How well does a telephone questionnaire measure drinking water intake?

Abstract

BACKGROUND: Few studies have assessed the validity or reliability of drinking water intake estimations. In studies investigating potential waterborne disease, this is very important. METHODS: We carried out a validity and reliability study to evaluate water intake estimations. The validity part of the study compared a telephone questionnaire to a diary. The reliability part of the study compared two telephone questionnaires. RESULTS: 253 participants were recruited. The most commonly consumed water intake categories were plain and boiled tap water. For persons aged less than 12 years, the median volume of plain water consumption was 2.9 glasses/day according to the diary. For persons aged 12..