Evaluation of plant sterol intake estimated with the Northern Sweden FFQ.

OBJECTIVE To evaluate plant sterol intake estimated with the eighty-four-item Northern Sweden FFQ against repeated 24 h dietary recalls (24-HDR) as the reference method. DESIGN Randomly recruited participants from the Västerbotten Intervention Programme (VIP) responded to an FFQ (FFQ1). Over the subsequent 12 months, ten repeated 24-HDR were carried out. After this, a second FFQ (FFQ2) was completed. SETTING Västerbotten county, northern Sweden. SUBJECTS Ninety-six men and ninety-nine women. RESULTS The Pearson correlation coefficient for absolute total plant sterol intake estimated with FFQ1 and 24-HDR was 0.58 and 0.55 for the men and women, respectively. Cross-classification of participants into quartiles of absolute plant sterol intake estimated with FFQ1 and 24-HDR showed that 90% of the men and 83% of the women were classified into the same or an adjacent quartile. For energy-adjusted plant sterol intake, 71% of the men and 74% of the women were classified into the same or an adjacent quartile. The agreement for cross-classification of participants into quartiles between FFQ1 and FFQ2 was good for both absolute and energy-adjusted plant sterol intake. CONCLUSIONS The FFQ is able to capture absolute plant sterol intake to the same extent as other nutrients, and to rank individuals according to both their absolute and energy-adjusted plant sterol intake. The reproducibility of the FFQ was good, suggesting that the method is reliable. This makes it possible to use plant sterol data from the FFQ in large-scale studies of the association between plant sterol intake and disease.