Objective: To validate the fruit and vegetable intake estimated from the Food Frequency Questionnaire (FFQ) used in the Danish National Birth Cohort (DNBC). Subjects and setting: The DNBC is a cohort of 101,042 pregnant women in Denmark, who received a FFQ by mail in gestation week 25. A validation study with 88 participants was made. A seven-day weighed food diary (FD) and three different biomarkers were employed as comparison methods. Results: Significant correlations between FFQ and FD-based estimates were found for fruit (r=0.66); vegetables (r=0.32); juice (r=0.52); fruit and vegetables (F&V) (r=0.57); and fruit, vegetables, and juice (F&V&J) (r=0.62). Sensitivities of correct classification by FFQ into the two lowest and the two highest quintiles of F&V&J intake were 58—67% and 50— 74%, respectively, and specificities were 71—79% and 65—83%, respectively. F&V&J intake estimated from the FFQ correlated significantly with urinary flavonoids (r=0.39, p<0.005), plasma β-carotene (r=0.21, p<0.05) and erythrocyte folate (r=0.33, p<0.005); all average biomarker levels increased across increasing quintiles of F&V&J intake. Conclusion: Data on F&V&J recorded by FFQ in DNBC can be used in etiological analyses of associations between fruit and vegetable intake and health outcomes, provided that the potential misclassification of dietary exposure is kept in mind.
Mathews F. , Yudkin P., Neil A.Influence of maternal nutrition on outcome of pregnancy: Prospective cohort study. Br Med J1999;319:339—43.
2.
Rush D.Maternal nutrition and perinatal survival. Nutr Rev2001;59:315—26.
3.
Kaiser LL, Allen L.Position of the American Dietetic Association: Nutrition and lifestyle for a healthy pregnancy outcome. J Am Diet Assoc2002;102:1479—90.
Ray JG, Meier C., Vermeulen MJ, Boss S., Wyatt PR, Cole DEAssociation of neural tube defects and folic acid food fortification in Canada . Lancet2002;360:2047—8.
6.
Gucciardi E. , Pietrusiak MA, Reynolds DL, Rouleau J.Incidence of neural tube defects in Ontario, 1986—1999. CMAJ2002;167:237—40.
7.
Moore LL, Bradlee ML, Singer MR, Rothman KJ, Milunsky A.Folate intake and the risk of neural tube defects: An estimation of dose—response . Epidemiology2003;14:200—5.
8.
Scholl TO, Hediger ML, Schall JI, Khoo CS, Fischer RLDietary and serum folate: Their influence on the outcome of pregnancy . Am J Clin Nutr1996;63:520—5.
9.
Rao S. , Yajnik CS, Kanade A., Fall CH, Margetts BM, Jackson AA, et al. Intake of micronutrient-rich foods in rural Indian mothers is associated with the size of their babies at birth: Pune Maternal Nutrition Study. J Nutr2001 ;131: 1217—24.
10.
Kushi LH, Lenart EB, Willett WCHealth implications of Mediterranean diets in light of contemporary knowledge, 1: Plant foods and dairy products. Am J Clin Nutr1995;61(Suppl):1407S—15S.
11.
Tavani A. , La Vecchia C.Beta-carotene and risk of coronary heart disease: A review of observational and intervention studies. Biomed Pharmacother1999;53:409—16.
12.
Renaud S.Diet and cardiovascular diseases. J Nutr Health Aging2001;5:131.
13.
Key TJ , Allen NE, Spencer EA, Travis RCThe effect of diet on risk of cancer. Lancet2002;360:861—8.
14.
Epstein KRThe role of carotenoids on the risk of lung cancer. Semin Oncol2003;30:86—93.
15.
Olsen J., Melbye M., Olsen SF, Sorensen TI, Aaby P., Andersen AM, et al. The Danish National Birth Cohort: Its background, structure and aim. ScandJ Public Health2001;29:300—7.
16.
Overvad K. , Tjonneland A., Haraldsdottir J., Ewertz M., Jensen OMDevelopment of a semiquantitative food frequency questionnaire to assess food, energy and nutrient intake in Denmark. Int J Epidemiol1991;20:900—5.
