RESUMO
OBJECTIVE: To investigate whether green tea consumption can reduce the risk of adult leukemia. METHODS: A hospital-based matched case-control study was conducted in 2005 - 2006. We recruited 107 confirmed leukemia cases and 110 inpatient controls with orthopedic disease without leukemia or other malignancy matched on gender, age and hospitals that patients stayed. Related information were gathered on quantity, duration and frequency of tea consumption, demographic characteristics, exposure to radiation and occupational hazards, medications, using a validated questionnaire by face-to-face interview. Univariate and multivariate unconditional logistic regression analysis were used to estimate odds ratios (ORs) and associated 95% confidence intervals (CIs) with SPSS 11.5 software. RESULTS: Compared with non-tea-drinkers, the OR of those who consumed green tea was 0.58 (95% CI:0.34-1.00, P< 0.05) under univariate statistical analysis. The OR was 0.52 ( 95% CI: 0.28- 0.98, P = 0.04), using logistic regression to count for age, gender, residential area, smoking, level of education, exposure to radiation, benzene and organo-phosphorus. Compared with non-drinkers, the risk of adult leukemia declined with increasing quantity, duration, and frequency of green tea consumption. Tests for trend on dose-response was statistically significant (P < 0.01). CONCLUSION: A higher consumption of green tea seemed to be associated with a declined risk of adult leukemia. Tea consumption might be of help to human health planning projects.