[Running and its influence on smoking habits].

Objective: To investigate whether running influences smoking habits.

Design: Study of cases and controls, with 1:1 pairing. Retrospective longitudinal observational study.

Setting: Primary care. City of Toledo, Spain.

Cases: 48 healthy volunteer runners of 47+/-7.8 years of age.

Controls: 48 healthy subjects, paired by gender and year of birth, chosen at random from the medical list assigned to the medical researcher.

Principal Measurements: Smoking habits and alcohol consumption in grams per week using a questionnaire, weight, height, blood pressure, and heart rate at rest. The odds ratio (OR) was obtained on the proportion of subjects who smoked or smoked at some time, those who continued smoking and the probabilities of giving up tobacco in each group.

Results: The OR of the proportion of subjects who smoked or had smoked between the groups of runners (54.2%) and controls (70.9%) was 0.486 (95% confidence interval [CI], 0.205-1.149; chi(2)=2.8; P=.093). The OR for continuing the habit between groups of runners (8.4%) and controls (41.7%) was 0.127 (95% CI, 0.035-0.456; chi(2)=14.0; P=.0002). In the group of runners, 45.8% had stopped smoking, as well as 31.2% of the controls (OR=7.85; 95% CI, 1.89-32.52; chi(2)=11.8; P=.0007); 50% of the runners who smoked had given it up since starting to run and 76.9% of these had given it up just at the time of starting to run.

Conclusions: There is a negative association between running and tobacco. If a smoker decides to run regularly he/she has high probabilities of giving up smoking and continue to do so.