Relative validity of a web-based food frequency questionnaire for patients with type 1 and type 2 diabetes in Denmark.
BACKGROUND
Diet has an important role in the management of diabetes. However, little is known about dietary intake in Danish diabetes patients. A food frequency questionnaire (FFQ) focusing on most relevant nutrients in diabetes including carbohydrates, dietary fibres and simple sugars was developed and validated.


OBJECTIVE
To examine the relative validity of nutrients calculated by a web-based food frequency questionnaire for patients with diabetes.


METHODS
The FFQ was validated against a 4-day pre-coded food diary (FD). Intakes of nutrients were calculated. Means of intake were compared and cross-classifications of individuals according to intake were performed. To assess the agreement between the two methods, Pearson and Spearman's correlation coefficients and weighted kappa coefficients were calculated.


METHODS
Ninety patients (64 with type 1 diabetes and 26 with type 2 diabetes) accepted to participate in the study. Twenty-six were excluded from the final study population.


METHODS
64 volunteer diabetes patients at the Steno Diabetes Center.


RESULTS
Intakes of carbohydrates, simple sugars, dietary fibres and total energy were higher according to the FFQ compared with the FD. However, intakes of nutrients were grossly classified in the same or adjacent quartiles with an average of 82% of the selected nutrients when comparing the two methods. In general, moderate agreement between the two methods was found.


CONCLUSIONS
The FFQ was validated for assessment of a range of nutrients. Comparing the intakes of selected nutrients (carbohydrates, dietary fibres and simple sugars), patients were classified correctly according to low and high intakes. The FFQ is a reliable dietary assessment tool to use in research and evaluation of patient education for patients with diabetes.
Department of Nutrition and Food Service, Steno Diabetes Center, Gentofte, Denmark.
S M R
SM
Bentzen
Division of Risk Assessment and Nutrition, National Food Institute, Technical University of Denmark, Søborg, Denmark.
V K
VK
Knudsen
Division of Risk Assessment and Nutrition, National Food Institute, Technical University of Denmark, Søborg, Denmark.
T
T
Christiensen
Department of Nutrition and Food Service, Steno Diabetes Center, Gentofte, Denmark.
B
B
Ewers
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