Department of Primary Care and Population Sciences, Royal Free and University College Medical School, London, UK.
Professor AG Shaper, 8 Wentworth Hall, The Ridgeway, Mill Hill, London NW7 1RJ, UK. E-mail: agshaper{at}wentworth.u-net.com
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Abstract |
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Methods Prospective study of 7735 men aged 4059 years drawn from general practices in 24 British towns with mean follow-up of 21.8 years. The outcome measures include major coronary heart disease (CHD) and stroke events, cancer incidence, and deaths from all causes.
Results There were 1133 major CHD events and 440 stroke events, 919 new cancers and 1994 deaths from all causes in the 7121 men with no diagnosed CHD, stroke, diabetes, or cancer at screening. Compared with never smokers, pipe/cigar smokers (primary and secondary combined) showed significantly higher risk of major CHD events (relative risk [RR] = 1.69, 95% CI: 1.32, 2.14) and stroke events (RR = 1.62, 95% CI: 1.08, 2.41) and of cardiovascular, non-cardiovascular, and total mortality (RR = 1.49, 95% CI: 1.13, 1.96, RR = 1.40, 95% CI: 1.08, 1.83 and RR = 1.44, 95% CI: 1.19, 1.74, respectively), after adjustment for lifestyle and biological characteristics. They also showed a significantly higher incidence of smoking-related cancers (RR = 2.67, 95% CI: 1.70, 4.26), largely due to lung cancer (RR = 4.35, 95% CI: 2.05, 8.94). Overall, the effects in pipe/cigar smokers were intermediate between never-smokers and light cigarette smokers, although risks for lung cancer were similar to light cigarette smokers.
Conclusion Pipe and cigar smoking, whether primary or secondary, carries significant risk of smoking-related ill health.
Accepted 14 April 2003
Cigarette smoking has been officially recognized as a health hazard for many decades,1 but despite numerous studies and reports indicating the ill effects of pipe and cigar smoking, there has remained a widespread belief that they are less hazardousto health than cigarette smoking. There is also uncertainty as to the level of risk to health associated with primary and secondary pipe/cigar smoking. After 20 years follow-up, the British Doctors study reported that primary pipe/cigar smokers had experienced mortality rates which were similar to men who did not smoke at all, although in the latter half of follow-up smoking-related risks were increased.2 In their 40 years follow-up, primary and secondary pipe/cigar smokers combined showed the same total mortality rates as ex-smokers.3 In a study of professional and business men in London, secondary pipe/cigar smokers had higher risk of smoking-related mortality than primary pipe/cigar smokers but a lower risk than continuing cigarette smokers, and it was suggested that it was better for cigarette smokers to switch to pipe/cigars than to continue smoking cigarettes.4 Earlier reports from the British Regional Heart Study (BRHS) showed no increase in risk of coronary heart disease (CHD) events in primary pipe/cigar smokers,5,6 although an increased risk of stroke was suggested after 13 years follow-up.7 These studies have conveyed the impression that pipe/cigar smoking, while not harmless, is less hazardous than smoking cigarettes and yet several recent reports from the US and Europe suggest that cigar smoking in particular may result in as much smoking-related disease as cigarette smoking.810 This study seeks to quantify the effects of primary and secondary pipe and cigar smoking on major cardiovascular events, cancer incidence, and all-cause mortality in middle-aged British men after 22 years follow-up.
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Design and Methods |
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Recall of doctor diagnosis
The men were asked whether a doctor had ever told them that they had CHD (i.e. angina, myocardial infarction, heart attack, coronary thrombosis), stroke, diabetes, and a number of other disorders. All men with recall of a doctor diagnosis of CHD, stroke or diabetes (n = 554) and diagnosed cancer (excluding skin cancer) prior to or in the same calendar year of screening (n = 45) and men with missing data on smoking (n = 15) were excluded, leaving 7121 men for analysis.
Smoking
The 7121 men were classified into seven groups on the basis of their smoking status at screening:
Follow-up
All men have been followed up for all-cause mortality and cardiovascular morbidity from screening in January 1978July 1980 to December 2000, a mean follow-up period of 21.8 years (range 2022.5 years); follow-up has been achieved for 99% of the cohort.15 Major CHD events include sudden cardiac death and myocardial infarction (fatal and non-fatal). Major stroke events refer to fatal and non-fatal events.15 Evidence regarding non-fatal heart attacks and stroke was obtained by reports from GPs, by biennial reviews of patients notes and from questionnaires to patients at 5th year and 1214th year after screening. Non-fatal stroke events were those that produced a neurological deficit that was present after more than 24 hours. A non-fatal heart attack was diagnosed according to WHO criteria.16
Information on death was collected through the established tagging procedures provided by the National Health Service registers. Cancer morbidity is based on follow-up until December 1997, a mean of 18.8 years. Cancer cases were ascertained by death certificates, the cancer registry, and by questionnaires on recall of doctor diagnoses sent to survivors in 1992, 1996, and in 1998.17 The shortened follow-up period for cancer cases was due to the time lag in Cancer Registry notifications.
