FLOW T H R O U G H P O R O U S MEDIA SYMPOSIUM
HELMUT R. R. WAKEHAM
Luncheon Address s is well-known, cigarette smoking has, at one time
A or another, been blamed for many of the physical ailments of mankind. Consequently, in recent years there has been a great deal of interest in cigarette filtration. The popularity of filter cigarettes has increased to the point that today in the United States 77y0 of cigarette sales are of the filter type. Undoubtedly many people prefer filters because they keep tobacco particles out of the mouth and generally deliver a milder taste. But many others also hope and/or believe that somehow filter cigarettes are less hazardous to health. Obviously, since we are in the cigarette business, we have done extensive researches in this field and examined all relevant studies by others. After all this, very honestly I do not know that any cigarettes are hazardous to health. (For a review of this subject, see 6.) Let me summarize now very briefly the cigarette filtration technology. The cigarette smoke one sees is composed of billions of liquid aerosol particles generally in the range of 0.1 to 1 p in diameter. If one passes such smoke through a Cambridge filter made up of very fine glass fibers, essentially all of the aerosol or particulate phase of cigarette smoke is removed from the stream. That part which passes through the filter is known as gas phase smoke. Since the original smoke contains many low-molecular-weight chemical compounds of high vapor pressure, these constituents are partitioned between the liquid particle phase and the gas phase. I t is not surprising then that in analyzinz the gas phase passing through the Cambridge filter, one finds some compounds which are also found in the particulate material picked u p by the Cambridge filter. For example, passing gas phase smoke through a Cambridge filter loaded with particulate phase material “scrubs out” some of the gas phase constituents. Cigarette filters on products in the marketplace are essentially of two types. One is composed of a fibrous substrate, usually cellulose acetate fibers, to which the smoke particles adhere when brought into contact by impaction or diffusion. This filter is generally not 10
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selective in its action, except for the gas-liquid partition effect and for a very few vapor phase substances which are highly soluble in the filter material. Phenol in cellulose acetate is the most notable of these exceptions. It is completely miscible with cellulose acetate. Otherwise, the conventional fibrous cigarette filter removes mainly particulate smoke to a greater or lesser extent, depending upon the usual parameters involving such items as fiber diameter, filter construction, flow rates, and pressure drop ( 4 ) . Aerosol filtration of cigarette smoke is, essentially, a nonselective physical process. T o the best of our knowledge, cigarette smoke particles in a given puff are all of the same composition. They must have differences in composition when they first start as condensation nucleii, but by the time they have grown to a micron in size by further condensation and coalescence, they are to all intents and purposes the same. Chemical analysis of the particulate phase taken out with a Cambridge filter, or of the total smoke condensate collected with a cold trap, has revealed the presence of about 1000 known chemical identities. We estimate that there may be another 10,000 found when our analytical tools become sufficiently sophisticated. This situation is not surprising when you stop to think of it. Tobacco i s a complex agricultural product containing hundreds of compounds. In the cigarette, these are subject to temperatures from ambient to over 1000°C with varying proportions of oxygen and nitrogen present. Needless to say, the chemistry of chemical breakdown and formation in the burning cigarette is horrendously complicated. The second type of commercial cigarette filter contains a gas phase adsorber such as activated charcoal. These filters generally remove volatile organic and some inorganic substances in the gas phase, depending upon the characteristics of the adsorber, the filter design, the flow rate, and the capacity of the limited amount of material which one can get into a filter of cigarette dimensions. Activated surface adsorbers do have some selectivity depending upon those pertinent factors such as pore size and surface area which have been fairly
Modification of cigarette filters raises questions concerned with reported health hazards of cigarette smoke and the psychological makeup of the smoker
completely described by the physical chemist. It is possible, therefore, to make some limited choices about the type of activated charcoal which one might use in a cigarette filter, depending upon what one wishes to emphasize in gas phase removal ( 3 ) . The really serious problem for the tobacco scientist, however, is not only how to remove selectively but what to remove. Obviously, highly efficient filters will remove much of what is in cigarette smoke leaving nothing for the smoker. Such products are on the market today; their total sales are less than 1%. TO make a marketable product, therefore, we must be interested in selective removal of certain substances from smoke, preserving in smoke those desirable elements which attract a large smoking public. For example, particulate smoke contains substances which soften the taste and harshness of gas phase smoke. Extensive reduction of particulate smoke, therefore, without gas phase modification is definitely not good. If we depend on chemical properties to remove selectively, we find ourselves dealing with whole classes of compounds, such as acids, or bases, with little chance of individual compound selectivity. Out of the thousand known constituents in smoke, the selective removal of some presents a very difficult problem which will require a tremendous scientific effort. Because we are in the cigarette business, we must deal with filtration. Cigarettes are enjoyed by many people, providing them with pleasure, release from tension, mental stimulation, and social relaxation. The large market for filter cigarettes exists because of public demand, since nonfilters are still very readily available. Hence, research on cigarette filtration is an important part of our program. What then should be the direction of this research?
