An evaluation of a food frequency questionnaire for assessing dietary intake of specific carotenoids and vitamin E among low-income black women.

The National Cancer Institute diet questionnaire was evaluated for use in a low-income black population. Data were collected from 91 women aged 30-69 years who were hospital outpatients in Atlanta, Georgia, June through August, 1988. Six ethnic and regional foods added to the questionnaire were found to be important contributors to intakes of several nutrients. Although 17 records were identified as containing probable recording or reporting errors, intakes of carotenes, alpha-carotene, beta-carotene, cryptoxanthin, and vitamin E were significantly and positively associated with serum levels of their referent nutrients. Among nonsmokers, correlation coefficients ranged from 0.32 to 0.45, adjusted for age, body mass index, alcohol and calorie intakes, medications and vitamin supplement use, and serum cholesterol and triglycerides. When questionnaires containing identified errors were omitted, correlations ranged from 0.30 to 0.54. There were no correlations between dietary intakes of lycopene and lutein and blood levels (-0.06 to 0.09). Among smokers, diet-serum correlations were reduced (0.00 to 0.32). These correlations are similar to those reported in research on vitamin E and carotenoids in other populations. These results suggest that the questionnaire is as valid for use in this population as it is in other populations.