A standard verbal and written explanation of the 24-
h urine collection process was provided to all participants
prior to participation. Eighty nine participants completed a
single 24-h urine collection. However, 6 did not complete
the FFQ and/or HLFQ and 6 did not wish to take the PABA
tablets. Three 80 mg doses of PABA (a biologically inert
substance rapidly excreted in urine) were administered to
all participants in tablet form the day of urine collection to
validate the completeness of the sample. Each participant
was provided with 2 three litre storage containers and one
500 ml storage container in a strong opaque carrier bag.
Participants were asked to outline whether or not they had
accidentally missed a urine collection.