HD: Food Security (2011)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
  • To assess the nutritional resource environment in targeted African-American communities in Los Angeles and to compare the findings with the nutritional resources available in a predominantly white area
  • To use community-based participatory research to build health promotion capacity among community residents.
Inclusion Criteria:

A coalition of African-American community residents and health and social service organizations held a series of conversations and identified three target communities to study. To complete the inventories of food markets in the identified areas, community groups submitted applications in a mini-grant process to receive up to $5,000 in funding. Applicants described how they would inventory the stores, who would complete the inventory and a budget. Applications were reviewed by the Economic Parity advisory group, made up of community members and supplemented by the Community Health Council staff and evaluators. The applications were scored for relevance, appropriateness, scope of work and three other categories not disclosed.

Exclusion Criteria:

 None discussed.

Description of Study Protocol:

Recruitment

The community coalition determined the three target African-American communities to inventory for their nutrition resource environment. Community groups applied for grants to conduct the inventories; a community advisory group selected the six grantees. Students from the University of Southern California were hired to inventory nutrition resource environment in the contrasting, predominantly white area.

Design

  • The community coalition determined three target areas to study and an advisory group selected grantees to conduct the nutrition resource environment inventories
  • Community and student surveyors were trained by the Community Health Council and project evaluators on the project's mission, the inventory methodology, surveying techniques and instrument procedures. Those completing inventories in the target areas were asked to focus attention on smaller markets and convenience stores, and were required to inventory every third store on their list of markets. Project staff supplemented inventorying  larger stores.
  • The instruments used to inventory were the "Shopping List," a one-page survey providing an overview of services and healthy items, and "The Healthy Food Assessment," a 12-page survey detailing the availability or vegetables, fruits, meats, other items and special food sections
  • For quality control, group coordinators from the community groups receiving grants checked the completed inventory forms for mis-coding and omissions, then sent the inventories to the Community Health Council community liaison for review
  • The project evaluation staff then further cleaned and entered data into a database. The data were shared with study participants, community residents and policy makers; the findings were presented by grant recipients in a community dialog called an Indaba
  • The intention of the dialog was to garner support in the community for challenging issues identified by the study.

Intervention

The instruments used to inventory were the "Shopping List," a one-page survey profiling the conditions of the store and the availability of a small selection of healthy items. The second instrument used was "The Healthy Food Assessment," a 12-page survey detailing the availability or vegetables, fruits, meats, other items and special food sections. The evaluation team and an academic sub-contractor developed the template of the instruments, both were finalized by the community advisory group. "The Healthy Food Assessment" was adapted from an existing, validated instrument.  

Statistical Analysis

Bivariate significance tests utilizing chi-squared and Fisher's exact tests. Statistical comparisons were made between combined target areas and the contrast area, as well as between the individual target areas.

Data Collection Summary:

Timing of Measurements

The timeframe in which surveys were conducted was not discussed.

Dependent Variables

Availability of healthy food products. 

Independent Variables

  • "Shopping List" survey
  • "The Healthy Food Assessment" survey.

Control Variables

A quality control process was put into place; completed surveys were reviewed by each group coordinator, then the Community Health Council Community Liaison and finally the project evaluation staff.

Description of Actual Data Sample:
  • Initial N: 261 stores in the target area (Inglewood, N=28; North Long Beach, N=75; South Los Angeles, N=156) and 69 stores in the contrast area were inventoried using the "Shopping List" instrument (total, N=331). The "Healthy Food Assessment" instrument was completed in 54 stores in the target area and 17 stores in the contrast area (total, N=71).
  • Ethnicity:
    • In the target areas:
      • North Long Beach is 23.2% African-American
      • Inglewood is 46.7% African- American
      • South Los Angeles is 49.2% African-American
    • In the contrast area: West Los Angeles is 8.1% African-American
  • Other relevant demographics: In the contrast area, the median household income is $45,917 and 17% of the population live below the poverty line. As a whole, the target areas have a median household income of $29,237 and a poverty rate of 28%.
  • Anthropometrics: The target areas have a total population of 679,148 and are an average of 47% African-American. In the target areas there are 114 grocery stores, meaning there are 5,957 people per store. The contrast area has a total population of 222,019 and is an average of 8% African-American. In this area there are 59 grocery  stores, meaning there are 3,763 people per store.
  • Location: North Long Beach, Inglewood, South Los Angeles and West Los Angeles, all located in California.
Summary of Results:

