientists have sought to measure particles from ETS directly. These ei~orts have been motivated by several considerations, in particular the relative case with w.ich particles in air can be measured and the assumption, made by a number of commentators, that ETS parricles would be responsible for the claimed health effects of ETS. In iacr, however, respirable suspended particles ("RSP") - the scientific phrase often used in &is context - have many sources. Fortunately, some rather sophisticated analytic techniques r---nrly have been developed to permit investigators to make a reasonably educated guess concerning ETS's contribution to RSP levels. But even those techniques are not precise, producing in many cases an overestimation of the amount of RSP in a room contributed by ETS. There are two ways of assessing exposure to substances in the air - fixed-sire monit- 0=g and personal monitoring. Fixed-sire monitoring provides data concerning the location, sucii as an office or resraurant, where the monitoring is conducted. Personal monitoring, which is accomplished by attaching a measurement device to a person, provides a more direct assessment of the person's chemical exposures as the person goes about his or her daily rourine. Many fixed-site monitoring studies have measured levels of nicotine, particles and o=er substances in a variety of environments and many parts of the world. In offices, resmurarirs; and public facilities where smoking is allowed, the level of nicotine in the air typically has ranged between 2 gg/ml (micrograms per cubic meter) and 20 Ag/ml. On commercial airliners, average airborne nicotine levels have been reported to range from I ~4m_` in nonsmoking sections to about 10 gglw in the smoking sections. A number of scientists have pointed out that, at the levels described above, a nonsmoker would have to spend more than 100 hours in a typical office, restaurant or other public facility to be exposed to a quantity of nicotine equivalent to A nonsmoker would have to spend that delivered by the smoking of a single cigarette. The results for airline more than 10 hours in a typical cabins are comparable and confirm the efficacy of office, restaurant or other public A passenger would bays to take I I facility to be exposed to a quantity of round trips between Now York and airline policies establishing smoking and nonsmoking nicotine equival no to that delivered Tokyo in the smoking section of a sections. One expert has noted, for example, that a by the smoking of a Fingle cigarette. Boeing 747 airliner be(w being exposed to the amount of nicotine passenger would have to take ETS round trips between New York and produced by the smoking of on* Tokyo in the smoking section of a Boeing 747 airliner before being cigarette. exposed to the amount of nicotine delivered in smoking of one cigarette. Put another way, the nicotine levels that have been found in office, restaurant and other indoor environments are the equivalent of making a gin and tonic drink by adding a thimble of gin to an Olympic-size pool of tonic water. Significantly, the The nicotine levels that have boon niczcine levels that have been found in even the 'smokiest' environments found in even the 'smokiese Url (stxfi as bars) are many times below applicable occupational exposure limits. environments (such as bars) are many CD times below applicable occupational CD exposure limits. ON 01- -j BATCo document for Legal Services : Health Canada 22 October 1999 ........ ... . I I .......... ..... .. 7he fixed-sitc monitoring studies also have found that ETS is a relatively minor contributor :a RSP levels in room air. Even when smokers are grouped in smoking areas, the ETS zoncribution to the respirable particle level seldom exceeds 100;lg/ml. This contribution is -ell below the daily exposure limits that have been set for occupational purposes. The studies that have measured other substances in the air leg carbon monoxide. 3ormaldehyde and volatile organic compounds), contributed by ETS as well as other sources. ~ave rended to reach the same conclusion: although smoking contributes measurable amounts Smoking does not aVvificartly affect of particles it does not significantly affect the levels of most chemicals in the levels of most cnamicals 1. the i, the air. To re-emphasise, there are two reasons for this finding. First, there I are many different sources for most of the chemicals found in ETS. Second. :~Le amount of each chemical contributed by those ocher sources often far exceeds the mnirribution from ETS. Personal exposure studies also have proven to be of value in placing ETS into 7-erspecrive. One such study, conducted in the United Kingdom, focused on a representative ;:oup of nonsmoking women. The women were asked to go about their normal business while wearing sampling 'badges' that measured the level of various chemicals, including =*corine, to which the women were exposed. When the data from the study were tabulated, =c investigators found char on average the women in the study would be A study conducted in the UK found mrposed to an amount of nicotine equivalent to that delivered by the that an average the woman in the smoking of a single cigarette only after a period of more than two years. study would be exposed to an amount of nicotine equivalent to that Overall, such investigations have shown