Performance of a shortened telephone-administered version of a quantitative food frequency questionnaire.
OBJECTIVE
We evaluated the performance of a telephone-administered food frequency questionnaire in a study of 190 men and women, 30-79 years of age, who participated as controls in a study of colon cancer.


METHODS
The telephone version of the questionnaire was modified from a longer food frequency questionnaire originally administered in person to each of the participants. One month later, the telephone questionnaire was administered to a subgroup of 190 participants and readministered to 169 members of the subgroup two weeks later to assess the reproducibility and comparative validity of the instrument.


RESULTS
The unadjusted correlation for energy between the original in-person full food frequency questionnaire and the abbreviated telephone version was 0.69. The median energy intake from the telephone version was 17% lower in men and 23% lower in women. The energy and sex-adjusted correlation coefficients for other nutrients ranged from 0.45 for vitamin E to 0.78 for fiber. The intraclass correlation coefficients to measure reproducibility ranged from 0.62 for animal protein to 0.83 for folate.


CONCLUSIONS
These data indicate that this brief, telephone-administered questionnaire is reproducible and provides a ranking of nutrient intake comparable to that provided by a full in-person interview.
Schaffer
D M
DM
Division of Research, Kaiser Permanente Medical Care Program of Northern California, Oakland 94611, USA.
Coates
A O
AO
Caan
B J
BJ
Slattery
M L
ML
Potter
J D
JD
D000328:Adult; D000368:Aged; D002140:California; D016022:Case-Control Studies; D003110:Colonic Neoplasms / Q000453:epidemiology* / Q000209:etiology; D004032:Diet / Q000009:adverse effects*; D004034:Diet Surveys; D004812:Epidemiologic Methods; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires; D013689:Telephone