EAL

NGHC: Prevention of Chronic Disease (2013)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

The Healthier Options for Public Schoolchildren (HOPS) was designed to pilot test a school-based obesity prevention program. The overall goal was to improve the health status of the children that participated in the program.

Inclusion Criteria:

Large, multi-ethnic population of six- to 13-year-old children attending five elementary schools in Osceola County in central Florida.

Exclusion Criteria:

Not described.

Description of Study Protocol:

Recruitment

Five elementary schools in Osceola County in central Florida were chosen from a sample of convenience.

Blinding

Blinding to intervention was not possible; however, objective measurements were conducted or obtained.

Design

Pilot quasi-experimental design study implemented over two school years. Schools were assigned to one of four intervention schools or one control school by district administration, but were not randomized. The study was approved by the Sterling Institutional Review Board, Atlanta, GA.

Intervention

HOPS involved an integrated set of interventions including nutrition, physical activity and curricula components.

The dietary component consisted of modifications to school-provided breakfasts, lunches and extended-day snacks. Menus were modified to include more high-fiber items, fewer items with high-glycemic effects and lower amounts of total, saturated and trans fats. On average, intervention menus contained approximately two times more fiber and 23% less fat than control menus.
The physical activity component consisted of increased opportunities for physical activity during the school day, though the amount and types of physical activity varied among intervention schools throughout the study. During Year 2, students were provided pedometers and tracking books; however, the use of pedometers in the HOPS program were discontinued. Instead, schools were encouraged to implement daily physical activity in the classroom using a 10- to 15-minute deskside physical activity program during regular teaching time. Schools were also asked to implement structured physical activity as much as possible during recess times. Other physical activities, such as walking clubs, encouraged children and adults to walk before school started each day.
The curricula component consisted of a school-based holistic nutrition and healthful lifestyle management program for children, parents and school staff. The curricula included a thematic set of nutrition educational activities developed by HOPS staff (including an RD) in collaboration with elementary school education experts and USDA Food and Nutrition Service staff. Each month, a multimedia set of materials highlighting especially nutrient-dense foods and healthful lifestyle habits were sent to intervention schools. Each intervention school also received a curriculum with nutrition, physical activity and other lifestyle behavior messages to help children understand the importance of making healthful choices and motivate them to implement these changes in their lives. This component also included fruit and vegetable gardens at intervention schools to teach children how fruits and vegetables are grown, cultivated and harvested.

Statistical Analysis

In order to account for between-cluster variation and to minimize type I errors where any intervention effect may become confounded with natural cluster-to-cluster analysis, a two-stage approach of analysis was incorporated.

First stage (individual level): All individual-level covariates to derive school-specific means that are adjusted for individual-level covariates were analyzed.
Second stage (school level): School-specific means and covariates adjusted for school site were analyzed to evaluate intervention effects. Univariate analysis consisted of simple frequency statistics for all demographic variables. To test for associations between intervention condition and demographic characteristics, x2 analyses were performed. Repeated measures analysis tested for changes in trends over time in BMI percentile, weight and blood pressure. P value was significant if less than 0.05. All tests were two-tailed.

Data Collection Summary:

Timing of Measurements

Demographic information, anthropometric data and blood pressure measurements were collected at baseline (Fall 2004) and each fall and spring of the study years (2004 to 2006).

Dependent Variables

Body mass index calculated as kg/m²; age and sex-specific BMI percentile converted to z-score based on normative data for age and sex
Weight: Participants removed shoes and heavy outer clothing and emptied pockets before being measured by trained school study staff; converted to z-score based on normative data for age and sex
Blood pressure was measured using automated measurement machines.

Independent Variables

Integrated nutrition, physical activity and lifestyle education curricula for children, parents and school staff
Modified school meals
Other school-based wellness activities (such as fruit and vegetable gardens).

Description of Actual Data Sample:

Initial N: 2,494 children (1,272 girls and 1,222 boys)
Attrition (final N): 2,494 children
Age: Range was six to 13 years. Average age was eight years.
Ethnicity:
- 48% Hispanic
- 36% white
- 8% African-American
- 8% other (multi-ethnic, Asian, American Indian)
Anthropometrics: There were no significant differences by baseline BMI percentile between treatment arms
Location: Osceola County, Florida.

Summary of Results:

Key Findings

BMI Z-score decreased significantly for girls in intervention group compared to controls (P<0.05)
Weight Z-score decreased significantly for girls in intervention group compared to controls (P<0.01)
No significant changes in BMI Z-scores or weight Z-scores by intervention or control groups were noted; however, both mean BMI Z-scores and mean weight Z-scores for boys in intervention group decreased slightly
Systolic blood pressure decreased significantly for girls in intervention group compared to controls during the first year (Fall 2004 to Fall 2005) of the study (P<0.05) but was not statistically significant the second year
Diastolic blood pressure decreased significantly for girls in intervention group compared to controls (P<0.05)
No significant changes in systolic or diastolic blood pressure by intervention or control groups were noted; however, blood pressure for boys in intervention group decreased slightly.

Author Conclusion:

School-based obesity prevention interventions that include changes to school-provided meals, nutrition and healthful lifestyle education and physical activity components show promise in improving health, particularly among elementary school-aged girls
School-based RDs are critical to ensuring successful prevention programming with respect to both dietary modification and nutrition curricula interventions
This pilot study suggests a correlation between weight/BMI percentile reduction and diastolic blood pressure improvements in children
If healthy weight and blood pressure can be maintained from an early age via prevention programs such as HOPS, children may be less likely to develop cardiovascular disease in early adulthood.

Funding Source:

Other:

Agaston Foundation

Reviewer Comments:

Strengths

The strengths of this pilot study are the large sample size (almost 2,500 children), the diversity of the sample, the use of objective measures of health improvement (BMI Z-scores that appear to correlate well with blood pressure measurements) and multiple measures of the same group of children over an extended time period (two years).

Limitations

HOPS was a school-based prevention intervention. As such, researchers could not control eating or exercise outside of school. Similarly, there are concerns about lack of study control on eating and physical activity during extended periods of out-of-school time (holidays and summer vacation). Because children in this study appeared to increase their BMI z-scores during summer break, consistent implementation of interventions was not possible.
Despite the use of simple-to-use blood pressure measurement equipment and training on measurement technique before each data collection period, the measurements were taken by study coordinators in non-clinical settings; thus, measurement may be susceptible to some errors. In addition, despite standardized approaches to measuring blood pressure four times during the two years, study findings are susceptible to error from measurement and from variation in blood pressure between measurement periods.
The study population was not selected at random, was of limited geographic variability (one school district), and only one school served as control
Although HOPS involved nutrition and healthful lifestyle curricula and physical activity components, the design did not include assessment of intervention exposures (e.g., minutes curriculum was used).

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?	No
	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?	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?	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?		???
	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?	???
	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?	No
	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?		No
	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?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	No
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)?	???
	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?	N/A
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