TY - JOUR
T1 - Relative validity of a food frequency questionnaire used in the Inter99 study
AU - Toft, U.
AU - Kristoffersen, L.
AU - Ladelund, S.
AU - Bysted, A.
AU - Jakobsen, J.
AU - Lau, C.
AU - Jørgensen, T.
AU - Borch-Johnsen, K.
AU - Ovesen, L.
PY - 2008/8/19
Y1 - 2008/8/19
N2 - Objective: To evaluate the validity of the Inter99 food frequency questionnaire (FFQ) compared with a 28-days' diet history and biomarkers. Subjects: A random sample of 13016 individuals were drawn from a general population and invited for a health screening programme. Participation rate was 52.5%. All high-risk individuals were re-invited for assessment after 1 and 3 years and completed a 198-item FFQ at all three occasions. Participants attending for 3 years follow-up were invited to participate in the validation study, including a 28-days' diet history, a 24-h urine collection and a fasting blood sample. Overall, 264 subjects participated. Results: Spearman's rank correlation coefficients between the two dietary methods ranged from 0.31(β-carotene) to 0.64 (fruits) in men and from 0.31 (polyunsaturated fat and sodium) to 0.64 (fruits) for women. The proportion of individuals classified in the same or adjacent quintiles were, on average, 72% for men and 69% for women. Gross misclassification was found on average in 2%. The correlation coefficients of the residuals ranged from 0.27 (sodium) to 0.61 (fruits) for men and from 0.21 (sodium) to 0.62 (B12-vitamin) for women. Correlation coefficients between fruit and vegetable intake and carotenoids ranged from -0.08 (lycopene) to 0.44 (α-carotene). For the residuals the correlation coefficients ranged from -0.004 (lycopene) to 0.47 (α-carotene). Conclusion: The Inter99 FFQ and the residuals of the intake provide acceptable classification of individuals according to their dietary intakes and the FFQ gives a good quantitative measurement of key dietary components.
AB - Objective: To evaluate the validity of the Inter99 food frequency questionnaire (FFQ) compared with a 28-days' diet history and biomarkers. Subjects: A random sample of 13016 individuals were drawn from a general population and invited for a health screening programme. Participation rate was 52.5%. All high-risk individuals were re-invited for assessment after 1 and 3 years and completed a 198-item FFQ at all three occasions. Participants attending for 3 years follow-up were invited to participate in the validation study, including a 28-days' diet history, a 24-h urine collection and a fasting blood sample. Overall, 264 subjects participated. Results: Spearman's rank correlation coefficients between the two dietary methods ranged from 0.31(β-carotene) to 0.64 (fruits) in men and from 0.31 (polyunsaturated fat and sodium) to 0.64 (fruits) for women. The proportion of individuals classified in the same or adjacent quintiles were, on average, 72% for men and 69% for women. Gross misclassification was found on average in 2%. The correlation coefficients of the residuals ranged from 0.27 (sodium) to 0.61 (fruits) for men and from 0.21 (sodium) to 0.62 (B12-vitamin) for women. Correlation coefficients between fruit and vegetable intake and carotenoids ranged from -0.08 (lycopene) to 0.44 (α-carotene). For the residuals the correlation coefficients ranged from -0.004 (lycopene) to 0.47 (α-carotene). Conclusion: The Inter99 FFQ and the residuals of the intake provide acceptable classification of individuals according to their dietary intakes and the FFQ gives a good quantitative measurement of key dietary components.
UR - http://www.scopus.com/inward/record.url?scp=49349099866&partnerID=8YFLogxK
U2 - 10.1038/sj.ejcn.1602815
DO - 10.1038/sj.ejcn.1602815
M3 - Article
C2 - 17538538
AN - SCOPUS:49349099866
VL - 62
SP - 1038
EP - 1046
JO - European Journal of Clinical Nutrition
JF - European Journal of Clinical Nutrition
SN - 0954-3007
IS - 8
ER -