Available and animal studies have shown cancer protective effects of tea polyphenols. addition to an in-person interview each participant provided a blood and urine sample at baseline. In the present study genotype (rs4680) and five urinary metabolites of tea polyphenols were determined in 660 cohort subjects who self-identified as daily drinkers of green tea. All urinary tea polyphenol measurements were expressed in units of urinary creatinine. Men possessing the homozygous low-activity associated genotype (genotype (and genotypes. The present study demonstrated that men carrying low-activity associated genotype excreted less tea polyphenols from urine which suggests that they may retain more tea polyphenols in their bodies and derive greater health benefits from green tea intake. genotype Introduction Tea one of the most widely consumed beverages in the world is brewed from dried leaves of the plant is polymorphic. A single G to A transition at codon 158 of (rs4680) results in an amino acid change from valine to methionine in the cytosolic/membrane-bound form of COMT. This amino acid change leads to a 3- to 4-fold decrease in enzymatic activity [9 10 Individuals possessing the homozygous variant LY3009104 genotype (allele . To date there are no direct data on the possible influence of genotype on the metabolism and excretion of tea catechins in humans. We conducted a cross-sectional analysis within the Shanghai Cohort Study to evaluate whether urinary levels of tea catechin metabolites differ significantly between subjects possessing the low- versus high-activity associated genotypes of among daily drinkers of green tea. Subjects and methods The Shanghai Cohort Study The design of the Shanghai Cohort LY3009104 Study has been described in detail previously [13 14 Briefly between January 1 1986 and September 30 1989 all eligible male residents of 4 small geographically defined communities over a wide area of the city of Shanghai were invited to participate in a prospective epidemiologic investigation of diet and cancer. The eligibility criteria were ages 45 to 64 years and no history of cancer. During the 3-year recruitment period 18 244 men (representing approximately 80% of eligible subjects) were enrolled in the study. At recruitment each participant was interviewed in person by a trained nurse using a structured questionnaire asking for information on demographic characteristics IKZF2 antibody histories of tobacco and alcohol use usual dietary habits and medical history. This study had been approved by the Institutional Review Boards of the University of Minnesota and the Shanghai Cancer Institute. Written informed consent was obtained from all subjects. At recruitment each participant was asked whether he had ever drunk alcoholic beverages at least once a week for LY3009104 6 months or more. If the answer was yes he was asked to provide the typically consumed amounts of beer wine and spirits separately. One drink was defined as 360 g of beer (12.6 g of ethanol) 103 g of wine (12.3 g of ethanol) or 30 g of spirits (12.9 g of ethanol). Smokers were identified as men who smoked at least 1 cigarette per day for 6 months or more. Information about current smoking status (yes or no) the number of cigarettes smoked per day and LY3009104 number of years of smoking over lifetime was obtained from all ever smokers. For those who had quit the smoking habit the number of years since quitting smoking was recorded. Current diet was assessed via a food frequency questionnaire that included 45 food groups or items representing commonly consumed local foods. The methods for computing selected dietary nutrients were previously described . At the completion of the baseline interview a 10-mL non-fasting blood sample and a single-void urine sample were collected from each participant. The collection of biospecimens from study subjects usually took place between 5 LY3009104 pm and 9 pm on average about 3 hr after the last meal. Following collection the urine sample was immediately placed in an ice box and transported on the same day to the processing laboratory where it was stored at 4°C overnight. The following morning three.