that a significant portion of the delivered by the s-oking of a single ciwatto only fter a period of m -opuladon in many countries is rarely exposed to ETS, char exposures than two you%. -d to be lower at work than at home and that, in any event, typical =onsmokef exposures to ETS are remarkably low. We have focused thus far on the typical or average situation. But what about 1-uildings, or areas of buildings, that are neither typical nor average - buildings in which the z~r is both state and polluted? The United States Government as well as private firms s--ecialising in indoor air quality have surveyed a substantial number of such buildings - so- cxUed 'sick buildings' - to develop a profile of causes and a menu of remedial measures. Inadequate or poorly maintained ventilation systems have been found repeatedly to be the predominant cause of the discomfort and health problems that result in buildings Inadequate or poorlif maintained being classified as 'sick buildings', with excessive levels of bacteria and vendlation systems We been (ound fungi, chemicals from exterior sources, formaldehyde from Carpets and repeatedly to be the predominant cause of the disco Wes and health furnishings and a variety of ocher pollution sources adding to the problems that remit in buildings problem. Environmental tobacco smoke has found to be a major cause in being classified as 'sidt buildings.' only two to four per cent of the buildings studied. In those few instances in which smoking has presented Ventilation - coupled with p-ablems, the preferred remedy has been improved ventilation. The appropriate filtration - can reduce he Overwhelming majority Q( rrason, in short, is that ventilation - coupled with appropriate filtration : bscauscos found indoom to ,u - =n reduce the overwhelming majority of substances found indoors to acceptable levels. =eprable levels. Indeed. as a number of experts have pointed out. smoking bans strike at a symprorn of a problem rather than the predominant causes - inadequate or inadequately maintained ventilation systems coupled with deficient filtration. When a building 5 C) 0% rNJ 0% - CD BATCo document for Legal Services : Health Canada 22 October 1999 ventilation system is operating properly and an adequate amount of filtered air is being supplied to occupied spaces. smoking can occur without discomfort or annovance. The samc Banning smokint will eliminate measures also will hold most other substances that can affect the quality on* of the ft. substances that can of the air indoors to acceptable levels. Banning smoking will eliminate be seen and smelled but will not one of the few substances that can be seen and smelled but will nor produce meaningful improvements in indoor air quality in the vast produce meaningful improvements in indoor air quality in the vast majority of cases. majority of cases. Some people may worry, of course, about being exposed to any ETS at all, even the minuscule level guaranteed by good ventilation. Logically, though, that worry - however irrational - should extend to all products of combustion as well as to the countless other sources of airborne chemicals. As noted, virtually all of the substances Virtually all e(th* substances found found in ETS will be in the air from sources unrelated to smoking. In ETS will be in the air from sources Further, many of the substances in ETS, including nicotine, also are unrelated to smoking. found in food or in water. The human body has quite natural ways of using or getting rid of trace amounts of such substances after they have been taken up.* If that were not so, life as we know it would not be possible. SUGGESTED READING W coni'.1 i in grid-1 Ai, P.1lini- P,.bk- rid Cbnd" u.ire.- P, pp 227-325,19921. =00FELLOW. M D. ri al. %smsbng EXPOI.- r. Tob.u. S=W in Eririme-sal TobteSoink. P-~tdi.g, of ib. 1.~-1 Sy.pi. MfAƒ t~,—-iy 1989. 6-k~ pp 53-67 (19901. cuisim Pt R, rr .1. 71. CIiny ( E.~ri-i.l Tb- S.ok* Cpitimil M--r~ Un~ Nblish- (19921. ou>.¯L G -il CO-I.-ZL P. E-.1 Mr Efi- ni Tb- Sk~ o. A. Q-li~y Viihi. P.-Ser C…b- i C--i .%.-it. Scum. -d T®h.0lzy. -t 2 1. pr 99~999 119871. -OCMK C; ci J. A-- ni E.p,r Tcib-c. 5-kr in Brirƒh W-. Enri--t 1--i 1. ..1 1-. Pr W%29-1199U wEETX~ 09. E-vientit Tobacce Smoke. in lnd- Air PoIJ--. Pbi-- and ffl.ririrt. Cbride, U-Y Prri& PP 193-239.1992S. -0 C) M) 01% ND BATCo document for Legal Services : Health Canada 22 October 1999 Does ETS affect the health of nonsmokers? Few health claims have received as much publicity over the past few years as The claim that ETS can affect the health of nonsmokers. In 1986, the United States Surgeon General issued a report, based on the studies that had been conducted w that time, concluding that ETS was a cause of lung cancer among nonsmokers and respiratory problems among the children of smoking parents. Over the succeeding years, health authorities in a Government reports an ETS issued after the 1986 US Surgeon Gen*rai's number of other countries - spurred on by national and international report often simply adopted the anti-smoking organisarions - issued similar reports. The Australian conclusions of that report ithout extended or independent analysis. National Health and Medical Research Council Working Group Report and the Fourth Report of the Independent Scientific Committee on Smoking and Health in the United Kingdom are