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Impact of Mediterranean Diet and Processed Food Consumption on Gastrointestinal Symptoms in Coeliac Patients on a Gluten-Free Diet

28 octobre 2026 mis à jour par: Istituti Clinici Scientifici Maugeri SpA

MEDITERRANEAN DIET, HIGHLY PROCESSED FOODS AND THEIR IMPACT ON GASTROINTESTINAL SYMPTOMS, NUTRITIONAL STATUS AND QUALITY OF LIFE IN ADULT COELIAC DISEASE PATIENTS ON A GLUTEN FREE DIET: A MULTICENTRE CROSS-SECTIONAL STUDY

Coeliac disease is a lifelong autoimmune condition in which the immune system reacts to gluten, a protein found in wheat, barley and rye, affecting about 1% of the general population. The only currently approved treatment is a strict, lifelong gluten-free diet (GFD). Although strict adherence to a gluten-free diet leads to mucosal recovery in most patients, up to 20-30% of coeliac patients continue to experience persistent gastrointestinal symptoms (such as abdominal pain, bloating, diarrhoea or constipation). Furthermore, commercially prepared gluten-free products often contain higher amounts of fat, sugar and salt, and lower amounts of fibre, protein, folate and vitamins compared with gluten-containing equivalents.

Conversely, the Mediterranean diet-rich in vegetables, fruits, legumes, fish, nuts and extra-virgin olive oil-is widely recognised for its benefits on cardiovascular, metabolic and gut health, as well as quality of life, in contrast to diets rich in highly or ultra-processed foods.

This multicentre cross-sectional observational study aims to evaluate whether adult coeliac patients on a long-term strict gluten-free diet whose habitual diet more closely aligns with the Mediterranean dietary pattern are less likely to experience persistent gastrointestinal symptoms and have a better quality of life and nutritional status, and conversely whether higher consumption of highly processed foods is associated with worse symptoms, poorer quality of life and less adequate nutritional status. No dietary intervention is provided as part of the study; participants complete validated questionnaires and undergo routine anthropometric and blood assessments during a single regular outpatient follow-up visit.

Aperçu de l'étude

Statut

Recrutement

Les conditions

Intervention / Traitement

Description détaillée

This is a multicentre, observational, cross-sectional, no-profit study promoted and coordinated by ICS Maugeri SpA IRCCS di Pavia (Protocol Code: CTSPV40-24).

Objectives:

  • Primary Objective: To evaluate the relationship between adherence to a Mediterranean diet and gastrointestinal symptoms, coeliac disease-related quality of life, and nutritional status in a population of adult coeliac patients on a strict gluten-free diet (GFD) regularly followed at participating gastroenterology outpatient clinics.
  • Secondary Objective: To evaluate whether coeliac patients who consume higher amounts of highly processed (ultra-processed) foods have more persistent gastrointestinal symptoms, a worse quality of life, and a less adequate nutritional status.

Study Procedures and Observational Nature:

Patients attending routine gastroenterology outpatient follow-up visits will be invited to participate. All enrolled patients must have been on a strict GFD for at least 12 months with histological evidence of duodenal mucosal recovery on a follow-up biopsy. As clarified with the Ethics Committee (CET Lombardia 6), no specific Mediterranean diet is prescribed or provided within this study: all patients were instructed on how to follow a strict GFD at the time of coeliac disease diagnosis by expert physicians or dietitians as part of standard clinical practice, completely independently of this study. During a single study visit (with no scheduled study follow-up), the degree of adherence to the Mediterranean diet, consumption of highly processed foods, GFD compliance, gastrointestinal symptoms, and quality of life are assessed using standardized, validated questionnaires:

  1. PyrMDS: 15-item Pyramid-based Mediterranean Diet Score (score range 0-15).
  2. sQ-HPF: Short screening Questionnaire of Highly Processed Food consumption (score range 0-14 and % HPF).
  3. Biagi GFD Score: Gluten-free diet adherence score (score range 0-4).
  4. GSRS-CD (CeD-GSRS): Gastrointestinal Symptom Rating Scale including the 10 items on the Celiac Disease domains (7-point Likert scale per item).
  5. CDQ (CD-QOL): Celiac Disease-specific Quality of Life scale, Italian validated version (20 items on a 5-point Likert scale).

