458 NICOTINE CHEWING-GUM
SIR,-Warren Lam and colleagues (July 4, p 27), in their meta-analysis of randomised controlled trials of nicotine chewinggum, present data from studies done in general medical practices and conclude that there is not yet convincing evidence to justify widespread use of the gum in this setting. This conclusion was based on two randomised controlled trials that compared nicotine gum with placebo gum/,2 one of which included patients with smoking-related diseases.2 We agree with your 1985 editorial3 which stated that further studies are necessary to assess the true value of nicotine gum when used as an adjunct to advice from the general practitioner. For this reason, our analysis4 was based on an assessment of the pharmacological effect of nicotine gum relative to placebo gum, combining the results from all placebo-controlled trials irrespective of the setting. Our results indicated that the cost per year of life saved with this intervention ranges from$4113 to$6465 for men and from$6880 to$9473 for women, reflecting substantially greater cost-effectiveness than treatment for hypertension. The conservative nature of these estimates is suggested by our calculation that only one additional patient among 250 cigarette smokers would quit smoking as a result of being offered nicotine gum. By measuring efficacy relative only to inactive gum, we ignored any placebo effect. The results from the only placebo-controlled trial in general practice that did not include patients with smoking-related diseases support our estimate of pharmacological efficacy.’ In this study of 200 patients, a 28% increase in smoking cessation was observed among those randomised to nicotine chewing-gum. This estimate is similar to the result (35 %) that we obtained when we combined data from seven randomised placebo-controlled trials.4 It may be inappropriate, as Lam and colleagues have done, to extrapolate the results from trials that include patients with smoking-related disease to the healthy general-practice population. Hence, the findings from the British Thoracic Society trial, which showed no increase in cessation rates among patients receiving nicotine gum, may not apply to those who do not have smokingrelated diseases. Despite this, do Lam et al believe that other placebo-controlled trials should be excluded when estimating the pharmacological efficacy of nicotine gum, as implied in their report? Harvard Medical School, Boston, Massachusetts 02115, USA
GRAHAM A. COLDITZ
Policy Analysis Inc, Brookline, Massachusetts
DANIEL M. HUSE THOMAS E. DELEA GERRY OSTER
Jamrozik K, Fowler G, Vessey M, Wald N Placebo controlled trial of nicotine chewing gum in general practice. Br Med J 1984; 289: 794-97. 2. British Thoracic Society. Comparison of four methods of smoking withdrawal in patients with smoking related diseases. Br Med J 1983; 286: 595-97. 3. Editorial. Nicotine chewing gum. Lancet 1985; i: 320-21. 4. Oster G, Huse DM, Delea TE, Colditz GA. Cost-effectiveness of nicotine gum as an adjunct to physician’s advice against cigarette smoking. JAMA 1986; 256: 1315-18. 1.
CIGARETTE TAR REDUCTION
SIR,-When the nicotine content of a cigarette (as measured by a smoking machine) is reduced, smokers appear to "compensate", chiefly by inhaling more smoke from each cigarette. 1-3 The
Independent Scientific Committee on Tobacco and Health (ISCTH)4 therefore proposed that a medium-nicotine, low-tar cigarette might be less hazardous than a low-nicotine low-tar cigarette. This suggestion assumes, however, that the chief determinant of compensation is nicotine rather than tar. To test this, we produced two cigarettes (A and B) with identical nicotine content (1 ’0 mg per cigarette, when smoked by machine) but with different tar content (29 and 19 mg per cigarette, respectively), and studied their effects in a double-blind crossover study. 45 male smokers (who had smoked more than 5 cigarettes per day for more than two years) participated. They smoked brand A cigarettes for two days, and in the afternoon of the second day, 5 ml blood was taken for measurement of nicotine by the Feyerabend method.s The subjects were then asked to smoke their usual brand for two days. Then they were asked to smoke brand B for two days,
and blood nicotine levels were measured again on the afternoon of the second day. The number of experimental cigarettes they were given to smoke was similar to the usual daily consumption that they reported before the study began. Both the participants and the researchers thought that only one type of cigarette was being tested, and did not know the purpose of the test. The mean blood nicotine levels (in ng/ml) were almost identical: 12.8 (SE 1-2) with cigarette A and 12.6 (1 -2) with brandB. No compensation. for the difference in tar content was seen, which reinforces the ISCTH suggestion. This result suggests that, as long as the nicotine yield is constant, the tar yield may have little effect on the amount of smoke taken from each cigarette. Office of the Dean, School of Public Health, Tianjin Medical College,
Tianjin, People’s Republic of China
Iyer R, Feyerabend C. Relation of nicotine yield of cigarettes to blood nicotine concentrations in smokers. Br Med J 1980; 280: 972-76. Sutton SR, Russell MAH, Iyer R, Feyerabend C. Saloojee Y. Relationship between cigarette yields, puffing patterns, and smoke intake: evidence for tar compensation. Br Med J 1982; 285: 600-03. Peach H. In: Zaridze DG, Peto R, eds. Tobacco: A major international health hazard Lyon: IARC, Scientific Publication No 74, 1986: 251-63. Froggatt M. Report of the Independent Scientific Committee on Tobacco & Health. London HM Stationery Office, 1983. Feyerabend C, et al. J Pharm Pharmacol 1980; 32: 178-81.
1. Russell MAH, Jarvis M, 2.
SMOKING AT WORK
SiR,—Your Aug 1 note about a non-smoking woman in Bristol winning a complaint against her employer that she was exposed to other people’s tobacco-smoke pollution at work mentions the Public Health Act 1936 and the Health and Safety at Work Act 1974 as laws which "could apply to smoking in the workplace and force employers to control and contain the habit". I have long been surprised that mention of such legislation is always made in the context of "passive" smoking. Why does no-one make the obvious leap? Active smoking at work is a danger to employees’ health and safety, and the Health and Safety at Work Act could therefore be construed as the legislation required to ban smoking altogether from the workplace. Such a ban would also take care of the fire hazards at work which threaten employees, employers, and the business itself (about one-third of all businesses that suffer a major fire never trade again and so never employ workers again). Part II of the Public Health (Scotland) Act 1897 lays a duty on local authorities "to detect the existence of any nuisance ... dangerous to health". Notices can be served ... "and if the nuisance is not removed or abated or is likely to recur the local authority can take action". The Act requires the local authority, if requested by ten ratepayers, to complain to the Sheriff of any trade, business, or process "causing a nuisance or any effluvia which constitute a nuisance". Local authorities and their officers are empowered to enter premises where there are grounds for suspecting the existence of a nuisance.! The ramifications of this law for smoking in any workplace in Scotland are enormous. Association for Nonsmokers’ 82 St Stephen Street, Edinburgh EH3 5AQ
1. Scottish Information Office. Fact sheet 32: Control of air
pollution m Scotland.
AIDS, EPIDEMIOLOGY, AND AFRICA SiR,—Dr Konotey-Ahulu (July 25, p 206) makes some worthwhile points about press coverage of AIDS in Africa. However, his reliance on the number of AIDS cases currently presenting as a measure of the seriousness of the AIDSepidemic is unfortunate; the proportion of HIV-infected individuals in the population is a much more useful index of the scale of the problem. The World Health Organisation estimates that 2 million or more Africans may already be carrying HIV;’ and the virus has an incubation period of at least five years. According to WHO Africa is the part of the world most severely affected by the AIDSpandemic. On the basis of the WHO estimate the Panos dossier AIDS and the Third World, which Konotey-Ahulu criticises, stated that 1 million Africans would probably die of AIDS over the next decade