Lung cancer and indoor air pollution arising from Chinese-style cooking among nonsmoking women living in Shanghai, China.

Associations between indoor air pollution from Chinese-style cooking and lung cancer have been found in several investigations. To provide more detailed estimates of the associations while accounting for key confounding factors, we conducted a population-based, case-control study of lung cancer among nonsmoking women living in Shanghai, the People's Republic of China. Five hundred four incident, primary lung cancer cases diagnosed from February 1992 through January 1994 were identified through the population-based Shanghai Cancer Registry. A control group of 601 nonsmoking women was selected randomly from the Shanghai-Residential Registry, and they were frequency-matched to the expected age distribution of the cases. Exposure to indoor air pollutants from Chinese-style cooking was ascertained through in-person interviews. We estimated adjusted odds ratios (OR) and 95% confidence intervals (CI) by unconditional logistic regression. There were similar patterns of excess risk for exposure to indoor air pollutants from Chinese-style cooking across different histological types of lung cancer. Women who did not have a separate kitchen experienced a 28% increased risk of lung cancer (OR = 1.28; 95% CI = 0.98-1.68). We found little association with area of the windows of the apartment where subjects had lived for the longest period of time. Heating cooking oils to high temperatures was associated with a 1.64-fold increased risk of lung cancer (95% CI = 1.24-2.17). An 84% excess risk was found among women who most often cooked with rapeseed oil (OR = 1.84; 95% CI = 1.12-3.02). Lung cancer risks were also related to "considerable" smokiness of the kitchen during cooking (OR = 2.38; 95% CI = 1.58-3.57), frequent eye irritation during cooking (OR = 1.68; 95% CI = 1.02-2.78), to a more than weekly use of frying (OR = 2.09; 95% CI = 1.14-3.84) and deep-frying (OR = 1.88; 95% CI = 1.06-3.32). This population-based case-control study confirmed that exposure to indoor air pollution from Chinese-style cooking, especially cooking unrefined rapeseed oil at high temperatures in woks, may increase the risk of lung cancer.     

Green tea and gastric cancer risk: meta-analysis of epidemiologic studies

OBJECTIVE: To evaluate the association between green tea consumption and the risk of gastric cancer. METHODS: Electronic search of the Cochrane Library, MEDLINE, EMBASE and Chinese Bio-medicine Database, which have articles published between (1966 and 2006), was conducted to select studies for this meta-analysis. RESULTS: This meta-analysis included 14 epidemiologic studies, with a total number of 6123 gastric cancer cases and 134006 controls. The combined results based on all studies showed that green tea consumption was not associated with the risk of gastric cancer [odds ratio (OR)=0.98, 95% confidence interval (CI)=0.77-1.24]. The summary OR from all population-based case-control studies showed a minor inverse association between green tea consumption and risk of gastric cancer (OR=0.68, 95% CI=0.49-0.92), while no associations were noted from hospital-based case-control studies (OR=1.12, 95% CI=0.70-1.77) and cohort studies (OR=1.56, 95% CI=0.93-2.60). No associations were noted both in males (OR=1.10, 95% CI=0.76-1.60) and females (OR=0.99, 95% CI=0.64-1.51). The summary OR from seven studies suggest that the highest consumption level of green tea was more than 5 cups per day and no associations were noted (OR=0.99, 95% CI=0.78-1.27). CONCLUSIONS: The results of this meta-analysis indicated that there is no clear epidemiological evidence to support the suggestion that green tea plays a role in the prevention of gastric cancer.     

