DM: Nutritive Sweeteners (2014)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To determine whether teaching free-living subjects with type 2 diabetes how to incorporate added sugars into their daily meal plan results in greater consumption of calories and deteriorates their glycemic or lipid profiles but improves their perceived quality of life.
Inclusion Criteria:
  • no specific dietary restrictions other than for diabetes
  • had not previously received formal training on how to incorporate the new sugar guidelines into their diets
  • diagnosis of type 2 diabetes
Exclusion Criteria:
  • lab results showed two values above the following thresholds:
    • fasting plasma glucose > 13.2 mmol/l
    • total cholesterol >6.8 mmol/l
    • HbA1c > 9.2%
    • triglyderides > 2.8 mmol/l
    • HDL <0.8 mmol/l
    • LDL > 4.5 mmol/l

 

Description of Study Protocol:

Recruitment:  subjects recruited from the Metabolic Day Center at Royal Victoria Hospital

Design:  Randomized Controlled Trial 

  • 8-month trial consisting of a nutrition education program
  • during first 4 months (baseline period) all subjects taught by a dietitian to follow a conventional meal plan and and avoid concentrated sweets. 
  • at 4 months subjects were randomized to the conventional (C) group, where they followed the same plan, or the sugar (S) group where they were taught how to use sugar choices acccording to the Canadian Dietetic Association's Good Health Eating Guide Resource
  • follow-up visits with dietitian every 2 months

Blinding used (if applicable)

  • recalls obtained through telephone calls made by a dietitian blinded to the study groups

 Intervention (if applicable):

  • subjects in the S group were advised that they could consume up to 10% of their daily calories as sugar choices, distributed throughout the day

 Statistical Analysis

  • unpaired t test used to compare the C and S groups at baseline and at the end of the study and to compare changes between the groups
  • Cronbach's alpha was calculated to determine the internal consistency reliability of the MOS and DQOL

 

Data Collection Summary:

Timing of Measurements

  • 6 random 24-h recalls collected during baseline period and during intervention period
  • fasting blood samples collected at entry and every 2 months
  • quality of life surveys administered at entry, at randomization, and at the end of study

Dependent Variables

  • fasting plasma glucose
  • total cholesterol
  • triglycerides
  • HDL
  • LDL
  • BMI
  • perceived quality of life using the Medical Outcome Survey (MOS) and the Diabetes Quality of Life(DQOL) measure

Independent Variables

  • accuracy of self-reported intake validated by comparing the ratio of the mean energy intake to the calculated BMR using the World Health Organization equation against a predetermined cutoff limit of 1.1
  • conventional (C) group or the sugar (S) group

 Control Variables

 

Description of Actual Data Sample:

Initial N: 59 recruited into study, with 11 dropping out before the randomization period

Attrition (final N): 48 subjects, 32 males

Age: 35-75 yrs

Ethnicity: not specified

Other relevant demographics: HbA1c  8.2±2.0%

Anthropometrics  BMI 30 ± 6. 

No significant differences between groups at entry.

Location: Canada

 

Summary of Results:

22% of C group and 24% of S group underreported food intake; not significant 

Changes in mean nutrient intake from baseline to end of study

Variables

Treatment Group

Conventional Group

Control group

Sugar Group

P

Calories, kcal

81±282 -77±304

0.067

CHO, g

10±45

 -15±2.9

 0.027

Starch, g

 8±27

 -7±21

 0.037

Total Fiber, g -0.3±7 -1±5 NS
Total Sugars, g 2±18 -6±21 NS
Fat, g 2±15 0.1±19 NS
Protein, g 4±16 -2±18 NS

 Changes in mean metabolic profile from baseline to end of study

Outcome Conventional Group Sugar Group P
Weight, kg -0.2±2.1 0.6±2.6 NS
BMI -0.1±0.7 0.2±1.0 NS
FPG, mmol/l -1.3±2.0 0.4±2.2 0.013
HbA1c, % -0.4±0.7 -0.2±2.1 NS
total cholesterol, mmol/l -0.31±0.58 0.07±0.30 0.006
triglycerides, mmol/l -0.19±0.59 0.01±0.61 NS
HDL, mmol/l 0.09±0.14 0.11±0.21 NS
LDL, mmol/l 0.36±0.45 -0.03±0.36 0.008
TC/HDL ratio -0.65±0.62 -0.20±0.63 0.016

Other Findings

Cronbach's alpha ranged from 0.77 to 0.87 for the MOS and 0.67 to 0.95 for the DQOL, indicating internal consistency reliability.

Changes in quality of life scores, ( <3%) from baseline to end of study, were not statistically different between treatment groups. 

Author Conclusion:

The educational intervention to permit 10% of total calories from added sugars did not result in an increased consumption of calories.

The subjects in the sugar group consumed less starch than the C group. Both groups consumed only slightly less sugar than the non-diabetic population. 

The educational intervention resulted in greater awareness of the CHO content of foods because the S group, not the C group, reduced their intake of CDA sugar choices by one serving.

Giving type 2 diabetic individuals the freedom to include added sugars into their daily meal plan had no negative impact on their dietary habits and metabolic control.

Funding Source:
Reviewer Comments:

No information is given about the power of the sample size to substantiate negative results.

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.) 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? Yes
  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? Yes
  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? Yes
  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? ???
  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)? No
  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? No
  9.1. Is there a discussion of findings? No
  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