Validity and reliability of the Block98 food-frequency questionnaire in a sample of Canadian women.
OBJECTIVE
To assess the validity and reliability of the most recent adaptation of Block's full-diet food-frequency questionnaire (FFQ) among a sample of Canadian women.


METHODS
Participants completed a self-administered FFQ (FFQ1), two unannounced 24-hour recalls (weekday and weekend) and a second FFQ (FFQ2) between October 2003 and February 2004. FFQs and recalls were analysed for 32 nutrients using Block Dietary Data Systems and the University of Minnesota's Nutrient Data System. Mean and median intakes were computed, along with crude and deattenuated Pearson correlation coefficients between FFQ1 and the average of two recalls (validity) and between FFQ1 and FFQ2 (reliability).


METHODS
Ontario, Canada.


METHODS
A random population-based sample (n = 166) of women aged 25 to 74 years.


RESULTS
One hundred and fifteen (69%) women completed FFQ1, 96 completed FFQ1 and both recalls, and 93 completed both FFQs, about 56 days apart. Mean intakes were similar for most nutrients. FFQ reliability was high, with Pearson correlation coefficients having a median of 0.75, ranging from 0.57 to 0.90 (macronutrients) and from 0.65 to 0.88 (micronutrients from supplements and food). FFQ validity was moderate to high, with deattenuated Pearson correlation coefficients having a median of 0.59, ranging from 0.11 to 0.73 (macronutrients) and from 0.50 to 0.76 (micronutrients from supplements and food). Our micronutrient correlations were similar to or higher than those of other studies that included supplements. Two correlations <0.40 were associated with fats.


CONCLUSIONS
The validity and reliability of this full-diet version of the Block FFQ were moderate to high, supporting its use in future studies among Canadian women.
Boucher
Beatrice
B
Division of Preventive Onoclogy, Cancer Care Ontario, Toronto, Ontario, Canada. beatrice.boucher@cancercare.on.ca.
Cotterchio
Michelle
M
Kreiger
Nancy
N
Nadalin
Victoria
V
Block
Torin
T
Block
Gladys
G
D000328:Adult; D000368:Aged; D004032:Diet; D004034:Diet Surveys; D004040:Dietary Carbohydrates / Q000008:administration & dosage; D004041:Dietary Fats / Q000008:administration & dosage; D004044:Dietary Proteins / Q000008:administration & dosage; D002149:Energy Intake; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D018977:Micronutrients / Q000008:administration & dosage; D008875:Middle Aged; D009864:Ontario; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*
D004040:Dietary Carbohydrates; D004041:Dietary Fats; D004044:Dietary Proteins; D018977:Micronutrients