DM: Carbohydrates (2007)
- type 1 diabetes
- adolescent
- diabetes duration of two years or more
- minimal or no insulin secretory capacity
- evidence of retinopathy, neuropathy, untreated hypothyroidism
- obesity
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)
- High-sucrose diet (35% 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
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
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
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.
Quality Criteria Checklist: Primary Research
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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 | |