Nutritional status is evaluated through standard anthropometric measurements (height, weight, BMI, waist circumference) and routine clinical practice biochemical blood tests (hemoglobin, ferritin, folate, vitamin B12, vitamin D, calcium, albumin, ALT, AST, GGT, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, and fasting glucose).

Sample Size and Statistical Plan:

A minimum of 300 adult coeliac patients will be enrolled across 10 Italian centres over approximately 12-18 months (providing ~75% power to detect a small-to-medium effect size of Cohen's d = 0.3 at alpha = 0.05, and >80% power for Cohen's d = 0.5, while supporting multivariable regression models). Descriptive statistics, independent samples t-tests or Mann-Whitney U tests, Chi-square or Fisher's exact tests, Pearson's or Spearman's correlation coefficients, multiple linear regression models (for continuous outcomes), and multivariable logistic regression models (for dichotomous outcomes such as presence/absence of persistent gastrointestinal symptoms) will be used, adjusting for potential confounders including age, sex, duration of GFD, and comorbidities. Missing data on key variables will be addressed via multiple imputation with sensitivity analyses. Two-sided p-values < 0.05 will be considered statistically significant.

Type d'étude

Observationnel

Inscription (Estimé)

300

Contacts et emplacements

Cette section fournit les coordonnées de ceux qui mènent l'étude et des informations sur le lieu où cette étude est menée.

Coordonnées de l'étude

Sauvegarde des contacts de l'étude

Lieux d'étude

    • BS
      • Brescia, BS, Italie, 25123
        • Recrutement
        • ASST Spedali Civili di Brescia, Gastroenterologia
        • Contact:
    • FE
      • Ferrara, FE, Italie, 44121
        • Recrutement
        • Università degli Studi di Ferrara
        • Contact:
          • Giacomo Caio
          • Numéro de téléphone: caigmp@unife.it
          • E-mail: caigmp@unife.it
    • Michigan
      • Milan, Michigan, Italie, 20122
        • Recrutement
        • Center for Prevention and Diagnosis of Celiac Disease - Gastroenterology and Endoscopy Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico
        • Contact:
    • PD
      • Padua, PD, Italie, 35128
        • Recrutement
        • University of Padua, Department of Surgery, Oncology and Gastroenterology
        • Contact:
    • PV
      • Pavia, PV, Italie, 27100
        • Recrutement
        • Fondazione IRCCS Policlinico San Matteo, SC Medicina Generale
        • Contact:
      • Pavia, PV, Italie, 27100
        • Recrutement
        • ICS Maugeri SpA IRCCS, Gastroenterology Unit
        • Contact:
    • RA
      • Ravenna, RA, Italie, 48121
        • Recrutement
        • Gastroenterology Unit, Santa Maria delle Croci Hospital
        • Contact:

Critères de participation

Les chercheurs recherchent des personnes qui correspondent à une certaine description, appelée critères d'éligibilité. Certains exemples de ces critères sont l'état de santé général d'une personne ou des traitements antérieurs.

Critère d'éligibilité

Âges éligibles pour étudier

18 ans et plus (Adulte, Adulte plus âgé)

Accepte les volontaires sains

Non

Sexes éligibles pour l'étude

Tout

Méthode d'échantillonnage

Échantillon non probabiliste

Population étudiée

Adult patients (age > 18 years) with biopsy-confirmed coeliac disease on a strict gluten-free diet for at least 12 months and with histological evidence of mucosal recovery on follow-up duodenal biopsy, consecutively recruited during routine follow-up visits at 10 participating Italian gastroenterology outpatient clinics.

La description

Inclusion Criteria:

  • Adult patients (age > 18 years)
  • Diagnosis of coeliac disease based on positive IgA tissue transglutaminase / endomysial antibodies and villous atrophy on duodenal biopsy in accordance with major international guidelines
  • Strict adherence to a gluten-free diet (GFD) for at least 12 months
  • Evidence of duodenal mucosal recovery on a follow-up biopsy
  • Regularly attending the participating gastroenterology outpatient clinics for follow-up

Exclusion Criteria:

  • Coeliac patients with poor gluten-free diet adherence and/or evidence of persistent villous atrophy on follow-up duodenal biopsy
  • Patients who follow a vegetarian/vegan diet or other restrictive diets

Plan d'étude

Cette section fournit des détails sur le plan d'étude, y compris la façon dont l'étude est conçue et ce que l'étude mesure.

