Trial Information

Calibration of Urine pH Strips for NCI Case-Control Studies on Bladder Cancer and Comparison of DNA Yields From Buccal Cells Collected Through Two Different Methods

We conducted a pilot study among 30 volunteers from the Division of Cancer Epidemiology and
Genetics (DCEG) in order to: (1) select the urine pH strip that most closely correlates
with urine pH measured by pH meter for the New England Bladder Cancer Study, (2) calibrate
the urine pH strip that was used for the Spanish Bladder Cancer Study against pH measured by
a pH meter, and (3) compare the DNA yields from buccal cells obtained from two different
methods: mouthwash vs toothbrush-rinse method. At the time of enrollment, study
participants were asked to provide information on age, gender, height, weight, consumption
of antacids and calcium supplements, and whether they ate, drank or brushed their teeth in
the last hour previous to the buccal cells sample collection. In addition, they measured
their urine pH with four different pH strips twice a day (early morning and before dinner)
for a week and record the measurements in a diary. During the same week, they were asked to
collect two spot urine samples each day from Monday to Thursday (early morning and before
dinner), and one more on Friday morning, and bring them into work in a cooler. Also, they
were asked to collect a continuous 24-hour urine sample during one of the three first days
of the week. Urine samples were picked up by lab personnel from BioReliance, and pH was
measured at their laboratory with the four pH strips again and with a pH meter. Buccal
cells sample collection was completed during the first and the last day of the urine sample
collection period. The first day, study participants were asked to provide a water rinse
sample after brushing the inside of their cheeks with a toothbrush, and a week later they
were asked to provide a mouth wash sample consisting of two consecutive rinses with Scope
mouthwash. All samples and questionnaire data was unlinked from personal identifiers after
the sample collection was completed. Participants were compensated with $100 for the
inconvenience of participating in this complex study and for their time. Information
collected from this pilot study has been used to prepare manuscripts, as well as select and
optimize the sample collection protocols in the New England Bladder Cancer Study.