绿茶与子宫内膜癌关系的病例对照研究

目的探讨饮茶特别是绿茶与子宫内膜癌的关系。方法采用以人群为基础的病例对照研究,调查上海市1997年1月至2002年12月间已确诊年龄30～69岁的子宫内膜癌患者(n=995)和全人群对照(n=1087)的一般情况、月经生育史、饮食及营养素、个人生活习惯、激素相关因素、疾病及家族史等资料,采用非条件logistic回归模型分析饮茶与子宫内膜癌的关系。结果与从未饮茶者相比,有饮茶史者患子宫内膜癌的危险略降低(OR=0.82,P=0.0466)。饮茶主要对绝经前女性有保护作用(OR=0.74,95%CI:0.54～1.01);以从不饮茶者为参比组,饮淡茶、浓淡适中及浓茶者的OR值分别为0.72、0.88和0.44,趋势检验有统计学意义(P=0.0431)。在不吸烟不饮酒者中,饮绿茶对子宫内膜癌有保护作用(OR=0.77,P=0.0199);每周饮绿茶频率越高,患子宫内膜癌的危险性越低;以从未饮茶者为参比组,每周饮绿茶<7次及≥7次者OR值分别为0.90(95%CI:0.53～1.54)和0.76(95%CI:0.60～0.95),趋势检验P=0.0163;饮绿茶量越大危险性越低,每月饮绿茶≤100g、～200g及>200g者的OR值分别为0.76、0.87和0.74,趋势检验有统计学意义。结论饮茶特别是绿茶对子宫内膜癌可能有弱的保护作用,且该作用可能局限于绝经前女性。     

Green tea and black tea consumption and prostate cancer risk: an exploratory meta-analysis of observational studies

Observational studies on tea consumption and prostate cancer (PCa) risk are still inconsistent. The authors conducted a meta-analysis to investigate the association between green tea and black tea consumption with PCa risk. Thirteen studies providing data on green tea or black tea consumption were identified by searching PubMed and ISI Web of Science databases and secondary referencing qualified for inclusion. A random-effects model was used to calculate the summary odds ratios (OR) and their corresponding 95% confidence intervals (CIs). For green tea, the summary OR of PCa indicated a borderline significant association in Asian populations for highest green tea consumption vs. non/lowest (OR = 0.62; 95% CI: 0.38-1.01); and the pooled estimate reached statistically significant level for case-control studies (OR = 0.43; 95% CI: 0.25-0.73), but not for prospective cohort studies (OR = 1.00; 95% CI: 0.66-1.53). For black tea, no statistically significant association was observed for the highest vs. non/lowest black tea consumption (OR = 0.99; 95% CI: 0.82-1.20). In conclusion, this meta-analysis supported that green tea but not black tea may have a protective effect on PCa, especially in Asian populations. Further research regarding green tea consumption across different regions apart from Asia is needed.     

Black tea consumption and risk of rectal cancer in Moscow population

PURPOSE: This population-based case-control study (663 cases and 323 controls) examined the effect of black tea intake on the risk of rectal cancer in Moscow residents. The Moscow population was selected for its wide range of black tea consumption. METHODS: This study used three measures of tea consumption: the volume of beverage (l/month), zavarka (tea concentrate, l/month), and dry tea (g/month). We calculated the adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for these three parameters of tea intake using logistic regression. RESULTS: Greater use of dry tea was associated with lower risk of rectal cancer in women (high vs. low: OR = 0.40; 95% CI, 0.23-0.70) and in men (high vs. low: OR = 0.77; 95% CI, 0.42-1.43). The observed effect was weaker when tea was measured as zavarka (high vs. low in women: OR = 0.47; 95% CI, 0.26-0.83; in men: OR = 0.99; 95% CI, 0.52-1.96) and as beverage volume (high vs. low in women: OR = 0.68; 95% CI, 0.39-1.19; in men: OR = 1.03; 95% CI, 0.53-2.09). CONCLUSIONS: These findings support the hypothesis that black tea consumption reduces the risk of rectal cancer. The attenuation of the effect across the three measures of tea intake can be explained by an increasing degree of exposure misclassification from dry tea to zavarka and beverage volume.     

