EAL

DM: Glycemic Index (2014)

Citation:

Cheong SH, McCargar LJ, Paty BW, Tudor-Locke C, Bell RC. The First Step First Bite Program: guidance to increase physical activity and daily intake of low-glycemic index foods. J Am Diet Assoc. 2009; 109 (8): 1,411-1,416.

PubMed ID: 19631048

Study Design:

Randomized Controlled Trial

Class:

A - Click here for explanation of classification scheme.

Quality Rating:

NEUTRAL: See Quality Criteria Checklist below.

Research Purpose:

The purpose of this study was to determine whether adding a low-glycemic index component to the First Step Program would result in improved glycemic control.

Inclusion Criteria:

Provided written informed consent
Having type 2 diabetes
Not taking insulin
Between the ages of 40 years and 70 years old
Having no cardiovascular disease or contraindications to self-paced walking
Not currently participating in an exercise program
Previously received basic diabetes education
Walking fewer than 8,800 steps per day on a three-day pedometer protocol.

Exclusion Criteria:

Not described.

Description of Study Protocol:

Recruitment: Participants with type 2 diabetes were recruited from the Edmonton, Alberta, Canada area through the local media
Design: Randomized controlled trial
Blinding used: Implied with measurements.

Intervention
Subjects were randomized to one of two programs:

First Step Program: A facilitated behavior modification program designed to help people with type 2 diabetes increase their physical activity. It is based on the principle of self-efficacy and social support as well as the premise that walking can be gradually increased over time.
First Step First Bite Program: This had the same theoretical basis as the First Step Program but in addition to the physical activity message, participants also received a nutrition-related message emphasizing that they increase their intake of foods with a low GI by substituting lower GI for higher GI choices whenever possible.
At each assessment point, participants were instructed on how to complete a three-day food record (two weekdays and one weekend day), which were used to assess nutrient intake and the number of low-GI foods eaten
GI values for carbohydrate containing foods were determined using published values and The Official Website of the Glycemic Index and GI Database.

Statistical Analysis

Statistical analyses were done using SPSS (version 12.0, 2004, SPSS Inc. Chicago, IL)
All data are presented as mean ± standard error of the mean
Two-way repeated measures analysis of variance were done to determine differences between the groups and over time
Bonferroni test was used for post-hoc analyses. A P-value of 0.05 was considered statistically significant.
Correlation analyses were done to explore the relationships between steps per day or intake of low-GI foods and body weight, anthropometry and HbA1c.

Data Collection Summary:

Timing of Measurements

Study participants were assessed at baseline and at Week 16, the end of the study.

Dependent Variables

Body weight, height, waist and hip circumference were measured in accordance with standard anthropometric procedures
Body fat, fat mass and lean body mass percentages were measured using dual-energy X-ray absorptiometry
Resting blood pressure and HbA1c were determined to further assess cardiovascular health and long-term blood glucose control.

Independent Variables

First Step Program: A facilitated behavior modification program designed to help people with type 2 diabetes increase their physical activity. It is based on the principle of self-efficacy and social support as well as the premise that walking can be gradually increased over time.
First Step First Bite Program: This had the same theoretical basis as the First Step Program but in addition to the physical activity message, participants also received a nutrition-related message emphasizing that they increase their intake of foods with a low GI by substituting lower GI for higher GI choices whenever possible.
At each assessment point, participants were instructed on how to complete a three-day food record (two weekdays and one weekend day), which were used to assess nutrient intake and the number of low-GI foods eaten
GI values for carbohydrate containing foods were determined using published values and The Official Website of the Glycemic Index and GI Database.

Description of Actual Data Sample:

Initial N
44 (22 randomly assigned to the First Step Program and 22 assigned to the First Step First Bite Program).

Attrition (Final N)
38 completed the study; 19 in each group:

First Step Program Group: 10 males, nine females
First Step First Bite program Group: 11 males, eight females.

Mean Age

First Step Program Group: 54.8±1.4 years
First Step First Bite Program Group: 55.4±2.2 years.

Ethnicity
Not reported.

Other Relevant Demographics
Time since type 2 diabetes diagnosis:

First Step Program Group: 44.6±8.9 months
First Step First Bite Program Group: 56.3±16.1 months.

Anthropometrics

Mean body mass index at 16 weeks for the First Step Program: 34.7±1.4kg/m² vs. 32.3±1.3kg/m²
Groups did not differ at baseline on any measured variable.

Location
Edmonton, Alberta, Canada.

Summary of Results:

Key Findings

Mean daily GI was similar between groups before and after the trial (from 53±1 to 54±1 in the First Step Program Group and from 52±2 to 52±4 in the First Step First Bite Program Group)
After 16 weeks, body weight significantly decreased by 2.7% in the First Step Program Group (from 102.4±4.5kg to 99.6±4.3kg, P<0.01), but did not change significantly in the First Step First Bite Program Group (from 95.4±4.6kg to 94.3±4.6kg)
Both the First Step and First Step First Bite Program Groups had increases in physical activity: At Week 16, both groups had increased steps per day by approximately 3,000 compared with baseline (P<0.01)
The First Step First Bite Program Group also increased their daily intake of low-glycemic index foods
In the First Step Program vs. First Step First Bite Program Groups, waist girth decreased by 5.9±0.9cm vs. 3.7±0.5cm and hip decreased by 3.7±0.6cm vs. 2.2±0.5cm (P<0.01 over time in both groups)
There was no significant difference between groups at Week 16 for anthropometric or metabolic variables measured including hemoglobin A1c and blood pressure.

Author Conclusion:

Adding a low-GI component to a walking program in people with type 2 diabetes in good glycemic control did not improve anthropometric or metabolic outcomes
A great number and or longer duration of low-GI foods may be required to observe improved clinical outcomes.

Funding Source:

Other:

Health Canada Diabetes Strategy

Reviewer Comments:

Small numbers of subjects in groups
The authors noted that this study did not include a true control group, so it is not possible to determine whether our programs produced changes that were significantly different compared with a group who received no intervention at all.

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?	???
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.)	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?	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?	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?	Yes
	6.6.	Were extra or unplanned treatments described?	Yes
	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)?	Yes
	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