Thorax 1986;41:203-207 Thorax: first published as 10.1136/thx.41.3.203 on 1 March 1986. Downloaded from Validity of smokers' information about present and past cigarette brands implications for studies of the effects of falling tar yields of cigarettes on health HEDLEY PEACH, D SHAH, RW MORRIS From the Department ofCommunity Medicine, United Medical and Dental Schools ofGuy's and St Thomas's Hospitals, London 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 brand name was the same in the questionnaire and on the packet in 74% of cases. The recalled brand was confirmed by past records in only 49% of cases. It is concluded that current smokers should be asked to return an empty packet or packets of the cigarette brand or brands usually smoked with a self administered questionnaire and that follow up studies of populations for which brands of cigarette smoked were copyright. previously recorded might be more valid.than studies relying on recall. Several studies have attempted to establish whether ing brands on health may have to collect information over a there is any benefit to cigarette smokers in changing on brands on the basis of recall long period http://thorax.bmj.com/ from a higher to a lower tar brand. Most of these are because of the time taken for some effects to become cross sectional,` prospective,7- 12 or retro- apparent. For example, Fletcher et al'8 showed that spective'13 16 studies in which information about at least eight years of follow up is needed to dis- cigarette type and brand, present or past or both, had tinguish even between smokers and ex-smokers on the to be obtained from smokers themselves. None of basis of lung function tests. Moreover, the validity of these studies tested the validity of smokers' answers information about current cigarettes smoked (type, about past and present cigarette type and brand. This tar group, or brand name) has never been established, is surprising, not only because of the fundamental for example, against the details on the packet. nature of the information but also because the In this paper we assess the validity of smokers' on September 26, 2021 by guest. Protected Tobacco Research Council showed 20 years ago that information about present and past cigarette brands the proportion of smokers of manufactured and hand and discuss the implications ofthe results for past and rolled cigarettes incorrectly recalling even the type of future studies of the effects of the falling tar yields of cigarette (manufactured or hand rolled) they had cigarettes on health. smoked increased from an average of 8% one and a half years after the initial interview to 35% at 15 Method years.' 7 Recall of the actual brand name of cigarettes smoked in the past is likely to be even poorer. Retro- The Heart Disease Prevention Project was a random- spective studies trying to assess the effects of switch- ised controlled trial of the benefits to middle aged men of mounting a preventive campaign in indus- try. 19 At the start of the study in 1971-3 a self admin- Address for correspondence: Mr RW Morris, Department of Com- istered questionnaire was used to obtain data on the munity Medicine, St Thomas's Hospital Medical School, London type and brand of cigarette smoked from all men SEI 7EH. employed in the 12 intervention factories and 10% of Accepted 23 September 1985 those in the 12 control factories. The men were asked 203 204 Peach, Shah, Morris Thorax: first published as 10.1136/thx.41.3.203 on 1 March 1986. Downloaded from whether they smoked manufactured cigarettes with Heart Disease Prevention Project (appendix). This filters, manufactured cigarettes without filters, or coding frame may produce an overestimate of the hand rolled cigarettes and were required to state pre- agreement between recalled and actual brands cisely the brand of cigarette or tobacco usually smoked at the start of the project since the precise smoked. Embassy cigarette, for example, smoked 12 years ago Ten factories, five intervention and five control, cannot be identified. which had not been closed and had not had many Two weeks after returning their questionnaires redundancies, were chosen for this study. At the start smokers were asked to send an empty packet of the of the Heart Disease Prevention Project these fac- cigarette or hand rolled tobacco usually smoked. The tories had 8743 male workers aged 40-59 years. Of type, tar group, and brand name of the usual cigarette the men who were still contactable at the last follow given on the questionnaire were compared with the up of the project in 1977-8 (62%), a random sample details on the packet. Smokers who returned a packet of 1204, stratified according to whether they were carrying a brand name or tar group that did not agree retired, were sent a self administered questionnaire in with those given on the questionnaire were asked by 1984. This inquired about the type (plain, filter, or letter or telephone whether they had changed brands hand rolled), tar group ("high," "middle high," since completing the questionnaire. The question- "middle," "low middle," "low," "not known"), naire inquired about the length of time that the men brand name, and the number of years they had had been smoking their cigarette brands and we could smoked their usual present cigarettes and the brand therefore check whether the brands cited were likely of cigarettes they thought they had been smoking at to be the smoker's usual brands. The brand alleged to the start of the project. have been smoked 12 years ago was also compared The respondents were asked to give the brand with that actually recorded at the start of the project. names as fully as possible and to include any words such as "King Size," letters as in "Craven A," or Results numbers as in "State Express 555" written on the front, back, or sides of the cigarette packet. The The response rate to the questionnaire after three present cigarette brands were coded by one observer mailings was 83%. Intervention and control factorycopyright. using a dictionary of brands on the market since 1978 workers were similar with respect to response, social (PN Lee, personal communication), to which hand class, and smoking habits 12 years previously. The rolled tobaccos were added. If the brand information respondents from the five intervention factories, how- in the questionnaire could not be matched with only ever, were slightly older (60.7 compared with 59.7 one cigarette described in the dictionary then the years; p < 0.05). Non-respondents were similar to http://thorax.bmj.com/ questionnaire data were recorded as uncodable. For respondents in age, social class, and smoking habits example, 12 years before. Workers from the 10 factories Questionnaire brand: surveyed in this study were also compared with the Player's No 6 original 24 factory populations with respect to their Dictionary brands: characteristics on entry. Smoking was slightly less 309 Player's No 6 Filter S F 1965- common in the 10 chosen factories than in the 101 Player's No 6 Plain S P 1965- remaining 14. The ages of the two populations were 310 Player's No 6 Extra Mild Filter S F 1972- similar. on September 26, 2021 by guest. Protected 618 Player's No 6 King Size Filter KS F 1971- Four hundred and twenty nine men who returned a (S-small; KS-King Size; F-filter; P-plain) questionnaire smoked cigarettes at the start of the Decision: uncodable Heart Disease Prevention Project. Of these, 243 still The recalled brands from 12 years ago were smoked cigarettes and all but 23 forwarded a current coded according to the original coding frame of the cigarette or tobacco packet when asked two weeks Table 1 Comparison between type ofcigarette on questionnaire andpacket Type ofcigarette on Type ofcigarette on packet questionnaire Manufacturedfilter Manufactured plain Hand rolled Missing packet Total Manufactured filter 135 1 2 13 151 Manufactured plain 2 11 0 1 14 Handrolled 2 0 64 6 72 Missing data 1 1 1 3 6 Total 140 13 67 23 243 Thorax: first published as 10.1136/thx.41.3.203 on 1 March 1986. Downloaded from Validity ofsmokers' information about present and past cigarette brands 205 Table 2 Comparison between tar groups on questionnaire and cigarette or tobacco packet Tar group on questionnaire Tar level on cigarette or tobacco packet "Middle" "Low middle" "Low" Hand rolled Missing packet Total ( "unknown") "Middle high" 7 3 0 1 0 11 "Middle" 50 12 3 10 0 75 "Low middle" 6 22 3 7 2 40 "Low" 1 2 41 2 1 47 "Unknown" 2 1 0 47 1 51 Total 66 40 47 67 4 224 Overall agreement 73% (160/220) after completing the questionnaire. Tables 3 and 4 compare the tar group on the ques- Table 1 shows that there was close agreement tionnaire and on the packet returned two weeks later between the type of cigarette named in the question- for smokers whose questionnaire and packet agreed naire and on the packet-that is, for 210 out of 217 and disagreed respectively over brand name.