Association of fluids from beverages with risk of rectal cancer

Little information is available about how fluid intake from beverages and sources of fluid intake influence risk of rectal cancer. We examined these associations with risk of incident rectal cancer in a population-based case-control study of 952 cases and 1,205 controls living in northern California and Utah. We also determined if intake of fiber (soluble and insoluble), physical activity, and nonsteroidal anti-inflammatory medications (NSAIDs) or aspirin modified the associations between fluid intake and rectal cancer. We identified a modest inverse association of water intake (odds ratio, OR = 0.70; 95% confidence interval, CI = 0.48, 1.02) and total fluid intake (high vs. low OR = 0.70; 95% CI = 0.46, 1.06) with risk of rectal cancer in men and a positive association with juice among women (high vs. low OR = 1.56; 95% CI = 1.00, 2.41). Risk of rectal cancer increased nonsignificantly among men with beer consumption, among women with high white wine use, and among men and women with high long-term alcohol use. NSAIDs modified the association of alcohol consumption with rectal cancer: 1) risk associated with beer increased among men who did not take NSAIDs and had a high beer intake (OR = 1.60; 95% CI = 1.08, 2.39) and 2) risk associated with long-term alcohol intake increased in a linear fashion in women who did not use NSAIDs (OR = 1.98; 95% CI = 1.15, 3.40). Risk of rectal cancer increased among estrogen-negative women if they consumed any beer or white wine but decreased among estrogen-positive women with beer. In men, low intake of water and low insoluble fiber intake were associated with increased risk of rectal cancer beyond that of either factor alone (OR = 1.82; 95% CI = 1.11, 3.00). The interactions of fiber with water intake suggest that bowel motility may be the mechanism responsible for modification of rectal cancer risk for water. Associations of alcohol to risk for rectal cancer may be related to cellular hyperproliferation and may be modified by NSAID use.     

Meta-Analysis of Black Tea Consumption and Breast Cancer Risk: Update 2013

Black tea is a commonly consumed beverage in the world, comprising approximately 80% of all tea consumed. We sought to examine the association between black tea consumption and risk of breast cancer, using all available epidemiologic evidence to date. PubMed, EMBASE, ISI Web of Science, Chinese National Knowledge Infrastructure Database, and China Biological Medicine Database were used to search for citations using the MeSH terms as “breast neoplasm” AND “black tea.” Then we performed a meta-analysis of studies of breast cancer risk published between 1985 and 2013 by using RevMan 5.0 software. The results showed that no association between black tea consumption and breast cancer risk in overall [odds ratio (OR) = 0.97; 95% confidence interval (CI) = 0.89–1.05]. We further performed a stratified analysis according to region (United States/Europe). Black tea consumption did not decrease breast cancer risk in the United States (OR = 0.91; 95% CI = 0.78–1.07) and in Europe (OR = 0.99; 95% CI = 0.93–1.06). In addition, the summary OR from all cohort studies (OR = 1.04, 95% CI = 0.91–1.18) or all case-control studies (OR = 0.95, 95% CI = 0.88–1.02) showed black tea intake has no effects on breast cancer risk. However, the association between black tea consumption and breast cancer incidence remains unclear based on the current evidence. Further well-designed large studies are needed to confirm our result.     

Green tea consumption and cause-specific mortality: Results from two prospective cohort studies in China

Background

Green tea is one of the most widely consumed beverages in Asia. While a possible protective role of green tea against various chronic diseases has been suggested in experimental studies, evidence from human studies remains controversial.

Tea consumption and risk of bladder and kidney cancers in a population-based case-control study

Recent epidemiologic studies have suggested that tea may be protective against cancers of the urinary tract. The authors examined the association between usual adult tea consumption and risk of bladder and kidney cancers in a population-based case-control study that included 1,452 bladder cancer cases, 406 kidney cancer cases, and 2,434 controls. For bladder cancer, the age- and sex-adjusted odds ratios (OR) (95% confidence intervals (CI)) referent to nonusers of tea were 0.9 (0.7, 1.1) for <1.0 cup/day, 1.0 (0.8, 1.2) for 1.0-2.6 cups/day, and 0.9 (0.7, 1.1) for >2.6 cups/day (cutpoints for users based on the tertile distribution among controls). When more extreme cutpoints were used, persons who consumed >5 cups/day (>90th percentile) had a suggestive decreased risk (OR = 0.7; 95% CI 0.5, 1.0), but there was no evidence of a dose-response relation. In analyses stratified by median total beverage intake (2.6 liters/day), there was an inverse association with tea use among persons who consumed less than the median (OR = 0.5; 95% CI 0.3, 0.8) but no association for persons who consumed at or above the median. In contrast, for kidney cancer, there was no association with tea use. Adjustment for site-specific risk factors did not alter these results. This study offers only minimal support for an inverse association between tea consumption and bladder or kidney cancer risk.     

