Development and Evaluation of the Semi-quantitative Food Frequency Questionnaire to Assess Folate Intake in Women of Child-bearing Age

Abstract

The aim of this study was to develop and evaluate the simple semi-quantitative food frequency questionnaire (FFQ) for assessing folate intake in women of reproductive age. We developed a 30-item FFQ, and tested the reliability and validity in 97 women aged between 20 and 39 yrs using the FFQs and 24-h recalls, which were carried out twice, respectively. Assessing the reliability, the correlation coefficients were 0.53 (Spearman’s) and 0.49 (Pearson’s) for folate. There was no significant difference of folate intake between FFQ1 and FFQ2. 36.1% subjects were classified into the same quartile and 83.5% into the same or adjacent quartile divided by folate intake. On determining the validity, the mean folate intake obtained from the FFQ (FFQ1) and 24h-recalls (2-d) were 306.6 ± 167.2 µg/d and 326.9 ± 103.3 µg/d, respectively. There was no significant difference between folate intakes from the two methods. The correlation coefficients for folate were 0.24 (Spearman’s) and 0.26 (Pearson’s). 39.2% of the subjects were categorized into the same quartile and 70.1% were into the same or adjacent quartile. In addition, sensitivity (64.3%) and specificity (62.3%) were estimated to evaluate the adequacy of folate intake. These results suggest that this FFQ would be a useful and a valuable instrument to assess the intake of folate among the Korean women of child-bearing age. (Korean J Community Nutr 17(2) : 156~166, 2012)