Pediatric Weight Management

Child Nutrition and Environment

Citation:

Cutts BB, Darby KJ, Boone CG, Brewis A. City structure, obesity and environmental justice: An integrated analysis of physical and social barriers to walkable streets and park access. Social Science & Medicine, 2009; 69: 1,314-1,322.

 
Study Design:
Cross-Sectional Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

To evaluate the relationship between proximity to parks and walkable street networks and the distribution of obesity among vulnerable populations in Phoenix, Arizona, using geographic information systems (GIS) within an environmental justice framework. 

Inclusion Criteria:

Residence in Phoenix, Arizona.

Exclusion Criteria:

Residence outside of Phoenix, Arizona.

Description of Study Protocol:

Recruitment

No recruitment of subjects in this case study.

Design

Use of census block data, geographic information systems (GIS) and crime frequency data from 2000 to assess physical and social barriers to parks and walkable streets. 

Statistical Analysis
  • Logistic regression analyses were used to determine variables most significantly related to walkability and park access. Analyses were controlled for percentage African-American, percentage under age 18 and the Latino- or immigrant-status variables.
  • Factor analysis was used to construct a Latino- or Immigrant-status variable
  • Logistic regression analyses, T-tests and multiple-regression analyses were used to assess the qualities of the built environment. Analyses were controlled for percentage African-American, percentage under age 18 and the Latino- or immigrant-status variables.
Data Collection Summary:

Timing of Measurements

Not specified.

Dependent Variables

  • Variable One: Proximity to parks; census block data
  • Variable Two: Walkability of neighborhoods; GIS-based techniques
  • Variable Three: Qualities of the built environment; proxies for perceptions of safety.

Independent Variables

Low-income and minority populations.

Description of Actual Data Sample:
  • Initial N: 1,046 census tracks
  • Age: Not specified
  • Ethnicity
    • Latino: 97%
    • African-American: 78%
    • Census tracks have more than a single race or ethnicity.
  • Anthropometrics: None 
  • Location: Phoenix, Arizona.
Summary of Results:

Key Findings

  • The most walkable census block groups had higher Latino scores (P<0.001), larger percentages of African-American residents (P=0.01) and a smaller number of residents under age 18 (P<0.001)
  • Latino factor (P=0.02) and percentage African-American (P=0.03) were positively associated with park access
  • Latino factor (P<0.001) and percentage African-American (P=0.06) were associated with built environments amenable to physical activity.
Author Conclusion:

Populations most vulnerable to obesity (i.e., Latino and African-American) are more likely to live in walkable neighborhoods and have enhanced access to neighborhood parks, compared to other population groups in Phoenix, Arizona.

Funding Source:
Industry:
National Science Foundation
University/Hospital: Early History President's Initiative at Arizona State University
Reviewer Comments:
  • No study limitations were discussed
  • Future areas of research included to assess whether macro-level variables in walkable neighborhoods accurately reflect micro-level conditions.
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) N/A
  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) N/A
 
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? 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? N/A
  4.1. Were follow-up methods described and the same for all groups? N/A
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  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? No
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  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? N/A
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  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? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  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? N/A
  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? N/A
  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? 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)? 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? N/A
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? 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