MNT: Gastrointestinal Disorders (2015


Pulido O, Zarkadas M, Dubois S, MacIsaac K, Cantin I, La Vieille S, Godefroy S, Rashid M. Clinical features and symptom recovery on a gluten-free diet in Canadian adults with celiac disease. Can J Gastroenterol. 2013; 27 (8): 449-453.

PubMed ID: 23936873
Study Design:
Cross-Sectional Study
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
To describe the clinical features, time to diagnosis and symptom recovery in Canadian adults diagnosed with celiac disease (CD) and dermatitis herpetiformis after treatment with a gluten-free (GF) diet.
Inclusion Criteria:
Members of two major celiac support organizations in Canada were surveyed:
  • Members of the Canadian Celiac Association (CCA) and the Fondation Québécoise de la Maladie Coeliaque (FQMC)
  • Older than 18 years old
  • Biopsy-confirmed CD and dermatitis herpetiformis diagnosis.
Exclusion Criteria:
Respondents who did not have a biopsy-confirmed CD and dermatitis herpetiformis diagnosis.
Description of Study Protocol:

Members of the Canadian Celiac Association (CCA) and the Fondation Québécoise de la Maladie Coeliaque (FQMC) were mailed questionnaires regarding demographic information, diagnoses, symptoms and recovery while on a GF diet.


Cross-sectional survey research design.

Statistical Analysis

  • Continuous variables were summarized using means (SD) and discrete variables were presented as frequency (percentage)
  • ANOVA and chi-square tests were used to determine statistical differences in frequency of recovery and quality of life between groups that had reported adhering to the GF diet for varying lengths of time (less than one year, one to five years and more than five years).
Data Collection Summary:
Timing of Measurements

Responses from questionnaire reported over one time period

Dependent Variables

Self-reported responses to questionnaire items regarding demographics (age, gender, age at diagnosis, year of diagnosis) and clinical features of CD (mean duration of symptoms, type and frequency of symptoms and quality of life).
Description of Actual Data Sample:

Initial N

10,693 households surveyed.

Attrition (Final N)

  • 7,823 completed questionnaire (72% response rate)
  • 5,912 of respondents reported having had a biopsy confirmed diagnosis (75% or respondents, or 55% of those surveyed),


  • Mean (SD):  56.4 (15.2) years, range 18 to 93 years
  • Mean (SD) at diagnosis: 45.4 (16.4) years, median 46 years.

Other Relevant Demographics

A 3:1 ratio of females to males; 76% female vs. 24% male.


Respondents resided within the 10 Canadian provinces and two of three territories (Northwest and Yukon).


Summary of Results:

Key Findings

Symptoms Before GF Diet Self Report Full Recovery Post GF Diet
Abdominal pain/bloating 84.9* 62.9†
Extreme weakness/tiredness 74.2* 65.7†
Diarrhea 71.7 75.3†
Anemia 67.8* 80.1†
Weight loss 63.5 89.9
Irritability 55.7* 58.9
Foul stools 54.4* 79.1
Feeling depressed 47.3* 55.7
Mood swings 45.1* 52.8
Bone/joint pain 44.2* 35.5
Itchy skin 40.3 39.4
Easy bruising 38.1* 34.0
Muscle cramps 37.9* 49.7†
Constipation 36.5* 52.3†
Oral ulcers 30.9* 66.9
Lactose intolerance 28.9* 42.9
Migraine 28.6* 52.5
Nausea/vomiting 26.9* 81.7

*Significantly more women than men experienced the symptom before starting a GFD (P<0.01)
†Significantly more men than women had fully recovered from the symptom at the time the survey was conducted

Other Findings

Duration of symptoms prior to diagnosis
  • Overall: 12±14.4 years
  • Females: 12.6±14.4 years
  • Males: 10.3±14.1 years.
Clinical symptoms and recovery after GF diet
  • No symptoms prior to diagnosis (N=43, 0.7%)
  • Anemia the only symptom prior to diagnosis (N=38, 0.6%)
  • Adherence  to GF diet:
    • 55.7% self-reported adhering for more than five years
    • 32.4% self-reported adhering for one to five years
    • 8.1% self-reported adhering for less than one year
    • Length of time on GF diet was significantly associated with symptom recovery; more men than women reported full recovery (p<0.01)
    • Full symptom recovery (abdominal pain/bloating, weakness, diarrhea, anemia, weight loss, irritability, foul stools, mood swings, itchy skin and nausea/vomiting) was higher in those who reported adhering to a GF diet for a longer time (P<0.01).
Quality of life (QOL)
  • 55.7% of respondents reported excellent to very good QOL; 54.4% women and 60% men (P<0.01)  
  • 47.8% following a GF diet less than one year vs. 57.2% following a GF diet more than five years rated QOL as excellent/very good (P<0.01).
Symptoms post-ingestion of gluten while on GF diet
  • 80% reported experiencing symptoms after ingestion of gluten
  • Median time between ingestion  and symptom onset was two hours (mean 6.4 hours):
    • Symptom duration median 24 hours (mean 39.3 hours).



Author Conclusion:

Diagnosis of CD in Canada remains long despite increased availability of serological testing. Many adult patients continue to experience symptoms even after adhering to a GF diet for more than five years, with women experiencing significantly more symptoms and a lower recovery rate than men. Effective strategies for both the public and the medical profession, especially family physicians and dietitians, need to be developed for timely diagnosis, appropriate management and follow-up of patients with CD.


Funding Source:
Government: Bureau of ChemicalSafety, Health Canada
J Alexander Campbell Research Fund of the Canadian Celiac Association
Reviewer Comments:
  • Good response rate and representation from various sections of Canada
  • Recall bias may affect responses
  • Random sampling and use of members in CD organizations may limit generalizability somewhat
  • Did not assess care provided by a RD; only noted the importance of referring CD patients to a dietitian for appropriate nutrition counseling.
  • Did not ask participants about the quality or usefulness of the RD care.
Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) N/A
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? N/A
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? No
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? Yes
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? No
  2.4. Were the subjects/patients a representative sample of the relevant population? No
3. Were study groups comparable? ???
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? ???
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? No
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) N/A
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? Yes
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? N/A
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? N/A
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? No
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? ???
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? No
  7.5. Was the measurement of effect at an appropriate level of precision? N/A
  7.6. Were other factors accounted for (measured) that could affect outcomes? No
  7.7. Were the measurements conducted consistently across groups? N/A
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  8.6. Was clinical significance as well as statistical significance reported? N/A
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes