BACKGROUNDEpidemiologic studies have reported inconsistent results regarding tea consumption and the risk of pancreatic cancer. This study aimed to investigate whether tea consumption is related to the risk of pancreatic cancer.

METHODSWe searched Medline, EMBASE, ISI Web of Science, and the Cochrane library for studies published up to November 2013. We used a meta-analytic approach to estimate overall odds ratio (OR) and 95% confidence interval (CI) for the highest versus the lowest tea consumption categories.

RESULTSThe summary OR for high versus no/almost never tea drinkers was 1.04 (95% CI: 0.91-1.20), with no significant heterogeneity across studies (P = 0.751; I(2) = 0.0%). The OR was 0.99 (95% CI: 0.77-1.28) in males and 1.01 (95% CI: 0.79-1.29) in females. The OR was 1.07 (95% CI: 0.85-1.34) in Asian studies, 1.05 (95% CI: 0.84-1.31) in European studies, and 0.98 (95% CI: 0.72-1.34) in the US studies. The OR was 0.87 (95% CI: 0.69-1.10) without adjustment for a history of diabetes and 1.16 (95% CI: 0.97-0.39) after adjustment for a history of diabetes. The OR was 0.90 (95% CI: 0.72-1.12) without adjustment for alcohol drinking and 1.16 (95% CI: 0.96-1.39) after adjustment for alcohol drinking. The OR was 0.97 (95% CI: 0.76-1.25) without adjustment for BMI and 1.07 (95% CI: 0.87-1.31) after adjustment for BMI.

CONCLUSIONThis systematic meta-analysis of cohort studies dose not provide quantitative evidence that tea consumption is appreciably related to the risk of pancreatic cancer, even at high doses.

Asia ; Humans ; Pancreatic Neoplasms ; epidemiology ; etiology ; Tea ; adverse effects

Green tea is a popular beverage and its health benefits are well known. However, inconsistent results have been reported in observational studies concerning the association between green tea consumption and the lung cancer risk. In this commentary, several methodological issues underlying the measurement of tea exposure are highlighted. The recommendations should be useful for designing and planning prospective cohort studies to ascertain the protective effect of green tea against lung cancer.
Humans ; Lung Neoplasms/*etiology/prevention & control ; Risk Assessment ; Tea/*adverse effects

Objective: To investigate the association between tea consumption and the risk of all-cause and cause-specific mortality among Chinese adults. Methods: This study was based on China Kadoorie Biobank (CKB). Tea consumption information was self-reported by participants at baseline. Death was mainly identified by linkage to the death registry system. Cox proportional hazard regression models estimated HR and 95%CI. Results: With a median follow-up of 11.1 years, there were 34 661 deaths in 438 443 participants. Compared with those who never drink tea, all-cause mortality HR(95%CI) were 0.89(0.86-0.91) and 0.92(0.88-0.95) for non-daily tea drinkers and daily tea drinkers, respectively. A statistically significant difference was found in the association of tea consumption and the risk of all-cause mortality between men and women(interaction P<0.05). The protective effect was mainly seen in men. Compared with those who never drink tea, daily tea drinkers had a reduced risk of death from ischemic heart disease, ischemic stroke, hemorrhagic stroke, cancer, respiration diseases and other causes of death, and the corresponding HR(95%CI) were 0.83(0.76-0.92), 0.82(0.69-0.97), 0.86(0.78-0.94), 1.03(0.97-1.09), 1.00(0.87-1.16), 0.84(0.78-0.90). Among never smokers and non-excessive drinkers, there was no statistically significant association between daily tea drinking and the risk of death from cancer. While smokers and excessive drinkers had an increased risk of death from cancer (interaction P<0.001). Conclusions: Tea consumers had reduced risks of all-cause mortality and partial cause-specific mortality, but not for the risk of death from cancer. On the contrary, daily tea drinkers with smoking habits and excessive alcohol drinking had an increased risk of death from cancer.
Adult ; Alcohol Drinking ; Asians ; China/epidemiology* ; Female ; Humans ; Male ; Prospective Studies ; Risk Factors ; Tea/adverse effects*

OBJECTIVE: To determine the optimum staining condition of tea solutions on bovine incisors in vitro, by comparing the color stability of tooth surface of different concentrations of tea solutions and methods on bovine incisors in vitro. METHODS: Twenty bovine incisors with color surface A1 were chosen, then randomly divided into 4 groups (n=10). Group 1: soaked with 2% tea solution continuously for 6 days; group 2: soaked with 2% tea solution for 6 days, but changed fresh tea solution everyday; group 3: soaked with 1% tea solution continuously for 6 days; group 4: soaked with 1% tea solution for 6 days but fresh tea solution changed every day. After 6 days of staining, the surface color (Δ E value) of all the samples were measured with crystal eye. After brushing 30 times with toothbrushes, the color of bovine incisors were measured again. Then the samples were soaked in artificial saliva at 37 ° C, and Δ E value was measured for 14 days. RESULTS: After staining for 6 days, the Δ E values of the 2% tea solution groups were better than those of the 1% groups (20.21 vs. 16.44, 24.09 vs. 19.22, P<0.05); the groups with the same tea solution concentration, a better result was observed for the group soaked with daily fresh tea solution than for the group that experienced continuous staining (24.09 vs. 20.21, 19.22 vs. 16.44, P<0.05). Groups 1 and 2 were selected for subsequent brushing experiments. The color of both groups became lighter after brushing, and a better result was observed for the continuous staining group than for the group stained in daily fresh solution (3.06 vs. 9.51, P<0.05). The samples with better coloring effect soaked with 2% tea solution continuously for 6 days were put into artificial saliva for 14 days. There was not any significant change in coloring at the end of the first two days (1.51 vs. 1.51, P>0.05), and the color was visibly lighter after the third day (1.51 vs. 5.89, P<0.05), and no further significant change was observed until the 14th day (5.81 vs.5.89, P>0.05), which was darker coloring than that of the pre-staining group. CONCLUSION Continuous staining on bovine incisors with 2% tea solution with subsequent soaking in artificial saliva resulted in consistent coloring from day 3 to day 14, and this method could be used as an ideal model for teeth staining in vitro.
Animals ; Cattle ; Color ; Incisor ; Materials Testing ; Staining and Labeling ; Tea/adverse effects* ; Tooth Discoloration/etiology*

OBJECTIVETo study the protective impact of tea polyphenols (TP) on the injury of fibrinolytic functions induced by high-methionine dietary in rats.

METHODS50 male Wistar rats were divided by stratified based on body weight into 5 groups with 10 in each group: namely control group, model group, low-dose TP group, medium-dose TP group and high-dose TP group. The rats in model group and TP groups were fed with 3% methionine dietary, control group rats with routine diet. In addition, rats in low-dose, medium-dose and high-dose TP groups were treated with TP at 50, 100 and 200 mg/kg dosage respectively by gavages every day, control group and model group rats were given with same amount distilled water. The animals were sacrificed after 8 weeks. The levels of tissue-type plasminogen activator (t-PA) and type-1 plasminogen activator inhibitor (PAI-1) in plasma were determined by ELISA assays, mRNA levels of t-PA and PAI-1 in aortic arch were detected by RT-PCR, t-PA and PAI-1 expression in aortic arch were detected by immunohistochemistry strept-avidin-biotin complex (SABC).

