EAL

HD: Food Security (2011)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine whether Food Stamp Program (FSP) participation is associated with body mass index (BMI) in adults, independent of food security status. Associations between FSP participation, food insecurity, sources of food and BMI were also examined.

Inclusion Criteria:

Households located in one of the 216 qualified census tracts in Massachusetts identified by the 2000 US Census data
Telephone number selected by random-digit dialing techniques
Adult aged 18 years or over
English speaking.

Exclusion Criteria:

Household located outside one of the 216 qualified census tracts in Massachusetts
Not selected using random digit-dialing techniques
Non-English speaking
Less than 18 years of age.

Description of Study Protocol:

Recruitment

Recruited by review and random selection from 216 qualified census tracts as determine by 2000 US Census data.

Design

Telephone interviews were conducted for randomly selected households in 216 qualified census tracts in Massachusetts. The survey included the US Department of Agriculture's (USDA) Household Food Security Module, which asks about conditions that characterize households having difficulty meeting basic food needs. The full 18-item survey was used for households with children while the adult specific 10 item survey was used for adult only households. More than three affirmative answers to the HFSM items were classified as food insecure. The survey also included questions on income, demographic characteristics, participation in three government sponsored nutrition programs, use of free or low-cost food from charitable sources and use of supermarkets for food purchases. Self-reported height and weight of the respondent, health coverage, self-perceived health and indicators of social capital were collected as well.

Statistical Analysis

Weight analyses conducted using PROC SURVEYMEANS and SURVEYFREQ
Univariate analyses
Multivariate linear regression models
Likelihood ratio test.

Data Collection Summary:

Timing of Measurements

Collected during phone interview:

HFSM and survey questions to assess food insecurity
Self-reported height and weight of respondent
Health coverage
Self-perceived health
Indicators of social capital.

Dependent Variables

BMI of respondent.

Independent Variables

Presence of food insecurity.

Control Variables

Number of children
Ethnicity
Income
Age
Gender
Place of birth for respondent
Martial status of respondent
Self-reported health score of respondent
Education level
Household size
Full-time employment status.

Description of Actual Data Sample:

Initial N: 465 households
Attrition (final N): 435 adult respondents reported height and weight (150 male, 285 female)
Age: 129 participants less than 35 years old, 196 participants 35 to 55 years of age, 103 participants more than 55 years old
Ethnicity: 75 Hispanics, 82 African Americans, 244 whites, eight other
Other relevant demographics:
- Place of birth: 348 born in US, 87 born in another country
- Martial status of respondent: 179 married or partnered, 255 other
- Highest education in household: 68 participants with some high school, 106 participants with high school diploma, 244 participants with college or more
Anthropometrics:
- 51% of respondents were overweight (BMI more than 25kg/m²)
- 25% of respondents were obese (BMI more than 30kg/m²)
- 6% of respondents were morbidly obese (BMI more than 40kg/m²)
- Men, married respondents, respondents in households with no full-time employment and those with fair to poor self-reported health scores had significantly higher mean BMI compared with their respective reference groups
Location: Massachusetts.

Summary of Results:

Key Findings

BMI did not differ by immigrant status respondent age, education, home ownership status, number of children, social capital score, household size, income eligibility for federal assistance, ethnicity, self-reported exercise in past month or health care coverage (P>0.05)
35% of households experienced food insecurity during the year preceding the survey and approximately 45% of these experienced severe food insecurity with hunger
Respondents classified as food insecure or food insecure with hunger had significantly higher BMI than those classified as food insecure (P<0.01)
Mean BMI did not differ between food-insecure groups with or without hunger
Proportions of respondents with BMI more than 30kg/m² was significantly higher in those who experienced food insecurity compared with food-secure respondents
Ever participating in the FSP and participation in any federal nutrition program in the 12 months prior to the survey remained significantly associated with higher BMI (difference in BMI 3.2±0.7kg/m²) after adjustment for sociodemographic factors as compared to the group not participating in programs
Among current FSP participants, participation for six months or longer was associated with significantly lower BMI (26.9±1.2kg/m²)compared with participation for less than six months (36.9±3.4kg/m²), P<0.01
Eating fast food at least once in the month prior to the survey remained significantly associated with higher BMI (27.4±0.6kg/m² vs. 24.8±0.7kg/m², P<0.01)
Neither food insecurity nor the individual components of the HFSM were associated with BMI after adjustment for sociodemographic characteristics and FSP participation.

	BMI kg/m²
Food secure	26±0.5
Food insecure without hunger	27.9±1.2 P<0.01
Food insecure with hunger	27.7±1.2 P<0.01

Author Conclusion:

The study examined whether participation in the FSP and other strategies for managing food security were associated with BMI independent of food security status in residents of low-income communities. Ever participating in the FSP, participating in any federal nutrition program at some point during the 12 months prior to the survey and fast food consumption at least once in the month prior to the survey were each associated with increased BMI independent of sociodemographic factors and food insecurity.

Funding Source:

Government:

National Institutes of Health, Massachusetts MSG/Nucleotides Class Action Settlement

Reviewer Comments:

Use of reported rather than measured height and weight may have acted as a confounder
Phone survey method may have excluded eligible participants.

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?		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?	No
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)	N/A
	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.)	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?	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?		Yes
	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%.)	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?		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?	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?	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?	Yes
	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?		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?	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?	Yes
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