title: Development and validation of an interview-administered FFQ for assessment of vitamin D and calcium intakes in Finnish women.
abstract: Increased vitamin D fortification of dairy products has increased the supply of vitamin D-containing products with different vitamin D contents on the market in Finland. The authors developed a ninety-eight-item FFQ with eight food groups and with a question on supplementation to assess dietary and supplemental vitamin D and Ca intakes in Finnish women (60ºN). The FFQ was validated in subgroups with different habitual vitamin D supplement use (0-57·5 µg/d) against the biomarker serum 25-hydroxyvitamin D (S-25(OH)D) and against 3-d food records (FR) (n 29-67). Median total vitamin D intake among participants was 9·4 (range 1·6-30·5) µg/d. Spearman's correlations for vitamin D and Ca ranged from 0·28 (P 0·146, FFQ v. S-25(OH)D, persons not using supplements) to 0·75 (P<0·001, FFQ v. FR, supplement use included). The correlations between the FFQ and S-25(OH)D concentrations improved within increasing supplement intake. The Bland-Altman analysis showed wide limits of agreement between FFQ and FR: for vitamin D between -7·8 and 8·8 µg/d and for Ca between -938 and 934 mg/d, with mean differences being 0·5 µg/d and 2 mg/d, respectively. The triads method was used to calculate the validity coefficients of the FFQ for vitamin D, resulting in a mean of 1·00 (95 % CI 0·59, 1·00) and a range from 0·33 to 1·00. The perceived variation in the estimates could have been avoided with a longer FR period and larger number of participants. The results are comparable with earlier studies, and the FFQ provides a reasonable estimation of vitamin D and Ca intakes.
authors: Department of Food and Environmental Sciences,Calcium Research Unit,Division of Nutrition,University of Helsinki,PO Box 66,FIN-00014 University of Helsinki,Helsinki,Finland.
authors: Suvi T
authors: ST
authors: Itkonen
authors: Department of Food and Environmental Sciences,Calcium Research Unit,Division of Nutrition,University of Helsinki,PO Box 66,FIN-00014 University of Helsinki,Helsinki,Finland.
authors: Maijaliisa
authors: M
authors: Erkkola
authors: Department of Food and Environmental Sciences,Calcium Research Unit,Division of Nutrition,University of Helsinki,PO Box 66,FIN-00014 University of Helsinki,Helsinki,Finland.
authors: Essi
authors: E
authors: Skaffari
authors: Department of Food and Environmental Sciences,Calcium Research Unit,Division of Nutrition,University of Helsinki,PO Box 66,FIN-00014 University of Helsinki,Helsinki,Finland.
authors: Pilvi
authors: P
authors: Saaristo
authors: Department of Food and Environmental Sciences,Calcium Research Unit,Division of Nutrition,University of Helsinki,PO Box 66,FIN-00014 University of Helsinki,Helsinki,Finland.
authors: Elisa M
authors: EM
authors: Saarnio
authors: Department of Food and Environmental Sciences,Calcium Research Unit,Division of Nutrition,University of Helsinki,PO Box 66,FIN-00014 University of Helsinki,Helsinki,Finland.
authors: Heli T
authors: HT
authors: Viljakainen
authors: Department of Food and Environmental Sciences,Calcium Research Unit,Division of Nutrition,University of Helsinki,PO Box 66,FIN-00014 University of Helsinki,Helsinki,Finland.
authors: Merja U M
authors: MU
authors: Kärkkäinen
authors: Department of Food and Environmental Sciences,Calcium Research Unit,Division of Nutrition,University of Helsinki,PO Box 66,FIN-00014 University of Helsinki,Helsinki,Finland.
authors: Christel J E
authors: CJ
authors: Lamberg-Allardt
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood; D000328:Adult; D015415:Biomarkers / Q000097:blood; D002112:Calcifediol / Q000097:blood; D002136:Calcium, Dietary / Q000008:administration & dosage*; D004032:Diet; D015930:Diet Records; D019587:Dietary Supplements; D005260:Female; D005387:Finland; D005527:Food, Fortified; D006801:Humans; D015596:Nutrition Assessment; D009749:Nutrition Surveys / Q000379:methods*; D015203:Reproducibility of Results; D014807:Vitamin D / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002136:Calcium, Dietary; D014807:Vitamin D; D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol
keywords: Calcium; FFQ; FR food records; Method of triads; Reproducibility; S-25(OH)D serum 25-hydroxyvitamin D; Validity; Vitamin D