RESULTSAfter experiment, the t-PA expression of aortic arch in control group, model group, low-dose TP group, medium-dose TP group and high-dose TP group were 133.03 ± 10.14, 95.46 ± 11.08, 111.97 ± 11.91, 130.23 ± 10.80, 139.39 ± 9.41 (F = 14.15, P < 0.01), respectively, and the PAI-1 expression were 90.91 ± 8.67, 166.76 ± 12.18, 139.63 ± 12.71, 134.66 ± 13.19, 109.49 ± 10.82 (F = 31.44, P < 0.01). The t-PA concentration of plasma were (10.69 ± 1.26), (6.13 ± 0.92), (8.56 ± 1.19), (9.69 ± 0.92), (11.97 ± 1.08) ng/ml, respectively (F = 41.98, P < 0.01), and the PAI-1 concentration of plasma were (6.31 ± 0.81), (16.98 ± 1.27), (11.39 ± 0.82), (8.46 ± 0.67), (8.08 ± 0.91) ng/ml, respectively (F = 207.74, P < 0.01). The mRNA levels of t-PA in aortic arch were 1.12 ± 0.02, 0.75 ± 0.14, 1.01 ± 0.09, 0.95 ± 0.08, 1.05 ± 0.13 (F = 5.77, P < 0.05), and the mRNA levels of PAI-1 in aortic arch were 1.25 ± 0.11, 1.74 ± 0.06, 1.23 ± 0.05, 1.09 ± 0.14, 1.23 ± 0.04 (F = 23.56, P < 0.01).

CONCLUSIONThe results indicate that TP seems to have regulatory function on transcription and protein levels of t-PA and PAI-1, in addition to maintaining the balance between PAI-1 and t-PA and healing the injury of fibrinolytic functions in rats induced by high-methionine dietary.

Animals ; Diet ; Fibrinolysis ; drug effects ; Male ; Methionine ; adverse effects ; Plasminogen Activator Inhibitor 1 ; blood ; Polyphenols ; pharmacology ; Rats ; Rats, Wistar ; Tea ; chemistry ; Tissue Plasminogen Activator ; blood

OBJECTIVETo investigate the inhibitory effect of tea polyphenols on renal cell apoptosis in rat test subjects suffering from cyclosporine A (CsA)-induced chronic nephrotoxicity.

METHODSFour groups of rats with CsA-induced chronic nephrotoxicity were respectively treated with vehicle olive oil, tea polyphenols, CsA and tea polyphenols plus CsA. At the end of the 28th day of treatment, 24 hours urine and blood samples were obtained, and the animals were then sacrificed. The serum and urine samples were analysed for creatinine clearance, and kidney tissue was used for pathologic analysis of renal tubular injury and interstitial fibrosis. The TUNEL assay, apoptosis-related enzyme caspase-3 mRNA detected by RT-PCR, and its enzymatic activity were analysed for the possible detections of cell apoptosis.

RESULTSCsA-treated rats displayed increased apoptosis of the tubular and interstitial cells, in comparison with vehicle-treated controls (18.3 +/- 4.6 vs 4.8 +/- 1.3 cells/mm(2), P < 0.05). In comparison with animals treated by CsA, animals treated with CsA plus tea polyphenols demonstrated significantly improved levels of creatinine clearance (0.12 +/- 0.03 vs 0.22 +/- 0.02 ml.min(-1).100 g(-1) body weight, P < 0.05), tubular injury (2.29 +/- 0.43 vs 1.42 +/- 0.26, P < 0.05), and interstitial fibrosis (2.83 +/- 0.20 vs 1.46 +/- 0.19, P < 0.05), and showed a statistically significant decrease in tubular and interstitial cell apoptosis (18.3 +/- 4.6 vs 7.7 +/- 2.1 cells/mm(2), P < 0.05). The expression of caspase-3 mRNA and caspase-3 activity was significantly higher in the CsA-treated group than that of the CsA plus tea polyphenols (TP)-treated group (P < 0.05).

CONCLUSIONThese results suggested that tea polyphenols significantly inhibits apoptosis of the tubular and interstitial cells in rats with cyclosporine-induced chronic nephrotoxicity, and that tea polyphenols may be useful to prevent CsA-associated kidney toxicity.

