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

MEDISTAR STUDY: Mediterranean Diet and Smoking in Tarragona and Reus

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.

Study Overview

• Status: Completed
• Conditions: Lung Diseases
• Intervention / Treatment: Behavioral: Mediterranean diet counseling

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.

• Study Type: Interventional
• Enrollment (Actual): 566
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Spain
  • Barcelona, Spain, 08007
    • Jordi Gol i Gurina Foundation

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 25 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: INTERVENTION GROUP: MEDITERRANEAN DIET COUNSELING; During 2 years a nutritional intervention will be carried out to increase adherence to DiMet based on: annual visit of personalized nutritional education, a telephone contact for intervention reinforcement and computer access to a nutrition blog	Behavioral: Mediterranean diet counseling; 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.
No Intervention: CONTROL GROUP: WITHOUT CHANGES IN DIET; The participants of health centers will carry out the same 5 visits (3 individual visits and 2 phone calls), although no changes are induced in their usual diet and they will not be offered access to the nutritional blog.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in lung function values in smokers without previous respiratory disease	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	2 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Nutritional intervention	The effectiveness of the intervention will be measured by dietary changes by a food frequency questionnaire	2 years
Nutritional intervention	Adherence to the Mediterranean diet will be measured by dietary changes in a mediterranean diet adherence score of 14-ítem	2 years
Anthropometric parameters	Changes in anthropometric parameters: weight in kilograms and height in meters. Weight and height will be combined to report BMI in kg/m2	2 years
Anthropometric parameters	Changes in anthropometric parameters: abdominal perimeter	2 years
Changes in food consumption markers	Changes in food consumption markers: excreted of total polyphenols in fresh urine.	2 years
Changes in inflammation markers	Changes in serum inflammation markers: high-sensitivity C-reactive protein	2 years
Changes in inflammation markers	Changes in serum inflammation markers: interleukin-6	2 years

Collaborators and Investigators

• Sponsor: Fundacio d'Investigacio en Atencio Primaria Jordi Gol i Gurina
• Collaborators: Preventive Services and Health Promotion Research Network
• Investigators: Principal Investigator: Francisco Martín Luján, Catalan Institute of Health

Publications and helpful links

General Publications

• Martin-Lujan F, Catalin RE, Salamanca-Gonzalez P, Sorli-Aguilar M, Santigosa-Ayala A, Valls-Zamora RM, Martin-Vergara N, Canela-Armengol T, Arija-Val V, Sola-Alberich R. A clinical trial to evaluate the effect of the Mediterranean diet on smokers lung function. NPJ Prim Care Respir Med. 2019 Nov 27;29(1):40. doi: 10.1038/s41533-019-0153-7.
• Catalin RE, Martin-Lujan F, Salamanca-Gonzalez P, Palleja-Millan M, Villalobos F Santigosa-Ayala A, Pedret A, Valls-Zamora RM and Sola R. Mediterranean Diet and Lung Function in Adults Current Smokers: A Cross-Sectional Analysis in the MEDISTAR Project. Nutrients. 2023;15(5):1272.

Study record dates

Study Major Dates

• Study Start (Actual): June 1, 2017
• Primary Completion (Actual): June 1, 2018
• Study Completion (Actual): July 1, 2020

Study Registration Dates

• First Submitted: October 9, 2017
• First Submitted That Met QC Criteria: December 4, 2017
• First Posted (Actual): December 5, 2017

Study Record Updates

• Last Update Posted (Actual): March 14, 2023
• Last Update Submitted That Met QC Criteria: March 10, 2023
• Last Verified: February 1, 2023

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Lung Diseases
• Other Study ID Numbers: SLT002/16/00155

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No