Tobacco Documents Online

52 I 1 I priori knowledge of potential confounders (i.e., by age even if it had not shown up as confounder in the data) (Greenland 1989) were used in model building. Concomitant variation in the stratified analysis step was assessed contrasting the rates of lung cancer among ETS unexposed non-smokers to k categories of ETS exposed non-smokers. Ordinai variables were created from categories of dummy variables to test the hypothesis of increasing rates by increasing levels of exposure to ETS using the likelihood ratio test. We treated k number of categories of cumulative exposure (i. e., k categories of number of hours exposed to ETS, or pack-years of cigarettes smoked by spouses), as continuous variables. Adjustment for covariates was allowed in testing this hypothesis by blocking for them. Regression diagr~ostics used include plotting survival curves [log -log (S l(t)) and log -log(S0(0] and checked for a pattern of parallelism (a constant ratio). For most analyses the estimates were obtained by blocking for them, rather than including them in the model However, when estimates were obtained for the covadates, all of them along with the main exposure were included in the model. Kaplan-Meier survival estimates were computed for the main exposure variables, as well as the covariates and the above mentioned graphic approach was used to check for the proportional hazard assumption. 3.11. Sample Size and Power Considerations The statistical power attained by the sample size of this study to detect different values of the rate ratio, including the point estimates from this study, was computed using the following estimator that assumes the rate ratio is a binomial parameter (Breslow 1987): 0 O~ 01 -0 0 I I I I I I I I

53 I I I I I I I I I I I I I I t-3=t-O(A)= where XA is the most extreme value in the acceptance zone under the the null hypothesis. One way of estimatin~ XA is by using the beta distribution with parameters 1- (z and tho expected number of exposed and unexposed cams under the null.

54 Chapter 4: Comparisons of Demographics and Smoking Habits in the US, CPS II, and the Study Populations Rationale A comparison of the 1980 US population with the CPS II population and specifically with the two analytic cohorts (i.e., 1) self-reported ETS and 2) spousal ETS by gender, age, race, occupation, education, geographic residence and smoking habits, is presented below. We used the population figures from the 1980 US Census as standard for age-adjustment, unless specified otherwise, because it was the Census closer in time to the cohort at the time of enrollment. Therefore, we excluded for the purpose of these comparisons those CPS II participants who resided in Puerto Rico, since they were not included in the 1980 US Census. Comparisons with the 1983 National Health Interview Survey (US DHHS Surgeon Genera/1989) figures are a/so presented. These comparisons lend a general perspective to better understand the analytic cohorts, and particularly to generate a profile of the demographics and smoking habits of the subjects in the study cohorts. Race Demographic information in the US is available by 'race'. Race is a proxy of socioeconomic status and was used here for the purpose of demographic comparisons. Twelve percent (or 26 million) in the US are blacks. In CPS II they represent 4.4 percent (or 52,038) of the participants. For these masons, further comparisons of demographics were restricted to whites. Gender and Age Structure The ratio of males to females (or gender ratio) in CPS II is considerably lower (0.75) than that among persons 30 years and older in the 1980 US Census 0 I I I I I / I