Comment l'étude est-elle conçue ?

Détails de conception

  • Modèles d'observation: OTHER
  • Perspectives temporelles: CROSS_SECTIONAL

Cohortes et interventions

Groupe / Cohorte
Intervention / Traitement
Adult Coeliac Disease Patients on a Long-Term Gluten-Free Diet

Adult patients (age > 18 years) with biopsy-proven coeliac disease on a strict gluten-free diet for at least 12 months and with documented duodenal mucosal recovery on follow-up biopsy, attending routine gastroenterology outpatient follow-up visits at the participating centres.

Observational assessment of the degree of adherence to the Mediterranean dietary pattern within the patient's habitual gluten-free diet, measured using the validated 15-item Pyramid-based Mediterranean Diet Score (PyrMDS, continuous score 0 to 15 across 15 food groups: vegetables, legumes, fruits, nuts, cereals, dairy, fish, red meat, processed meat, white meat, eggs, potatoes, sweets, alcohol, and olive oil). No dietary intervention is administered.

Autres noms:
  • 15-Items Pyramid-based Mediterranean Diet Score (PyrMDS)

Observational assessment of habitual consumption of highly processed / ultra-processed foods within the patient's gluten-free diet, measured using the validated short screening Questionnaire of Highly Processed Food consumption (sQ-HPF, score range 0 to 14 and estimated % HPF). No dietary intervention is administered.

Autres noms:
  • Short Questionnaire of Highly Processed Food consumption (sQ-HPF)
  • Ultra-Processed Foods (UPF) intake

Que mesure l'étude ?

Principaux critères de jugement

Mesure des résultats
Description de la mesure
Délai
Celiac Disease Gastrointestinal Symptom Rating Scale (CeD-GSRS) Score
Délai: Baseline (Single cross-sectional study visit, Day 1)

Severity of gastrointestinal symptoms over the past week, measured with the 10-item CeD-GSRS. Each item is rated on a 7-point Likert scale (1 = no discomfort at all; 7 = very severe discomfort). The score is the mean of the 10 items, ranging from 1 to 7, and higher scores indicate more severe symptoms. The score will be analysed in relation to Mediterranean diet adherence (PyrMDS) and highly processed food consumption (sQ-HPF), using correlation and multivariable linear regression.

Baseline (Single cross-sectional study visit, Day 1)
Celiac Disease-Specific Quality of Life (CD-QOL) Score
Délai: Baseline (Single cross-sectional study visit, Day 1)

Coeliac disease-specific quality of life over the past 30 days, measured with the Italian validated 20-item CD-QOL. Items are rated on a 5-point Likert scale and the total score is transformed to a 0-100 scale, where higher scores indicate better quality of life. The score will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation and multivariable linear regression.

Baseline (Single cross-sectional study visit, Day 1)
Pyramid-based Mediterranean Diet Score (PyrMDS)
Délai: Baseline (Single cross-sectional study visit, Day 1)

Adherence to the Mediterranean dietary pattern, measured with the 15-item PyrMDS. The score is continuous and ranges from 0 to 15, where higher scores indicate greater adherence.

Baseline (Single cross-sectional study visit, Day 1)
Body Mass Index (BMI)
Délai: Baseline (Single cross-sectional study visit, Day 1)

BMI is calculated from measured weight and height (kg/m²). It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation and multivariable linear regression.

Baseline (Single cross-sectional study visit, Day 1)

Mesures de résultats secondaires

Mesure des résultats
Description de la mesure
Délai
Short Questionnaire of Highly Processed Food Consumption (sQ-HPF) Score
Délai: Baseline (Single cross-sectional study visit, Day 1)

Habitual consumption of highly processed foods, measured with the sQ-HPF. The score ranges from 0 to 14, where higher scores indicate greater consumption.

