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

DM: Carbohydrates (2007)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To study the effects of added sucrose on lipid and carbohydrate metabolism in subjects with diabetes.
Inclusion Criteria:
Non-insulin-dependent diabetes.
Exclusion Criteria:
None mentioned.
Description of Study Protocol:

Recruitment: not specified

Design: nonrandomized crossover design with two 15-day diet periods

Blinding used (if applicable): none

Intervention (if applicable)

  • eucaloric diets with mixed foods prepared in a diet kitchen
  • both diets were 50% CHO, 30% fat, 20% protein
  • diet variation
    • added sucrose diet:  16% of total calories from sucrose
    • sucrose-free diet: 1% of total calories from sucrose

Statistical Analysis

Student's t-test used to assess statistical significance between the two dietary periods.

 

Data Collection Summary:

Timing of Measurements:  fasting and day-long hourly plasma samples obtained on days 14 and 15 of each dietary period

Dependent Variables

  • glucose
  • insulin
  • triglyceride
  • cholesterol
  • VLDL
  • LDL
  • HDL

Independent Variables

  • diet variation:  added sucrose diet:  16% of total calories from sucrose or sucrose-free diet: 1% of total calories from sucrose
  • Subjects advised to maintain usual level of physical activity

Control Variables

 

Description of Actual Data Sample:

Initial N: 11; 6 women

Attrition (final N): 11

Age: 50-70 yrs

Ethnicity: not specified

Other relevant demographics: 6 subjects treated with sulfonylureas, 5 treated with diet alone; mean fasting plasma glucose 141 mg/dl

Anthropometrics : BMI 22.5-30.0 

Location:  California

Summary of Results:

 Other Findings

  • day-long plasma glucose responses were significantly greater when subjects consumed the diet with added sucrose (p<0.05)
  • the day-long incremental plasma glucose response area above basal was significantly greater when subjects ate the diet with added sucrose (392±72 vs. 255±72 mg/dl x hour; P<0.01)
  • the addition of sucrose to the diets of patient with NIDDM led to significant (P<0.05) increases in both fasting total and VLDL -triglyceride concentrations. 
  • the day-long plasma triglyceride responses were significantly greater (P<0.05) on the added sucrose diet.
  • mean total plasma colesterol concentraion was significantly elevated on the added sucrose diet (P<0.001)
  • the elevation in total plasma cholesterol concentration was due to increases in both VLDL (P<0.01) and LDL (P<0.10)
Author Conclusion:
The addition of sucrose to the diets of individuals with diabetes, in amounts comparable to those typically consumed by the general population, resulted in a significant increase in day-long postprandial hyperglycemia, fasting and postprandial hypertriglyceridemia, and fasting hypercholesterolemia.
Funding Source:
Government: Veterans Association, NIH
Reviewer Comments:

Using today's standards, 15 days would not be considered long enough to assess changes in cholesterol  and serum lipid values.  Three weeks is the minimum recommended.

It's unclear whether the diet periods were assigned randomly or in some order.

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? N/A
  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? ???
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? N/A
  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? 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? ???
  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? No
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? No
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? Yes
  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? N/A
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? No
  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? N/A
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? ???
  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? No
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