Key Findings

  • The target areas had a higher proportion of convenience stores and local markets than the contrast area, which had larger franchised markets
  • Fruits and vegetables, non-fat milk and low-fat snacks were less often available in the target areas as compared to the contrast area
  • Meat was sold less in the target areas than in the contrast area
  • 70.4% of stores in the target areas sold fresh fruits and vegetables, compared with 93.8% in the contrast area (P<0.05)
  • Target areas had about half the selection of fruits and vegetables that the contrast area did (13 types of fruit vs. 26, P<0.05; 21 types of vegetables vs. 38, P<0.05). In target areas fruit and vegetable sections were significantly less likely than contrast areas to be in the front of the store (53% vs. 87%, P<0.05). 
  • Color, texture, consistency, damage and cleanliness of apples, grapes, strawberries, lettuce, green beans, avocados and celery were found to be inferior in target area markets compared to contrast area markets
  • The availability of meat, poultry and fish products, including lower-fat meat options, was similar in all areas
  • There was significant variation in the availability of lower-fat milk products between target and contrast areas. Half of stores in the target area carried 2% milk (50.0% vs. 81.3%, P<0.05), 29.6% carried 1% milk (compared with 56.3% in contrast area, P<0.05), and 37.0% carried skim milk (vs. 81.3% in contrast area, P<0.01). In addition, low-fat cheese and non-fat cheeses were more commonly found in the contrast area (P<0.05).
  • Whole grain pasta was found in only 1.9% of target area markets vs. 31.3% in the contrast area (P<0.01)
  • Target areas were less likely to have low-fat potato chips (33.3% vs. 68.8%, P<0.05), sugar-free cookies (16.7% vs. 50.0%, P<0.05) or have a diabetic food section (3.9% vs. 33.3%, P<0.01) or a low-salt food section (3.9% vs. 26.7%, P<0.05).  
Shopping List Survey Target Area Contrast Area

Statistical Significance of Group Difference

Store type  

P<0.001

  Convenience 34.8

26.1

 
  Local market

60.2

44.9

 
  Supermarket

5.0

46.0

 
Chain store, percentage 18.3 46.2 P<0.001
Meat sold, percentage 41.0 71.0 P<0.001
Fruit and vegetables sold, percentage 49.4 66.7 P<0.05
Non-fat milk sold, percentage 37.9 79.7 P<0.001
Low-fat snacks sold, percentage 42.2 69.6 P<0.001

 

 

Healthy Food Assessment survey Target Areas Contrast Area Statistical Significance of Group Difference
Not a chain store, percentage 69.2 46.7 P<0.05
Service: Excellent/good, percentage 70.4 100.0 P<0.05
Sells fresh fruit or vegetables, percentage 70.4 93.8 P<0.05

Sells milk, percentage

  Whole

88.9

100.0

NS
  2%

50.0

81.3

P<0.05

  1%

29.6

56.3

P<0.05

  Skim

37.0

81.3

 P<0.01

Sells cheese, percentage
  Regular 68.5 68.8 NS
  Low-fat 20.4 50.0

P<0.05

  Non-fat

7.4

31.3

P<0.05

Sells whole-grain pasta, percentage 1.9 31.3 P<0.01
Sells low-fat potato chips, percentage 33.3 68.8 P<0.05
Sells sugar-free cookies, percentage 16.7 50.0 P<0.05
Has a diabetic food section, percentage 3.9 33.3 P<0.01
Has a low-salt food section, percentage 3.9 26.7 P<0.05

 

Author Conclusion:

Health disparities found in African-American communities extend beyond the health care system and may be rooted in the fact that a healthier lifestyle is more difficult in nutrition-resource-poor neighborhoods than in nutrition-resource-rich ones. South Los Angeles residents are significantly less likely to have access to healthy food items encouraged by health advocates, such as low-fat or skim milk, low-fat or non-fat cheese, whole grain pasta and a greater variety of fruits and vegetables. The community-based participatory research process used in this study provides an opportunity to develop a collaborative project that could improve the health of communities confronting such inequities.

Funding Source:
Government: Centers for Disease Control and Prevention
Reviewer Comments:

The authors mention that the participatory research method poses threats to the validity and reliability of the data, as the method requires less elaborate survey instruments and less control over the data collection process. The authors also state that this study experienced problems in the quality of the initial inventories.

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? 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? Yes
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? No
  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? Yes
  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.) Yes
  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? 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? 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? 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? 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? ???
  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? 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