Validation of a 24-hour Caffeine Intake Recall

A 24-hour Caffeine Intake Recall (CIR-24) was developed to estimate caffeine consumption in the previous 24 hours, modeled after the Automated Self-Administered 24-hour Dietary Assessment Tool (ASA24), using a brand-specific database of caffeine-containing foods, beverages and supplements. The objective of this study was to evaluate the accuracy of the CIR-24 compared to caffeine concentration biomarkers in urine and a caffeinated beverage intake frequency screener (CBQ) among a young adult population. 79 young adults ages 18 to 29 years provided 24-hour urine samples and completed the CIR-24 and CBQ. Excretion rates for caffeine and eight caffeine metabolites were quantified from urine samples using high performance liquid chromatography-polarity switching electrospray ionization-tandem quadrupole mass spectrometry with stable isotope labeled internal standards.