Animals ; Apoptosis ; drug effects ; Cyclosporine ; adverse effects ; Flavonoids ; pharmacology ; Kidney ; pathology ; Kidney Diseases ; chemically induced ; Male ; Phenols ; pharmacology ; Polyphenols ; Rats ; Rats, Sprague-Dawley ; Tea

Objective: To prospectively explore the association between tea drinking and incidence of stroke of adults of Zhejiang province. Methods: After excluding participants with heart disease, stroke, cancer and diabetes at baseline study, 53 916 participants aged 30-79 years in the China Kadoorie Biobank (CKB) study from Tongxiang were included for final analysis. Cox regression model was used to estimate the hazard ratio (HR) for the association of tea drinking with incident stroke. Results: The main type of drinking tea was black tea (79.78%), followed by green tea (20.08%). Of the 53 916 participants, the proportion of participants who drank tea at least once per week was 31.27%. The corresponding proportions for men and women were 60.24% and 10.30%, respectively. Among 391 512 person-years of the follow-up program (median 7.26 years), a total of 1 487 men and 1 769 women were diagnosed with stroke. After adjusting for socio-demographic status, lifestyle, BMI, waist circumference, and systolic blood pressure, HR for incident stroke decreased with the increase of daily average tea consumption amount (P=0.000 6). Compared with participants who did not drink tea weekly, the HRs for incident stroke in those consuming tea 0.1-, 3.0- and ≥5.0 g/d were 0.93 (95%CI: 0.85-1.00), 0.88 (95%CI: 0.77-0.99) and 0.79 (95%CI: 0.69-0.89), respectively. The HRs for incident stroke in smokers and non-smokers who consumed tea ≥5.0 g/d were 0.71 (95%CI: 0.59-0.86) and 0.97 (95%CI: 0.77-1.21), respectively, compared with current smokers and non-smokers who did not drink tea weekly (P=0.040 0). The corresponding HRs for alcohol drinkers and non-drinkers were 0.96 (95%CI: 0.76-1.22) and 0.70 (95%CI: 0.58-0.84), respectively (P=0.040 0). The corresponding HRs for central obese persons and non-central obese persons were 0.60 (95%CI: 0.44-0.81) and 0.86 (95%CI: 0.73-1.01), respectively (P=0.040 0). Conclusion: Tea drinking had an effect on reducing the possibility of incident stroke, especially among those who were current smokers, non-alcohol drinkers and central obese.
Adult ; Aged ; China/epidemiology* ; Female ; Humans ; Male ; Middle Aged ; Prospective Studies ; Risk Assessment/methods* ; Risk Factors ; Stroke/ethnology* ; Tea/adverse effects*

Fifty male Wistar rats were fed a standard chow diet or a high-fat (HF) diet, and different concentrations of green tea polyphenols (GTPs) (0.8, 1.6, and 3.2 g/L) were administered in the drinking water. We found that the malondialdehyde (MDA) level in the HF diet group was significantly higher than that in the control (CON) group (P<0.05). Decreased peroxisome proliferator-activated receptor (PPAR)-α and sirtuin 3 (SIRT3) expression, and increased manganese superoxide dismutase (MnSOD) acetylation levels were also detected in the HF diet group (P<0.05). GTP treatment upregulated SIRT3 and PPARα expression, increased the pparα mRNA level, reduced the MnSOD acetylation level, and decreased MDA production in rats fed a HF diet (P<0.05). No significant differences in total renal MnSOD and PPAR-γ coactivator-1α (PGC1-α) expression were detected. The reduced oxidative stress detected in kidney tissues after GTP treatment was partly due to the higher SIRT3 expression, which was likely mediated by PPARα.
Acetylation ; drug effects ; Animals ; Antioxidants ; pharmacology ; Diet, High-Fat ; adverse effects ; Gene Expression Regulation, Enzymologic ; drug effects ; Kidney ; drug effects ; metabolism ; Male ; Oxidative Stress ; drug effects ; Polyphenols ; pharmacology ; Rats ; Rats, Wistar ; Reactive Oxygen Species ; metabolism ; Sirtuin 3 ; metabolism ; Tea ; chemistry

