Placebo controlled trial of nicotine chewing gum in general practice.

Of 2110 adult cigarette smokers originally recruited to a study of the effect of antismoking advice in general practice, 429 who reported at follow up after one year that they had tried unsuccessfully to stop smoking were offered "a special antismoking chewing gum," either nicotine gum or a placebo gum, in a double blind study. Of 200 who were willing to try the gum, 101 were randomly allocated to the nicotine gum and 99 to the placebo gum. They were followed up at six months by an unannounced home visit, at which they were interviewed and asked to provide a breath sample for analysis of carbon monoxide. Twenty five claimed that they had stopped smoking, but, of them, seven exhaled levels of carbon monoxide indicative of continued smoking. Of the 18 in whom giving up smoking was validated, 10 had received active gum and eight placebo gum, a difference which was not significant (odds in favour of nicotine gum = 1.25, 95% confidence limits 0.47-3.31). The value of nicotine chewing gum, if any, can be quite small when it is used in general practice.