R. R. Wakeham since 7964 has been Vice President Corporate Research and Development for Philip Morris, Inc., Richmond, Va. 23206. Dr. Wakeham is responsible f o r all basic and abplied research and for new consumer products development. AUTHOR Helmut
The field of total particulate removal has been covered. There is left selective filtration. Presumably the object of this research is to find a way to relieve the statistical association between smoking and health. Selective filtration assumes the presence in smoke of specific ingredients which act as causative agents of those diseases associated with cigarette smoking. If this hypothesis is wrong, we are working in vain; we are aimed in the wrong direction. In pursuing this question, we have had occasion to examine the. biomedical studies on smoking and disease and to search for clues on those constituents which one should attempt to eliminate from smoke. And here is where the trouble really begins. During the past 20 years, millions upon millions of dollars worth of effort have been expended in trying to discover guilty chemicals in smoke, to establish plausible mechanisms whereby smoking could in fact cause any human disease. After all this, we have not found anything definitive. We are faced with the situation that the cigarette causation hypothesis is not adequate to explain the statistical association. Here are some specific points : (1) Human-type lung cancer has never been produced in the lungs of experimental animals by inhalation of cigarette smoke, even though it has been produced experimentally by inhalation of other suspected agents ; (2) the production of cancers by painting artificially prepared smoke condensates on mouse skins does not parallel the exposure of man to smoke; (3) the quantities of suspected chemicals in smoke are too low to account for the incidence of disease expected from statistical data on the association of smoking to disease in man; (4) some anomalies exist with the human system which raise serious doubts about the hypothesis : (a) Ten to 20y0 of lung cancer in man occurs in nonsmokers and is indistinguishable from similar lung cancers in smokers; (b) cancers of the oral cavity (the mouth, the larynx, and the trachea) have not increased in proportion to cancer of the lung as one would expect from the exposure to smoke sustained in these areas; (c) suspected ingredients in cigarette smoke are present VOL. 6 1
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in much greater quantity in pipe smoke, but pipe smokers who inhale have disease rates similar to those of nonsmokers; and (d) studies of heart disease and mortality rates in identical twins show no difference between the smoking twin and the nonsmoking twin. T h e cigarette causation hypothesis fails to account for these observations, as well as other observations which I will cite later. When a hypothesis cannot be reconciled with the facts, then science demands that a better explanation be sought. There is an alternative to the cigarette causation hypothesis which has received far too little attention. It is one which says that when people are grouped as smokers and nonsmokers, there is a greater concentration of susceptible, or high-risk people among the smokers. People differ in their susceptibility to hazards such as accidents, injury, and illness. Physicians and psychologists have long known there are accident-prone people and illness-prone people. One can think of a risk scale; people susceptible to hazards would be placed high on the scale; people less susceptible would be placed low on the scale. The “susceptible person” hypothesis holds that the susceptible, high-risk people find cigarette smoking gratifying and are therefore present in greater numbers among cigarette smokers than among nonsmokers. There is a growing body of observations which supports the “susceptible person” hypothesis. I will now cite some of the more striking of these observations. PROPOSITION A: CERTAIN PEOPLE WHO EXPERIENCE HIGH LEVELS OF TENSION AND ANXIETY, AND PEOPLE SUBJECT TO MORE DISTRESSING INNER EMOTIONS ARE MORE LIKELY THAN OTHERS TO FIND CIGARETTE SMOKING GRATIFYING.
