A Case-control Study On Green Tea Consumption And The Risk Of Leukemia

Objective To explore the association between Leukemia and green tea drinking. Methods A hospital-based matched case-control study was carried out. 107 leukemia cases were recruited from patients identified between January 2005 and October 2006 at Second and First Affiliated Hospital, College of Medicine, Zhe Jiang University,and 110 nontumorous controls matched on gender,age.A unified questionnaire of risk factors was used to identify demographic characteristics. personal living habits such as tea drinking,smoking and vocational contact for all cases and controls. Univariate and multivariate unconditional logistic regression analysis were carried out with SPSS 1 1.5 software. Results OR value for leukemia in tea-drinkers was 0.58(95 % CI:0.34-1.0 P<0.05)compared to non-tea-drinkers. After an unconditioned logisticregression analysis of multiple factors, adjusted OR was 0.52(95%CI: 0.28-0.98; P=0.04).OR declined with increase in the amount of tea drinking and with longer duration of tea consumption. The multivariate ORs for green tea consumption <500g/year,500-1000g/year, >1000g/ year were 1.90,0.23 and 0.42;The duration of tea drinking was also categorized into four consumption levels (0, <10 years, 10-20 years, and >20 years), and the homologousORs were 1.00, 0.71(95%CI:0.32-0.1.61),0.71(95%CI:0.27-1.83),0.23(95%CI:0.08-0.68),respectively(P for trend<0.001);Data on tea consumption frequency were reclassified as never or seldom (reference group representing the non-tea-drinkers), at most once a week (but at least once a month), two to six times a week, and at least once a day, each OR value of which was 4.60,0.48 and 0.46 with the trend test of P<0.01.Likewise,the multivariate ORs for number of new batches =1 time/week,2-6 times/week and ≥1 time/day were 4.62,0.43 and 0.48 with the trend test of P=0.001. Conclusion Green tea drinking may be associated with reduced risk of leukemia,and it may conduct as one of human health planning contents.