DM: Carbohydrates (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To compare the glycemic responses of adolescents with type 1 diabetes and fasting euglycemia to high-sucrose and moderate-sucrose-containing foods eaten in test meals.
Inclusion Criteria:
  • type 1 diabetes
  • adolescent
  • diabetes duration of two years or more
  • minimal or no insulin secretory capacity

 

Exclusion Criteria:
  • evidence of retinopathy, neuropathy, untreated hypothyroidism
  • obesity
Description of Study Protocol:

Recruitment: not specified

Design:  Randomized Controlled Crossover Design.  Method of randomization not described. 

  • each participant underwent two 4-hour study periods during which they were randomized in crossover design to receive a high-sucrose meal or a moderate-sucrose meal.
  • a modified insulin clamp technique used overnight before the study to achieve fasting euglycemia.  Insulin and 20% dextrose were infused to achieve a blood glucose level of approximately 5.0 mmol/L at the start of the study period.
  • regular insulin was administered 15 minutes before the breakfast meal

Blinding used (if applicable):  not specified.  Lab tests used.

Intervention (if applicable):

  • Test meals for breakfast and a mid-morning snack
    • High-sucrose diet (35% sucrose)
      • isocaloric to moderate-sucrose diet
      • some starch replaced with sucrose
    • Moderate-sucrose diet (17% sucrose)
  • All foods weighed, measured, and consumed completely
  • The only biologically meaningful difference between diets were the intakes of starch and sucrose
  • Glucose, fructose, and fiber differed slightly between the two diets

Statistical Analysis

  • Areas under the glucose and free insulin response curves were calculated using the trapezoidal rule
  • 2-way repeated measures of analysis of variance used to assess differences between the blood glucose response curves for the two diets

 

 

 

Data Collection Summary:

Timing of Measurements: 

  • blood samples were drawn through an indwelling catheter in the opposite arm from the insulin infusion
  • blood glucose concentrations determined hourly during the night and every 15 minutes during the 4-hour study period
  • free insulin concentrations determined every 30 minutes
  • urine collected to determine urinary glucose excretion during the study period

 Dependent Variables

  • blood glucose concentration analyzed enzymatically
  • HbA1C measured immunoturbidmetrically with DCA 2000
  • free insulin concentration measured using double antibody method that used plasma subjected to the polyethylene glycol separation technique

Independent Variables

 Food items

  • moderate-sucrose breakfast consisted of Carnation Instant Breakfast made with 2% milk, cracked wehat toast, margarine, jelly and 7 g sucrose; high-sucrose breakfast consisted of instant breakfast made 2% milk, 29 g sucrose, and 10g safflower oil
  • mid-morning snack consisted of Instant Breakfast Bar, low-fat cheese, and Kool-Aid.  Kool-Aid was made with artificial sweetener for the moderate-sucrose meal.

 Control Variables:  not specified

 

Description of Actual Data Sample:

Initial N: 10; 6 boys, 4 girls

Attrition (final N): 10

Age: 15.6±1.6 years, range 12.9-18 years

Ethnicity: not specified

Other relevant demographics:

  • duration of diabetes: 7.2±4.1 years; range 2.0-13.7 years
  • daily insulin dose: 0.9±0.2 U/kg/d
  • HbA1C: 8.6±0.8 %

Anthropometrics: none specified

Location: United States

 

Summary of Results:

 Fasting euglycemia was comparable on both study days (means of 4.6±0.2 and 4.4±0.2 mmol/L).

Variables

High-sucrose Diet

Moderate-Sucrose Diet

Statistical Significance of Group Difference

Area under glucose response curveabove baseline, mmol/L x 4 hours

 

17.1±8.6

 

16.0±11.3

P=0.72

Urinary glucose excretion, 6/4 hours

1.4±1.7

2.9±5.1

P=0.413

Area under free insulin response curve above baseline, ng/ml x 4 hours

0.17±0.76

0.75±0.15

P=0.43

Other Findings

The sample size of 10 provided 80% power to predict a difference of 1.0 standard deviation or 9.4 mmol/L x 4 hours at a significance level of P=0.05.  a sample size of 576 subjects would be needed for the difference seen in this sample to be significant.

 

Author Conclusion:
In adolescents with type 1 diabetes and euglycemia glycemic responses of the high-sucrose and moderate-sucrose diets did not differ.
Funding Source:
Reviewer Comments:
Recruitment methods not described and small sample size used.
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? ???
  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? No
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) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  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.) 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? Yes
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? No
  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? 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? 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? No
  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)? No
  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? Yes
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