examples. The later reports often simply adopted the conclusions of the US Surgeon General's report without extended or independent analysis. The 1986 Surgeon General's report prompted a storm of controversy in the international scientific community - a controversy that, unfortunately, has been largely ignored in the popular press. The press also has tended to ignore the many studies of ETS and nonsmoker health char have been published since 1986. Nor surprisingly, the later studies generally have been far superior to the earlier studies in design, particularly in controlling so-called 'confounding' factors. Developments of that sort are typical in science, as later Most mdtos published since 1986, investigators learn from and seek to avoid the mistakes made by their parCcularly an the lung cancer issue. he,. not reported a statistically predecessors. Most studies published since 1986, particularly on the lung significant association beeween ETS cancer issue, have not reported a significant association berween ETS and and nonsmoker health problems. health problems among nonsmokers. The discussion that follows summarises the ETS health effects literature as ic exists today. The discussion begins with lung cancer among nonsmokers, and then addresses adult and childhood respiratory health, cardiovascular disease and the remaining health problems that have been claimed, in one forum or another, to be associated with nonsmoker exposure to ETS. The information described in earlier sections in this series, confirming the minuscule amounts of ETS to which most nonsmokers are exposed as they go about their daily activities, provides an important context for the discussion that follows. 1. Lung Cancer among nonsmokers Concern that ETS might be a cause of lung cancer among nonsmokers was prompted by the publication of rwo studies in the early 1980s - a study by Hirayama in Japan and a study by Trichopoulos and co-workers in Greece. Both were epidemiologic (or population-based) studies. comparing the incidence of lung cancer among nonsmoking women married to smokers and nonsmoking women married to nonsmokers. Both reported a statistically significant increased incidence of lung cancer among women married to smokers, a finding that prompted some people to suggest that ETS might actually cause lung cancer among nonsmokers. Ul From almost the moment of publication, the Hirayama and Trichopoulos studies C) prompted controversy. Parr of the controversy involved doubts about the value of epidemiology C:) 0% CD BATCo document for Legal Services : Health Canada 22 October 1999 . - I ..... . - I From almost the moment of as an investigatory too[ ior low-dose exposures and diseases (like lung publication, the Hiralama and cancer) hLiving 30 to 40 year latency periods and a variety of causes. Trichopoulos studies prompted controversy. %lany scientists pointed out at the rime, and have continued to insist, that epidemiology is simply too blunt a root to use in such circumstances. Among the points that have been made in that connection are that the origin of lung cancer is not well understood, a host of factors has been linked to lung cancer (including diet, hereditv and a number of high-dose chemical exposures) and it is virtually impossible to control for the effects of such confounding factors over a 30 to 40 year period. Without 2 degree of precision not possible in an epidemiologic study, many scientists have emphasised, an investigator can never know whether a slight increase in the incidence of lung cancer among women married to smokers was caused by ETS or any number of other factors. The Hirayama and Trichopoulos studies also drew substantial criticism, and continue to be viewed with scepticism in much of the scientific community, because of unique aspects of each study. Hiray3ma failed, for example, to adjust for many of the most important confounders for lung cancer, relied upon statistical techniques a nd adjustments that are nor accepted by many leading biosratisticians, and did not follow-up with study participants to monitor their actual exposure to ETS. He also assumed, without extended follow-up and contrary to expectations, that the smoking/nonsmoking, status of study participants would remain unchanged over the fifteen-year Without a degree of precision not possible In " epidernioloilic study. period of the study and that no divorce or other long-term separations many scientisU have amphasis*d. an would occur among study participants. investigator can never know whether a slight increase in the Incidence of Unfortunately, the Trichopoulos study suffers from many of the lung cancer among women married to k.rs was caused by ETS or any same methodological problems as the Hirayama study. A number of onm.,:"ber of other factors. scientists have noted, in addition, that the patients and the people used for control purposes in the Trichopoulos study came from different hospitals, increasing the likelihood of methodological bias affecting the outcome. Unlike the Hirayarna study, moreover, the Trichopoulos study was quite small, involving a total of only 77 nonsmokers suffering from lung cancer, thus adding to the uncertainty of the results. Dr Trichopoulos himself has acknowledged many of these problems, suggesting that his study should have been viewed primarily as an invitation for further