Smoking-related cancers included cancer of the lip, tongue, oral cavity and larynx (ICD 140, 141, 143149), oesophagus (ICD 150), pancreas (ICD 157), respiratory tract (ICD 160163), bladder (ICD 188), and kidney (ICD 189).
Statistical methods
The Cox proportional hazards model was used to obtain the hazard ratios (relative risks [RR]) for the smoking groups adjusted for age and potential confounders.18 Smoking was fitted as a categorical variable. In the adjustment, physical activity, social class, alcohol intake, and anti-hypertensive treatment were fitted as categorical variables. Age, BMI, systolic blood pressure, and serum total cholesterol were fitted as continuous variables. Full adjustment includes both categorical and continuous variables. Direct standardization was used to obtain age-adjusted rates/1000 person-years by smoking categories.
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Results |
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Table 1 shows the baseline characteristics for the smoking groups. Primary pipe and cigar smokers showed personal and biological characteristics similar to those who had never smoked cigarettes or pipe/cigars and they had the lowest percentages of manual workers and obesity and the lowest levels of mean systolic blood pressure and serum total cholesterol (Table 1
). Secondary pipe/cigar smokers had characteristics similar to those of light cigarette smokers but with a lower percentage of manual workers.
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Major cardiovascular events
With never smokers as the baseline, primary pipe and cigar smokers showed increased age-adjusted risk (non-significant) of major CHD and stroke events (Table 2). Because of their favourable personal and biological characteristics, full adjustment increased their RR and the differences became significant for major CHD events and marginally significant for stroke. Secondary pipe/cigar smokers had significantly increased risk of both CHD and stroke events after adjustment. Ex-cigarette smokers (who did not currently smoke pipe/cigars) showed similar risk of major CHD and stroke events to never smokers after full adjustment (Table 2
). Combined primary and secondary pipe/cigar smokers showed RR of major CHD and stroke events significantly greater than non-smokers and similar to light cigarette smokers (RR = 1.69, 95% CI: 1.32, 2.14 and RR = 1.62, 95% CI: 1.08, 2.41, respectively). The highest risks for both CHD events and stroke were seen in heavy current smokers.
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Discussion |
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Changes in smoking behaviour
After 5 years follow-up, three-quarters of pipe/cigar smokers were still smoking and about one-quarter had stopped smoking. The cigarette smokers showed a similar pattern with about one-quarter having stopped smoking. It seems likely that this similarity in smoking behaviour will have continued over the 22-year follow-up period and there seems little likelihood of bias arising from differential changes in smoking patterns over time. While cessation of smoking is likely to reduce the absolute risk of events over follow-up, this would apply in similar measure to all smoking categories. The trend towards stopping or diminishing smoking is likely to underestimate the effects on outcome in all the smoking categories.
Duration of effect
The absence of effect of primary pipe/cigar smoking on CHD events observed in the earlier BRHS reports after 6.2 and 9.5 years follow-up5,6 and the small increase in risk of stroke after 12.8 years follow-up,7 suggest that primary pipe/cigar smoking might require longer exposure than cigarette smoking to manifest pathological effects. This appears to be true for CHD events, with a significant increase in risk in primary pipe/cigar smokers seen only in the later period of follow-up. For both stroke and for smoking-related cancers, the effect of primary pipe/cigar smoking is seen in both early and later periods. The import of this observation is that, at least for CHD, shorter term follow-up may not reveal the pathology developing in these subjects. However, for both stroke and for smoking-related cancers the ill effects are apparent and significant in the shorter period of follow-up.
