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Adolescent Questionnaire
practice applications
LETTERS TO THE EDITOR
Validity and Reliability of the Youth/Adolescent Questionnaire To the Editor: I am writing in response to the article by Cullen and Zakeri about the validity and reliability of the Youth/ Adolescent Questionnaire among African-American and Hispanic youth (1). The article contained several statements that are incorrect. In fact, the Youth/Adolescent Questionnaire was developed for youth 9 to 18 years, designed for self-administration, and our study group is located in Boston. The author cites Field and colleagues’ validation study as a validation of the Youth/Adolescent Questionnaire. In Field and colleagues’ study, the Youth/Adolescent Questionnaire is never referenced as the questionnaire in this study, but is described as “modified from the Willett Food Frequency Questionnaire” (2). The questionnaire is similar to the Youth/Adolescent Questionnaire, but there are major differences between the one used in the Eat Well and Keep Moving study and the Youth/Adolescent Questionnaire. At least 20 foods on the Youth/Adolescent Questionnaire are not on the Eat Well and Keep Moving questionnaire, and the frequencies for some of the similar foods are quite different. Although this may seem like a trivial difference, the additional foods are likely to have a meaningful impact on the perLETTERS TO THE EDITOR ARE WELCOME Letters may have a maximum of 500 words; references should be kept to 20 or fewer. Relevant charts or graphs are acceptable. Letters should be typed double-spaced with wide margins. Submission of a letter constitutes permission for the American Dietetic Association to use it in the Journal, subject to editing and abridgement. Financial associations or other possible conflicts of interest should always be disclosed. Letters relating to articles published in recent Journal issues have priority. Letters can be submitted online at www.editorialmanager.com/adaj.
formance of the food frequency questionnaire. My second concern is the study design and analysis of Cullen and Zakeri’s validation study. They reference Field and colleagues’ article as the reason they read the questionnaire to seventh and eighth graders. However, Field and colleagues’ stated that the questionnaire was read to minimize problems due to the reading level in grades four and five. The students in sixth and seventh grades completed it on their own. Most young people in seventh and eighth grades can read and have the cognitive ability necessary to complete a self-report food frequency questionnaire. Therefore, it is unclear why these students had to have the questionnaire read to them. The rationale should not be linked to the article by Field and colleagues. In addition, there was a serious methodological problem with the design of the study by Cullen and Zakeri. Food records were considered the gold standard against which the Youth/Adolescent Questionnaire was compared. However, the 6 days of food records were collected over a 21day period, but the Youth/Adolescent Questionnaire is designed to collect data over the past year. The gold standard should obviously cover the same period as the Youth/Adolescent Questionnaire in order to assess the validity of the Youth/Adolescent Questionnaire. The difference in time frames make it impossible to draw meaningful inference from the analysis. The analysis of the data also raises serious concerns. First, given the very low intake of fruit, juice, and high-fat vegetables, it is not surprising that the correlation coefficients are so low. If the intake is low and the range is limited or skewed due partially to outliers, one should expect the correlations to be low. The estimates of fruit, juice, and high-fat vegetables are lower than those from national data sets, which make one question the validity of the gold standard in the Cullen and Zakeri article. Furthermore, percentage of calories from fat (or protein or carbohydrate for
© 2005 by the American Dietetic Association
that matter) should be expected to have lower validity than intake of grams of fat due to the fact that there is measurement error of the numerator and denominator; thus the ratio will have more error than either the numerator (fat intake) or the denominator (calories) alone. I welcome validations of the Youth/ Adolescent Questionnaire by other investigators, but I hope that future validations are more methodologically rigorous and that investigators carefully read Field and colleagues’ article before referencing it. Helaine R. H. Rockett, MS, RD Nutrition Research Manager Department of Medicine Brigham and Women’s Hospital Harvard Medical School Boston, MA References 1. Cullen KW, Zakeri I. The Youth/ Adolescent Questionnaire has low validity and modest reliability among low-income African-American and Hispanic seventh- and eighth-grade youth. J Am Diet Assoc. 2004;104:1415-1419. 2. Field AE, Peterson KE, Gortmaker SL, Cheung L, Rockett H, Fox MK, Colditz GA. Reproducibility and validity of a food frequency questionnaire among fourth to seventh grade inner-city school children: Implications of age and day-to-day variation in dietary intake. Public Health Nutr. 1999;2:293-300. doi: 10.1016/j.jada.2005.10.007 Author’s Response: We appreciate the comments from Ms Rockett concerning our validation study of the Youth/Adolescent Questionnaire (1). Our intent was to determine whether this instrument, developed and validated with primarily white youth (2), was a reliable and valid instrument with low-income, ethnic, minority youth. Since many of our school-based studies are with minority youth, it was important to test dietary assessment measures with the target population.
