An observational study in Celiac Disease, Gluten-free Diet and Gastrointestinal Symptoms, sponsored by Istituti Clinici Scientifici Maugeri SpA. Recruiting at 7 sites in Italy. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-04.
Sponsored by Istituti Clinici Scientifici Maugeri SpA · Observational
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.
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:
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:
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.
340 studies on the registry are indexed under Celiac Disease; 80 are open to participants now.
This study's planned enrollment of 300 is above the median of 160 across 129 observational studies indexed under Celiac Disease.
Browse Celiac Disease studies →Istituti Clinici Scientifici Maugeri SpA is the lead sponsor of 125 studies on the registry; 52 are open to participants now.
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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.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
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.
Other: Mediterranean Diet Adherence Evaluation · Other: Highly Processed Food Consumption Evaluation
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.
Also known as: 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.
Also known as: Short Questionnaire of Highly Processed Food consumption (sQ-HPF), Ultra-Processed Foods (UPF) intake
Celiac Disease Gastrointestinal Symptom Rating Scale (CeD-GSRS) Score
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.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Celiac Disease-Specific Quality of Life (CD-QOL) Score
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.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Pyramid-based Mediterranean Diet Score (PyrMDS)
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.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Body Mass Index (BMI)
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.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Short Questionnaire of Highly Processed Food Consumption (sQ-HPF) Score
Habitual consumption of highly processed foods, measured with the sQ-HPF. The score ranges from 0 to 14, where higher scores indicate greater consumption.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Gluten-Free Diet Adherence (Biagi Score)
Adherence to the gluten-free diet, measured with the Biagi score. The score ranges from 0 to 4, where higher scores indicate stricter adherence.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Percentage of Participants with Persistent Gastrointestinal Symptoms
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.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Waist Circumference
Waist circumference (cm), measured according to standard procedures. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Total Cholesterol
Serum total cholesterol (mg/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
LDL Cholesterol
Serum LDL cholesterol (mg/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
HDL Cholesterol
Serum LDL cholesterol (mg/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Triglycerides
Serum triglycerides (mg/dL) from routine blood tests. They will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Fasting Glucose
Fasting plasma glucose (mg/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Hemoglobin
Serum hemoglobin concentration (g/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Ferritin
Serum ferritin concentration (ng/mL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Folate
Serum folate concentration (ng/mL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Vitamin B12
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.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Vitamin D (25-hydroxyvitamin D)
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.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Albumin
Serum albumin concentration (g/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Alanine Aminotransferase (ALT)
Serum ALT (U/L) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Aspartate Aminotransferase (AST)
Serum AST (U/L) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Gamma-Glutamyl Transferase (GGT)
Serum GGT (U/L) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Calcium
Serum calcium concentration (mg/dL) from routine blood tests. It will be analysed in relation to PyrMDS and sQ-HPF scores, using correlation analysis.
Time frame: Baseline (Single cross-sectional study visit, Day 1)
Plan to share: No — IPD not shared due to privacy and data protection regulations.
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