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

28. října 2026 aktualizováno: 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.

Přehled studie

Detailní popis

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.

Typ studie

Pozorovací

Zápis (Odhadovaný)

300

Kontakty a umístění

Tato část poskytuje kontaktní údaje pro ty, kteří studii provádějí, a informace o tom, kde se tato studie provádí.

Studijní kontakt

Studijní záloha kontaktů

Studijní místa

    • BS
      • Brescia, BS, Itálie, 25123
        • Nábor
        • ASST Spedali Civili di Brescia, Gastroenterologia
        • Kontakt:
    • FE
      • Ferrara, FE, Itálie, 44121
        • Nábor
        • Università degli Studi di Ferrara
        • Kontakt:
    • Michigan
      • Milan, Michigan, Itálie, 20122
        • Nábor
        • Center for Prevention and Diagnosis of Celiac Disease - Gastroenterology and Endoscopy Unit, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico
        • Kontakt:
    • PD
      • Padua, PD, Itálie, 35128
        • Nábor
        • University of Padua, Department of Surgery, Oncology and Gastroenterology
        • Kontakt:
    • PV
      • Pavia, PV, Itálie, 27100
        • Nábor
        • Fondazione IRCCS Policlinico San Matteo, SC Medicina Generale
        • Kontakt:
      • Pavia, PV, Itálie, 27100
        • Nábor
        • ICS Maugeri SpA IRCCS, Gastroenterology Unit
        • Kontakt:
    • RA
      • Ravenna, RA, Itálie, 48121
        • Nábor
        • Gastroenterology Unit, Santa Maria delle Croci Hospital
        • Kontakt:

Kritéria účasti

Výzkumníci hledají lidi, kteří odpovídají určitému popisu, kterému se říká kritéria způsobilosti. Některé příklady těchto kritérií jsou celkový zdravotní stav osoby nebo předchozí léčba.

Kritéria způsobilosti

Věk způsobilý ke studiu

18 let a starší (Dospělý, Starší dospělý)

Přijímá zdravé dobrovolníky

Ne

Pohlaví způsobilá ke studiu

Všechno

Metoda odběru vzorků

Vzorek nepravděpodobnosti

Studijní populace

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.

Popis

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

Studijní plán

Tato část poskytuje podrobnosti o studijním plánu, včetně toho, jak je studie navržena a co studie měří.

Jak je studie koncipována?

Detaily designu

  • Observační modely: OTHER
  • Časové perspektivy: CROSS_SECTIONAL

Kohorty a intervence

Skupina / kohorta
Intervence / Léčba
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.

Ostatní jména:
  • 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.

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

Co je měření studie?

Primární výstupní opatření

Měření výsledku
Popis opatření
Časové okno
Celiac Disease Gastrointestinal Symptom Rating Scale (CeD-GSRS) Score
Časové okno: 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
Časové okno: 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)
Časové okno: 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)
Časové okno: 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)

Sekundární výstupní opatření

Měření výsledku
Popis opatření
Časové okno
Short Questionnaire of Highly Processed Food Consumption (sQ-HPF) Score
Časové okno: 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)
Časové okno: 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
Časové okno: 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
Časové okno: 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
Časové okno: 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
Časové okno: 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
Časové okno: 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
Časové okno: 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
Časové okno: 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)

Další výstupní opatření

Měření výsledku
Popis opatření
Časové okno
Hemoglobin
Časové okno: 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
Časové okno: 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
Časové okno: 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
Časové okno: 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)
Časové okno: 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
Časové okno: 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)
Časové okno: 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)
Časové okno: 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)
Časové okno: 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
Časové okno: 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)

Spolupracovníci a vyšetřovatelé

Zde najdete lidi a organizace zapojené do této studie.

Termíny studijních záznamů

Tato data sledují průběh záznamů studie a předkládání souhrnných výsledků na ClinicalTrials.gov. Záznamy ze studií a hlášené výsledky jsou před zveřejněním na veřejné webové stránce přezkoumány Národní lékařskou knihovnou (NLM), aby se ujistily, že splňují specifické standardy kontroly kvality.

Hlavní termíny studia

Začátek studia (Aktuální)

1. července 2025

Primární dokončení (Odhadovaný)

31. prosince 2026

Dokončení studie (Odhadovaný)

31. prosince 2026

Termíny zápisu do studia

První předloženo

23. října 2026

První předloženo, které splnilo kritéria kontroly kvality

28. října 2026

První zveřejněno (Aktuální)

4. listopadu 2026

Aktualizace studijních záznamů

Poslední zveřejněná aktualizace (Aktuální)

4. listopadu 2026

Odeslaná poslední aktualizace, která splnila kritéria kontroly kvality

28. října 2026

Naposledy ověřeno

1. října 2026

Více informací

Termíny související s touto studií

Plán pro data jednotlivých účastníků (IPD)

Plánujete sdílet data jednotlivých účastníků (IPD)?

NE

Popis plánu IPD

IPD not shared due to privacy and data protection regulations.

Informace o lécích a zařízeních, studijní dokumenty

Studuje lékový produkt regulovaný americkým FDA

Ne

Studuje produkt zařízení regulovaný americkým úřadem FDA

Ne

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