SAS Code

In the table below, sample SAS code is available for calculating the HEI with different dietary assessment tools. These include:

  • 24-hour recall(s) example: Automated Self-Administered 24-Hour Dietary Assessment Tool
  • National Health and Nutrition Examination Survey: NHANES weighted national survey with 24-hour recall(s) example
  • Cohort with food frequency questionnaire example: NIH-AARP Diet and Health Study: NIH-AARP

Where possible, the zip files provided in the table below include sample SAS code, macros for scoring, and sample output. These macros can be used to calculate HEI–2015, HEI–2010, and HEI–2005 component and total scores and can be applied to any SAS dataset containing the requisite variables.

In the 2010 and 2005 versions, there are two macros, one of which allows for the allocation of legumes (beans and peas) to count as part of the vegetable or protein food groups, and the other creates ratios and scores them using the applicable standards.

HEI-2015 includes only the macro for scoring, as legumes (beans and peas) are now allocated to both the vegetable and protein food groups. For some applications, such as an analysis of the food environment, the scoring macro can be used (provided below).*

Download HEI Sample Code

Click each to expand for more information.

Simple HEI Scoring Algorithm - Per Day

ASA24 Example

To calculate HEI scores for each intake day regardless of how many recalls or record days are available per person.

HEI-2015
HEI-2010

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.

FFQ Example

This code uses NIH-AARP Diet and Health Study data as an example. This code estimates component and total HEI scores for each individual and can be modified for use with other FFQs.

HEI-2015
HEI-2010
HEI-2005

Simple HEI Scoring Algorithm - Per Person

ASA24 Example

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.

In this 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.

HEI-2015
HEI-2010

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.

NHANES Example

The programs below correctly calculate ratios used in the HEI algorithm when a participant has more than one day of 24HR data. For example, 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, in this case on a cup equivalent per 1000 kcal basis.

HEI-2015
HEI-2010

Population Ratio Method

ASA24 Example

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.

The output includes mean component and total HEI scores for the population, along with their standard errors and confidence intervals. Because the HEI is a multi-dimensional construct involving multiple 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. 2008 for a description and application of the population ratio method. This code can be modified to use with other datasets that do not involve complex sampling designs.

HEI-2015
HEI-2010
HEI-2005

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.

NHANES Example

HEI-2015
HEI-2010

For the calculation of HEI-2010 scores using NHANES data, two examples are available.


HEI-2005

SAS code for calculating HEI-2005 scores using NHANES data is also available. This code uses NHANES 2001-2002 data as an example and links to the MPED.

Bivariate Methods

NHANES Example

HEI-2015, HEI-2010 and HEI-2005

If more than one recall is available for at least a subsample, a bivariate approach can be used to estimate distributions of scores for the components of the HEI. This approach is described in detail in Freedman et al. 2010. SAS code for implementing this approach is available here.

With individual-level data, it also is possible to calculate mean scores or scores of the mean ratio. This approach is not recommended for the purposes of describing mean HEI scores. See Freedman et al. 2008 for details.

The use of food frequency questionnaire (FFQ) data for the estimation of means or distributions of HEI scores is not recommended.

Multivariate Markov Chain Monte Carlo (MCMC) Method

The MCMC method estimates the distribution of HEI component and total scores. The method addresses measurement error, episodic consumption, skewness, and the correlation between the components and energy.

NHANES Example

HEI-2015

MCMC SAS code for the HEI-2015 (including a wrapper) [ZIP - 4.25 MB] is available here. Although this example is for NHANES 2011-12 data, the programs can be used with other cycles of NHANES and any data with a similar survey structure with BRR weights.  For analyses using other types of weights, additional modifications would be needed. Please note that this code may take 1 to 3 days to run. 


HEI-2010 and HEI-2005

The MCMC approach has been described for the HEI–2005 by Zhang et al. 2011 and applied in the Evaluation of the HEI–2010. SAS macros for the implementation of this approach are available here.

* Scoring macros for HEI-2015, HEI-2010, and HEI-2005.