Effect of the Mediterranean Diet on Lung Function in Smokers Without Previous Respiratory Disease
Condition: Lung Diseases
MeSH terms: Lung Diseases
Study type: Interventional

Summary: 
      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.
    

Detailed description: 
      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.
    

Intervention name(s): Mediterranean diet counseling
Intervention type(s): Behavioral
Intervention description(s): The participants of the intervention CAP will enter into an educational program to increase adherence to the DiMet that will integrate three operational components:
Explain the particularities of DiMet and the benefits of its monitoring. It will be an individual visit of 25-30 minutes (V1) where the study variables will be collected and the medical tests will be performed and repeated annually for two years (V3 and V5).
Clarify the doubts of the DiMet monitoring and the advice received. It will be a telephone visit to reinforce the intervention, with annual frequency, for two years (V2 and V4).
Report on DiMet's own foods, cooking habits, adapted recipes and other related topics. It will be for access to an ad hoc designed nutrition blog.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Controlled, parallel, multicenter, cluster-randomized clinical trial.
Masking: None (Open Label)
Primary purpose: Prevention