Baseline (Single cross-sectional study visit, Day 1)
Gluten-Free Diet Adherence (Biagi Score)
Délai: Baseline (Single cross-sectional study visit, Day 1)

Adherence to the gluten-free diet, measured with the Biagi score. The score ranges from 0 to 4, where higher scores indicate stricter adherence.

Baseline (Single cross-sectional study visit, Day 1)
Percentage of Participants with Persistent Gastrointestinal Symptoms
Délai: Baseline (Single cross-sectional study visit, Day 1)

The proportion of participants with persistent self-reported gastrointestinal symptoms. This proportion will be analysed in relation to PyrMDS and sQ-HPF scores using multivariable logistic regression.

Baseline (Single cross-sectional study visit, Day 1)
Waist Circumference
Délai: Baseline (Single cross-sectional study visit, Day 1)

Waist circumference (cm), measured according to standard procedures. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Total Cholesterol
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum total cholesterol (mg/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
LDL Cholesterol
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum LDL cholesterol (mg/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
HDL Cholesterol
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum LDL cholesterol (mg/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Triglycerides
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum triglycerides (mg/dL) from routine blood tests. They will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Fasting Glucose
Délai: Baseline (Single cross-sectional study visit, Day 1)

Fasting plasma glucose (mg/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)

Autres mesures de résultats

Mesure des résultats
Description de la mesure
Délai
Hemoglobin
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum hemoglobin concentration (g/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Ferritin
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum ferritin concentration (ng/mL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Folate
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum folate concentration (ng/mL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Vitamin B12
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum vitamin B12 concentration (pg/mL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Vitamin D (25-hydroxyvitamin D)
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum 25-hydroxyvitamin D concentration (ng/mL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Albumin
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum albumin concentration (g/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Alanine Aminotransferase (ALT)
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum ALT (U/L) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Aspartate Aminotransferase (AST)
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum AST (U/L) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Gamma-Glutamyl Transferase (GGT)
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum GGT (U/L) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)
Calcium
Délai: Baseline (Single cross-sectional study visit, Day 1)

Serum calcium concentration (mg/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.

Baseline (Single cross-sectional study visit, Day 1)

Collaborateurs et enquêteurs

C'est ici que vous trouverez les personnes et les organisations impliquées dans cette étude.

Parrainer

Collaborateurs

Les enquêteurs

  • Chercheur principal: Annalisa Schiepatti, MD, PhD, ICS Maugeri SpA IRCCS

Dates d'enregistrement des études

Ces dates suivent la progression des dossiers d'étude et des soumissions de résultats sommaires à ClinicalTrials.gov. Les dossiers d'étude et les résultats rapportés sont examinés par la Bibliothèque nationale de médecine (NLM) pour s'assurer qu'ils répondent à des normes de contrôle de qualité spécifiques avant d'être publiés sur le site Web public.

Dates principales de l'étude

Début de l'étude (Réel)

1 juillet 2025

Achèvement primaire (Estimé)

31 décembre 2026

Achèvement de l'étude (Estimé)

31 décembre 2026

Dates d'inscription aux études

Première soumission

23 octobre 2026

Première soumission répondant aux critères de contrôle qualité

28 octobre 2026

Première publication (Réel)

4 novembre 2026

Mises à jour des dossiers d'étude

Dernière mise à jour publiée (Réel)

4 novembre 2026

Dernière mise à jour soumise répondant aux critères de contrôle qualité

28 octobre 2026

Dernière vérification

1 octobre 2026

Plus d'information

Termes liés à cette étude

Autres numéros d'identification d'étude

  • CTSPV40-24

Plan pour les données individuelles des participants (IPD)

Prévoyez-vous de partager les données individuelles des participants (DPI) ?

NON

Description du régime IPD

IPD not shared due to privacy and data protection regulations.

Informations sur les médicaments et les dispositifs, documents d'étude

Étudie un produit pharmaceutique réglementé par la FDA américaine

Non

Étudie un produit d'appareil réglementé par la FDA américaine

Non

Ces informations ont été extraites directement du site Web clinicaltrials.gov sans aucune modification. Si vous avez des demandes de modification, de suppression ou de mise à jour des détails de votre étude, veuillez contacter register@clinicaltrials.gov. Dès qu'un changement est mis en œuvre sur clinicaltrials.gov, il sera également mis à jour automatiquement sur notre site Web .