EAL

AWM: Nutrition Education (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To estimate population percentages of US adults who have adopted behaviors promoted by dietary guidance about how to reduce fat intake and to assess the relationships between these behaviors and intake of energy from total and saturated fat.

Inclusion Criteria:

Individuals aged 20 and older who provided food intake data for two days in the 1994-1996 CSFII and completed the follow-up DHKS.

Exclusion Criteria:

Excluded if not included above.

Description of Study Protocol:

Recruitment

National probability samples of individuals drawn from 50 states and Washington, DC.

Design

Cross-sectional study.

Blinding used (if applicable)

Not applicable.

Intervention (if applicable)

CSFII and DHKS data analysis.

Statistical Analysis

Sample weights were applied to calculate descriptive statistics showing population estimates for the fat-related dietary behaviors. The sample weights adjust for differential rates of selection and nonresponse in part by calibrating the sample to match the US population on characteristics thought to be correlated with eating behavior, such as gender, age, race, ethnicity, income, household composition, employment status, region and urbanization. The data presented for both frequencies of food intake behaviors and average predicted effects (regression coefficients) reflect estimates for the US population.

Multiple regression models were used to test the statistical significance of dietary behaviors, demographic factors and personal characteristics in predicting total fat and saturated fat intake. Individuals with incomplete data were eliminated from the regression analysis.

Data Collection Summary:

Timing of Measurements

Relationships were examined between intake of total and saturated fat from USDA's 1994-1996 Continuing Survey of Food Intakes by Individuals and responses to behavior questions on the Diet and Health Knowledge Survey. Response rate for sample was 72%.

Dependent Variables

Fat-related behavior measured through 19 questions on DHKS.
Respondents answered questions about their knowledge, attitudes and behaviors related to putting dietary guidance into practice.
Many of these questions were derived from the validated Food Habits Questionnaire.

Independent Variables

Dietary intake of total and saturated fat measured through two nonconsecutive 24-hour recalls in CSFII.

Description of Actual Data Sample:

Initial N: National sample of 5,649 individuals.
Attrition (final N): Analysis based on complete data for 5,026 individuals.
Age: Aged 20 and older.
Ethnicity: National sample
Location: National sample.

Summary of Results:

Other Findings

In this study, the percentage of US adults who consistently followed the low-fat behaviors ranged from 8% to 70%, depending on the behavior.
The most highly adopted behaviors (45% or more of adults) included trimming fat from meat, removing skin from chicken and eating chips infrequently.
The least highly adopted behaviors (15% or fewer of adults) included eating baked or boiled potatoes without added fat, avoiding butter or margarine on breads, eating low-fat instead of regular cheeses and having fruit for dessert.
About 1/3 of adults have adopted the behavior of using fat-free or 1% milk instead of 2% or whole milk.
About half of the behaviors had been adopted by larger proportions of women than men.
Together, the 19 fat-related behavior questions on the DHKS formed a statistically significant predictor for total fat and saturated fat intake, expressed as a percentage of energy (P<0.0001).
Predicted effects of these key behaviors, in terms of lowering fat intake as a percentage of energy were >1.5 percentage points for total fat and >0.5 percentage points for saturated fat.

Author Conclusion:

This study provides data about the prevalence of dietary behaviors widely promoted in messages to reduce fat consumption. Results have applications for designing brief fat assessment instruments and for identifying key nutrition education messages that promote important fat-lowering behaviors.

Funding Source:

Government:	USDA
University/Hospital:	Texas A&M

Reviewer Comments:

National sample, validated questionnaire.

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?	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)	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?	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?	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?		N/A
	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?	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?		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?	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?	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?	N/A
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