EAL

NGHC: Prevention of Chronic Disease (2013)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To compare the effects of Taking Action Together, a YMCA-based type 2 diabetes mellitus prevention intervention designed for high body mass index African American children from disadvantaged neighborhoods of Oakland, California, on insulin resistance, diet and physical activity and potential mediating variables (self-esteem, self-efficacy, and psychobehavioral characteristics) with a control group.

Inclusion Criteria:

Children included in this study:

Had at least one African-American biological parent
Were nine to 10 years old
Had a body mass index at or above the 85th percentile
Were free of any systematic disorder or medication known to affect energy metabolism or body weight
Did not have severe physical or emotional conditions that could interfere with study participation.

Parental informed consent was obtained for all participants.

Exclusion Criteria:

Children were excluded if they:

Did not have at least one African-American biological parent
Were younger than nine or older than 10 years old
Had a body mass index below the 85th percentile
Were not free of any systematic disorder or medication known to affect energy metabolism or body weight
Had severe physical or emotional conditions that could interfere with study participation.

Description of Study Protocol:

Recruitment

Announcements describing incentives, risks and benefits of participating in the study were distributed at elementary schools in regions of Oakland, CA ihabited by low-income African-American families. Three cohorts of participants were recruited over three successive years.

Design

At baseline, end of year one and end of year two, height, weight, waist and hip circumference and body fat percentage were measured. Weight and height were used to calculate body mass index and body mass index Z-score. At baseline, nutrient intakes and servings of foods consumed were calculated using three-day food diary records; physical activity diary records were also used to assess the children's physical activity.

Child physical activity habits, knowledge, competence and self-efficacy were assessed using subjective questionnaires. Psychosocial variables were assessed using subjective questionnaires administered to the child or parent. Socio-demographic factors and other subjective data were measured using subjective questionnaires administered to an adult family member.

Dietary goals of the intervention were to: Increase intake of fruit, vegetables, whole grains and low-fat dairy foods; reduce intake of high-fat and high-sugar foods and beverages; sharpen awareness of cues to satiety. The physical activity goal was to increase time spent in moderate-to-vigorous intensity physical activity by developing skills, knowledge and self-efficacy with respect to having endurance and being flexible, strong, coordinated, quick and agile.

The self-esteem component goal was to develop: Awareness of one's strength, challenges, behaviors and styles of interacting; ability to effectively interact and communicate with others; respect for self and others; ability to describe self using art, writing and verbal means; ability to assess positive change in one's behavior and personal interactions. Focus was placed on improving diet and physical activity rather than on body weight.

Children in the control group had no hands-on involvement in intervention activities. Families received information focusing on community opportunities for health promoting activities in the monthly mail, and children were offered a free week of traditional YMCA summer day camp. Families who volunteered for the study self-selected to attend programming at one of two sites, prior to assignment of treatment for that site.

For the intervention group, each program year was started with two weeks of YMCA day camp to kick off. The intervention involved 10 days (eight hours per day) of program-specific summer day camp, one (two-hour) session per week, three weeks per month, 11.5 months a year at the YMCA facility for a total of 150 hours (50% devoted to physical activity, 25% to nutrition, 25% to self-esteem building). Parents and guardians of children in the intervention group were also invited to attend nine education sessions each year.

Blinding Used

No blinding was used. However, staff evaluating outcome data were different from staff implementing the intervention.

Intervention

Nutrition component

Core nutrition lessons utilized the approach of "The Power of Choice: Helping Youth Make Healthy Eating and Fitness Decisions" and included hands-on learning via preparation of low-cost, culturally appropriate foods, taste-testing and exposure to new foods and ingredients.

Self-esteem component

Core self-esteem lessons were developed based on the curricula Body Positive, a program designed to promote health at every size, body satisfaction and self-esteem, and Kwanzaa-based activities designed to promote cultural pride and build community.

Physical activity component

Activities were based on the After-School SPARK physical activity program; they were child-centered, encouraged enthusiasm and participation and aimed to increase enjoyment through games, dance and sports.

Parent component

Monthly mailings of health education materials, educational meetings, phone calls, or in-home visits to target overcoming barriers to adopting healthy behaviors were scheduled
Three healthy lifestyle events and family celebrations were scheduled for children and families
Parents and guardians were invited to nine one- to two-hour sessions each year; the curriculum for these sessions was based on the interactive "Eating Smart. Being Active" adult EFNEP lessons.

