Table 6

Mean intakes estimated from the 2nd DHQ across quintiles of intakes estimated from the 1st DHQ (n = 58)

1st DHQ

Agreement (% classified into the same or adjacent quintile)1

Discordance (% classified into the opposite quintile)1

Linear trend2

p


1st quintile

2nd quintile

3rd quintile

4th quintile

5th quintile


Mean ± SD

Mean ± SD

Mean ± SD

Mean ± SD

Mean ± SD


2nd DHQ

Energy [kcal/day]

1452 ± 498

1786 ± 292

1591 ± 227

1908 ± 300

2120 ± 323

70.7

1.7

< 0.001

Folate [μg/day]3

185 ± 44

241 ± 37

243 ± 60

288 ± 63

447 ± 126

81.1

0

< 0.001

Vitamin B12 [μg/day]3

4.44 ± 2.32

5.03 ± 2.41

5.27 ± 1.51

6.16 ± 1.78

8.77 ± 4.36

77.6

1.7

< 0.001


DHQ: self-administered diet history questionnaire

1Agreement and discordance in quintile ranking was assessed as the percentage classification for the pregnant women based on the two-time DHQ in the same, adjacent, and opposite quintiles

2Linear regression analyses were performed to test for significant linear trends between estimated intakes from the two-time DHQ

3Linear regression analyses were conducted after log-transformation of the variables

Shiraishi et al. Nutrition Journal 2012 11:15   doi:10.1186/1475-2891-11-15

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