Tobacco Documents Online

A REVIEW OF: SMDKIIrj-REIAM DEATf1S ADID FINANCIAL CCQSTS (Of the Preli.annazy Draft Prepared by the Office of Technwlogy Assessment on May 10, 1985) T. Sterling, Pfa. D. A. Arundel, B.A. -J. Weinkan, D. Sc. Faculty of Applied Science and School of Canputer Science Si.mon Fraser Uizi..vvessity Btsnaby, British Colvmbi.a V5A 1S6 June•, 1985 *Dr. Sterling can be reached by phone at (604) 291-4685 (604) 733-1348 TIMN 308164

ACKNOWLEDGEMENTS We thank Mary Hehn, Ted Irwin, Wilf Rosenbaum and Mary Weinkam for valuable assistance in programming and manuscript preparation. TIMN 308165

INTRODIICTION The Office of Technology Assessment, at the request of Congressman Fortney H..(Pete) Stark, prepared an analysis of the "Financial Costs of Smoking" for the Subcommittee on Health of the House Ways and Means Committee, with special attention on the impact of smoking-related disease on the Medicare and Medicaid program. A workshop was organized by Karl Kronebusch and staff of the OTA on April 9 and resulted in a Preliminary Draft: Smokinq-Related Deaths and Financial Costs, of May 10, 1985. (We will refer to this document henceforth as the OTA Draft.) The OTA Draft estimates smoking-related deaths and the number of life-years lost due to smoking-related disease categories and discusses the health care costs and lost productivity costs for each category. Also planned was a discussion of how health care costs and costs of other social programs might change as a result of reduced smoking. Congressman Donald_Sundquist asked us to review the OTA Draft and the assumptions on which its calculations were based. In agreeing to do so, we intend to provide OTA staff with a constructive critical evaluation of the strength, weaknesses, and validity of the available database on which any estimates of costs will be based in the final analysis. in order to help reach a consensus we have asked a number of knowledgeable colleagues to comment on our review. These reviews will be passed on to OTA. We also intend to discuss our review with OTA staff and consultants. 1 . .~.~ 308166 TI

The OTA Draft bases estimates of attributable risk due to smoking on specific sets of data and procedures. There are a number of concerns about the suitability of the OTA methodology. The most important are: 1. The original data and the analysis used in the OTA Draft ignore the significant confounding between smoking and other factors that are associated with disease, especially hazardous occupations. The prevalence of smoking differs substantially for different occupations and is highest for those occupations where workers are exposed to toxic and carcinogenic materials. 2. Employment opportunities vary by the health status of individuals and so, of course, do mortality and years of In survival. Estimates of expected disease frequencies can only be made from populations with similar employment patterns. This effect has been called the 'healthy worker effect' for cohorts of employed workers or the 'volunteer effect' for cohorts of volunteers enrolled in studies on the effect of various risk factors on mortality rates. consequence, estimates of attributable risk due to tobacco use are riot valid if these estimates are derived from the comparison of populations that differ substantially with respect to employment patterns and occupational hazards, especially the possibility of exposure to toxic chemicals, dusts or fumes. A background discussion in Section I will deal with these two major variables that affect the attributable risks for 2 ,TIMN 308167

smoking. Both of these variables were neglected in the OTA Draft. Section II will evaluate the procedure used in the OTA Draft to compute the attributable risks of smoking and Section III will briefly review the frequency with which smokers and nonsmokers require medical care. Our final discussion in Section IV will deal with the assertj,o_n that smoking shortens the life span of smokers. There ar fve appendices that provide additional support to the discussion in the text. SECTION I: CONSEQUENCES OF CONFOUNDING 1. Smokinq Characteristics ~j Ty e of Employment Smokers are more likely to work in occupations with exposure to toxic dusts and fumes than non-smokers. This relationship, and the relationship between smoking and many other environmental and cultural factors, was noted by Haenszel (1956) almost 30 years ago. The basic confounding between smoking and.occupation and other potential risk factors means that many cancers that are attributed to smoking may in fact have occupational or other etiologies. The National Center for Health Statistics obtained information on smoking and occupation for members of 39,011 households in its yearly Household Interview Survey (HIS). This data was used by Sterling (1976; 1978a) to determine the prevalence of smoking by occupation. Table 1 compares 40 occupational categories with the highest smoking prevalence and 3 ,rIMN 308168

TABLE 1: Comparison of 40 Occupation Categories with the Highest and Lowest Smoking Prevalence Among White Males Prevalence Percent Type of worker Highest Lowest Highest Lowest 40 40 40 40 Blue collar 29 4 72.5 10.0 Service 9 7 22.5 17.5 White collar, Technical, Professional 2 29 5.0 72.5 and managerial Total No. of 40 40 100% 100% Occupations 40 occupations with the lowest smoking prevalence for white males. While 72.5% of occupations with the highest smoking prevalence are blue-collar, that is, exposed to hazardous work and toxic fumes and dusts with relatively high probability, only 10% of those with the lowest smoking prevalence fall into that category. Conversely, only 5% of occupations with the highest smoking prevalence but. 72.5% of occupations with the lowest smoking prevalence are white-collar, technical, professional or management occupations, that is, unlikely to be exposed to hazards, fumes and dusts at 'the work place. In fact, detailed inspection of occupations finds that those with high smoking prevalence also tend to be dirty and hazardous while those with low smoking prevalence tend to be clean and relatively free of 4 TIMN 308169