I I I I- I I I I I I I I I I I I I I 55 (0.88). Participants in this larg~ cohort were more likely to be in their 50's 60's at enrollment (Tables 5 and 6). Nonsmoking men and women (i.e., in our analytic cohorts) did not differ in their age distribution from the entire cohort (median 57 years in both groups). I Table 5. Comparison of age distributions of white males 30 years and over, in the US population in 1980, with CPS II participants*, .................. andI analytic c, ohorts* ..... Men Age 1980 Entire Self- Husbands Group Census % CPS II % reported % (spousal % 30-34 7,386,562 16.1 7,610 1.6 3,078 3.0 1,126 1.2 35-39 5,848,891 12.7 9,270 1.9 2,890 2.8 1,875 2.0 40-44 4,862,473 10.6 15,052 3.2 3,890 3.7 3,.286 3.4 45-49 4,616,347 10.1 6~,776 14.4 l 7,079 16.4 16,003 16.8 50-54 4,925,489 I0.7 87,030 18.2 19,14I 18.4 18,480 I9.4 55-59 4,877,635 10.6 91,236 19.l 17,647 16.9 16,893 17.7 60-64 4,199,446 9.1 79,344 16.6 15,804 15.2 15,306 16.0 65-69 3,470,295 7.6 58,162 12.2 11,861 11.4 11,406 11.9 70-74 2,565,929 5.6 35,487 7.4 7,069 6.8 6,534 6.8 75-79 1,652,668 3.6 17,045 3.6 3,687 3.5 3,206 3.4 80-84 918,166 2.0 5,909 1.2 1,361 1.3 1,029 1.1 85+ 603,663 1.3 ~.419 0.5 624 0.6 330 0.3 Total 45,927,564 I00 477.340 i00 104,131 100 95,474 100 *Excludes CPS II participants who resided in Puerto Rico

56 Table years and over, in the US population in 1980, with CPS II I I I I I ! I ! ! ! 6. Comparison of age distributions of white females 30 participants*, and analytic cohorts* Women Age 1980 Census Entire Self- Wives Group % CPS H % reported % (spousal % ETS ETS) 30-34 7,411,223 14.2 I 1,764 1.9 5,591 2. I 2,971 1.5 35-39 5,949,670 11.4 18,831 3.0 7,579 2.9 5,753 2.8 40-44 4,981,237 9.5 44,595 7.1 18,241 6.9 16,858 8.3 45-49 4,807,473 9.2 91,972 14.7 37,349 14.2 34,006 16.8 50-54 5,249,428 I0.0 106,175 17.0 43,434 16.5 38,805 19.2 55-59 5,409,320 I0.3 107,900 17.2 43,756 16.7 38,098 18.8 60-64 4,826,403 9.2 92,102 14.7 38,274 14.6 30,949 15.3 65-69 4,344,316 8.3 68,889 11.0 28,367 10.8 19,637 9.7 70-74 3,562,454 6.8 44,568 7.1 19,731 7.5 10,295 5.1 75-79 2,667,233 5. I 23,892 3.8 11,736 4.5 3,866 1.9 80.84 1,756,793 3.4 9,916 1.6 5,366 2.0 881 0.4 85+ 1,400,053 2.7 5,350 0.9 3, I65 1.2 160 0.1 Total 52,365,603 100 625.954 I00 262,589 100.0 202,279 100 *Excludes CPS rr participants who resided in Puerto Rico Occupation The types of occupations presently held by CPS H employed white participants were categorized into white and blue collar occupations. Managerial and professional specialty occupations, technicians and related support occupations, sales occupations, and administrative support occupations including clerical represented white collar occupations. Precision production, craft, and repair occupations, operators, fabricators, and laborers were classified as blue collar occupations. For these comparisons we excluded subjects with the following occupational codes in CPS II: housewives, disabled, retired, and subjects with none or unspecified data on occupations. I i I I

I I I I- I I I I I I I I I I I I I I 57 CPS II participants were more likely to be engaged in white collar occupations (Table 7). White women in CPS II were more likely to hold white collar jobs than white men, in a higher proportion than their counterparts in the entire US population do. Nonsmokers di~ not differ from the entire cohort with respect to their occupations. Table 7. Comparison of occupations of employed white persons 30 years and over, in the US population in 1980, in CPS II participant*, and analytic cohorts* a. Men 1980 Entire Type of Census CPS 17 Jobs (%) f (%) White Collar 18,I65,788 200,612 (55.8) (73.7) Blue Collar 14,409,714 1 71,718 (44.2) (26.3) Total 32,575,502 272,330 (100.0) (100.0) Self-reported Husbands ETS (spousal (%) ETS) (%) 47,889 43,901 (74.3) (73.7) 16,573 I5,684 (25.7) (26.3) 64,462 59,585 (100.o) (IOO.O) b. Women 1980 Entire Self-reported Wives Type of Census CPS II ETS (spousal Jobs (%) I (%) (%) ETS) (%) White Collar 18,464,642 221,093 91,700 70,404 (84.8) (94.6) (94.3) (94.5) Blue Collar 3,299,972 I 12,553 5,518 (5.7) 4,137 (5.5) (15.2) (5.4) Total 21,764,614 233,646 97,218 74,541 (lOO.O) (lOO.O) (ioo.o) (ioo.o) *Excludes CPS II participants who resided in Puerto Rico 0 Ol 01