research. By the time of the US Surgeon General's report in 1986, 11 additional ETS/lung cancer studies had been reported in sufficient detail to permit analysis. In addition to the Surgeon General. three other major reviewing bodies issued reports on ETS in the year - the US National Academy of Sciences ('NAS'), the International Agency for Research on Cancer CIARC') and the Australian National Health and Medical Research Council Working Group. The conclusions reached by these groups were nor entirely consistent. for example, while acknowledging most of the problems inherent in the epiderniologic studies of ETS and lung cancer among nonsmokers, the NAS concluded - based on a controversial pooling or 'mera-an2lySiS' of the studies published to that time - that exposure to ETS appeared to be responsible for a 34 per cenr increase in lung cancer among nonsmokers. C:) ON N) '-4 BATCo document for Legal Services : Health Canada 22 October 1999 Aft IARC monograph concluded in Reviewing the same studies, the [ARC monograph concluded char no 1986 that no definitive conclusions definitive conclusions could be drawn - chac the perrinenc could be drawn from the apid*mialogic stud$es of ETS and lung: epiderniologic studies were 'compatible either with an increase or with cancer among nonsmokers - that: the an absence of risk,' pertinent apid*miologic studies wars, 'compatible either with in increase or Since 1986, the number of epidemiologic studies of ETS and with an absence of risk.' nonsmoker lung cancer has approximately doubled and the number of study participants has tripled. When the NAS mera-analysis technique (which involves adding all the studies together and then making certain adjustments) is applied to the expanded universe of studies, the statistical association between marriage to a smoker and the incidence of lung cancer among nonsmokers largely disappears. When the MAS pooling technique is Again, this reflects the fact char most of the recent studies, which are applied to the expanded universe of arnong the largest and best of the studies conducted on the issue, have studio*, the statistical association between marriage to a smoker and nor found a scaristically significant association between ETS and lung the Incidence of lung cancer among 01 cancer among nonsmokers. nonsmokers largely disappean. The largest: recent studies on the lung cancer issue for which full data are available are the Janerich/Varela study in the United States (1990) and the Wu-Williams study in China (1991), the latter study having been funded by the National Cancer Institute ("NCM in the United Stares and involving NCI personnel on the study team. Both studies looked at exposure to ETS in a variety of settings, at home, at work and in social settings. The janerich/Varela study reported no significant association between ETS and lung cancer among nonsmokers in spousal or work settings, a statistically significant negative association in social serrings (ie nonsmokers - men and women exposed to ETS in social serrings were reported to have a lower relative risk of lung cancer than nonsmokers without comparable exposures), and a weak positive association with exposure from childhood. The Wu-Williams study reported a statistically significant negative association between ETS and spousal smoking, in direct contrast to Hiray2ma and TrichopoUlos, and no association at work or in social serrings. In total, more than 30 epidemiologic studies of ETS and lung cancer among nonsmokers have now been published. Of chose, approximately 80 per cent reported no statistically significant positive association with the primary index of More than 30 epid&mlologic studies of ETS and lung cancer among ETS exposure - marriage to a smoker. Although fewer studies focusing nonsmokers have now been publishad, on the workplace have been completed, an even larger percentage have Of those. approximacoly SO par cent reported no statistically significant reported no statistically significant association between exposure to ETS association with the primary Index of ETS exposure. and the incidence of lung cancer among nonsmokers. In surn, exposure to ETS has not been proven to be a cause of lung cancer among nonsmokers. Unfortunately, many of the pertinent studies are flawed in both design and execution. with confounding factors (ic other exposures and activities known to be associated with lung cancer) having receiving woefully inadequate attention and no monitoring of actual exposures having even been attempted. Since a number of lifestyle confounders, such as diet, have been demonstrated to be more prevalent in the spouses of smokers than of nonsmokers. the failure to control adequately for In surn. exposure to ETS has not been confounders is especially troubling. Future studies must seek to remedy proven to be a cause o(Jung cancer Ul this and other deficiencies. among nonsmokers. C:) C) NJ --4 N-) BATCo document for Legal Services : Health Canada 22 October 1999 2. Adult Nonsmoker and Childhood Respiratory Health The possible imp3cr of ETS on adult nonsmoker and childhood respiratory health has been investigated from a varier~ . of perspectives. with different investigators urilising a series of complementary techniques. These include epiderniologic studies comparing lung function and the prevalence of adverse respiratory