The effects of a smoking cessation intervention on mortality after a 32.5-year follow-up period: a randomized clinical trial

The Lung Health Study was a randomized clinical trial of smoking cessation that took place between 1986 and 1988. Special intervention participants received the smoking intervention program and were compared with usual care participants. Vital status was followed up to 32.5 years. Previous work sought to assess the effect of the cessation program on all-cause and cause-specific mortality at 14.5 years. Our objective was to do so at 32.5 years. We analyzed data from 5279 participants from the United States from the Lung Health Study. The three arms were smoking intervention plus bronchodilator, smoking intervention plus placebo, or no intervention. We compared all-cause and cause-specific mortality at 32.5 years between the combined special intervention groups and usual care group. The hazard ratio for the usual care group compared with the special intervention group was 1.05 (95% CI, 0.97-1.18) at 32.5 years. The cause-specific hazard ratio for the usual care group compared with the special intervention group for death due to respiratory disease that was not lung cancer was 1.21 (95% CI, 1.04-1.42) at 32.5 years, indicating that the smoking cessation program had a protective effect against death due to non-lung cancer respiratory disease, even after a long period.