58 Schooling Nonsmoking CPS IT men and women were more educated than smokers in CPS II as is also true for the rest of the US population, as reflected by their considerably higher rates of college graduates (Table 8). The entire CPS II cohort, after adjustment for age is also more educated than the US population as a whole (28% of college graduates in CPS II women versus 12% in the US populations over 30 years of age). Nonsmoking men in the analytic cohorts (in the cohort for analyses of self-reported ETS and among nonsmoking husbands for analyses of ETS from spousal smoking) were more educated than the rest of the CPS rr men. Table 8. Comparison of the proportion (%) of college graduates among whites in the US population in 1980, CPS II participants§, and analytic cohorts§ I- Men -I I- Women -I Age US CPS II SRETS Hus- US CPS II SRETS Wives • ga~o~ up .... C.ensus ~[ bands Census q[ 30-34 31.5' ' 49.~' 62.5 66.0 21.4 40.4 47.1 43.7 35-39 27.7 48.4 61.1 64.3 17.2 34.9 39.9 37.9 40-44 23.6 43.8 56.7 56.6 13.6 30.8 32.0 31.3 45-49 22.6 46.2 56.9 56.5 11.6 28.9 28.8 28.4 50-54 19.7 43.1 53.1 52.4 10.3 26.6 25.3 25.0 55-59 t 7.0 39.0 47.6 47. I 8.5 23.0 21.7 21.4 60-64 13.2 32.6 40.0 39.8 8.2 21. I 20.3 20.6 65-69 11.4 27.1 32.9 33.2 8.0 20.8 20.0 20.5 70-74 II.I 26.1 30.2 30.9 8.5 22.4 21.1 22.2 75+ 9. I 24.8 27.8 30.0 6.7 21.2 13.0 20.3 Adjusted 20.6 40.4 50.1 51.0 12.0 27.9 28. I 28.2 § Excludes CPS II participants who resided in Puerto Rico ~ SRETS: Serf-reported ETS cohorts * The standards are taken from 1980 US Census race-gender specific populations 0 0"~ O- I I I I i I ! I I I I I I

59 I I I I I I I I I I I I I I I Marital Status As shown in table 9, CPS I1 participants were more likely to be married than the rest of the US population, a fact that may be related to their more affluent status and the way they were enrolled. There were more unmarried women, and particularly single women in CPS II than unmarried men. This difference may be explained by a more active participation of women in recruiting people (i.e., ACS volunteers), whereas the men ~ere more likely to get enrolled in CPS 11 as members of family ~oups. Table 9. Comparison of the proportion (%) of married whites in the US population in 1980, white CPS II ..~ partieipants§~ and lanalytie cohorts.§ Men Women Age group US CPS 1I SRETS US CPS II SRETStJ[ __ Census ~ ~[ Cens~us _ . .................. 30-34 77.4 62.4 60.61 79.4 67.4 67.6 35-39 83.5 80.7 77.2 82.0 82.3 82.4 40-44 85.8 91.3 90.4 82.8 91.4 92.4 45-49 86.6 95.9 95.7 82.2 88.6 90.9 50-54 86.5 96.4 96.5 79.6 87.0 89.1 55-59 86.8 96.8 96.6 75. I 83.3 85.9 I 60-64 86.3 96.7 96.8 ' 67.2 77.0 79.9 65-69 84.2 95.9 96.2 56.2 65.7 68.4 70-74 80.8 94.2 94.3 43.6 51.7 54.3 75-79 74.8 90.8 91.7 30.1 35.3 36.2 80-84 65.3 83.2 83.6 17.9 19.8 19.9 85+ 48.8 62.0 60.8 : 8.3 7.9 7.7 Age 82.8 87.3 86.5 67.9 71.8 73.3 Adjusted* §Excludes CPS II participants who resided in Puerto Rico ~ SRETS: Self-reported ETS cohorts * The standards are taken from the 1980 US Census race-gender specific populations

