Persistence of the effect of the Lung Health Study (LHS) smoking intervention over eleven years

Background: Research on the long-term persistence of effects of interventions aimed at smoking cessation is limited. This paper examined the quitting behavior of individuals who were randomized to a smoking cessation intervention (SI) or to usual care (UC), at a point approximately 11 years later.

Methods: The initial sample consisted of 5,887 adult smokers in 10 clinics who had evidence of airways obstruction. Two-thirds of the original participants were offered an intensive 12-week smoking cessation intervention. Of these, 4,517 were enrolled in the long-term follow-up study.

Results: Randomized group assignment was a strong predictor of smoking behavior after 11 years, in that 21.9% of SI participants and only 6.0% of UC participants maintained abstinence throughout the interval. Logistic regressions identified covariates associated with abstinence. A higher proportion of abstinence was observed in participants that had been assigned to SI (OR = 4.45), were older (OR = 1.11, increment 5 years), had more years of education (OR = 1.05), and fewer cigarettes/day at baseline (OR = 0.90, increment 10 cigarettes).

Conclusions: Smokers exposed to an aggressive smoking intervention program and who sustain abstinence for a five-year period are very likely to still be abstinent after 11 years.