[Age of smoking initiation as predictor in smoking cessation]

To determinate the relationship between the age of smoking initiation and the success of the smoking cessation program.

Prospective cohort.

Smoking Cessation Unit, in the University Hospital of Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain.

2801 smokers of 10 or more cigarette per day, who started a smoking cessation program between January 1993 to December 2002.

Kaplan-Meier method was used to obtain the probability of relapse. The log-rank test was used to determine relapse differences in time between groups of age at smoking initiation. Hazard ratios (HR) of quitting were estimated with a Cox model.

The mean age at smoking onset was 15.5+/-4.1 years for men and 17.7+/-5.4 years for women. The age of onset smoking was significant for relapse during smoking cessation in men with a HR=1.42 (95% CI, 1.09-1.86), and for women who started to smoke before 14 years old compared with the reference group a HR=1.25 (95% CI, 0.76-1.49).

This study shows that age of smoking onset predicts higher rates of relapse in a smoking cessation program in men. The low motivation for cessation was in both sex a significative factor for relapse and the low and high nicotine dependence were in women.