中国非吸烟女性肺癌危险因素的病例-对照研究

目的探讨中国非吸烟女性患肺癌的危险因素。方法应用1∶2配对的病例对照方法,收集2001年9月~2004年2月在北京、上海和成都指定医院经病理诊断确诊的非吸烟女性新发肺癌住院病例157例,按照性别、年龄(±2岁)、不吸烟等配对因素选取医院对照和人群对照。利用统一调查表对调查对象进行面对面问卷调查,收集病例和对照有关危险因素的暴露史等情况。通过单因素分析和多因素条件Logistic回归分析筛选肺癌的主要危险因素。结果单因素分析发现28个暴露因素与非吸烟女性肺癌发生有关。多因素分析发现,被动吸烟指数≥50人年(OR=1·77,95%CI为1·07~2·92)、经常吃动物内脏(OR=1·85,95%CI为1·06~3·22)、职业接触粉尘(OR=2·47,95%CI为1·21~5·03)和工作场所通风不良(OR=4·02,95%CI为1·74~9·29)为非吸烟女性肺癌发生的危险因素;常吃蔬菜(OR=0·26,95%CI为0·12~0·59)、经常服用维生素(OR=0·53,95%CI为0·30~0·93)、结婚后家庭人均月收入≥500元(OR=0·50,95%CI为0·28~0·91)和初次生育年龄在24~30岁之间(OR=0·53,95%CI为0·32~0·90)为非吸烟女性肺癌发生的保护因素。趋势性检验发现,被动吸烟与非吸烟女性发生肺癌的相对危险度之间存在一定剂量反应关系。结论被动吸烟、职业接触粉尘、经常吃动物内脏和工作场所通风不良会增加非吸烟女性患肺癌的危险性。常吃蔬菜和经常服用维生素等因素可以降低非吸烟女性发生肺癌的危险性。     

Green Tea Consumption and Risk of Esophageal Cancer: A Meta-Analysis of Published Epidemiological Studies

We performed a meta-analysis to analyze the association of various levels of green tea consumption with risk of esophageal cancer. We searched MEDLINE, EMBASE, and the Cochrane Library for studies of green tea consumption and esophageal cancer and identified 12 observational studies. For esophageal cancer, the pooled relative risk (RR) was 1.09 [95% confidence interval (CI), 0.76–1.55] for greatest vs. non/least green tea consumption; however, there was significant heterogeneity across studies (P = 0.00, I² = 75.5%). Compared with subjects who drank no/least green tea, the pooled RR was 1.14 (95% CI = 0.97–1.35) for moderate drinkers, 0.94 (95% CI = 0.77–1.13) for those who drank little, and 0.97 (95% CI = 0.77–1.22) for all subjects who had ever drunk green tea. Subgroup analysis showed that the RR was 0.46 (95% CI = 0.29–0.73) for female subjects. The results of the present meta-analysis are that any association between green tea and risk of esophageal cancer remains unclear. Subgroup analyses indicated that greater consumption of green tea might reduce the risk of esophageal cancer in female subjects. However, the results are based on limited research. Further research is needed to confirm the results and clarify the likely biological mechanisms.     

Green Tea and Incidence of Colorectal Cancer: Evidence from Prospective Cohort Studies

A systematic meta-analysis of prospective cohort studies on green tea consumption and colorectal cancer was performed to determine whether green tea has a chemopreventive effect against colorectal cancer. Six eligible cohort studies involving 352,275 participants and 1675 cases of colorectal cancer were identified. Combined relative risk (RR) ratios for the highest vs. lowest and increment of 1 cup/day green tea consumption levels were calculated. The combined RR of 0.90 (95% CI: 0.72–1.08) was found comparing highest vs. lowest green tea consumption levels for colorectal cancer. No significant differences by cancer-site were found, but an inverse association between green tea and incidence of colorectal cancer (RR: 0.70; 95% CI: 0.55–0.85) and colon cancer (RR: 0.69; 95% CI: 0.48–0.98) was demonstrated in Shanghai population. Singapore men had a higher risk of colorectal cancer (RR: 1.36; 95% CI: 1.06–1.74). Furthermore, an increase in green tea consumption of 1 cup/day was not associated with incidence of colorectal cancer (RR: 0.97; 95% CI: 0.91–1.03). Despite the limited evidence from Shanghai studies in support of green tea as potential chemopreventive agents against colorectal cancer, available data from prospective cohort studies are insufficient to conclude that green tea may protect against colorectal cancer.     

