Green tea drinking and multigenetic index on the risk of stomach cancer in a Chinese population.

The purpose of our study was to examine the roles of green tea drinking, other risk and protective factors, and polymorphism of susceptibility genes such as GSTM1, GSTT1, GSTP1, and p53 codon 72 and their possible joint effects on the risk of stomach cancer. A population-based case-control study was conducted in Taixing, China, including 206 newly diagnosed cases with stomach cancer and 415 healthy control subjects. Epidemiological data were collected by in-person interviews using a standard questionnaire. Polymorphisms of susceptibility genes were assayed by PCR-RFLP techniques. A multigenetic index was created by summing up the number of risk genotypes. The data were analyzed using the logistic regression model. A reverse association between green tea drinking and risk of stomach cancer was observed with an adjusted odds ratio (OR) of 0.59 (95% confidence interval [CI] = 0.34-1.01). Dose-response relationship was shown (p-trend < 0.05). A higher score on the multigenetic index was associated with increased risk of stomach cancer with an adjusted OR of 2.21 (95% CI = 1.02-4.79) for those with at least 3 risk genotypes compared to those with <2 risk genotypes. Green tea drinking was suggested to have more than multiplicative interactions with alcohol consumption with an adjusted OR for interaction of 4.57 (95% CI = 1.62-12.89), and with higher multigenetic index with adjusted OR for interaction of 2.31 (95% CI = 0.88-6.03). The protective effect of green tea drinking was observed on the risk of stomach cancer and the possible effect modification by susceptibility genes was suggested.

[A case-control study on the relationship between methyl-tetra-hydrofolic acid reductase 677 gene polymorphism and the risk of stomach cancer].

OBJECTIVE: To explore the relationship between methyl-tetra-hydrofolic acid (MTHFR) 677 gene polymorphism and the risk of stomach cancer. METHODS: A population based case-control study was conducted and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method was used to detect its genotypes. RESULTS: Among cases with stomach cancer, the frequency of C/C, C/T, T/T genotype were 25.8%, 54.6%, 19.6%, compared with controls as 34.5%, 50.9%, 14.6% respectively. Using C/C genotype as reference, the OR of C/T or T/T genotype was 1.52 (95% CI: 1.04 - 2.23). 53.3% C and 46.7% T allele were distributed in stomach cancer cases, while 60.0% C and 40.0% T in controls. The OR for T allele in relation to C allele was 1.31 (1.02 - 1.69) when C allele was used as reference. In addition, the present study showed that MTHFR677 AnyT genotype might interact with smoking, moldy food intake, wheat porridge intake, eating salty food and Hp CagA infection to increase the risk of stomach cancer. No interaction was observed between MTHFR677 AnyT genotype and alcohol drinking or green tea intake. CONCLUSION: MTHFR677 AnyT genotype, might increase the risk of stomach cancer development and the genotype might also interact with other environmental risk factors to increase the risk of stomach cancer.

[A new statistical method on familial correlation dealing with family data from case-control studies].

OBJECTIVE: This paper presents a statistical method of familial correlation on family data from case-control studies. METHODS: Marginal mean models of the probands and the relatives conditional on the proband's disease status, as well as the marginal association model of the relatives were modeled integrately. Conditional odds-ratio and marginal odds-ratio were used to measure the familial correlation. RESULTS: The parameter's interpretation in the model was in accordance with sample characteristics. This method is more efficient due to making fully use of information of the probands and relatives. In addition, the method has all advantages of GEE2. CONCLUSION: The method in this paper efficiently and conveniently analyzes the family data from case-control studies to estimate the familial correlation on disease.

[Study on the protective effect of green tea on gastric, liver and esophageal cancers].

OBJECTIVE: To assess the protective effect of drinking green tea on the development of gastric, liver and esophageal cancers. METHODS: A population based study was conducted in Taixing, Jiangsu province, including 206, 204, 218 cases, respectively, and 415 population controls. RESULTS: Green tea decreased the development of gastric cancer risk by 40%. Dose-response relationships were observed between the length of time, concentration and quantity of green tea drinking and its protective effects on gastric cancer. For individuals who drink green tea for more than 250 g per month, the risk of gastric cancer reduced about 60%. Green tea might have protective effect on liver cancer. However, no protective effect of green tea was observed on esophageal cancer. CONCLUSION: Green tea drinking might be a protective factor for gastric cancer. However, the protective effects of green tea on liver and esophageal cancer were not obvious.

[A case-control study on drinking green tea and decreasing risk of cancers in the alimentary canal among cigarette smokers and alcohol drinkers].

OBJECTIVE: To explore the role of green tea in decreasing the risks of gastric cancer, liver cancer, esophageal cancer among alcohol drinkers or cigarette smokers. METHODS: A population based case-control study was conducted in Taixing, Jiangsu province. RESULTS: In Taixing city, identified cases of stomach, liver and esophageal cancers were chosen with informed consent. The numbers were 206, 204, 218 respectively. Controls were chosen from normal population having lived in the area for longer than 10 years, also with informed consent. Green tea drinking seemed to have decreased 81%, 78%, 39% risk for the development of gastric cancer, liver cancer and esophageal cancer among alcohol drinkers. It might also have decreased 16%, 43%, 31% on the risks of developing the three kinds of cancers among cigarette smokers. Interaction assessment showed that drinking green tea could significantly decrease the risk of gastric cancer and liver cancer among alcohol drinkers, with ORs of interaction item 0.23 (95% CI: 0.10 - 0.55) and 0.25 (95% CI: 0.11 - 0.57) respectively. CONCLUSION: Habit of drinking green tea seemed to have significant protective effects on the development of both gastric and liver cancer among alcohol drinkers while, green tea also having some protective effect on esophageal cancer among alcohol drinkers and on three kinds of cancers among cigarette smokers.