symptoms (such as coughing and wheezing) in ETS-exposed and non-exposed individuals, both adults and children. Other studies have used clinical settings to focus on both healthy and compromised individuals and those suffering from asrhma or claiming 2 special sensitivity to ETS. For ease of presentation. the discussion that follows is divided into three parts. We look first at studies of healthy adults. We then review the studies that have focused on children (pre-school and school-age) and, finally, we consider the studies that have looked at individuals suffering from asthma or claiming a special sensitivity to tobacco smoke. (a) Adules In contrast to the lung cancer issue, few studies have been published during the past five years on ETS and adult respiratory health. The reason, in part at least, is that the issue was largely settled by 1986 when the US Surgeon General and National Academy of Sciences reports were being prepared. According to the Surgeon General. the studies available as of 1986 indicated 'that 2 previously healthy individual would nor develop chronic lung disease solely on the basis of 'A previously healthy individual would - (exposure to ETS) in adult life.' Similarly, even when confronted not develop chronic lung disease with artificially high levels of ETS in clinical tests, the Surgeon General solely on,the basis 0 ~ (exposure to JETS) In adult II(a.' found at most 'quite small' changes in air flow from the lung, leading US Surgeon General (1986). him to conclude that 'ir is unlikely char this change in airflow, per se, results in symptoms.' The NAS reached similar conclusions, as have virtually all other government health reports from around the world that have examined the issue. The few studies of ETS and respiratory health in normal adults Them is "subs'al basis for the that have been published since 1986 have essentially confirmed the results claim that ETS signiffc~antly affecft lung function or respiratory health In of earlier studies. There is thus no substantial basis for the claim that ETS h*aithy adults. adversely affecrs lung function or respiratory health in healthy adults. (b) Chillciren The situation with infants and children is a bit more complicated. A reasonably consistent statistical association has been reported between parental smoking and an increased incidence of respiratory symptoms (such as cough) and respiratory illness (such as bronchitis and pneumonia) in children up to five years of age. Studies of school-age children have been markedly inconsistent, with some studies reporting an association and other studies reporTing no association. These results prompted the US Surgeon General to conclude in 1986 that parental smoking 11) increases the risk of respiratory symptoms and illness in children, especially younger children, (2) may be associated with small decreases in pulmonary function and (3) may impair pulmonary growth and development. The Surgeon General pointed to the variable results of studies on school-age children in explaining the conditional nature of the second and third conclusions. C) BATCo document for Legal Services : Health Canada 22 October 1999 ........ I . ~ . . ............... A number of scientific papers published since 1986 have pointed our that the data on childhood respiratory health contain many more ambiguities than were acknowledged in the Surgeon General's report. Reviewers have noted, for example, that the majority of the Th* data an childhood respiratory pertinent studies have relied upon responses to questionnaires to assess health contain many more exposure to ETS as well as to develop a health profile of the children ambiguities than were acknowledged included in the studies. Reviewers have emphasised char questionnaire in the Surgeon General's repom responses can at best provide only very crude exposure estimates. Parental reporting of symptoms and illness also has been criticised, with reviewers pointing our that the accuracy of information collected in that manner may depend in part on which parent is reporting, how much time has elapsed between the illness and the report and che reporting parent's education level. In addition, scientists have emphasised that a variety of factors other than exposure to ETS may account for the association between parental smoking and impaired respiratory health in pre-school age children. A number of studies have reported. for example, a significant association between the respiratory health of Scientists he" amphasised that a children and parental respiratory health, household crowdingl number of variety of factors other than exposure siblings and attendance at day care facilities. Cross infection may well be ` ETS may account for the "satiation b*meon parental smoking the mechanism of such associations. and Impaired respiratory health in Poor respiratory health also has been linked in a number of pro,,chool age child,*n* studies with low socioeconomic status, the strength of that association being much stronger than the association with parental smoking. Among the factors related to low socioeconomic Non* of the studies of ETS and pre. status are damp and moldy living conditions, the fuel used for cooLng school age children bas yet controlled and heating, poor hygiene, the frequency and quality of medical care and adequately for all potentially Important