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Open Access Research

Validity and reproducibility of folate and vitamin B12 intakes estimated from a self-administered diet history questionnaire in Japanese pregnant women

Mie Shiraishi1*, Megumi Haruna1, Masayo Matsuzaki1, Ryoko Murayama1, Satoshi Sasaki2 and Sachiyo Murashima3

Author Affiliations

1 Department of Midwifery and Women's Health, Division of Health Sciences and Nursing, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

2 Department of Social and Preventive Epidemiology, School of Public Health, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

3 Department of Community Health Nursing, Division of Health Sciences and Nursing, Graduate School of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

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Nutrition Journal 2012, 11:15  doi:10.1186/1475-2891-11-15

Published: 15 March 2012

Abstract

Background

No validated dietary questionnaire for assessing folate and vitamin B12 intakes during pregnancy is available in Japan. We evaluated the validity and reproducibility of intakes of folate and vitamin B12 estimated from a self-administered diet history questionnaire (DHQ) in Japanese pregnant women.

Methods

A sample of 167 healthy subjects with singleton pregnancies in the second trimester was recruited at a private obstetric hospital in metropolitan Tokyo from June to October 2008 (n = 76), and at a university hospital in Tokyo from June 2010 to June 2011 (n = 91). The dietary intakes of folate and vitamin B12 were assessed using the DHQ. The serum concentrations of folate and vitamin B12 were measured as reference values in the validation study. To assess the reproducibility of the results, 58 pregnant women completed the DHQ twice within 4-5 week interval.

Results

Significantly positive correlations were found between energy-adjusted intakes and serum concentrations of folate and vitamin B12 (r = 0.286, p < 0.001 and r = 0.222, p = 0.004, respectively). After excluding the participants with nausea (n = 121), the correlation coefficient for vitamin B12 increased to 0.313 (p = 0.001). When participants were classified into quintiles based on intakes and serum concentrations of folate and vitamin B12 , approximately 60% were classified in the same or adjacent quintile. The intraclass correlation coefficients of the two-time DHQ were 0.725 for folate and 0.512 for vitamin B12 .

Conclusion

The present study indicated that the DHQ had acceptable validity and reproducibility for assessing folate and vitamin B12 intakes in Japanese pregnant women.

Keywords:
Diet history questionnaire; Pregnant women; Validation; Folate; Vitamin B12