Other studies
Early studies from Canada,23 the UK,2 and the US24 all showed a considerably lower risk of lung cancer for pipe and cigar smokers than for cigarette smokers, and may have helped foster the belief that pipe/cigar smoking was a lesser hazard to health in general than cigarette smoking. Since then, increasing evidence suggests that pipe or cigar smoking may result in as much smoking-related disease as cigarette smoking. A Swedish study (32% cigarettes, 27% pipe, 5% cigar) showed that pipe (only) smokers experienced similar mortality risk to cigarette smokers for smoking-related cancers, respiratory disease, and CHD with a linear relationship with the amount of tobacco smoked, whether it was cigarettes, pipe, or cigars.25 In British men (Whitehall study), all-cause mortality rates for secondary pipe/cigar smokers were higher than for primary pipe/cigar smokers and those who switched from cigarettes to pipe smoking had a higher mortality than those who gave up smoking completely.26 A case-control study from seven European centres suggested that the smoking of cigars, cigarillos, and pipe tobacco exerted a carcinogenic effect on the lungs comparable to smoking cigarettes.10 A similar case-control European study showed pipe and cigar smoking to be associated with cancer of the urinary bladder.27 In two large follow-up studies of US men who had never smoked cigarettes (Kaiser Permanente and Cancer Prevention Study II) cigar smoking was associated with increased risk of CHD and smoking-related cancers8,9,28 as well as bronchitis and emphysema.8 A 28-year study of Norwegian men and women found a doseresponse relationship between lung cancer, cancer of the upper digestive and respiratory tracts and both cigarette smoking and pipe smoking in men.29,30 Our findings of increased risk of smoking-related cancers and CHD in primary and secondary pipe/cigar smokers support these earlier findings and extend the evidence to risk of stroke.
Magnitude of effect
Comparison of the magnitude of effect of primary and secondary pipe/cigar smoking, or of combined pipe/cigar smoking, has proved extremely difficult There are marked differences between studies in the definitions used for smoking categories and in the relative proportions of pipe and cigar smokers. The studies have a wide range of duration of exposure to smoking and not all express their results in terms of RR or make appropriate adjustments for confounding variables. However, despite these restrictions, it is evident that recent prospective studies are in general agreement that pipe and/or cigar smokers have risks approximating or similar to those of regular light cigarette smokers and significantly higher than those who have never smoked.
Limitations
The number of primary pipe/cigar smokers is relatively small and thus the findings for primary and secondary pipe/cigar smokers have been presented both separately and combined. We cannot draw any firm conclusion as to whether the risks of primary pipe/cigar smokers differ from those of secondary pipe/cigar smokers but both appear to be at increased risk. The magnitude of effect of pipe/cigar smoking on CVD and smoking-related cancers is substantial even after adjustment for confounders. While adjustment can never entirely remove the effects of these confounders, it is unlikely that the significant effects are simply due to residual confounding by factors such as social class, as social class differences between secondary pipe/cigar smokers and never smokers were relatively small. Indeed, the primary pipe/cigar smokers are far more likely to be non-manual workers and precise measurements of social class would increase the risk further.
Public health implications
The American Cancer Society (1998) concluded that (1) smoking cigars instead of cigarettes does not reduce the risk of nicotine addiction, (2) cigar smoke contained higher concentrations of toxic and carcinogenic compounds than cigarettes and was a major source of carbon monoxide, (3) cigar smoking causes cancers of the oral cavity, larynx, lung, and oesophagus, and (4) with increasing numbers of cigars smoked, the risk of death approached that of cigarette smoking.31 The findings in the present study in middle-aged men who are pipe and/or cigar smokers supports these conclusions and suggests that cessation of all tobacco products is the best strategy for decreasing exposure to tobacco smoke.32
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Conclusion |
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Acknowledgement |
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KEY MESSAGES
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References |
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2 Doll R, Peto R. Mortality in relation to smoking: 20 years observations in male British doctors. BMJ 1976;ii:152536.
3 Doll R, Peto R, Wheatly K, Gray R, Sutherland I. Mortality in relation to smoking: 40 years observations on male British doctors. BMJ 1994;309:90111.
4 Wald NJ, Watt HC. Prospective study of effect of switching from cigarettes to pipes or cigars on mortality from three smoking related diseases. BMJ 1997;314:186063.
5 Cook DG, Shaper AG, Pocock SJ, Kussick SJ. Giving up smoking and the risk of heart attacks. A report from the British Regional Heart Study. Lancet 1986;ii:137680.[CrossRef]
6 Tang JL, Cook DG, Shaper AG. Giving up smoking: How rapidly does the excess risk of ischaemic heart disease disappear? J Smoking-Related Diseases 1992;3:20315.
7 Wannamethee SG, Shaper AG, Whincup PH, Walker M. Smoking cessation and the risk of stroke in middle-aged men. JAMA 1995;274:15560.[Abstract]
8 Iribarren C, Tekawa IS, Sydney S, Friedman GD. Effect of cigar smoking on the risk of cardiovascular disease. chronic obstructive pulmonary disease, and cancer in men. New Engl J Med 1999; 340:177380.
