This Academy member benefit temporarily has been made public to allow all practitioners access to content that may assist in patient care during the national pandemic response. Click here for information on joining the Academy. 

Health Disparities

HD: Food Security (2011)

Citation:
Moore LV, Diez Roux AV. Associations of neighborhood characteristics with the location and type of food stores. Am J Public Health. 2006 Feb; 96(2): 325-331. Epub: 2005 Dec 27.
PubMed ID: 16380567
 
Study Design:
Descriptive Study
Class:
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To investigate differences in the local food environment across neighborhoods associated with varying racial and ethnic composition and income.

Inclusion Criteria:
  • Areas from which participants in the Multiethnic Study of Atherosclerosis were sampled
  • information on food establishments in the area must be found on Info USA Inc., a commercial database on businesses regarding openings and closings.
Exclusion Criteria:

None identified.

Description of Study Protocol:

Design

Descriptive study (ecologic study).

Statistical Analysis

  • Census tracts and food store characteristics were compared across study areas and racial and ethnic categories using Χ2 tests for proportions and analysis of variance for continuous variables
  • Poisson regression used to examine associations of census tract racial and ethnic compositions and income with number of stores
  • Logistic regression used to model the types of stores in each tract with census tract racial and ethnic composition, the square mile area of the tract and the population size.
Data Collection Summary:

Timing of Measurements

  • Information on businesses updated on a weekly basis by InfoUSA Inc., a proprietary information service
  • All locations for businesses were geocoded to the 2000 US Census
  • All census tract characteristics were obtained from 2000 US Census 

Dependent Variables

Stores present within each census tract.

Independent Variables

Census tracts in North Carolina, Maryland and New York:

  • Ethnicity
  • Income.

Control Variables

  • Census tract size (square miles)
  • Census tract site (MD, NY, NC).
Description of Actual Data Sample:
  • Initial N:
    • 75 census tracts in Forsyth County, North Carolina
    • 276 census tracts in Baltimore County and parts of Baltimore City, Maryland
    • 334 census tracts in northern Manhattan and the Bronx, New York
    • 685 total census tracts
  • Attrition (final N): Same as initial sample
  • Ethnicity:
    • Census tracts with greater than 60% of residents in any particular racial or ethnic group were defined as predominantly non-Hispanic white, predominantly non-Hispanic black or predominantly Hispanic areas
    • Tracts not defined as above were categorized as racially mixed areas:
      • Maryland (MD): 41.3% tracts predominantly white, 47.1% predominantly black, 11.6% mixed
      • North Carolina (NC): 64% predominantly white, 16% predominantly black, 20% mixed
      • New York (NY): 19.5% predominantly white, 13.5% predominantly black, 34.1% predominantly Hispanic, 32.9% mixed
  • Other relevant demographics:
    • Total area, square miles
      • MD: 241.5 (4,127 people per square mile)
      • NC: 409.6 (747 people per square mile)
      • NY: 26 (65,230 people per square mile)
    • Median population:
      • MD: 3,341
      • NC: 3,779
      • NY: 4,629
    • Median household income:
      • MD: $37,758
      • NC: $$41,579
      • NY: $25,063
  • Location:
    • North Carolina
    • Maryland
    • New York. 
Summary of Results:

Key Findings

  • Predominantly black and Hispanic neighborhoods had lower median incomes and proportionately more people without a vehicle than did predominantly white neighborhoods (P<0.0001)
  • Predominantly white areas generally had lower numbers of stores per population, possibly reflecting larger sizes of stores in these areas (P<0.0001) 
    • Overall, 19% of stores in predominantly black areas were 2,500 square feet or more
    • Overall, 42% of stores in predominantly white areas were 2,500 square feet or more
  • The types of stores present differed significantly across categories of racial and ethnic composition (P<0.001, in all sites)
  • Differences in income between neighborhoods were analogous to those seen between minority and predominantly white neighborhoods.

Ratios of Food Stores per 10,000 Population, by Racial and Ethnic Composition and Site (Overall Adjusted for Site, Reference, Predominantly White)

Variables

Racially Mixed, Ratio (95% CI)

Predominantly Black, Ratio (95% CI)

Grocery stores 2.2 (1.9, 2.7) 2.7 (2.2, 3.2)
Supermarket 0.7 (0.5,1.0) 0.5 (0.3, 0.7)
Fruit and vegetable market

0.9 (0.5, 1.4)

0.6 (0.3, 1.1)

Bakeries 0.6 (0.5, 0.8) 0.4 (0.3, 0.5)
Natural food stores 0.8 (0.5, 1.2) 0.3 (0.2, 0.6)
Specialty food stores 0.4 (0.2, 0.7) 0.2 (0.1, 0.5)

Other Findings

  • Low-income neighborhoods had four times as many grocery stores per populations as the wealthiest neighborhoods [SR=4.3 (3.6, 5.2)] and half as many supermarkets (SR=0.5, 0.3, 0.8)
  • Fruit and vegetable markets, bakeries, natural food stores and specialty stores were also less common in low-income neighborhoods
  • Liquor stores were more common in the poorest than in the wealthiest neighborhoods (SR  = 1.3 (1.0-1.6).
Author Conclusion:
  • Neighborhoods differ in the types of food stores that are available
  • The location of food stores is associated with neighborhood racial and ethnic and socioeconomic composition
  • In general, the food environment appears to be less diverse in poor and minority neighborhoods than in wealthier and predominantly white neighborhoods
  • Identifying the processes that allow poor and minority neighborhoods to attract and retain healthy food choices may suggest important avenues for intervention.
Funding Source:
Government: Columbia Center for the Health of Urban Minorities, National Center on Minority Health and Health Disparities, National Institues of Health, and the National Heart, Lung, and Blood Institute
Reviewer Comments:
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? No
  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? N/A
  2.2. Were criteria applied equally to all study groups? N/A
  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? No
3. Were study groups comparable? No
  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.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? No
  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? N/A
  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? No
  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? N/A
  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? No
  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? 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