Study of lung cancer histologic types, occupation, and smoking in Missouri

A case-control study of lung cancer was conducted to evaluate the relationship between lung cancer histologic types and occupation, adjusted for smoking. A total of 4,431 white male cases and 11,326 cancer controls, diagnosed between 1980 and 1985, were identified through the Missouri Cancer Registry. For all histologic types combined, excess risk was observed among many a priori suspected high-risk occupations. Lung cancer was elevated among men employed as insulators (odds ratio [OR] = 6.0; 95% confidence interval [CI] = 0.7, 137.8), carpenters (OR = 1.3; 95% CI = 1.0, 1.7), painters, plasterers, and wallpaper hangers (OR = 2.0; 95% CI = 1.2,3.3), structural metal workers (OR = 1.9; 95% CI = 0.6,6.0), mechanics and repairers (OR = 1.3; 95% CI = 1.0,1.7), motor vehicle drivers (OR = 1.5; 95% CI = 1.2,1.8), police and firefighters (OR = 1.6; 95% CI = 1.1,2.3), and food service personnel (OR = 1.8; 95% CI = 1.0,3.5). A deficit of lung cancer was observed among farmers (OR = 0.9; 95% CI = 0.7,1.0). Adenocarcinoma of the lung was elevated among carpenters (OR = 1.6; 95% CI = 1.0,2.5) and cabinet and furniture makers (OR = 2.0; 95% CI = 0.4,8.1), which is interesting because of the previous reports of excess adenocarcinoma of the nasal cavity associated with wood dust exposure. Adenocarcinomas were also elevated among plumbers (OR = 2.0; 95% CI = 1.0,3.8) and printers (OR = 1.8; 95% CI = 0.7,4.2). Electricians were at slightly increased risk for adenocarcinoma (OR = 1.5; 95% CI = 0.7,2.8) and "other" or mixed cell types of lung cancer (OR = 1.5; 95% CI = 0.8,2.9) but at decreased risk for small cell (OR = 0.8; 95% CI = 0.3,2.0) and squamous cell (OR = 0.8; 95% CI = 0.4,1.6) tumors. Among welders, adenocarcinoma (OR = 1.7; 95% CI = 0.7,3.8) and squamous cell (OR = 1.7; 95% CI = 0.9,3.3) cancers were elevated, but small cell and "other" lung cancers were not. Despite the limitations of the Cancer Registry data, some interesting associations were observed that merit further study, particularly the association between lung adenocarcinoma and occupational exposure to wood and wood dust.     

中国六城市女性生理生育因素与乳腺癌关系的病例对照研究

目的研究城市女性乳腺癌的危险因素,探讨城市女性生理生育因素的变化与城市女性乳腺癌发病的关联强度,促进乳腺癌的预防和控制。方法采用病例对照的研究方法,新发病例通过北京、天津、上海、重庆、武汉、广州六城市的乳腺癌监测点确定,对照从当地正常人群数据库中随机抽样,对收集到3332对1：1年龄配对的病例和对照进行问卷调查。通过条件Logistic模型进行相对危险度及剂量-反应效应估计。结果在调整年龄、职业、饮食等因素后,城市女性中乳腺癌发病的危险因素为初潮年龄的提前（≤14岁,OR=1.37,95％CI=1.12－1.66）、月经持续天数长（〉7天,OR=1.18,95％ CI=1.00－1.38）、有痛经（OR=1.21,95％ CI=1.03－1.42）、结婚晚（≥28岁,OR：2.13,95％ CI=1.63－2.79）、首次怀孕晚（≥30岁,OR=2.13,95％CI=1.63－2.79）等,而保护性因素有月经间隔天数长（ 〉28天,OR=0.81,95％ CI=0.68－0.95）、绝经年龄早（≤45岁,OR=0.58,95％ CI=0.47－0.72）、怀孕次数多（≥2次,OR=0.67,95％ CI=0.45－0.99）,哺乳（≥4个月,OR=0.70,95％CI：0.60－0.83）。结论女性生理生育因素是影响城市女性乳腺癌发病的主要危险因素,可部分解释中国城市女性乳腺癌呈逐年上升趋势的原因。     