SUPPORTING EVIDENCE FACT1. I n 1968, a research team of the Tavistock Institute of Human Relations in England concluded a study of approximately 2500 people with this statement: “We have found that the most persistent precondition for smoking is a high degree of experience of emotion which is seen as disturbing by the individual” (7). FACT2. A 1968 paper, published by the Midtown Manhattan Study, reported that people who smoke are characterized by “a high level of tension and anxiety,” resulting in “a special adult susceptibility to overdependence on tobacco’’ (14). FACT3. An extensive medical study of 10 classes of medical students a t Johns Hopkins University (1968) concluded that heart rate and anxiety level were the two factors that most clearly distinguished the smokers from the nonsmokers, with heavy smokers exhibiting 12
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the fastest heart rate and admitting to the most anxiety (77). FACT4. A number of psychological studies, using such standard tests of psychological adjustment as the Minnesota Multiphasic Personality Inventory (73), the Cornel1 Medical Index (7), the California Psychological Inventory (15), and the Taylor Manifest Anxiety Scale (70) report a greater incidence of smoking among people showing the higher degrees of psychological maladjustment. FACT5. Lawton and Phillips (7) have reported a much higher incidence of smoking among psychiatric than among nonpsychiatric patients. Also heavy smokers of another study presented a higher number of somatic and psychological complaints (9). PROPOSITION B: SOME PERSONALITY TYPES FIND SMOKING MORE GRATIFYING THAN DO OTHER PERSONALITY TYPES.
SUPPORTING EVIDENCE FACT 1. Studies in which standard personality tests-e.g., Rorschach Ink Blot Test ( 7 7 ) and GuilfordZimmerman Temperament Scale (5) have been employed-report that smokers consistently test out as more extroverted, more gregarious, more impulsive, more “acting-out” in behavior than nonsmokers. FACT 2. I t is reported that extroversion increases with progression from the nonsmoker to the light, to the medium, and finally to the heavy smoker ( 2 ) . FACT3. An increasing percentage of people whose behavior was characterized by enhanced competitiveness, drive, aggressiveness, and hostility, and an excessive sense of time urgency was found among smokers contrasted with nonsmokers (79). PROPOSITION C: A SELF-INDULGENT, EXCITEMENTORIENTED, RESTLESS STYLE OF LIFE IS MORE CHARACTERISTIC OF THE SMOKER THAN THE NONSMOKER.
SUPPORTING EVIDENCE FACT 1. There are more beer drinkers, whiskey drinkers, and heavy coffee drinkers among smokers than among nonsmokers (70). FACT2. The incidence of smoking is much higher in the business world than in the nonbusiness world ( 7 1). FACT3. Cigarette smoking is more frequent among divorcees, job changers, residence changers, and nonchurchgoers (8, I S ) . FACT4. Death from accident, suicide, and violence is higher among smokers than among nonsmokers (20). FACT5. The incidence of smoking is greater among those drivers with records of accidents than among those with records of no accidents (70).
FACT6. Injury is higher among smokers than nonsmokers, with the rate increasing with increased smoking rates (78). PROPOSITION D: THERE IS A HIGHER INCIDENCE OF CIGARETTE SMOKING AMONG THOSE WITH THE MORE STRESSFUL AND TURBULENT HISTORIES IN FORMATIVE
YEARS. SUPPORTING EVIDENCE FACT1. Heavy smokers among high school seniors had poorer family relationships than nonsmokers (72) FACT2. Adult smokers report greater dissension with parents during adolescence than nonsmokers (14).
I have cited some obvious psychosocial indications that smoking is associated with “high risk” people. From the foregoing observations, it is a logical step to the “susceptible person” hypothesis. This reasoning coupled with the serious failure of a massive program of biomedical research to produce confirmation of the cigarette causation hypothesis, provides adequate basis for an extensive program of investigation of this alternate hypothesis. Verification or rejection of the “susceptible person’’ hypothesis is possible with modern experimental methods and tools. There are those who say it has already been tested and found wanting. Not surprisingly, they are those dedicated to biomedical tests aimed at establishing the cigarette chemical causation hypothesis. For them the controversy is closed. And yet there are many people who enjoy the benefits and pleasures of smoking and who do not wish to be needlessly frightened by persons trying to impose their views on others. For them, and for the sake of objectivity, there are three studies bearing on the “susceptible person” hypothesis which should be undertaken: (1) The extent to which a person’s background and style of life contribute to his health and mortality experience should be determined by a multivariate analysis of data in a roster of a large cross-section of the adult population. Such a data bank already exists. I t contains information relative to such items as age, weight, height, alcoholic beverage consumption, occupation, education, marital status, nationality of birth, race, sex, disease, mortality, and smoking habits. With modern computers, a multivariate analysis of this information would not be a difficult task. I n this way, we could find out if variables other than smoking habits relate significantly to health factors. (2) With the same or similar data a second useful study would be to carry out a rigorous matched-pair analysis. I n this study people with similar characteristics would be matched into pairs in which the partners of the pair would constitute a smoker and a nonsmoker.