9 Jacobs EJ, Thun MJ, Apicella LF. Cigar smoking and death from coronary heart disease in a prospective study of US men. Arch Intern Med 1999;159:241318.
10 Boffetta P, Pershagen G, Jockal K-H et al. Cigar and pipe smoking and lung cancer risk in a multicenter study from Europe. J Natl Cancer Inst 1999;91:697701.
11 Shaper AG, Pocock SJ, Walker M, Cohen NM, Wale CJ, Thomson AG. British Regional Heart Study: cardiovascular risk factors in middle-aged men in 24 towns. BMJ 1981;282:17986.
12 Walker M, Shaper AG, Cook DG. Non-participation and mortality in a prospective study of cardiovascular disease. J Epidemiol Community Health 1987;41:29599.[Abstract]
13 Shaper AG, Wannamethee G, Weatherall R. Physical activity and ischaemic heart disease in middle-aged British men. Br Heart J 1991; 66:38494.[Abstract]
14 World Health Organization. Report of a WHO Consultation. Obesity: Preventing and Managing the Epidemic. Geneva: WHO, 1998.
15 Walker M, Shaper AG, Lennon L, Whincup PH. Twenty years follow-up of a cohort based in general practices in 24 British towns. J Public Health Med 2000;22:47985.
16 Rose G, Blackburn H, Gillum RF, Prineas RJ. Cardiovascular Survey Methods. 2nd Edn. Geneva: WHO, 1982.
17 Wannamethee SG, Shaper AG, Walker M. Physical activity and risk of cancer in middle-aged men. Br J Cancer 2001;85:131116.[ISI][Medline]
18 Cox DR. Regression models and life tables (with discussion). J R Stat Soc B 1972;34:187220.[ISI]
19 Mulcahy R. Cigar and pipe smoking and the heart. BMJ 1985;290: 95152.[ISI][Medline]
20 Kaufman DW, Palmer JR, Rosenberg L, Shapiro S. Cigar and pipe smoking and myocardial infarction in young men. BMJ 1987;294: 131516.[ISI][Medline]
21 Nelson DE, Davis RM, Chrismon JH, Giovino GA. Pipe smoking in the United States, 19651991: prevalence and attributable mortality. Prev Med 1996;25:9199.[CrossRef][ISI][Medline]
22 National Cancer Institute. Cigars: health effects and trends. Smoking and tobacco control monograph No. 9. Bethesda, MD. NIH Publication No. 984302. 1998.
23 Best EWR. A Canadian Study of Smoking and Health. Ottawa: Department of National Health and Welfare, 1966.
24 Hammond EC, Seidman H. Smoking and cancer in the United States. Prev Med 1980;9:16973.[ISI][Medline]
25 Carstensen JM, Pershagen G, Eklund G. Mortality in relation to cigarette and pipe smoking: 16 years observation of 25 000 Swedish men. J Epidemiol Community Health 1987;41:16671.[Abstract]
26 Ben-Shlomo Y, Smith GD, Shipley MJ, Marmot MG. What determines mortality risk in former cigarette smokers? Am J Public Health 1994;84:123542.[Abstract]
27 Pitard A, Brennan P, Clavel J et al. Cigar, pipe and cigarette smoking and bladder cancer risk In European men. Cancer Causes Control 2001;12:55156.[CrossRef][ISI][Medline]
28 Shapiro JA, Jacobs EJ, Thun MJ. Cigar smoking in men and risk of death from tobacco-related cancers. J Natl Cancer Inst 2000;92:33337.
29 Engeland A, Haldorsen T, Anderson A, Tretli S. The impact of smoking habits on lung cancer risk: 28 years observation of 26 000 Norwegian men and women. Cancer Causes Control 1996;7:36676.[ISI][Medline]
30 Engeland A, Anderson A, Haldorsen T, Tretli S. Smoking habits and risks of cancers other than lung cancer: 28 years observation of 26 000 Norwegian men and women. Cancer Causes Control 1996;7:497506.[ISI][Medline]
31 Baker F, Ainsworth SR, Dye JT et al. Health risks associated with cigar smoking. JAMA 2000;284:73540.
32 Ockene JK, Pechacek TF, Svendsen K. Does switching from cigarettes to PIPES or cigars reduce tobacco smoke exposure? Am J Public Health 1987;11:141216.