Are coffee and tea consumption associated with urinary tract cancer risk? A systematic review and meta-analysis

BACKGROUND: Narrative reviews have concluded that there is a small association between coffee consumption and an increased risk of urinary tract cancer, possibly due to confounding by smoking. No association for tea consumption has been indicated. This systematic review attempts to summarize and quantify these associations both unadjusted and adjusted for age, smoking and sex. METHOD: Thirty-four case-control and three follow-up studies were included in this systematic review. Summary odds ratios (OR) were calculated by meta-regression analyses. RESULTS: The unadjusted summary OR indicated a small increased risk of urinary tract cancer for current coffee consumers versus non-drinkers. The adjusted summary OR were: 1.26 (95% CI : 1.09-1.46) for studies with only men, 1.08 (95% CI : 0.79-1.46) for studies with only women and 1.18 (95% CI : 1.01-1.38) for studies with men and women combined. Neither unadjusted nor adjusted summary OR provided evidence for a positive association between tea consumption and urinary tract cancer. Even though studies differed in methodology, the results were rather consistent. We did not perform dose-response analyses for coffee and tea consumption due to sparse data. CONCLUSIONS: In accordance with earlier reviews, we found that coffee consumption increases the risk of urinary tract cancer by approximately 20%. The consumption of tea seems not to be related to an increased risk of urinary tract cancer.     

Commuting physical activity and risk of colon cancer in Shanghai, China

Colon cancer incidence rates have been rapidly increasing in Shanghai, China, for reasons still unclear. Low physical activity is a known risk factor for colon cancer. The authors examined the effects of physical activity, particularly commuting physical activity, and its joint effects with body mass index on colon cancer risk in a population-based, case-control study. The study included 931 incident colon cancer patients and 1,552 randomly selected controls in Shanghai between 1990 and 1993. Colon cancer risk was significantly reduced among subjects with high commuting physical activity (odds ratio (OR) = 0.52, 95% confidence interval (CI): 0.27, 0.87 for men; OR = 0.56, 95% CI: 0.21, 0.91 for women), particularly among those who had high commuting physical activity for at least 35 years (OR = 0.34, 95% CI: 0.09, 0.76 for men; OR = 0.31, 95% CI: 0.07, 0.72 for women). Commuting physical activity significantly modified the risk conferred by high body mass index, with the highest risk observed among those at the highest quintile of body mass index and the lowest activity level (OR = 6.43, 95% CI: 1.82, 8.54 for men; OR = 7.42, 95% CI: 2.84, 10.01 for women). Our results suggest that regular and frequent physical activity over a long period of time protects from colon cancer and significantly modifies the body mass index-associated risk.     

Green Tea Consumption and Risk of Pancreatic Cancer: A Meta-analysis

Emerging laboratory and animal studies indicate that green tea inhibits development and progression of pancreatic cancer, but evidence from epidemiologic studies appears inconsistent and inconclusive. A meta-analysis summarizing published case-control and cohort studies was performed to evaluate the association of green tea consumption with risk of pancreatic cancer. Pertinent studies were identified by a search of PubMed and EMBASE up to April 2014. A random-effects model was assigned to compute summary risk estimates. A total of three case-control studies and five prospective studies were included, comprising 2317 incident cases and 288209 subjects. Of them, three studies were from China and the reminders were conducted in Japan. Overall, neither high vs. low green consumption (odds ratio (OR) = 0.99, 95% confidence interval [CI] = 0.78–1.25), nor an increase in green tea consumption of two cups/day (OR = 0.95, 95% CI = 0.85–1.06) was associated with risk of pancreatic cancer. The null association persisted when the analysis was stratified by sex or restricted to non-smokers. In the stratification by study location, the summary OR for the studies from China and for those from Japan was 0.77 (95% CI = 0.60–0.99) and 1.21 (95% CI = 0.94–1.54), respectively (P for differences = 0.04). Cumulative epidemiologic evidence suggests that green tea consumption is not associated with pancreatic cancer.     

