Smoking reduction promotes smoking cessation: results from a double blind, randomized, placebo-controlled trial of nicotine gum with 2-year follow-up.

Aim: To test the effect of nicotine gum and placebo in smokers not motivated or not able to quit smoking with regard to smoking reduction and smoking cessation.

Design: This randomized study evaluated nicotine gum versus placebo for up to 1 year in 411 healthy smokers highly motivated to reduce cigarette use. Smoking reduction was defined as self-reported daily smoking less than 50% of baseline and any decrease (1 p.p.m. or more) in carbon monoxide.

Setting: Pulmonary department, Copenhagen, Denmark.

Findings: The overall success rate for sustained smoking reduction was significantly higher at all time-points for active versus placebo gum (6.3% versus 0.5% after 24 months). Nicotine gum achieved significantly higher point prevalence cessation rates than placebo at 12 and 24 months [11.2% versus 3.9% (odds ratio = 3.1; 95% CI, 1.4-7.2 and 9.3% versus 3.4% (odds ratio = 2.9; 95% CI, 1.2-7.1), respectively]. There was a linear relationship between decrease in number of daily cigarettes and decrease in plasma cotinine, exhaled carbon monoxide and plasma thiocyanate, with significantly greater reduction in the nicotine gum group after 4 and 12 months (maximum treatment duration) but not after 24 months. The decrease in toxin intake was smaller than the decline in daily cigarette consumption, suggesting that compensatory smoking occurred.

Conclusions: Nicotine gum promoted cessation in this population of smokers unwilling to quit. Among reducers, the toxin intake correlated with reduced cigarette consumption although some compensatory smoking occurred.