Coffee and green tea consumption with the risk of COVID-19 among the vaccine recipients in Japan: a prospective study.

BACKGROUND: While coffee and green tea have been suggested to have immunoprotective effects, it remains elusive whether they can decrease the risk of COVID-19. OBJECTIVE: We prospectively examined the association between coffee and green tea consumption and the risk of COVID-19 among mRNA vaccine recipients during the epidemic of the Omicron variant. METHOD: Participants were 2,110 staff (aged 18 to 76 years) of a large medical facility in Tokyo, who attended a serosurvey in June 2022, predominatly received ≥3 doses of vaccine, and were followed for COVID-19 until December 2022. Coffee and green tea consumption was ascertained via a questionnaire. COVID-19 was identified through the in-house registry. Cox proportional hazards model was used to estimate the hazard ratios (HRs) of COVID-19 across the categories of beverage consumption. RESULT: During 6 months of follow-up, 225 (10.6%) cases of COVID-19 were identified. Contrary to the expectation, higher consumption of coffee was associated with a significant increase in the risk of COVID-19; multivariable-adjusted HRs (95% CI) was 1.00, 0.92 (0.62-1.35), 1.48 (0.99-2.22), and 1.82 (1.20-2.76) for <1 cup/day, 1 cup/day, 2 cups/day, and ≥3 cups/day, respectively (p trend=0.003). Green tea consumption was not significantly associated with the risk of COVID-19. The association with coffee was attenuated if serologically detected infection was added to the cases. CONCLUSION: In a cohort of Japanese hospital staff who received COVID-19 vaccine, higher consumption of coffee was associated with an increased risk of COVID-19 during the epidemic of the Omicron variant. There was no evidence of a significant association between green tea consumption and COVID-19 risk.

Combined effects of cigarette smoking, DNA methyltransferase 3B genetic polymorphism, and DNA damage on lung cancer.

BACKGROUND: Smoking increases DNA methylation and DNA damage, and DNA damage acts as a vital cause of tumor development. The DNA methyltransferase 3B (DNMT3B) enhances promoter activity and methylation of tumor suppressor genes. Tea polyphenols may inhibit DNMT activity. We designed a case-control study to evaluate the combined effects of smoking, green tea consumption, DNMT3B - 149 polymorphism, and DNA damage on lung cancer occurrence. METHODS: Questionnaires were administered to obtain demographic characteristics, life styles, and family histories of lung cancer from 190 primary lung cancer cases and 380 healthy controls. Genotypes and cellular DNA damage were determined by polymerase chain reaction and comet assay, respectively. RESULTS: The mean DNA tail moment for lung cancer cases was significantly higher than that for healthy controls. Compared to nonsmokers carrying the DNMT3B - 149 CT genotype, smokers carrying the TT genotype had a greater lung cancer risk (odds ratio [OR]: 2.83, 95% confidence interval [CI]: 1.62-4.93). DNA damage levels were divided by the tertile of the healthy controls' values. Compared to nonsmokers with low DNA damage, smokers with moderate DNA damage (OR: 2.37, 95% CI: 1.54-3.63) and smokers with high DNA damage (OR: 3.97, 95% CI: 2.63-5.98) had elevated lung cancer risks. Interaction between smoking and DNA damage significantly affected lung cancer risk. CONCLUSIONS: Our study suggested that the DNMT3B - 149 TT genotype, which has higher promoter activity, can increase the lung cancer risk elicited by smoking, and DNA damage may further promote smoking related lung cancer development.

Association of green tea consumption with mortality from all-cause, cardiovascular disease and cancer in a Chinese cohort of 165,000 adult men.

Tea is the most ancient and popular beverage in the world, and its beneficial health effects has attracted tremendous attention worldwide. However, the prospective evidence relating green tea consumption to total and cause-specific mortality is still limited and inconclusive. We recruited 164,681 male participants free of pre-existing disease during 1990-1991, with green tea consumption and other covariates assessed by the standardized questionnaire and mortality follow up continued until 2006 (mean 11 years; total person-years: 1,961,791). Cox regression analyses were used to quantify the associations of green tea consumption with all-cause (n = 32,700), CVD (n = 11,839) and cancer (n = 7002) mortality, adjusting simultaneously for potential confounders. At baseline, 18 % reported regular consumption of green tea. Compared with non-green tea drinkers, regular drinkers had significantly lower all-cause mortality, with adjusted hazard ratios (HRs) being 0.94 (95 % CI 0.89, 0.99) for ≤5 g/day, 0.95 (0.91, 0.99) for 5-10 g/day and 0.89 (0.85, 0.93) for >10 g/day. For CVD mortality, the corresponding HRs were 0.93 (0.85, 1.01) 0.91 (0.85, 0.98) and 0.86 (0.79, 0.93), respectively, while for cancer they were 0.86 (0.78, 0.98), 0.92 (0.83, 1.00) and 0.79 (0.71, 0.88), respectively. The patterns of these associations varied by smoking, alcohol drinking and locality. This large prospective study shows that regular green tea consumption is associated with significantly reduced risk of death from all-cause, CVD and cancer among Chinese adults.

Association between Green Tea Consumption and Abdominal Obesity Risk in Middle-Aged Korean Population: Findings from the Korean Genome and Epidemiology Study.

The prevalence of general and abdominal obesity is increasing with rapid economic growth and the westernization of dietary habits in Korea, especially in the middle-aged population. Data were obtained from the Korean Genome and Epidemiology Study (KoGES), which recruited 10,030 participants between the ages of 40 and 69 years. Information on green tea consumption was obtained from the food frequency questionnaire and categorized as none, <1 cup, between 1 and <4 cups, and ≥4 cups. Multivariable logistic regression models were used to estimate the ORs and 95% CIs to examine any possible associations between green tea consumption and the risk of abdominal obesity after controlling for potential confounders. High consumption of green tea was associated with a 44% lower odds ratio for abdominal obesity (none vs. ≥4 cups/week: OR, 0.56; 95% CI 0.41-0.78; p for trend = 0.001). When stratified by sex, an inverse association between green tea consumption and abdominal obesity was observed only in women (none vs. ≥4 cups/week: OR, 0.71; 95% CI 0.57−0.88; p for trend = 0.004). No significant association was found among men. Our findings indicate that green tea consumption has beneficial effects in the prevention of abdominal obesity in middle-aged Korean women.