Validation and Reliability of a Water Frequency Questionnaire to Estimate Daily Water Intake in Adults (P13-006-19)

Objectives Investigators sought to: 1) evaluate the validity of a water frequency questionnaire (WFQ) to estimate mean daily water intake (WI) in adults through comparison to the gold standard, deuterium oxide (D2O) disappearance, and 2) evaluate reliability of WFQ to estimate WI. Methods Data collection occurred over three weeks, with validity of WFQ (vs. D2O) assessed during week one (W1) and reliability assessed between W1 and week three...