Resources Related to the Healthy Eating Index (HEI)

The Healthy Eating Index (HEI) is a measure of diet quality that can be used to assess compliance with the Dietary Guidelines for AmericansExternal Web Site Policy. The HEI–2010 is the latest iteration; its predecessor is the HEI–2005. When HEI-2015 is released, we will provide updates as they become available.

There is a Canadian version of the HEIExternal Web Site Policy, but the information presented here pertains to the U.S. HEI. Data based on ASA24-Canada-2016 can be used to calculate the U.S. HEI, however, Researchers may wish to consider whether this is appropriate for their research.

Calculating HEI Scores for Person-Level ASA24 Intake

It is important to consider that an HEI score at the individual or person level based on one or several days of intake data does not represent usual intake and that meeting dietary recommendations is meant to be achieved over time.

Two SAS programs are provided to calculate the HEI–2010 using ASA24-2016 dietary intake data and two separate SAS programs are provided to calculate the HEI-2010 using ASA24-2014 dietary intake data. Because the pyramid equivalents databases for 2016 vs. 2014 versions are different (2016 uses USDA's Food Pyramid Equivalents Database or FPED, and 2014 versions use the MyPyramid Equivalents Database or MPED), these SAS programs are slightly different.

The SAS programs can be used to calculate mean HEI total and component scores for individuals. The first set of programs calculate the HEI for each day of intake data regardless of how many ASA24 intake days are available from each person. The second set of programs correctly calculate ratios used in the HEI algorithm when a Respondent has more than one day of ASA24 intake data. For example, in the second program:

The cup equivalents of total fruit summed over x days is divided by the total energy summed over the x days:

∑ total fruit over x days
∑ total energy over x days

rather than the daily average:

total fruit/total energy per day
x days

The ratio is compared with the HEI standard on a cup equivalent per 1000 kcal basis as are many HEI components.

To calculate HEI scores for each intake day regardless of how many recalls are available per person:

To calculate one HEI score per individual across all days of ASA24 recalls or records collected, even if some Respondents have varying number of intake days, including only one:

Note: Some users have found that these SAS programs will drop observations from the analysis if the ID field is not the same length for all observations. To prevent this error, the observations with the longest ID length should be listed first when the data is imported into SAS.

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Calculating HEI scores for Group-Level ASA24 Intake

Mean HEI scores for a population, subpopulation, or group can be estimated using ASA24 data and the population ratio method. This approach has been shown to be the preferred method of estimating a population's mean usual HEI component and total scores on the basis of a single day of data, which is sufficient for this purpose.

This program performs the preliminary steps for creating the requisite variables and calls two macros that allocate beans and peas to the protein and vegetable components and applies the HEI–2010 scoring algorithm. The output includes mean component and total HEI–2010 scores for the population, along with their standard errors and confidence intervals. Because the HEI–2010 is a multi-dimensional construct involving 12 densities (amounts of food per 1,000 calories and ratios of fatty acids), a simple method for estimating standard errors is not available. In this code, a Monte Carlo simulation step is included for the calculation of standard errors.

To apply the population ratio method, the mean intake of the relevant food groups, nutrients and energy among the population of interest is calculated first; then ratios of the means are calculated and compared with the applicable standards for scoring. See Freedman et al. 2008External Web Site Policy for a description and application of the population ratio method.

This code performs the preliminary steps for creating the requisite variables from ASA24 data and calls macros that allocate beans and legumes to the protein and vegetable components and applies the HEI–2010 scoring algorithm. The output includes mean component and total HEI–2010 scores for the population, along with their standard errors confidence intervals. This code can be modified to use with other datasets that do not involve complex sampling designs.

The HEI Tools for Researchers page provides other SAS programs to calculate mean and component HEI scores for a subpopulation or group using ASA24 output. Information is also provided on estimating distributions of HEI scores and on estimating relationships between HEI scores and another variable, such as health.

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