Validation of a quantitative FFQ for the Barbados National Cancer Study.
OBJECTIVE
To assess the validity of a 148-item quantitative FFQ (QFFQ) that was developed for the Barbados National Cancer Study (BNCS) to determine dietary intake over 12 months and examine the dietary risk factors.


METHODS
A cross-sectional validation study of the QFFQ against 4 d food diaries. Spearman's rank correlations (ρ), intra-class correlation coefficients (ICC) and weighted κ were computed as measures of concordance, adjusting for daily variations in the food diaries. Cross-classification tables and Bland-Altman plots were created for further assessment.


METHODS
BNCS is a case-control study of environmental risk factors for breast and prostate cancer in a predominantly African-origin population in Barbados.


METHODS
Fifty-four individuals (21 years and older) were recruited among controls in the BNCS who were frequency-matched on sex and age group to breast and prostate cancer cases.


RESULTS
Similar mean daily energy intake was derived from the food diary (8201 kJ (1960 kcal)) and QFFQ (7774 kJ (1858 kcal)). Rho for energy and macronutrients ranged from 0·66 (energy) to 0·17 (dietary fibre). The percentage of energy from carbohydrates and protein showed the highest and lowest ICC among macronutrients (0·63 and 0·27, respectively). The highest weighted κ was observed for energy (0·45). When the nutrient intake was divided into quartiles, approximately 34 % of the observations were in the same quartile.


CONCLUSIONS
This investigation supports the validity of the QFFQ as a method for assessing long-term dietary intake except for dietary fibre, folate, vitamins A, E and B12. The instrument will be a useful tool in the analysis of diet-cancer associations in the BNCS.
Pakseresht
Mohammadreza
M
Nutrition Research Institute, Department of Nutrition, University of North Carolina at Chapel Hill, Kannapolis, NC 28081, USA.
Sharma
Sangita
S
Cao
Xia
X
Harris
Rachel
R
Caberto
Christian
C
Wilkens
Lynne R
LR
Hennis
Anselm J M
AJ
Wu
Suh-Yuh
SY
Nemesure
Barbara
B
Leske
M Cristina
MC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001460:Barbados; D044383:Black People; D001943:Breast Neoplasms / Q000473:pathology / Q000517:prevention & control; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D004032:Diet; D015930:Diet Records; D004034:Diet Surveys; D004043:Dietary Fiber / Q000008:administration & dosage; D005069:Evaluation Studies as Topic; D005247:Feeding Behavior; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D015596:Nutrition Assessment; D011471:Prostatic Neoplasms / Q000473:pathology / Q000517:prevention & control; D011795:Surveys and Questionnaires; D014801:Vitamin A / Q000008:administration & dosage; D014805:Vitamin B 12 / Q000008:administration & dosage; D014810:Vitamin E / Q000008:administration & dosage; D014815:Vitamins / Q000008:administration & dosage
D004043:Dietary Fiber; D014815:Vitamins; D014801:Vitamin A; D014810:Vitamin E; D005492:Folic Acid; D014805:Vitamin B 12