CD: Bone Density (2006)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To evaluate outcome, continuity of care and adherence to a gluten-free diet in adults with celiac disease followed-up after 28 years.
Inclusion Criteria:

Original childhood diagnosis of celiac disease confirmed, arbitrarily included only those with a minimum disease duration of > 20 years.  Original childhood diagnosis confirmed if one of the following criteria were fulfilled:

  • Verifiable subtotal villous atrophy or partial villous atrophy on duodenojejunal biopsy obtained after the age of 24 months and positive endomysial antibody (EMA or antitissue transglutaminase) serology in adulthood if not adhering to a GFD
  • Duodenojejunal histology consistent with celiac disease during childhood and positive serology in adult life.
Exclusion Criteria:

A patient was considered not celiac if they were found to have negative serology on a full gluten-containing diet and either a nondiagnostic biopsy after the age of 24 months, or had only a single abnormal biopsy.

Description of Study Protocol:

Recruitment

Childhood celiac disease patients diagnosed in a pediatric unit during 1959 - 1976 were selected.

Design

Cross-sectional.

Blinding used (if applicable)

Not applicable.

Intervention (if applicable)

Outcome, continuity of care and adherence to GFD for 28 years.

Statistical Analysis

Frequencies were reported.

Data Collection Summary:

Timing of Measurements

Selected participants were invited for a follow-up medical assessment.

Dependent Variables

  • Bone mineral density measurement using DEXA at lumbar spine and left femoral neck
  • Quality-of-life assessment using Short Form 36 Health Survey (SF-36)
  • Dietary evaluation - classify dietary compliance as complete (0 g gluten), partial (<10 g gluten) or none (>10 g gluten), with reasons for dietary adherence or noncompliance established during interview.  Formal dietary assessment for quantification of gluten ingestion was performed by a clinical nutritionist, using a random 24-hour assessment.   
  • Clinical history and examination - measurements of height, weight, BMI, height/weight ratios
  • Hematological and biochemical parameters
  • Small intestinal biopsy offered if it was considered required for confirmation of the original diagnosis in childhood

Independent Variables

  • Gluten free diet

Control Variables

 

Description of Actual Data Sample:

Initial N: 327 patients identified.  Medical records traced for 293 patients.  6 were deceased.  287 were contacted, 141 replied and 101 attended (34 were unable and 4 refused).  Of 101 reviews, a confident diagnosis of celiac disease confirmed in 50 cases.

Attrition (final N):  50

Age:  Mean and median age of group was 35 years old. 

Ethnicity:  Not mentioned 

Other relevant demographics:  Mean duration of celiac disease was 28.5 years, median 28.7 years, range 22 - 45 years. 

Anthropometrics (e.g., were groups same or different on important measures)

Location:  Cork and Affiliated Teaching Hospitals, Cork, Ireland 

 

Summary of Results:

Other Findings

Only 22% of patients were enrolled in an adult gastroenterology clinic.  50% were fully compliant with GFD, 18% were partially compliant, 32% were not adhering to the diet.  The main motivating factor for dietary compliance was avoidance of symptoms rather than avoidance of complications.

83% of the females and 21% of the males had iron deficiency (ferritin < 50 ng/ml), although hemoglobin was within normal limits in 83% of females and 95% of males (>12 g/dl in females and >14 g/dl in males).  There were no biochemical abnormalities.

Bone mineral density was subnormal in 32%.  28.9% were osteopenic and 2.6% were osteoporotic.

Quality of life scores were normal, and in fact scored marginally higher on each of the 8 scales measured.

Author Conclusion:
In conclusion, patients who are diagnosed with celiac disease in childhood are frequently lost from active follow up in adulthood.  One-third are not compliant with diet; in those who do comply, the primary motivating factor for those who do comply is avoidance of symptoms rather than avoidance of complications.  Therefore, continual formal review in adulthood is desirable.  These young adults have a worrisome prevalence of iron deficiency and low BMD that are preventable and treatable.  While the risk of autoimmunity needs further study, the development of malignancy can be offset by gluten restriction.
Funding Source:
Not-for-profit
0
Foundation associated with industry:
Reviewer Comments:
More sophisticated statistical analysis would have clarified relationships between dietary compliance and the other outcomes related to iron deficiency and bone density.  Findings would have been stronger if compared to age- and sex-matched healthy controls.
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) Yes
  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) Yes
 
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? Yes
  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? Yes
  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? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? Yes
3. Were study groups comparable? N/A
  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? No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) No
  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.) No
  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? Yes
  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? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  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? Yes
  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? Yes
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  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? No
  8.1. Were statistical analyses adequately described and the results reported appropriately? No
  8.2. Were correct statistical tests used and assumptions of test not violated? No
  8.3. Were statistics reported with levels of significance and/or confidence intervals? No
  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? No
  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