Evaluation of three short dietary instruments to assess fruit and vegetable intake: the National Cancer Institute's food attitudes and behaviors survey.

BACKGROUND: Fruit and vegetable (F/V) intake assessment tools that are valid, reliable, brief, and easy to administer and code are vital to the field of public health nutrition. OBJECTIVE: To evaluate three short F/V intake screeners (ie, a 2-item serving tool, a 2-item cup tool, and a 16-item F/V intake screener) among adults using multiple 24-hour dietary recalls (24-hour recalls) as the reference instrument and evaluate test-retest reliability of the screeners across a 2- to 3-week time period. DESIGN: Validity and reliability study. PARTICIPANTS/SETTING: Two hundred forty-four adults for the validity study and 335 adults for test-retest reliability. STATISTICAL ANALYSES PERFORMED: Median values for F/V intakes were calculated for the screeners and 24-hour recalls. The Wilcoxon signed rank test was used to compare screeners with the 24-hour recalls. Deattenuated Pearson correlations were reported for validity and intraclass correlation coefficient used for reliability. RESULTS: The estimated median daily servings/cups of F/V for the 2-item serving screener was lower, for the 2-item cup screener was equivalent for men but higher for women, and for the 16-item F/V intake screener were about the same when compared with 24-hour recall values. The deattenuated correlations comparing the 24-hour recalls with the screeners were positive but weak for the 2-item serving screener, and were positive and moderate in strength for the 2-item cup and 16-item F/V intake screeners. The test-retest intraclass correlation coefficients were all positive and fairly strong for all of the screeners. CONCLUSIONS: Although dietary screeners offer a more cost-effective, less burdensome way to obtain gross estimates to rank individuals with regard to F/V intake, these methods are not recommended for assessing precise intake levels.

Development of a food frequency questionnaire module and databases for compounds in cooked and processed meats.

There is ample evidence from basic research and animal carcinogenicity studies that heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) are mutagens and carcinogens. However, there was a paucity of human data due to a lack of appropriate investigative tools. We developed the first validated cooked meat module within a food frequency questionnaire (FFQ) in the United States of America and created databases to be used in conjunction with this FFQ to estimate intake of HCAs and benzo[a]pyrene, a marker of PAHs. It became clear that other aspects of meat may also contribute to carcinogenesis; in particular, we are pursuing two additional areas: processed meat and iron exposure in relation to cancer risk. To investigate these hypotheses, we have expanded the cooked meat module to include detailed information on processed meats and fish. In addition, we are developing two databases, one for total iron and heme iron in cooked meat and the other for nitrite, nitrate, and N-nitroso compounds in processed meats. In this report, we will outline the methods used to develop the meat questionnaires, the databases, a software package for generating the intake values, and the methods used to generate nutritional data from nationally representative samples.