Journal of the AMERICAN DIETETIC ASSOCIATION
1867
LETTERS TO THE EDITOR
Validity and Reliability of the Youth/Adolescent Questionnaire To the Editor: I am writing in response to the article by Cullen and Zakeri about the validity and reliability of the Youth/ Adolescent Questionnaire among African-American and Hispanic youth (1). The article contained several statements that are incorrect. In fact, the Youth/Adolescent Questionnaire was developed for youth 9 to 18 years, designed for self-administration, and our study group is located in Boston. The author cites Field and colleagues’ validation study as a validation of the Youth/Adolescent Questionnaire. In Field and colleagues’ study, the Youth/Adolescent Questionnaire is never referenced as the questionnaire in this study, but is described as “modified from the Willett Food Frequency Questionnaire” (2). The questionnaire is similar to the Youth/Adolescent Questionnaire, but there are major differences between the one used in the Eat Well and Keep Moving study and the Youth/Adolescent Questionnaire. At least 20 foods on the Youth/Adolescent Questionnaire are not on the Eat Well and Keep Moving questionnaire, and the frequencies for some of the similar foods are quite different. Although this may seem like a trivial difference, the additional foods are likely to have a meaningful impact on the perLETTERS TO THE EDITOR ARE WELCOME Letters may have a maximum of 500 words; references should be kept to 20 or fewer. Relevant charts or graphs are acceptable. Letters should be typed double-spaced with wide margins. Submission of a letter constitutes permission for the American Dietetic Association to use it in the Journal, subject to editing and abridgement. Financial associations or other possible conflicts of interest should always be disclosed. Letters relating to articles published in recent Journal issues have priority. Letters can be submitted online at www.editorialmanager.com/adaj.
formance of the food frequency questionnaire. My second concern is the study design and analysis of Cullen and Zakeri’s validation study. They reference Field and colleagues’ article as the reason they read the questionnaire to seventh and eighth graders. However, Field and colleagues’ stated that the questionnaire was read to minimize problems due to the reading level in grades four and five. The students in sixth and seventh grades completed it on their own. Most young people in seventh and eighth grades can read and have the cognitive ability necessary to complete a self-report food frequency questionnaire. Therefore, it is unclear why these students had to have the questionnaire read to them. The rationale should not be linked to the article by Field and colleagues. In addition, there was a serious methodological problem with the design of the study by Cullen and Zakeri. Food records were considered the gold standard against which the Youth/Adolescent Questionnaire was compared. However, the 6 days of food records were collected over a 21day period, but the Youth/Adolescent Questionnaire is designed to collect data over the past year. The gold standard should obviously cover the same period as the Youth/Adolescent Questionnaire in order to assess the validity of the Youth/Adolescent Questionnaire. The difference in time frames make it impossible to draw meaningful inference from the analysis. The analysis of the data also raises serious concerns. First, given the very low intake of fruit, juice, and high-fat vegetables, it is not surprising that the correlation coefficients are so low. If the intake is low and the range is limited or skewed due partially to outliers, one should expect the correlations to be low. The estimates of fruit, juice, and high-fat vegetables are lower than those from national data sets, which make one question the validity of the gold standard in the Cullen and Zakeri article. Furthermore, percentage of calories from fat (or protein or carbohydrate for
© 2005 by the American Dietetic Association
that matter) should be expected to have lower validity than intake of grams of fat due to the fact that there is measurement error of the numerator and denominator; thus the ratio will have more error than either the numerator (fat intake) or the denominator (calories) alone. I welcome validations of the Youth/ Adolescent Questionnaire by other investigators, but I hope that future validations are more methodologically rigorous and that investigators carefully read Field and colleagues’ article before referencing it. Helaine R. H. Rockett, MS, RD Nutrition Research Manager Department of Medicine Brigham and Women’s Hospital Harvard Medical School Boston, MA References 1. Cullen KW, Zakeri I. The Youth/ Adolescent Questionnaire has low validity and modest reliability among low-income African-American and Hispanic seventh- and eighth-grade youth. J Am Diet Assoc. 2004;104:1415-1419. 2. Field AE, Peterson KE, Gortmaker SL, Cheung L, Rockett H, Fox MK, Colditz GA. Reproducibility and validity of a food frequency questionnaire among fourth to seventh grade inner-city school children: Implications of age and day-to-day variation in dietary intake. Public Health Nutr. 1999;2:293-300. doi: 10.1016/j.jada.2005.10.007 Author’s Response: We appreciate the comments from Ms Rockett concerning our validation study of the Youth/Adolescent Questionnaire (1). Our intent was to determine whether this instrument, developed and validated with primarily white youth (2), was a reliable and valid instrument with low-income, ethnic, minority youth. Since many of our school-based studies are with minority youth, it was important to test dietary assessment measures with the target population.
Journal of the AMERICAN DIETETIC ASSOCIATION
1867