Reversible thermal injury to the esophagus as the result of drinking hot liquids has been reported to generate alternating white and red linear mucosal bands, somewhat reminiscent of a candy cane. This phenomenon is associated with chest pain, dysphagia, odynophagia, and epigastric pain. Here, we report a case of thermal injury to the esophageal and oral cavity due to the drinking of hot tea, including odynophagia and dysphagia. A 69-year-old man was referred due to a difficulty in swallowing which had begun a week prior to referral. The patient, at the time of admission, was unable to swallow even liquids. He had recently suffered from hiccups, and had consumed five cups of hot adlay tea one week prior to admission, as a folk remedy for the hiccups. Upon physical examination, the patient's oral cavity evidenced mucosal erosion, hyperemia, and mucosa covered by a whitish pseudomembrane. Nonspecific findings were detected on the laboratory and radiological exams. Upper endoscopy revealed diffuse hyperemia, and erosions with thick and whitish pseudomembraneous mucosa on the entire esophagus. The stomach and duodenum appeared normal. We diagnosed the patient with thermal esophageal injury inflicted by the hot tea. He was treated with pantoprazole, 40 mg/day, for 14 days, and evidenced significant clinical and endoscopic improvement.
Tea/*adverse effects ; Mouth Mucosa/injuries ; Male ; Humans ; Heat/adverse effects ; Esophagus/*injuries ; Deglutition Disorders/*etiology ; Chest Pain ; Burns/drug therapy/*etiology/physiopathology ; Anti-Ulcer Agents/therapeutic use ; Aged ; 2-Pyridinylmethylsulfinylbenzimidazoles/therapeutic use

OBJECTIVETo evaluate interactions between lifestyle, methylanetetrahydrofolate reductase gene (MTHFR) and polymorphisms in the 3'-untranslated region (3'-UTR) of the thymidylate synthase gene (TS) with reference to development of stomach cancer (SC).

METHODSWe conducted a case-control study with 107 cases of SC and 200 population-based controls in Huaian city of Jiangsu province, China. TS genotypes were identified by polymerase chain reaction.

RESULTS(1) The frequencies of TS genotypes (+6 bp/+6 bp, +6 bp/-6 bp and -6 bp/-6 bp) among the cases were 5.6%, 47.7% and 46.7% and among the controls were 9.0%, 54.0% and 37.0%, respectively. Individuals identified as -6 bp/-6 bp genotype had a slightly higher risk for SC than those individuals with +6 bp alleles (the crude OR = 1.49, 95% CI: 0.90 - 2.47; adjusted OR = 1.36, 95% CI: 1.00 - 1.78, P = 0.047). (2) Individuals having TS -6 bp/-6 bp genotype and having smoking habit were at a significantly higher risk of developing SC (adjusted OR = 2.79, 95% CI: 1.51 - 5.18) compared with those who had +6 bp alleles with no smoking habit. Individuals having TS -6 bp/-6 bp genotype and habit of frequent alcohol drinking were at an increased risk of developing SC (adjusted OR = 1.76, 95% CI: 1.07 - 2.90) compared with those with +6 bp alleles and low consumption of alcohol. As compared with individuals with +6 bp alleles and who had habit of tea drinking, individuals who had TS -6 bp/-6 bp genotype and but without habit of tea drinking had an increased risk of developing SC (adjusted OR = 2.34, 95% CI: 1.43 - 3.82). (3) Individuals with TS -6 bp/-6 bp genotype and with MTHFR T alleles had an increased risk of developing SC (adjusted OR = 2.67, 95% CI: 1.07 - 6.70) compared with those with +6 bp alleles and with MTHRF C/C genotype.

CONCLUSIONResults in the present study suggested that there was a combined effect between lifestyle, MTHFR C/T or T/T genotype and TS -6 bp/-6 bp genotype in the development of SC.

Alcohol Drinking ; adverse effects ; Case-Control Studies ; China ; epidemiology ; Female ; Genetic Predisposition to Disease ; Humans ; Life Style ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Point Mutation ; Polymorphism, Genetic ; Risk Factors ; Smoking ; adverse effects ; Stomach Neoplasms ; epidemiology ; genetics ; Tea ; chemistry ; Thymidylate Synthase ; genetics