• Increase Font Size
  • Decrease Font Size
  • View as PDF

CD: Nutritional Adequacy (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To investigate body composition, energy expenditure, substrate oxidation rate and dietary habits in patients with the classic form of celiac disease and to assess whether differences exist between newly diagnosed adult patients on a free diet and adult patients on a gluten-free diet, comparing both groups with healthy subjects.
Inclusion Criteria:
  • Diagnosis of celiac disease based on previously reported histologic evidence of subtotal or total duodenal villous atrophy
  • Euglycemic
  • Normal blood pressure
  • Normal plasma lipid profiles
Exclusion Criteria:
  • Secondary causes of intestinal atrophy
  • Consumption of drugs able to influence data collection
  • Evidence of intestinal bacterial overgrowth
  • Endocrine disorders
  • Liver or renal disease
  • Fever
  • Pregnancy
  • More than 10 cigarettes smoked daily
  • Intensive physical activity
  • None of the women were menstruating
  • Subjects under age 16, over age 60
Description of Study Protocol:

Recruitment

From March 1995 to June 1996, consecutive outpatients with celiac disease came to the Metabolism Unit of the Catholic University of Rome.

Design

Case-Control Study.

Blinding used (if applicable)

Not applicable.

Intervention (if applicable)

Gluten-free diet for those who had been treated.

Statistical Analysis

Chi-square test conducted to check for differences in distribution of sexes in the groups.  Mann Whitney U test used to compare groups.  Spearman's correlation coefficient calculated for estimates of level of association between 2 variables.

Data Collection Summary:

Timing of Measurements

One time measurements among patients and controls.

Dependent Variables

  • Body composition assessed by bioimpedance, skinfold measurements, waist, hip and arm circumferences
  • Weight, height, BMI 
  • Energy expenditure measured by indirect calorimetry
  • Antigliadin and antiendomysium antibodies assessed with ELISA
  • Blood samples drawn for determination of hemoglobin, hematocrit, albumin, total protein, transferrin, and iron concentration
  • Analysis of fecal lipid and carbohydrate through 3-day fecal samples

Independent Variables

  • Gluten-free diet - 7-day food diary collected by RD 

Control Variables

 

Description of Actual Data Sample:

Initial N: 16 newly diagnosed (4 males, 12 females) and 18 patients on a gluten-free diet (5 males, 13 females), 20 healthy volunteers (6 males, 14 females)

Attrition (final N):  as above

Age:  newly diagnosed mean age:  30.4 years; treated mean age:  27.3 years, controls mean age:  31.2 years 

Ethnicity: not mentioned

Other relevant demographics:  mean duration of GFD treatment was 43.9 months (12 - 76 months)

Anthropometrics:  Controls were age and sex matched

Location:  Italy

 

Summary of Results:

 

 

Controls (n=20)

Untreated CD (n=16)

 Treated CD (n=18)

Energy expenditure by Harris-Benedict (kJ/day)

6480 (5480 - 7650)

5710 (4810 - 6810), P < 0.001

 5860 (5060 - 7060), P < 0.001

BMR by IC (kJ/day)

6650 (5640 - 7860)

6300 (4890 - 7270)

6620 (5270 - 8070)

BMR/FFM (kJ/kg/day)

135 (122 - 162)

153 (124 - 175), P < 0.001

152 (131 - 185), P < 0.001
nonprotein RQ 0.83 (0.79 - 0.90) 0.87 (0.80 - 1.00), P < 0.05 0.79 (0.72 - 0.88), P < 0.05
Energy intake (kJ/day) 9350 (8030 - 11030) 8900 (7190 - 10570) 9040 (8110 - 10530)
CHO intake (%) 54.5 (52.6 - 55.9) 56.1 (54.0 - 58.5), P < 0.001 55.4 (54.0 - 56.4), P < 0.001
Fat intake (%) 26.3 (25.1 - 27.5) 25.8 (24.5 - 27.0), P < 0.05 27.5 (26.6 - 29.0), P < 0.05
Protein intake (%) 19.2 (16.5 - 22.1) 18.1 (14.5 - 21.4), P < 0.05 17.0 (14.7 - 19.4), P < 0.05

Other Findings

AGA and EMA were found to be positive in all untreated patients and negative in all treated ones. 

Celiac patients showed reduced body weight components but not a different fat free mass percentage compared with age- and sex-matched healthy volunteers. 

Basal metabolic rate normalized by fat free mass was higher in celiac patients than in controls.

Untreated patients showed a significantly higher non-protein respiratory quotient with regard to both treated patients (P < 0.01) and controls (P < 0.05), an increased percentage of carbohydrate intake, and a good correlation between lipid fecal loss and carbohydrate oxidation (Spearman R = 0.74, P < 0.01).

Treated patients ate more fat than untreated patients and controls, and the protein intake was lower in celiac disease patients than controls.

Author Conclusion:
In conclusion, both untreated newly diagnosed celiac patients and patients on a gluten-free diet showed a lower body weight than controls.  Since the energy intake did not differ between patients and controls, it seems reliable that weight loss can be due to the energy requirements of these patients.  Furthermore, untreated celiac disease patients utilized more carbohydrates than both treated and control subjects, probably as a consequence of the lipid malabsorption and/or of the high carbohydrate intake in the diet.
Funding Source:
University/Hospital: Universita Cattloica del Sacro Cuore
Reviewer Comments:
Compliance to GFD through food diaries and antibody testing.
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? Yes
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) Yes
  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? N/A
  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.) Yes
  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? Yes
  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.) Yes
  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? Yes
  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? Yes
  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? Yes
  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? Yes
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? Yes
  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? No
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