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Completed

NCT Number: NCT03362372

Effect of the Mediterranean Diet on Lung Function in Smokers Without Previous Respiratory Disease

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.

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Key information

Conditions

Lung Diseases Respiratory Tract Diseases

Age range

25 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Jordi Gol i Gurina Foundation

Barcelona, 08007, Spain

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

Mediterranean diet counseling

Behavioral

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.

Primary outcomes

  1. Change in lung function values in smokers without previous respiratory disease

    Time frame: 2 years

    Changes in lung function measured by spirometry. An altered lung function was considered if values of FVC <80% and / or FEV1 <80% and / or FEV1 / FVC <0.7

Secondary outcomes

  1. Nutritional intervention

    Time frame: 2 years

    The effectiveness of the intervention will be measured by dietary changes by a food frequency questionnaire

  2. Nutritional intervention

    Time frame: 2 years

    Adherence to the Mediterranean diet will be measured by dietary changes in a mediterranean diet adherence score of 14-ítem

  3. Anthropometric parameters

    Time frame: 2 years

    Changes in anthropometric parameters: weight in kilograms and height in meters. Weight and height will be combined to report BMI in kg/m2

  4. Anthropometric parameters

    Time frame: 2 years

    Changes in anthropometric parameters: abdominal perimeter

  5. Changes in food consumption markers

    Time frame: 2 years

    Changes in food consumption markers: excreted of total polyphenols in fresh urine.

  6. Changes in inflammation markers

    Time frame: 2 years

    Changes in serum inflammation markers: high-sensitivity C-reactive protein

  7. Changes in inflammation markers

    Time frame: 2 years

    Changes in serum inflammation markers: interleukin-6

Sponsors and collaborators

Lead sponsor

Fundacio d'Investigacio en Atencio Primaria Jordi Gol i Gurina

Other

Collaborators

  • Preventive Services and Health Promotion Research Network

Registry information

Official study title

MEDISTAR STUDY: Mediterranean Diet and Smoking in Tarragona and Reus

Acronym: MEDISTAR

Important dates

Study start
2017
Primary completion
2018
Study completion
2020
First posted
Dec 5, 2017
Registry last updated
Mar 14, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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