Several studies have shown the influence of the eating pattern on lung function. However, the benefits of the Mediterranean diet (DiMet) in preventing pulmonary dysfunction are not well known.

Objective: To evaluate the effect of adherence to DiMet on the deterioration of lung function in smokers.

Methodology: Design: Controlled, parallel, multicenter, cluster-randomized clinical trial. Participants: 566 active smokers with a cumulative consumption of more than 10 packets a year, within 25 to 75 year-old age group, without previous respiratory disease and who agree with the conditions of the study and sign an informed consent . Scope: 20 Primary Care Centers managed by the Catalan Health Institutes in Tarragona that will be randomly assigned to a control or an intervention group (1: 1). Intervention: During 2 years a nutritional intervention will be carried out to increase adherence to DiMet based on: 1) annual visit of personalized nutritional education, 2) annual telephone contact for intervention reinforcement, and 3) computer access to a dietary block designed ad hoc. The control group will follow their usual diet style. All participants will receive advice to quit smoking. It will be evaluated: a) pulmonary function by forced spirometry and b) adherence to the DiMet with a questionnaire of 14 items and biological determinations. Statistical analysis: For intention to treat. The unit of analysis will be the individual smoker. Parameters of pulmonary function and adherence to the DiMet of both groups will be compared.

Expected results: DiMet prevents the appearance of altered lung function in smokers without previous respiratory pathology. Thus, DiMet will be key in pulmonary prevention, together with the fundamental recommendation of smoking cessation.

Several studies have shown the influence of the eating pattern on lung function. However, the benefits of the Mediterranean diet (DiMet) in preventing pulmonary dysfunction are not well known.

Objective: To evaluate the effect of adherence to DiMet on the deterioration of lung function in smokers.

Methodology: Design: Controlled, parallel, multicenter, cluster-randomized clinical trial. Participants: 566 active smokers with a cumulative consumption of more than 10 packets a year, within 25 to 75 year-old age group, without previous respiratory disease and who agree with the conditions of the study and sign an informed consent . Scope: 20 Primary Care Centers managed by the Catalan Health Institutes in Tarragona that will be randomly assigned to a control or an intervention group (1: 1). Intervention: During 2 years a nutritional intervention will be carried out to increase adherence to DiMet based on: 1) annual visit of personalized nutritional education, 2) annual telephone contact for intervention reinforcement, and 3) computer access to a dietary block designed ad hoc. The control group will follow their usual diet style. All participants will receive advice to quit smoking. It will be evaluated: a) pulmonary function by forced spirometry and b) adherence to the DiMet with a questionnaire of 14 items and biological determinations. Statistical analysis: For intention to treat. The unit of analysis will be the individual smoker. Parameters of pulmonary function and adherence to the DiMet of both groups will be compared.

Expected results: DiMet prevents the appearance of altered lung function in smokers without previous respiratory pathology. Thus, DiMet will be key in pulmonary prevention, together with the fundamental recommendation of smoking cessation.

Inclusion Criteria:

• Active smoking and cumulative consumption ≥10 pack-years.
• Age between 25-75 years.
• Internet connection.

Exclusion Criteria:

• History of respiratory disease.
• Chronic or terminal disorder that alters basal parameters.
• Any reason that limits follow up.