6O I Residence The distribution of the CPS II by territory in general resembles the distribution of the US population (Table I0). A few States in the South (e.g., Texas, Oklahoma), the Mid-West (e.g., Missouri) and the North-East (e.g., New York) showed a deficit with respect to the distribution of the US population. Two States, Minnesota and Utah, had an outstanding participation rate, reflecting the activities of the ACS Divisions and perhaps the advancement of public health in those communities. Smoking Habits The age-adjusted prevalence of smoking habits in CPS lI and the 1983 HIS is shown in Table 11. Prevalence fi~mares of smoking habits in CPS 1I are similar to those of the US population by 1982. ~0 0 0~ I I ! I I I I I <1 I :~1 I '1 I I

I I I I I I I I I I I I I I I I I I Table State US Alaska 0.2 Arizona 1.2 Arkansas 1.0 Caiifomia 10.5 Colorado 1.3 Connecticut 1.4 Delaware 0.3 D.C. 0.3 Florida 4.3 Georgia 2.4 Hawaii 0.4 Idaho 0.4 Illinois 5.0 Indiana 2.4 Iowa 1.3 Kansas 1.0 Kentucky 1.6 Lousiana 1.9 Maine 0.5 Maryland 1.9 Masss 2.5 Michigan 4. I Minnesota 1.8 Mississippi I. I Missouri 2.2 10. US population in 1980, and CPS II by State of residence cPS rrI Men Wamen 1,7 1.8 0.I 0.I 1.4 1.4 1.3 1.3 8.7 8.9 1.2 1.2 1.7 1.7 0.3 0.3 0.1 0.i 4.8 4.9 2.6 2.6 0.2 0.2 0.6 0.5 5.6 5.6 2.8 2.8 1.5 1.4 1.5 1.5 1.5 1.6 0.9 1.0 0.6 0.6 2.8 2.7 2.0 2.0 3.8 3.7 3.2 3.0 0.9 0.9 1.3 1.3 participants* CPS II State U S Men Women Montana 0.4 " 0.4 0.4 Nebraska 0.7 I. 1 1.0 Nevada 0.4 0.2 0.2 N Hamp. 0.4 0.4 0.4 New Iet~ey 3.3 3.7 3.7 New Mcx 0.6 0.5 0.5 New York 7.8 5.8 6.0 NCarolina 2.6 1.8 1.8 N Dakota 0.3 0.6 0.5 Ohio 4.8 4.5 4.5 Oklahoma 1.3 0.0 0.0 Oregon 1.2 1.3 1.4 Penn 5.2 6.4 6.5 R Island 0.4 0.7 0.7 S Carolina 1.4 1.2 1.3 S Dakota 0.3 0.6 0.5 Tennessee 2.0 2.6 2.7 Texas 6.3 4.6 4.5 Utah 0.6 2.0 1.9 Vermont 0.2 0.2 0.2 Virginia 2.4 2.7 2.8 Washington 1.8 1.8 1.8 W Virginia 0.9 1.0 I. i Wisconsin 2.1 2.7 2.6 Wyoming 0.2 0.2 0.2 *Excludes CPS II participants who resided in Puerto Rico 61 I