confoundinii factors, which parental neglea. None of the studies of ETS and pre-school age chil&cn precludes the a"ilcament of a causal has yet controlled adequately for all potentially important confounding role cc ETS. factors, which precludes the assignment of a causal role to ETS. While awaiting further research in this area. it is worth noting char no substantial concern has been expressed about the occasional exposure of a child to ETS in public places or in the workplace. The reason, in short, is chat any such ixposures are too infrequent and limited to have conceivable effect. No one would quarrel with the No substantial concarn has been suggestion that parents refrain from smoking for prolonged periods expressed &bowl the occasional around infants, any more than one would quarrel with making sure that exposure *(& citild to ETS In public Th. use that "me anci-smaking an infanr is protected from cold or dampness before places or in the wvAplace activists have act ip ad to make of taking the inf3nr outdoors. The use. however, that some anti-smoking the ETSIchildhood respiratory health Issue In campaigns Mar public or activists have attempted to make of the ETS/childhood respiratory hcaith workplace smoking r-crictions is issue in campaigns for public or workplace smoking restrictions is cleady clearly Inappropri"t. inappropriate. (c) People suffering from Asthma and those claiming a special sensitivity to Tobacco smoke Several groups of investigators have focused on the possibility that ETS might present ,problems to people already suffering from asthma or claiming a special sensitivity to tobacco smoke. A clinical approach has been used in such investigations, with case and control subjects being placed in enclosures and being exposed to machine-generared ETS 'or V71 C) C) BATCo document for Legal Services: Health Canada 22 October 1999 ........... I ............. a claimed surrogatei - often at levels substantially exceeding real-life exposure levels. The results of such tests have been inconclusive. In fact. even at unrealistically high exposure levels. prompting a measurable response to ETS by asthmatics and others claiming a special sensitivity to tobacco smoke has proven to be difficult. One group of investigators has suggested that a small subset of asthmatics may be intolerant to ETS. The same investigators have failed to find. however. any relationship Even az -realistically high exposure between perceived intolerance, as determined by pulmonary function levels. ;eompting a measurable testing or the subject's own statements, and sensitivity or reaction to response to ETS by asthmatics and tobacco leaf extract. This finding is consistent with earlier reports others claiming a special sensitivity to tobazze, smoke has proven to be Finding no association between subjectively reported sensitivity to ETS - difficult. by some asthmatics as well as others claiming to be 5moke-sensirive - and objective immunologic rests. One difficulty chat scientists have faced in this area stems from the fact that asthmatic episodes can be triggered by stress as well as by environmental factors. Identifying the actual cause of an asthmatic episode from a much longer list of 'Biasos in observation and In the candidate causes is, moreover, seldom easy. As the US Surgeon General selection of sublects'and the observed in 1986, '(b)iases in observation and in the selection of subjects subiacts'own expectations may account for the widely divergent and the subjects' own expectations may account for the widely divergent sultsA that have been reported in studies of ETS and asthmatics. results' that have been reported in studies of ETS and asthmatics. US Surgeon General (1986). Responding to any concerns people suffering from asthma may have about exposure to ETS seldom presents any real problem. In the workplace, a simple re-arrangement of workstations is generally sufficient to deal with any problem, whether Responcing to any concerns people actual or perceived. Accommodating non-asthmarics who claim a special suffering "m asthma may have sensitivity to tobacco smoke can be achieved in a similar manner, about exv*swre to ETS seldom generally with little or no disruption and without affecting productivity. presents any real problem. 3. Cardiovascular Disease The possibility that exposure to ET5 might be associated with cardiovascular disease, especially coronary heart disease, has received considerable press attention during the past two years. Much of the attention was prompted by a review article written by Glantz and P2fMICY in the United Stares claiming that ETS might be responsible for as many as 37,000 coronary heart disease deaths per year in the United States alone. None of the press reports attempted to analySe the basis of the claims made by Glanrz/Parmlcy, The primary proponent of the and none bothered to mention the fact that Glantz is one of the founders suggestion that ETS adversely affects nonsmoker cardiovascular health Is of Americans for Nonsmokers Rights, a leading anti-smoking political a founding member of one of the action group in the United States. The press also maintained a curious leading anti-smoking political action silence when an official of the Environmental Protection Agency in the groups in the United States. a fact that has been Ignored in the United Scares, after