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Dietary Screener in the 2009 CHIS: Validation

In the Eating at America's Table Study (EATS) and the Observing Protein and Energy Nutrition Study (OPEN), Risk Factor Monitoring & Methods Branch staff assessed the validity of created aggregate variables from the 2009 CHIS Dietary Screener. In these studies, multiple 24-hour recalls (24HR) in conjunction with a measurement error model were used to assess validity. The screeners used in these studies included questions similar but not identical to those in CHIS 2009. We have constructed parallel variables based on the data available and the scoring algorithms developed for CHIS 2009. For added sugars, questions answered on the Diet History Questionnaire (administered in both studies) were used as proxies for the screener items.

Estimates of cup equivalents of fruits and vegetables and teaspoons of added sugars in EATS and OPEN are shown below. The cup equivalents are based on the US Department of Agriculture’s (USDA) MyPyramid Equivalents Database (MPED; version 2.0 for USDA Survey Foods, 2003-2004) and cited in the 2010 Dietary Guidelines for Americans.

Variable/Survey Men (median intake) Women (median intake)
Recalls Screener Recalls Screener
Fruits and vegetables, excluding legumes (cup equivalents)
EATS 3.23 2.78* 2.35 2.38
OPEN 3.48 2.80* 3.03 2.48*
Fruits and vegetables, excluding legumes and French fries (cup equivalents)
EATS 3.04 2.67* 2.26 2.32
OPEN 3.38 2.71* 2.95 2.43*
Added sugars (teaspoons)
EATS 17.4 18.7* 11.7 12.7*
OPEN 17.4 16.7 13.2 11.6*

*Screener significantly different from 24-hour recall (24HR; p < 0.05).

These validation results suggest that dietary exposure estimates computed for the CHIS 2009 using the screener may be misestimates of the actual intakes. For fruits and vegetables, the underestimates ranged from 0 (nonsignificant) to 2/3 cup equivalent per day. For added sugars, misestimates ranged from 0.7 (nonsignificant) to 1.6 tsp per day. While statistically significant, the relative differences are small. Differences by gender for all variables seen with 24HR data were reflected in the screener estimates. Thus, the screener estimates may best be used to estimate approximate levels of these exposures and relative differences among demographic groups. The estimates may be less useful for populations with ethnic diets, including Asian and possibly Latino populations.

At the individual level, estimated correlations between the screener and true intake for cup equivalents of fruits and vegetables and teaspoons of added sugars in EATS and OPEN are shown below.

Variable Men Women
Fruits and vegetables, excluding legumes (cup equivalents)
EATS 0.61 0.51
OPEN 0.55 0.75
Fruits and vegetables, excluding legumes and French fries (cup equivalents)
EATS 0.62 0.53
OPEN 0.56 0.76
Added sugars (teaspoons)
EATS 0.59 0.70
OPEN 0.71 0.61

The square of the correlation between screener and true intake (R-square) represents the percentage of variability in true intake that is explained by the screener. Overall, about 25 to 50 percent of the variability in the true intake of fruits and vegetables and added sugars will be captured by the screener questions. Thus, although significant error may be associated with these estimates of diet, we believe the exposure estimates still substantially reflect what individuals are actually consuming.

Validation results for the Multifactor Screener, which includes a similar fruit and vegetable component, are reported in detail in:

Thompson FE, Midthune D, Subar AF, Kahle LL, Schatzkin A, Kipnis V. Performance of a short tool to assess dietary intakes of fruits and vegetables, percentage energy from fat and fibre. Public Health Nutr 2004 Dec;7(8):1097-105. [View Abstract]

National estimates based on the 2000 NHIS Multifactor Screener are presented and compared with other national data in:

Thompson FE, Midthune D, Subar AF, McNeel T, Berrigan D, Kipnis V. Dietary intake estimates in the National Health Interview Survey, 2000: methodology, results, and interpretation. J Am Diet Assoc 2005 Mar;105(3):352-63; quiz 487. [View Abstract]

CHIS 2005 estimates of fruit and vegetable intake from the CHIS 2005 screener are presented and compared with national 24-hour recall data in:

Colón-Ramos U, Thompson FE, Yaroch AL, Moser RP, McNeel TS, Dodd KW, Atienza AA, Sugerman SB, Nebeling L. Differences in fruit and vegetable intake among Hispanic subgroups in California: results from the 2005 California Health Interview Survey. J Am Diet Assoc 2009 Nov;109(11):1878-85. [View Abstract]

National estimates using added sugars screener questions compared to NHANES 24HR-derived estimates of added sugars intake are in:

Thompson FE, McNeel TS, Dowling EC, Midthune D, Morrissette M, Zeruto CA. Interrelationships of added sugars intake, socioeconomic status, and race/ethnicity in adults in the United States: National Health Interview Survey, 2005. J Am Diet Assoc 2009 Aug;109(8):1376-83. [View Abstract]

Last Modified: 11 Apr 2014