journal of the american dietetic association

JOURNAL OF THEAMERICAN DIETETICASSOCIATION

Guenther PM, et al. J Am Diet Assoc. 2008;108 (Nov).


Evaluation of the Healthy Eating Index-2005

Patricia M. Guenther, PhD, RD: US Department of Agriculture, Center for Nutrition Policy and Promotion

Jill Reedy, PhD, RD: National Cancer Institute (NCI)Susan M. Krebs-Smith, PhD, RD: NCI

Bryce B. Reeve, PhD: NCI



• Content validity

• Construct validity

• Internal consistency (reliability)


Tests



• Extent to which the measure captures the variety of attributes that make up the construct

• Includes face validity

• Test– Check against Dietary Guidelines


Content validity



• Extent to which the measure is consistent with theoretical hypotheses

• Tests– Exemplary menus– Smokers vs nonsmokers– Correlations with energy– Principal components analysis


Construct validity



• MyPyramid.gov

• Dietary Approaches to Stop Hypertension (DASH) Eating Plan

• Eat, Drink, and Be Healthy: The Harvard Medical School Guide to Healthy Eating

• American Heart Association No-Fad Diet


Sources of exemplary menus




Healthy Eating Index-2005 scores for exemplary menusMyPyramid DASH Harvard AHA

Total Grains 5 4.8 5 5

Whole Grains 5 5 5 5

Total Vegetables 5 5 5 5

Dark Green/Orange Vegetables & Legumes

5 5 5 4.9

Total Fruit 5 5 5 5

Whole Fruit 5 5 5 5

Milk 10 10 0.9 8.7

Meat & Beans 10 10 10 10

Oils 10 10 10 10

Sodium 10 10 10 10

Saturated Fat 10 10 10 10

Calories from SoFAAS 20 20 20 20

Total 100 99.8 90.9 98.6

SoFAAS: Solid Fats, Alcoholic beverages, and Added Sugars



• National Health and Nutrition Examination Survey, 2001-2002

• N = 8650

• One 24-hour recall per respondent– Nutrients– MyPyramid food groups


Population data used



• Distinguishes between groups with known differences in the quality of their diets

• Test– Smokers vs nonsmokers


Concurrent criterion validity



• Number of differences in mean component scores– Original Healthy Eating Index 5 of 10– Healthy Eating Index-2005 9 of 12

• Differences in mean total score– Original Healthy Eating Index 5.5 points– Healthy Eating Index-2005 8.6 points

• Conclusion: Healthy Eating Index-2005 distinguishes between smokers and nonsmokers better than original Healthy Eating Index


Smokers vs nonsmokers



• Component scores – Fruit .05– Vegetables, Milk, Variety, Meat, Grains .29 to .44– Fat, Saturated fat (% calories) -.08 to .09– Cholesterol -.43– Sodium -.69

• Total score .09– Low because some food-group correlations are positive

and others negative


Correlations of original Healthy Eating Index scores and energy intake



• Component scores– Calories from SoFAAS -.22– Sodium, Saturated Fat -.08 to -.11– Vegetables, Grains, Fruit -.05 to -.10– Milk 0– Oils, Meat and Beans .06 to .08

• Total score -.14– Low because all component correlations are low

• Conclusion: Healthy Eating Index-2005 successfully uncouples diet quantity and diet quality


Correlations of Healthy Eating Index-2005 scores and energy intake

SoFAAS: Solid Fats, Alcoholic beverages, and Added Sugars



Variance accounted for by each factor


Principal component analysis scree plot

Number of factors

Eig

enva

lue

Conclusion: Multiple factors underlie the Healthy Eating Index-2005



• Test-retest reliability does not apply– All sources of error attributable to

• Respondent recall • Data collection and coding

• Inter-rater reliability does not apply– No judgment required

• Internal consistency– Only type that could be tested


Types of reliability



• Degree of association among the components of an index

• Test– Cronbach’s alpha coefficient


Internal consistency



• Cronbach’s coefficient alpha = 0.43

• Anticipated to be low because – Healthy Eating Index-2005 components

• Do not all measure the same thing• Relationships among them vary

• Conclusion: Healthy Eating Index-2005 is best used as a set of profile scores; otherwise, much information will be lost


Internal consistency



• Is a valid measure of compliance with the 2005 Dietary Guidelines for Americans

• Yields high scores for exemplary menus• Distinguishes between groups with known

differences in diet quality • Uncouples diet quality and diet quantity by using a

density approach• Provides a valid set of profile scores for assessing

diet quality


ConclusionsThe Healthy Eating Index-2005

journal of the american dietetic association

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