reviewing the Glanrz/Parmley article. characrerised popular press. the conclusions reached in the article as 'gratuitous.' If true. the Glantz/Parmley claims (as well as similar claims advanced more recently by Steenland) would represent a rapid turnaround indeed. In 1986, the US Surgeon General, National Academy of Sciences and Australian National Health and Medical Research Council Working Group all concluded that there was insufficient evidence of an U1 association bet-ween ETS and cardiovascular disease. That conclusion was echoed by C) C:) (_n BATCo document for Legal Services: Health Canada 22 October 1999 ..... ..... . - . . subsequent international reviewing bodies, culminating in the 1989 Proceedings of the International (ETS1 Symposium ac McGill University. After concluding that the epidemiologic studies that had been published failed to demonstrate any increased risk of A number of leading scioncists have ' cardiovascular disease from exposure to ETS, several of the .1vlcGill emphasised that the suggestion that participants pointed to the implausibility of the ETS/ cardiovascular ETS might be associated with nonsmoker cardiovascular disease is disease hypothesis from a biological perspective. The symposium biologically implausible. organiser, Dr Joseph Wu of New York University Medical College. summarised the discussion on the latter point as follows: "Several discussants doubted that an association between ETS exposure and cardiovascular disease could ever be demonstrated, given the extremely low exposure levels and, thus, [he biological implausibility of any relationship. AccordinglYt there may be little or no reason to pursue further studies in this area. The panelists agreed that attention may be more profitably directed toward factors other than ETS such as diet, weight, cholesterol, stress and blood pressure.- 0 The studies on ETS and cardiovascular disease among nonsmokers that have been published since 1986 are consistent with those published before that time, with not reporting a significant association. Furthermore, as pointed our by a The studies an M and cardiova4cular number of commentators, the studies that have reported a scarisrically disease among nonsmokers that have b C::n published since 19116 ars significant association, most appearing before 1986, have ignored major sistent with those published b afore cardiovascular disease risk factors. Thus, even if those studies are viewed that time, with moit not reporting a in isolation, there would be no basis for knowing whether the reported significant association. ETS/cafdiovascular disease association was due to ETS or any one or combination of the approximately 300 cardiovascular disease risk factors that have been reported in the scientific literature. Other commentators have pointed to still other deficiencies in the No investigator has yet produced data pertinent studies, including the failure to verify ETS exposure or to countering the biological provide objective measures of.rhe extent of that exposure. Finally, a Implausibility of any association number of leading commentators have emphasised, in response to the between ETS and cardlevascular disease among nonsmokers. Glantz/Parmley article, that no investigator has yet produced data countering the biological implausibility of any association between ETS and cardiovascular disease among nonsmokers. In sum, exposure to ETS has nor been proven to cause or exacerbate cardiovascular disease among nonsmokers. The epiderniologic studies char have addressed the ETS/cardiovascular disease issue are, at most, inconclusive. One is left, then, to ponder the biological implausibility of the hypothesis. As noted, that consideration In sum. exposure to ETS hxs not been alone prompted a number of the participants at the McGill symposium to 'r to or urge that future efforts to untangle the cardiovascular disease riddle "I""cul" disease ame.2 nonsmokers. should focus on factors such as diet, weight, cholesterol, stress and blood pressure. Unlike the situation that exists with respect to ETS. there is a substantial basis for believing that improvements in cardiovascular health might actually be realised through control of such factors. Lrl CD C) N) C71 BATCo document for Legal Services : Health Canada 22 October 1999 ............. I . . ....... . . ........... 4. Other health effects issues Isolated reports can be found in The scientific literature claiming an association between ETS and a variety of other health problems. Few of those reports have been taken seriousl~ within the scientific community. and those that have prompted further investigation have On examination. only on* conclusion produced results that are far from conclusive. Because of the political seems appropriate: ETS has not been implications of the ETS controversy, few substances in air have been shown to cause 'disease in nonsmokers or to present a significant health risk subject to as much research or inquiry as ETS. Yet, on examination, to People with PrO-existing medical only one conclusion seems appropriate: ETS has nor been shown to cause problems such as asthma. disease in nonsmokers or to present a serious problem to people with pre-existing medical problems such as asthma. L%~CANCIRA~NCKWWRM SUGGESTED READING Pj= I oil GA= ~ in Eputerri.logy. ith Special Reicrence to Srudies of