17.
Tjonneland A., Overvad K., Haraldsdottir J., Bang S., Ewertz M., Jensen OMValidation of a semiquantitative food frequency questionnaire developed in Denmark. Int J Epidemiol1991;20:906—12.
18.
Friis S., Kruger Kjaer S., Stripp C., Overvad K.Reproducibility and relative validity of a self-administered semiquantitative food frequency questionnaire applied to younger women. J Clin Epidemiol1997;50:303—11.
19.
Willett WC, Lenart E.Reproducibility and Validity of food-frequency questionnaires. In: Willett W, editor. Nutritional epidemiology . New York: Oxford University Press ; 1998. p. 101—147.
20.
Nielsen SE , Freese R., Cornett C., Dragsted LOIdentification and quantification of flavonoids in human urine samples by column-switching liquid chromatography coupled to atmospheric pressure chemical ionization mass spectrometry. Anal Chem2000;72:1503—9.
21.
Standing Nordic Committee on Foods, Nordiske Näringsrekommendationer [Nordic Nutrition Recommendations 1996]. Nord 1996: 28. Copenhagen, Denmark: Nordisk Ministerråd; 1996.
22.
Erkkola M. , Karppinen M., Javanainen J., Räsänen L., Knip M., Virtanen SMValidity and reproducibility of a food frequency questionnaire for pregnant Finnish women . Am J Epidemiol; 2001. p. 154.
23.
Van Assema P., Brug J., Ronda G., Steenhuis I., Oenema A.A short Dutch questionnaire to measure fruit and vegetable intake: Relative validity among adults and adolescents. Nutr Health2002;16:85—106.
Domel SB, Baranowski T., Davis H., Leonard SB, Riley P., Baranowski J.Fruit and vegetable food frequencies by fourth and fifth grade students: Validity and reliability. J Am Coll Nutr1994 ;13:33—9.
26.
Smith-Warner SA, Elmer PJ, Fosdick L., Tharp TM, Randall B.Reliability and comparability of three dietary assessment methods for estimating fruit and vegetable intakes. Epidemiology1997;8:196—201.
27.
Andersen LF, Johansson L., Solvoll K.Usefulness of a short food frequency questionnaire for screening of low intake of fruit and vegetable and for intake of fat. Eur J Public Health2002;12:208—13.
28.
Johansson I., Hallmans G., Wikman A., Biessy C., Riboli E., Kaaks R.Validation and calibration of food-frequency questionnaire measurements in the Northern Sweden Health and Disease cohort . Public Health Nutr2002;5: 487—96.
29.
Nielsen SE , Freese R., Kleemola P., Mutanen M.Flavonoids in human urine as biomarkers for intake of fruits and vegetables. Cancer Epidemiol Biomarkers Prev2002;11: 459—66.
30.
McEligot AJ, Rock CL, Flatt SW, Newman V., Faerber S., Pierce JPPlasma carotenoids are biomarkers of long-term high vegetable intake in women with breast cancer . J Nutr1999;129:2258—63.
31.
Resnicow K., Odom E., Wang T., Dudley WN, Mitchell D., Vaughan R., et al. Validation of three food frequency questionnaires and 24-hour recalls with serum carotenoid levels in a sample of African-American adults. Am J Epidemiol2000;152):1072—80.
32.
Hunter D.Biochemical indicators of dietary intake. In: Willett W, editor. Nutritional epidemiology. New York: Oxford University Press; 1998. p 174—243.
33.
Joshipura KJ, Hu FB, Manson JE, Stampfer MJ, Rimm EB, Speizer FE, et al. The effect of fruit and vegetable intake on risk for coronary heart disease. Ann Intern Med2001;134: 1106—14.
34.
Paeratakul S., Popkin BM, Kohlmeier L., Hertz-Picciotto I., Guo X., Edwards LJMeasurement error in dietary data: Implications for the epidemiologic study of the diet—disease relationship. Eur J Clin Nutr1998;52:722—7.
