Ej. Mayer-davis et al., Validity and reproducibility of a food frequency interview in a multi-cultural epidemiologic study, ANN EPIDEMI, 9(5), 1999, pp. 314-324
PURPOSE: There is limited support for the validity and reproducibility of d
ietary assessment in culturally diverse populations. The goal of this study
was to evaluate the comparative validity and reproducibility of a Food Fre
quency Questionnaire (FFQ) used in the observational, multi-culcural Insuli
n Resistance Atherosclerosis Study (IRAS).
METHODS: Women (n = 186) were approximately equally distributed by ethnicit
y from one urban center (African Americans and non Hispanic whites) and one
rural center (Hispanics and non Hispanic whites). The IRAS FFQ was modifie
d from the National Cancer Institute Health Habits and History Questionnair
e to include ethnic and regional foods. Validity was assessed by comparing
dietary values, including supplements, obtained from the FFQ to the average
intake estimated from a series of 8 24-hour dietary recalls collected by t
elephone over the same 1 year period. Reproducibility was assessed among wo
men who reported no change in their usual diet (n = 133) by comparing data
from the original IRAS FFQ (in person) with the FFQ administered for the va
lidity study (two to four years later, by telephone).
RESULTS: Correlation coefficients for validity were statistically significa
nt for most nutrients (mean r = 0.62 urban non Hispanic white, 0.61 rural n
on-Hispanic whites, 0.50 African American, 0.41 Hispanic) and did not diffe
r among subgroups of obesity or diabetes status. The median correlation coe
fficient for the total sample was 0.49. Correlations were lower for women w
ith less than 12 years of education (mean r = 0.30; median r = 0.25). The l
ower correlations among Hispanics was largely explained by the lower educat
ional attainment in that sample. For reproducibility, the mean correlation
for nutrients evaluated was r = 0.62 (median r = 0.63) and did not differ f
or subgroups.
CONCLUSIONS: Although educational attainment must be considered, the IRAS F
FQ appears to be reasonably valid and reliable in a diverse cohort. (C) 199
9 Elsevier Science Inc. All rights reserved.