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UBC Theses and Dissertations

Fruit and vegetable intake and factors influencing intake of adolescents : developing the questionnaires Li, Liming


Studies have suggested that fruit and vegetable intake might reduce the risk of cancer, cardiovascular disease, and other chronic diseases. Adolescents' fruit and vegetable intake appears to be below the recommended level according to Canada's Food Guide to Healthy Eating. There are many factors that may influence adolescents' fruit and vegetable intake. The objectives of this study were to develop a food frequency questionnaire (FFQ) to assess adolescents' fruit and vegetable intake, to develop an Attitude/Behaviour questionnaire looking at factors influencing their consumption of these foods and to test the validity and reliability of these 2 questionnaires. Students in grades 7 through 12 from 4 secondary schools were asked to participate in this study. The statements in the Attitude/Behaviour questionnaire were generated based on the literature and 3 focus group discussions with a total of 26 students. The FFQ was adapted from an existing questionnaire developed by the National Cancer Institute and was used to assess the fruit and vegetable intake over the previous 1 week. The FFQ was validated with a group of 63 students who completed the FFQ as well as a written 24-hour dietary record. The internal consistency reliability of the Attitude/Behaviour questionnaire and the face validity of the FFQ and the Attitude/Behaviour questionnaire were assessed with a group of 48 students. The test-retest reliabilities of these 2 questionnaires were tested with a group of 43 students who completed questionnaires on 2 occasions approximately 2 months apart. The correlation coefficient of the FFQ against the 24-hour dietary record was 0.52 and the test-retest reliability coefficient was 0.46. The internal consistency reliability of the Attitude/Behaviour questionnaire was 0.71 and the test-retest reliability was 0.59. Questionnaires were revised based on comments obtained from the face validity test. These results suggest that our developed questionnaires could be further used as research tools for the target group.

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