A Chemoprevention Trial to Study the Effects of High Tea Consumption on Smoking-Related Oxidative Stress
Annual rept. 13 Jul 2006-12 Jan 2007
ARIZONA UNIV TUCSON
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The authors overall goal is to develop a safe and feasible model for the chemoprevention of a wide range of tobacco-related diseases. Their immediate goal, addressed over a 4-year study period, is to determine the effects of high tea consumption on the biological markers of oxidative stress that mediate lung cancer risk. They are conducting a 6-month randomized, controlled, double-blinded chemopreventive trial with subjects who have chronic obstructive pulmonary disease COPD and who were, or are, chronic smokers. The subjects are being randomized to green or black tea preparations or a control intervention matching placebo. Levels of 8-hydroxydeoxyguanosine and 8-F2-isoprostanes are being used to measure DNA damage and lipid damage, respectively. Changes in biomarkers of oxidative damage are being measured in urine, blood, and exhaled breath condensate. The study protocol was approved by all parties in September 2003. Recruitment and screening of participants for eligibility started in October 2003. By the end of December 2006, 275 participants had signed the consent form and were screened for confirmation of COPD eligibility i.e., spirometry for lung function. Thirteen subjects were not eligible and 262 subjects were enrolled in the study. Ninety-six of the participants dropped out of the study in the first week. The main reported causes of drop-out were as follows could not stop drinking coffee, did not like the taste of the tea, and caffeine intolerance. A total of 158 subjects completed the 1-month run-in and were randomized to one of the study arms green tea, black tea, or placebo. All randomized subjects provided blood and urine samples, exhaled breath condensate, and buccal cell samples during the 6-month intervention period. To date, 114 subjects have completed the study and 19 subjects are actively enrolled in it. The authors expect that adherence to a regular pattern of tea is feasible and quantifiable in this high-risk population.
- Medicine and Medical Research
- Food, Food Service and Nutrition
- Stress Physiology