Statistical Analysis

Mean changes in HOMA-IR, secondary anthropometric, dietary and activity variables were evaluated using multiple regression techniques
Multiple linear regression was used to examine the effect of intervention on HOMA-IR, adjusting for baseline HOMA-IR, BMI Z-score, psychosocial measures such as self-esteem, diet and physical activity behaviors, and other potentially relevant factors such as family and intrauterine history of type 2 diabetes mellitus
The authors calculated that 50 children were needed in the intervention group and in the control group for 80% power to detect a difference in plasma insulin levels.

Data Collection Summary:

Timing of Measurements

Measures were taken at baseline and again following either one or two years of intervention.

Dependent Variables

Change in insulin resistance (as measured by HOMA-IR, defined as fasting glucose (mmol per L x insulin (U per ml) / 22.5)
Change in glycosylated hemoglobin (HgbA1c).

Independent Variables

YMCA-based intervention consisting of:

Nutrition component
Self-esteem component
Physical activity component
Parent component.

Control Variables

Transportation was provided for children to the YMCA sites in order to improve attendance due to safety concerns.

Description of Actual Data Sample:

Initial N

111 children in the control group (51 boys, 60 girls)
124 children in the intervention group (52 boys, 72 girls).

Attrition (Final N)

38 children in the control group (16 boys, 22 girls)
35 children in the intervention group (17 boys, 28 girls).

Age

Mean age at baseline for control group was 9.84 years
Mean age at baseline for intervention group was 9.85 years.

Ethnicity

African-American.

Other Relevant Demographics

Groups were fairly matched on socio-economic index:

Family history of type 2 diabetes mellitus
Intrauterine risk for type 2 diabetes mellitus
Food habits
Physical activity habits
Family cohesion
Family conflict.

Anthropometrics

Groups were fairly matched on BMI Z-score, waist-to-hip ratio, body fat percentage, pubertal stage, fasting HgbA1c, fasting HOMA-IR, energy intake, composition of food intake, nutrition knowledge, food preferences, snack habits, fitness, moderate and high-intensity physical activity, global self-worth and athletic competence.

Location

Oakland, California.

Summary of Results:

Key Findings

In the intervention group, glucoregulation stabilized or improved after one year, with a larger effect in boys than in girls
A larger percentage of children in the intervention group decreased BMI Z-score after one year.

Author Conclusion:

Improved glucoregulation in children after this intervention suggests that the protocol studied has a great potential to serve as a guideline protocol for future interventions in children's health related area
In addition, the more favorable pyschobehavioral score for children in the intervention group suggest potential for improvements in characteristics that may broadly influence a child's ability to be successful in school and elsewhere.

Funding Source:

Government:

USDA CSREES grants 2004-35214-14254 and 2005-35215-15046; Agriculture Experiment Station

Not-for-profit

YMCA

Reviewer Comments:

The authors discussed several limitations of this study. Because one YMCA site was the control group and the other site was the intervention, differences due to program sites could not be evaluated. Also, the results of this study may not be generalizable to other populations of children (younger than nine, older than 10; ethnicities other than African American; or children in middle or upper-income populations).
I found this study difficult to review due to much essential information not being provided by the study authors. Abbreviations were used throughout the published paper but not explained (for example, HOMA-IR stands for homeostasis model assessment of insulin resistance; this was never given by the authors).
According to the authors measurements (waist, height, weight, blood draws) were done, but we do not know how the measurements were taken, where they were taken, or by whom. And although the authors mentioned taking measurements, no outcome data were reported at all in table form or otherwise.
The authors concluded that the intervention improved glucoregulation and psychobehavioral scores, without providing any evidence to back up their claim. The authors also did not describe who facilitated the intervention (YMCA staff or study staff) or how it was implemented, as well as if they monitored the implementation of the intervention to see if it was being implemented as designed and in a standardized way.

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)	???
	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)	???

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?	???
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?		No
	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.)	No
	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?	No
	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?	???
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	Yes
	6.6.	Were extra or unplanned treatments described?	???
	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?		???
	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?	???
	7.5.	Was the measurement of effect at an appropriate level of precision?	???
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	???
	7.7.	Were the measurements conducted consistently across groups?	???
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?	No
	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?	No
	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)?	Yes
	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?	N/A
	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?		N/A
	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