Crowdsourced Asparagus Urinary Odor Population Kinetics

: The consumption of asparagus is associated with the production of malodorous urine with considerable interindividual variability (IIV). To characterize the urinary odor kinetics after consumption of asparagus spears, we conducted a study with consenting attendees from two American Society for Clinical Pharmacology and Therapeutics (ASCPT) meetings. Subjects were randomized to eat a specific number of asparagus spears, and then asked to report their urinary odor perception. Eighty-seven subjects were included in the final analysis. A mixed effect proportional odds model was developed that adequately characterized the dose-response relationship. We estimated the half-life of the asparagus effect on malodorous urine to be 4.7 hours (relative standard error (RSE) = 13.2%), and identified a dose-response slope term with good precision (24.3%). Age was found as the predictor of IIV in slope estimates. This study design and tools can be used as a demonstration "crowdsourcing" project for studying population kinetics in organizational and educational settings.