Validity of smokers' information about present and past cigarette brands--implications for studies of the effects of falling tar yields of cigarettes on health.

Abstract

Four hundred and twenty nine current smokers and ex-smokers who had provided details 12 years previously completed a self administered questionnaire about their present and past smoking habits, and two weeks later current smokers supplied an empty cigarette packet. The tar group and brand name of the current cigarette given on the questionnaire were compared with details on the packet, and the brand alleged to have been smoked 12 years ago was compared with that actually recorded at that time. Only 55% of "low middle" tar cigarettes as indicated by returned packets had been correctly identified in the questionnaire. The ing brands on health may have to collect information on brands on the basis of recall over a long period because of the time taken for some effects to become apparent. For example, Fletcher et al'8 showed that at least eight years of follow up is needed to distinguish even between smokers and ex-smokers on the basis of lung function tests. Moreover, the validity of information about current cigarettes smoked (type, tar group, or brand name) has never been established, for example, against the details on the packet.In this paper we assess the validity of smokers' information about present and past cigarette brands and discuss the implications of the results for past and future studies of the effects of the falling tar yields of cigarettes on health. MethodThe Heart Disease Prevention Project was a randomised controlled trial of the benefits to middle aged men of mounting a preventive campaign in industry. 19 At the start of the study in 1971-3 a self administered questionnaire was used to obtain data on the type and brand of cigarette smoked from all men employed in the 12 intervention factories and 10% of those in the 12 control factories. The men were asked 203 on 11 April 2019 by guest. Protected by copyright.

Serum placental-like alkaline phosphatase levels and nicotine intake in smokers

“…This accords with previous evidence concerning the reduced efficiency with which cigarettes are smoked when daily consumption is very high (Feyerabend et al, 1982;Peach et al, 1985).…”

“…The marked individual differences in the amounts of nicotine inhaled by smokers in each of the three selfreporting categories (Table I) is in accordance with previous evidence for differences in the efficiency with which cigarettes are smoked (Feyerabend et al, 1982;Peach et al, 1985), as well as inadvertent or deliberate errors of recall regarding cigarette consumption (Sillet et al, 1978;Peach et al, 1986). Thus in the current study 14 (3%) of the 475 volunteers who denied smoking were unequivocally identified as smokers by the diethylthiobarbituric acid method, and had NM/C ratios averaging 7.6 which was only slightly less than the mean for the self-admitted smokers (8.4).…”

“…The nicotine metabolite/ creatinine (NM/C) ratios (as ,ug apparent cotinine per mg creatinine) of the 955 urine samples available for analysis from the first 2,000 volunteers were determined colorimetrically using the barbituric acid and alkaline picrate methods described previously (Peach et al, 1985). The actual smoking status of these 955 subjects was biochemically proven by testing aliquots of urine for nicotine metabolites by the specific qualitative diethylthiobarbituric acid extraction method (Peach et al, 1985) since the only source of nicotine intake is by smoking tobacco or taking snuff. Among the 2,000 volunteers, smoking histories had been elicited from 1,100 and estimates of PLAP-like AP were made on serum samples from 663.…”

Saliva Cotinine Levels in Smokers and Nonsmokers

“…However, a weak association between nicotine yield and saliva cotinine may have been obscured by imprecise self-report. Several studies suggest that the smokers' knowledge and understanding of the tar content of their cigarettes are inaccurate (30)(31)(32)(33), but equivalent data on the associations between self-reported nicotine yields and the values printed on cigarette packs are not available.…”

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“…The calculation of tar and nicotine exposure from cigarettes might have been confounded by misclassification of the cigarette brand most commonly smoked if the validity of self-reporting for ex-smokers is lower than for current smokers. This might be possible because of recall bias [42]. However, the RRs for tar and nicotine exposure from cigarettes were comparable between ex-and current smokers.…”