[Effectiveness of the physician's advice to quit smoking: evaluation of the impact a year after the fact].

The results of a physician-based intervention on smoking done by general practitioners in Barcelona (Spain) are described one month and one year after its inception. Among the 208 smokers in the intervention group there were more attempts to quit, and they were more successful than in the 216 smokers in the control group. The proportions of quitters after a year was 5.3% and 2.3% in each group (p less than 0.05). Among the variables related to success in quitting are self-reliance, the willingness to reduce or quit smoking, the intensity of the habit and the family environment.