773 



436 



AMERICAN REVIEW Of RESPfRATORY DISEASE VOL 148 1993 



lube. The specimens were frozen ai -20* C uniil the cotintne assays were 

 performed, within 6 months of collection. The assays were performed with- 

 out Knowledge of the reported smoking status. 



Cotinine Assay 



Cotinine was quantified by double-anftbody radioimmunoassay, as de- 

 scnbed by Langone and coworKera (7). A specific antiserum produced 

 in rabbits was supplied by Or Helen Van Vunakis (Brandeis university), 

 and all assays were performed at the University of New Mexico (8) Saliva 

 samples were diluted 1:2 or 1:5 for the assay, and an equal quantity of 

 saliva from a person not exposed to tobacco products was added to each 

 standard. The sensitivity of the assay in our hands was 36 pg/tube or 0.78 

 ng/ml saliva (4.204 pmol/L). intraassay coefficienis of variation were 71. 

 4 0. and 9.6% at low. middle, and high concentrations of cotinine stan- 

 dard, respectively, and interassay coefficients of vanatjon were 15.7. 10.2. 

 and 8 4ivt) at low. middle, and high concentrations of cotinine standard, 

 respectively. 



Statistical Analysis 



The present analysis included participants 18 yr of age and older, reganl- 

 lesa of ethnicity, who identified themselves as current smokers, defined 

 as smoking cigarettes within 6 months of the intenrtew. Subjects using 

 cigars, pipes, snuf t, or chewing tobacco were excluded t>ecause the use 

 of these products elevates cotinine andfor carbon monoxide levels. We 

 also excluded manjuana smokers because of the potential for elevated 

 carbon monoxide levels. 



We obtained information on current cigarette brands, types of ciga- 

 rettes currently smoked (nonfilter, filter, or rolled own), cigarette length, 

 and number smoked per day. For each cigarette brand, type, and length, 

 we matched available FTC data lor 1984 and 1985 on cigarette yields of 

 tar. nicotine, and cartwn monoxide (9. lO) with the self-reported cigarette 

 information. Because respondents frequently claimed cigarette lengths 

 that were not possible, we assigned them the closest length available 

 from the FTC tables. We also ascertained inhalation patterns dunng smok- 

 ing by asking whether the subject inhaled into the mouth only, into the 

 back of the throat, into the top ot the lungs, or deeply into the lungs. 



To assess determinants of levels of cartxjn monoxide and salivary coti- 

 nine and numbers of cigarettes smoked daily, we calculated Spearman 

 correlation coefficients ar 1 used multiple linear regression. Dependent 

 variables for the regression analysis included cartxin monoxide level, coti- 

 nine level, and current numt»r of cigarettes smoked per day as continu- 

 ous vanables. The independent factors included current number of ciga- 

 rettes smoked par day as a continuous variable and. as categoncal 

 vanables. sex. age (below or atsove 50 yr). ethnicity (Hispanic or non- 

 Hispanic), time since last cigarette (less than i h or 1 h or more). ar>d 

 inhalation patterns (into top of lungs or deeply into lungs versus into mouth 

 only or into back of throat). 



Data analyses were performed with standard pnjgrams of the Statisti- 

 cal Analysis System (11). 



RESULTS 



A Iota! of 298 current smokers. 39.5% males and 60.4% females, 

 hat] sufficient data available for this analysis (table 1). An addi- 

 tional 51 smokers were excluded because they were currently 

 using marijuana (n » 39) or other tobacco products (n = 12). Of 

 the available smokers. S'.5% ot the males and 92.2% of the fe- 

 males virere Hispanic. The remaining 24 smokers were non- 

 Hispanic whites. For the Hispanic and non-Hispanic males, mean 

 ages were 465 and 44.1 yr. respectively Mean ages for the fe- 

 males were 39.9 and 3S.7 yr, respectively. 



In contrast to the 298 smokers included in this analysis, the 

 51 smokers excluded were largely male (68.6%) anj younger, with 

 mean ages of 36.3 yr for males and 25.9 yr for females. The aver- 

 age numbers of cigarettes smoked per day by those excluded were 

 21.2 and 15.7 for males and females, respectively. 



Although 298 smokers were included, the numbers of subjects 

 available for the variotjs analyses varied widely. Information on 

 numbers ol cigarettes currently smoked, current cigarette brand, 

 and current cigarette length were obtained from 96.3. 99.0. and 

 98.0% of the subjects, respectively. Based on this information we 

 were able to determine FTC tar and nicotine yields for 80.2%. Be- 

 cause of incomplete FTC data on cartx>n monoxide yields, how- 

 ever, we were able to determine this value in only 470% of the 

 smokers. Salivary cotinine levels were available for 89.6% and 

 end-expired cartron monoxide levels in 983% ot the subjects. 



Patterns of reported smoking and levels of biomarkers varied 

 between males and females and between Hispanics and non- 

 Hispanics (table 1). For both ethnic groups, females smoked fewer 

 cigarettes per day than males, and on average Hispanics smoked 

 fewer cigarettes per day than non-Hispanics. Except for Hispanic 

 males. 90.0% or more ot the subjects smoked filter cigarettes. 

 Among Hispanic males. 81.1% smoked cigarettes with high tar 

 contents (15 mg or greater) compared with 63.4% of Hispanic fe- 

 males (figure 1). Similarly, for selt-reports on depth of inhalation 

 of cigarette smoke, a higher proportion of Hispanic males (45.4%) 

 reported inhalation deeply into the lungs than Hispanic females 

 (23.2%). Although the subject numbers were much smaller, simi- 

 lar smoking pattemswere observed lor the non-Hispanics. As for 

 the self-reports on cigarette smoking practices, sutistantial differ- 

 ences were observed for levels of salivary cotinine and end-expired 

 carbon monoxide among the sex and ethnic groups. 



Spearman correlation coefficients were used to examine the 

 relationships among the various measures of exposure to ciga- 

 rette smoke. The correlation was highest between salivary coti- 



MEASURES or CIQARETTE SMOKE EXPOSURE AMONO CURRENT SMOKERS 

 FROM A NEW MEXICO SAMPi-E. 19M TO 1965 



