Validity of a Self-administered Food Frequency Questionnaire Used in the 5-year Follow-up Survey of the JPHC Study to Assess Selenium Intake: Comparison with Dietary Records and Blood Levels

Selenium (Se) levels in serum and erythrocytes were measured in 215 adults to assess the relative validity of Se intake estimated from 28-day dietary records (DR) and the food frequency questionnaire (FFQ) used in the 5-year follow-up survey of the JPHC study. Se intake estimated from DR was correlated with that from the FFQ both in males and females (r=0.36 and r=0.32, respectively). Se levels in erythrocytes were weakly correlated with Se intake by DR for men (r=0.21) after adjustments for the total energy intake, though no significant correlation was found for women nor in crude values for either sex. Although Se intake estimated from our FFQ was correlated with that from the DR, no correlation was observed between the Se level in serum and estimated Se intake. In this population, the serum Se level was not a good biomarker for estimated Se intake.