Validity and calibration of food frequency questionnaires used with African-American adults in the Jackson Heart Study

Abstract

Objective: To examine the relative validity of two food frequency questionnaires (FFQs) developed for use in investigating diet and disease relationships within the adult African-American population in the southern United States.

Design: Cross-sectional analyses of dietary nutrient intake data, comparing four 24-hour dietary recalls with an FFQ developed by the Lower Mississippi Delta Nutrition Intervention Research Initiative, and its shorter version adapted for use in the Jackson Heart Study.

Subjects: A representative subset of participants (n=499, aged 35 to 81 years) from the baseline Jackson Heart Study cohort (N=5,302) was selected for this study. Data collection took place between winter 2000 and spring 2004.

Statistical analyses: Pearson's correlation coefficients (energy adjusted and de-attenuated) for 26 nutrients estimates from each of the FFQs, comparing them with the mean of four 24-hour dietary recalls. The ability of the FFQs to rank individuals based on nutrient intakes was compared to that of the mean of four 24-hour dietary recalls and attenuation coefficients were also calculated.

Results: Median nutrient intake estimates tended to be higher on the long and lower on the short FFQ compared to the median for the mean of four 24-hour dietary recalls. Energy adjusted and deattenuated correlations of FFQ intake estimates with recalls ranged from 0.20 for sodium to 0.70 for carbohydrate for the short FFQ and from 0.23 for polyunsaturated fat to 0.75 for dietary fiber and magnesium for the long. Attenuation coefficients for men on average were 0.42 for the short and 0.49 for the long FFQ. For women, these were 0.31 for the short and 0.42 for the long FFQ.

Conclusions: Both FFQs appear to be reasonably valid for assessment of dietary intake of adult African Americans in the South. The Lower Mississippi Delta Nutrition Intervention Research Initiative FFQ exhibited higher intake estimates and stronger correlations with recalls than the Jackson Heart Study FFQ for most nutrients analyzed, more so for women than men.

Figures

Figure 1

Bland-Altman plot of the difference between energy intake from Mean of Four-24 Hour Dietary Recalls and the short FFQ against the mean of the two for the male participants of the JHS-DPASS conducted in Jackson, Mississippi, 2000-2004. Difference (energy intake from Mean of Four-24 Hour Dietary Recalls - the short FFQ) ------- 95% limits of agreement FFQ: Food Frequency Questionnaire JHS-DPASS: Jackson Heart Study- Diet and Physical Activity Sub-Study

Figure 2

Bland-Altman plot of the difference between energy intake from Mean of Four-24 Hour Dietary Recalls and the long FFQ against the mean of the two for the male participants of the JHS-DPASS conducted in Jackson, Mississippi, 2000-2004. Difference (energy intake from Mean of Four-24 Hour Dietary Recalls - the long FFQ) ------- 95% limits of agreement FFQ: Food Frequency Questionnaire JHS-DPASS: Jackson Heart Study- Diet and Physical Activity Sub-Study

Figure 3

Bland-Altman plot of the difference between energy intake from Mean of Four-24 Hour Dietary Recalls and the short FFQ against the mean of the two for the female participants of the the JHS-DPASS conducted in Jackson, Mississippi, 2000-2004. Difference (energy intake from Mean of Four-24 Hour Dietary Recalls - the short FFQ) ------- 95% limits of agreement FFQ: Food Frequency Questionnaire JHS-DPASS: Jackson Heart Study- Diet and Physical Activity Sub-Study

Figure4

Bland-Altman plot of the difference between energy intake from Mean of Four-24 Hour Dietary Recalls and the long FFQ against the mean of the two for the female participants of the JHS-DPASS conducted in Jackson, Mississippi, 2000-2004. Difference (energy intake from Mean of Four-24 Hour Dietary Recalls - the long FFQ) ------- 95% limits of agreement FFQ: Food Frequency Questionnaire JHS-DPASS: Jackson Heart Study- Diet and Physical Activity Sub-Study