Performance of a shortened telephone-administered version of a quantitative food frequency questionnaire

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.

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.

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.

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.