Eric B Rimm, Donna Spiegelman, Meir J Stampfer, Walter C Willett, Laura K Sampson, Bernard A Rosner, Changzheng Yuan, Jorge E Chavarro, Junaidah B Barnett, Lisa J Harnack, Jennifer C Rood
The authors evaluated the performance of a semi-quantitative food frequency questionnaire (SFFQ), web-based 24-hour recalls (ASA24s), and 7-day dietary records (7DDRs) compared to biomarkers among 627 women in Women's Lifestyle Validation Study (US, 2010-2012). Two paper SFFQs, one web-based SFFQ, four ASA24s (beta version), two 7DDRs, four 24-hour urine samples, one doubly-labeled water (repeated among 76 participants), and two fasting blood samples were collected over a 15-months-period. Dietary variables evaluated were energy, energy-adjusted intakes of protein, sodium, potassium, and specific fatty acids, carotenoids, α-tocopherol, retinol and folate. In general, relative to biomarkers, averaged ASA24s had lower validity than SFFQ2; SFFQ2 had slightly lower validity than one 7DDR; the averaged SFFQs had similar validity to one 7DDR; and the averaged 7DDRs had the highest validity. The de-attenuated correlation of energy-adjusted protein intake assessed by SFFQ2 with its biomarker was 0.46, similar to its correlation with 7DDRs (de-attenuated r = 0.54). These data indicate that the SFFQ2 provides reasonably valid measurements for most energy-adjusted nutrients assessed in our study, consistent with earlier conclusions using 7DDRs as the comparison. The ASA24 needs further evaluation for use in large population studies, but an average of 3 days will not be sufficient for some important nutrients.