hazards. The HIS 1970 data was also used to compare the occupation of different series of smokers, nonsmokers, former smokers, smokers of regular and filter cigarettes, smokers who started early or late in life and of households with more or fewer smoking members. Figure 1 summarizes the results for whites. (The same observations hold for blacks.) The proportions along each horizontal line represents the percentage of individuals who are either blue-collar or have professional/managerial/proprietary, or other jobs. For example, for white males who smoked 20 or more cigarettes a day, 44.1% are blue-collar, only 6.2% are professional/management, and the rest are in other occupations. Of individuals who smoked between 10 and .19 cigarettes a day, 42.7% are•blue-collar and 5.8% professional/management. For nonsmokers, 37.5% are blue-collar while 10.9% are professional/managerial. As a consequence, any comparison of those who smoke with those who smoke less also compares groups with different proportions of individuals exposed to toxic . dusts, fumes, and hazardous conditions. It is not possible to determine the cause of a difference in mortality or morbidity between groups that differ with respect to smoking, without analysing the occupational distributions of the two groups. In short, it is not clear if smoking kills workers or working kills smokers. 5 , ViM.S 308170

TOTAL NUMBER ShIOKING FOR ALL PERCENT HABITS . OCCUPATIONS BLUE COLLAR Current Amount Smoked Smoke 20+ 8.951 Smoke 10-19 2,589 Smoke 1- 0 1,572 None 18,203 Smoking Ststus Never Smoked 9,694 Former Smokers 0.609 Type o/ ClQerette Smoke Rsyular 3,638 Smoke Fblter 8,778 Ape Surted Younger thin 20 9,E$5 Older than 20 1.744 i , 50.. 5.6 49.2 ' 9.9 143.2 10.8 . 11.0 E f Mothers of Intants - • Smok(n0 389 49.1 10•3 69.4 Not Smoktng 828 38.7 U.1 52.8 Houtehold Smokiny Husbsnd & Wl/e 2,701 Hutband Only 2,965 Wi/e Only 1,610 Ndther 6.391 f I 30.5 30.9 N.1 42.7 138.8 PERCENT PERCENT PROFESSIONAL OTHER OCCUPATION 41.8 , 41.3 I 41.9 50.3 48.6 46.2 46.9 3.9 7.2 141.8 43.7 133.3 27.0 u0 46.1 40.9 t 49.0 47.4 45.0 139.8 Figure 1. Cocnparison of proportions of blue-collar and professional workers in series of white males and within households headed by white mal.es, differentiated by smoking habit. Comparisons based ori data obtained during the 1970 Household Interview Survey of the U.S. National Center for Health Statistics. Each horizontal line represents the proportion of individuals.who are either blue-collar workers or professionals, managers, or proprietors. From Sterling, 1978b. 9 'I ~_A

Independent verification of our results comes from a study by Friedman (1973) which found that smokers enrolled in the Permanente Insurance Plan had occupations with much higher exposure to industrial hazards, especially fumes and dusts, than nonsmokers. There is also independent verification that when smoking and occupational effects are explored in occupational health studies, the observed effect of smoking often is much diminished or entirely lacking compared to the effect of occupation. In fact there are a number of studies in which the relative risk and sometimes the absolute risk for nonsmokers exceeds that for smokers. (See for instance Axelson 1978, Dahlgren 1979, Pinto 1978, Wagoner 1975, Weiss 1976, 1980 and the discussion in Sterling 1983.) Occupational effects become even more complex and perhaps more important when differences between blacks and whites and the sexes are considered. Black lung cancer mortality rates are significantly higher than the rates for whites, with a 1976 age-standardized rate per 100,000 of 93 for black males compared to 63 for white males and 19.5 for black females compared to 17.4 for white females (NCI, 1978). The difference cannot be attributed to smoking, as even though fewer blacks than whites are exsmokers, more blacks are never smokers and black smokers consume fewer cigarettes than white smokers (Sterling, 1978a). The difference in mortality rates by race is probably partly a result of differences in occupational exposures. Boucot (1970) 7 0 ,VIM-S 308172

noted that almost twice as many blacks were employed in jobs with an increased cancer risk compared to whites; 22.6% versus 13.5%. Similar results were found by Mancuso (1975). Women are exposed to hazards at work-as well as in the household. (We consider housework as an occupation.) Housewives tend to smoke approximately as much as other women and, at the same time, they are exposed to a variety of hazards, such as solvents or combustion byproducts from gas stoves&hich ~ represen more than a trivial source of toxic and carcinogenic materials ( terling 1979a; 1981). Also, as shown in Figure 1, there is a strong association between the number of women and men smokers in the household 4nd the occupation of the husband. A large number of women who smoke also.have a blue-collar family background and may be exposed not only to hazards at work on their own but also to toxic materials brought home from work on the hair, skin and clothing of their spouses. The distribution of smoking by occupation (and consequently also by socioeconomic class) indicates that the occupation of the smoker is one of the'variables that must be included in any, evaluation of attributable risks. All cancers presently associated with smoking are also associated with occupation, such as cancer of the esophagus, bladder, pancreas and oral cavity, but especially of the lung. Yet, the effect of occupation is not considered in most of the studies on which the OTA Draft report is based. The OTA's own estimates for the attributable risk for cancer and heart disease did not consider 8 t TIMN 308173