Such a comparison would enable us to determine which partner has a disadvantage as far as disease and mortality experience are concerned. Obviously, the categories in which the matching is done must not be too broad; otherwise we would only observe the broad association already found. The study of identical twins is, of course, the ultimate in matched-pair analysis. (3) With new technologies in biochemical analyses, it should be possible to evaluate biochemical characteristics of smokers and nonsmokers prospectively and to determine whether a single biochemical variable or a group of variables could be used as predictors of morbidity or mortality experience. For example, it was suggested that smokers and nonsmokers differ in their basal metabolism rates. Such a program would represent a rather formidable undertaking. But the identification of disease-susceptible individuals by means of regular biochemical tests is a goal which promises far-ranging medical benefits. Research and development, in response to the statistical association between smoking and health, must cover all aspects of the problem if it is to be fruitful. And, of course, in the industry other approaches to the modification of smoke composition are being exploited. Engineered into the cigarette are such items as methods for diluting smoke, lowering coal temperature, treating tobacco, and changing the effects of cigarette paper in addition to modifications of the filter. All of these factors interact to influence responses of the smoker. It is no surprise then that the problem of the cigarette filter presents a dilemma far beyond the mere choice of a fiber or an activated charcoal. REFERENCES (1) Emery, F. E., Hilgendorf E. L
and Irving, B. L., Tobacco Research Council (London), Research Pape; 10, p”12, 1968. (2) E senck, H. J., ‘Smoking, Health and Personality,” Basic Books, New York, N. 1965. (3) George, T. W., and Keith C. H in “Tobacco and Tobacco Smoke ” E. L. Wynder and D. Hoffman, p;’ 577-222, Academic Press, New York, N. 1967. (4) Kiefer, J. E., and Touey, G. P., ibid., pp 545-75. (5) Lane N. E., Oberman A Mitchell R. E and Graybiel A NASA-CR75902,’NAMI-961, NASA Oyder R-138, W a d n g t o n , D. C., Aprii 27, 1966. (6) Larson,,P. S., and Silvette, H. “Tobacco: Experimental and Clinical Studies, Suppl. I, Williams & Wilkens’Co., Baltimore, Md., 1968. (7) Lawton, M. P., and Phillips, R. W., Amer. J. M e d . Sct., 232, 397-402 (1956). (8) Lilienfeld, A. M., J. Nut. Cancer Inst., 22, 259-82 (1959). (9) Matarazzo, J. D., Guze, J. D., and Matarazzo, R. G., J. A b . Soc. Psych., 51, 276-80 (1955). (10) Matarazzo, J. D., and Saslow, G., Psychological Bull., 57 (61, 493-513 (1960). (11) McArthur, C., Waldron, E., and Dickinson, J., J. Ab. SOL.Psych., 56 (2), 267-75 (1958). (12) Salber, E. J., and Rochman, J. E., Arch. Enuiron. Health, 8 , 459-65 (1964). (13) Schuberg, D. S. P., I n t . J. Soc. Psych., 1 1 , 221-5 (1965). (14) Srole, L., BulI. N . Y . h a d . M e d . , 44 (12), 1502-13 (1968). (15) Stewart, L., and Livson, N., J. Consult. PJych., 30 (3), 225-9 (1966). (16) Straits, B. C., and Sechrest, L., tbtd., 27, 282 (1963). (17) Thomas, C. B., Johns Hopktns M e d . J.,122, 69-76 (1968). (18) U. S . Dept. Health, Education, and Welfare “Cigaret Smoking and Health Characteristics,” Washington, D. C., U.S.F.H.S.’Pub. No. 1000, p 16, 1967. (19) U.S.P.H.S., 1968 Supplement, Pub. No. 696, 1969, “The Health Consequences of Smoking,” Washington, D. C., 1968. ( 2 0 ) U.S.P.H.S. Pub. No. 1103 “Smoking and Health. Report of the Advisory Committee t o the Surgeon Geheral of the Public Health Service,” p 102, Washington, D. C., 1964.
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