Cancer-Preventive Effects of Drinking Green Tea among a Japanese Population

Background.Laboratory studies have revealed the cancer preventive effects of green tea, so the association between green tea consumption and cancer was examined in a human population.Methods.The association between green tea consumption and cancer incidence was studied in our prospective cohort study of a Japanese population. We surveyed 8,552 individuals over 40 years of age living in a town in Saitama prefecture on their living habits, including daily consumption of green tea. During the 9 years of follow-up study (71,248.5 person-years), we identified a total of 384 cases of cancer in all sites.Results.We found a negative association between green tea consumption and cancer incidence, especially among females drinking more than 10 cups a day. The slowdown in increase of cancer incidence with age observed among females who consumed more than 10 cups a day is consistent with the finding that increased consumption of green tea is associated with later onset of cancer. Age-standardized average annual incidence rate was significantly lower among females who consumed large amounts of green tea. Relative risk (RR) of cancer incidence was also lower among both females (RR = 0.57, 95% CI = 0.33–0.98) and males (RR = 0.68, 95% CI = 0.39–1.21) in groups with the highest consumption, although the preventive effects did not achieve statistical significance among males, even when stratified by smoking and adjusted for alcohol and dietary variables.Conclusion.Our epidemiological study showed that green tea has a potentially preventive effect against cancer among humans.     

Dietary factors and the risk of lung cancer in New Caledonia (South Pacific)

Our objective was to study the relations between the risk of lung cancer and dietary factors in New Caledonia, in the South Pacific. A population-based case-control study of respiratory cancers was conducted between 1993 and 1995 in New Caledonia; we analyzed data for 134 incident lung cancer cases (109 men and 25 women) and 295 controls (227 men and 68 women) who had completed a food frequency questionnaire. Odds ratios (ORs) associated with food and nutrient intakes were calculated with unconditional logistic regression, with adjustment for smoking, age, and ethnicity. Analyses were performed separately for men and women. Among men, no significant associations were observed with any foods, including vegetables and fruits. Nonetheless, high consumption of dark green leafy vegetables (highest vs. lowest tertile of intake) was associated with decreased risk (OR = 0.5, 95% confidence interval = 0.2-1.2, P for trend = 0.12), particularly among Melanesians (OR = 0.4, 95% confidence interval = 0.1-1.0, P for trend = 0.07). A similar protective effect was also suggested for high consumption of poultry (P for trend = 0.06) and fresh fish (P for trend = 0.08). No significant association was found with nutrients. Among women, the analyses concerned few subjects and were not informative. This study suggests that high consumption of dark green leafy vegetables may reduce the risk of lung cancer among men in this population.     

Coffee,Green Tea,and Caffeine Intake and Liver Cancer Risk: A Prospective Cohort Study

We aimed to investigate whether coffee, green tea, and caffeine intake are associated with liver cancer risk, using data of a prospective cohort study. This study included 30,824 participants (14,240 men and 16,584 women) aged 35 years or older in the Takayama study, which was launched on September 1, 1992. The consumption frequencies of coffee and green tea were assessed using a self-administered questionnaire. Caffeine intake was estimated from the consumption frequencies of caffeine-containing beverages and foods and their caffeine content per serving. The incidence of liver cancer was confirmed using regional population-based cancer registries. During the follow-up period of 16 years, a total of 172 participants developed liver cancer. The adjusted hazard ratios and 95% confidence intervals (CIs) in relation to coffee consumption were 0.65 (95% CI: 0.46–0.93) for less than once per day, 0.63 (95% CI: 0.39–1.02) for once per day, and 0.40 (95% CI: 0.20–0.79) for twice per day or more, compared with nondrinkers. No associations with green tea, black tea and caffeine intake were observed. The present study confirmed that coffee consumption significantly reduces liver cancer risk and raises the possibility that caffeine intake might not account for the association.