the Association Brivvern Exposure in Environmental Tco-4o Smoke and Lung Cancer, Jourrul of Clim-1 Epidemiology. ~.l 44. pp 12'- 139115911. KOO. L Emircammennal Tobacco Smoke and Lung Cancer: Is it the Smok. or he 13-1. in Presion, asid funue, of led- Air Quality, E..r,. XW.L N*m York, 19991. LA .. A . . Eoinince-rat Tobacco Smoke oil Came,: The Epidemiologx Evidence. in Environmental Tobacco Smoke Proccedings,of the International Sysipinizarn -M.Gill University 1989. Lit.itigm. Books, pp 9114 16 11990). LEL PKIMisdansificaution of Smoking Habits and Passi,e Smoking. Springer-VM19 119881. USULG a Ennaommestal Tobacco Smoke and Lung Cancer. in Oth~ Proples'Tobacre, Smoke. Galm Prerss. pp, 91-98 0"11. wUTm^ D F. Environmental Tobacco Smoke. in Indoor Air Pollution: Problems ..it Priorities. Cambridge Pm, pp 193-23- ADULT -0 CMDRIEWS RESPIRATORY MCALTM M000. K 0. Is L Eni-rurims.1 Tobacco Smoke Ep..,c and Respiratory H,.ITh in Childrc. An Upd-d Critical It- ad Arudyiis re ch. Epd-legic Lner.- Woor Envirimasumt. r] 1. pp 19-35,1992). WnOPRKP. Effect" ETS F~posure on Pulmonary Function and Respiratory Heafth in Adults. in Environmental Teaser* Smok. Fine: ipf wrTORS04 It j. Parental Smoking and Ropiratory Health and Pulmonary Function in Children: A miew of the Literature. in Environmental ' T.I.- $.ch. proceidi.s. f.h. I.-ti ... I syrapaii.. air McGill 1989. pr 205.2-16 (3990). CARCHOVaMICIA." P"REAS2 ARWrAGL & Environmental Tobacco Smoke and Cot ry Heart Disease, in other Peoples* Tobacco Smoke. Calen Presupp 109-116 119911. vdfrmAK D. arid istmor. I. En,urartmerital Tobarcri Smoke (ETS, oil Di-sc. in Indoor Air O.Airy and ventilation. Selper, P,, Pp '11,216 11990, wVQM L K Erstrommoul Tobacco Stroke and Cadi-tilar Dii,ease. A Critique of the Epiderniologic Literature and Recommendation, for F.- R-h.,n F-i-mimcal Tobacco Smoke: P-dings of the In-tional Symposium -McGill 1989, pp 139-152 119901. 0 Ln Is BATCo document for Legal Services : Health Canada 22 October 1999 I . . . . . . . . . . . . - I., .... ................................ ............ 1. What about the annoyance sometimes felt with ETS? If ETS is permitted to accumulate, it can of course be an annoyance - to smokers as well as nonsmokers. But so can other substances found indoors, including the carbon dioxide produced by human respiration. the formaldehyde emanating from carpets and wallboards and the ozone produced by office copying machines. In fact, literally thousands of chemicals can reach excessive levels indoors from myriad sources and activities if inadequate ventilation is provided and filtration is deficient. An earlier section in rhis'series summarised the results of investigations that have been conducted worldwide on so-called 'sick buildings'- buildings characcerised by frequent complaints from occupants of symproms ranging from scratchy eyes to dizziness and headaches. Because ETS is one of the few substances that is both visible and can be smelled, many such complaints are initially attributed to smoking. Bur, as noted in chac earlier section, actual investigations overwhelmingly have identified other causes - with inadequate ventilation leading the list. As a number of international standard setting organisarions have concluded, smoking should not presenr a serious problem or widespread annoyance with adequate As a number of international standard ventilation and appropriate filtration. Further, the simple rearrangement setting organisations have concluded. of workspaces (separating smokers from nonsmokers nearer ventilarioa smoking should not present a serious exhausts) is generally sufficient: to deal with individual complaints. or widespread annoyance problem with adequate ventilation ~d Partitions, plants and portable air cleaners also can be effective. appropriate filtration. Smoking bans or severe restrictions, in addition to being unnecessary from a. scientific perspective, also raise a host of philosophical or policy questions char deserve to be considered by governments and others responsible for the operation of workplaces and buildings frequented by members of the Courtesy and common sense long public. This is nor the place for an extended discussion of those have permitted smokers and nonsmokers to live and work together considerations. Suffice it to say here that courtesy and common sense in harmony. The science of ETS . long have permirred smokers and nonsmokers to live and work together provide$ no reason to abandon those in harmony. The science of ETS provides no reason to abandon those fundamental principles. fundamental principles. 54JGGESTED READINIG Amm"a Smery ot fleanm Refripr3ung And W.Condid ; Enginettv. Ssadad 62-199% V-61.6- fe, A-Ptble (ad- Air Q-6". ASHRAE.1-891. ~wKa&LJMrJ11on And Sensory Effectsof Environavental Tobwc~ Smk,. w Chher l`.pk%'T*bx,o Smk. G,len Pr., pp $1.90 - 1991). ~f. Th. NmM- of JaJoo,Air Q.Arv. . led- Air Pollan- ftebl-And P-nes. CA-bnda Un-ru~ Pr-. pp 4.13 1199.11. RCIUMOK Q Indoor Pollunan: Souo~ Eff"7s And Mioit- Sn-g- Tb-. 5-k. P~vedisix. .1 he lonns-1 S?niposnan .MGal Univerury 1939. pp.1,13-355. I"),. Ln C) CD Co BATCo document for Legal Services : Health Canada 22 October 1999 4k, BRITISH-AMERICAN TOBACCO COMPANY LIMITED M-- Y.-G.40. 5-TWIS IVY UK Ln C) C) ..... C-1 - II.- N) NO BATCo document for Legal Services : Health Canada 22 October 1999