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Table 4 Agreement of quartile membership between estimated iodine intake from the iodine-specific food frequency questionnaire (I-FFQ) and the food diary, and urinary iodine concentration (UIC)

From: Validation and reproducibility of a new iodine specific food frequency questionnaire for assessing iodine intake in Norwegian pregnant women

 

I-FFQa vs. Food diaryb (n = 122)

I-FFQa vs. UICc (n = 123)

Food diaryb vs. UICc (n = 133)

Stable quartile, n (%)

57 (47%)

41 (33%)

53 (40%)

Adjacent quartile, n (%)

51 (42%)

51 (42%)

50 (38%)

Opposite quartile, n (%)

14 (11%)

31 (25%)

30 (23%)

Weighted kappa, kw d

0.60

0.21

0.40

  1. aIodine specific food frequency questionnaire (I-FFQ)
  2. bIodine specific food diary from six consecutive days
  3. cUrinary iodine concentration (UIC): Pooled sample of spot urinary samples from six consecutive days
  4. dTracking coefficient of Cohen’s weighted kappa. A kw of 0.01–0.20 represents slight agreement, 0.21–0.40 fair agreement, 0.41–0.60 moderate agreement, 0.61–0.80 substantial agreement, and 0.81–1.00 almost perfect agreement [33]
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Nutrition Journal

ISSN: 1475-2891

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