Cancer deaths and cases attributable to lifestyle factors and infections in China, 2013.

BACKGROUND: The burden of cancer in China is high, and it is expected to further increase. Information on cancers attributable to potentially modifiable risk factors is essential in planning preventive measures against cancer. We estimated the number and proportion of cancer deaths and cases attributable to ever-smoking, second-hand smoking, alcohol drinking, low fruit/vegetable intake, excess body weight, physical inactivity, and infections in China, using contemporary data from nationally representative surveys and cancer registries. METHODS: The number of cancer deaths and cases in 2013 were obtained from the National Central Cancer Registry of China and data on most exposures were obtained from the China National Nutrition and Health Survey 2002 or 2006 and Global Adult Tobacco Smoking 2010. We used a bootstrap simulation method to calculate the number and proportion of cancer deaths and cases attributable to risk factors and their corresponding 95% confidence intervals (CIs), allowing for uncertainty in data. RESULTS: Approximately 718 000 (95% CI 702 100-732 200) cancer deaths in men and 283 100 (278 800-288 800) cancer deaths in women were attributable to the studied risk factors, accounting for 52% of all cancer deaths in men and 35% in women. The numbers for incident cancer cases were 952 500 (95% CI 934 200-971 400) in men and 442 700 (437 200-447 900) in women, accounting for 47% of all incident cases in men and 28% in women. The greatest proportions of cancer deaths attributable to risk factors were for smoking (26%), HBV infection (12%), and low fruit/vegetable intake (7%) in men and HBV infection (7%), low fruit/vegetable intake (6%), and second-hand smoking (5%) in women. CONCLUSIONS: Effective public health interventions to eliminate or reduce exposure from these risk factors, notably tobacco control and vaccinations against carcinogenic infections, can have considerable impact on reducing the cancer burden in China.

Hypertension and mortality in the Golestan Cohort Study: A prospective study of 50 000 adults in Iran.

High blood pressure has been the second most important determinant of disease burden in Iran since the 1990s. Despite well-recognized evidence on the association of high blood pressure and mortality in other countries, this relationship has not been fully investigated in the demographic setting of Iran. The current study is the first large-scale longitudinal study of this association in Iran. Briefly, 50 045 subjects between 40 and 75 years of age have been recruited and followed. Blood pressure measurements were carried out at baseline. Causes of death were reported and verified by verbal autopsy throughout the follow-up period. The outcomes of interest were all-cause deaths and deaths due to ischemic heart disease (IHD) or stroke. Cox proportional hazards regression models were used to estimate hazard ratios (HRs). A total of 46 674 subjects free from cardiovascular disease at baseline were analyzed. Absolute mortality rates increased along with increasing systolic or diastolic blood pressure above 120 and 80 mm Hg, respectively. Adjusted HRs (95% confidence intervals) for each 20 mm Hg increase in systolic blood pressure in all age groups were 1.18 (1.13-1.23) for all-cause mortality, 1.21 (1.13-1.31) for deaths due to IHD and 1.50 (1.39-1.63) for deaths due to stroke. Unadjusted and adjusted HRs were higher in younger subjects and decreased with increasing age of the participants. High blood pressure is a serious threat to the health of Iranians. The entire health-care system of Iran should be involved in a comprehensive action plan for controlling blood pressure.

Breastfeeding and breast cancer risk by receptor status--a systematic review and meta-analysis.

BACKGROUND: Breastfeeding is inversely associated with overall risk of breast cancer. This association may differ in breast cancer subtypes defined by receptor status, as they may reflect different mechanisms of carcinogenesis. We conducted a systematic review and meta-analysis of case-control and prospective cohort studies to investigate the association between breastfeeding and breast cancer by estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) status. DESIGN: We searched the PubMed and Scopus databases and bibliographies of pertinent articles to identify relevant articles and used random-effects models to calculate summary odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: This meta-analysis represents 27 distinct studies (8 cohort and 19 case-control), with a total of 36 881 breast cancer cases. Among parous women, the risk estimates for the association between ever (versus never) breastfeeding and the breast cancers negative for both ER and PR were similar in three cohort and three case-control studies when results were adjusted for several factors, including the number of full-term pregnancies (combined OR 0.90; 95% CI 0.82-0.99), with little heterogeneity and no indication of publication bias. In a subset of three adjusted studies that included ER, PR, and HER2 status, ever breastfeeding showed a stronger inverse association with triple-negative breast cancer (OR 0.78; 95% CI 0.66-0.91) among parous women. Overall, cohort studies showed no significant association between breastfeeding and ER+/PR+ or ER+ and/or PR+ breast cancers, although one and two studies (out of four and seven studies, respectively) showed an inverse association. CONCLUSIONS: This meta-analysis showed a protective effect of ever breastfeeding against hormone receptor-negative breast cancers, which are more common in younger women and generally have a poorer prognosis than other subtypes of breast cancer. The association between breastfeeding and receptor-positive breast cancers needs more investigation.

Family history of cancer and the risk of squamous cell carcinoma of oesophagus: a case-control study in Kashmir, India.

BACKGROUND: Only a few studies have examined the association between family history of cancer (FHC) and the risk of oesophageal squamous cell carcinoma (ESCC) in high incidence areas of ESCC. We conducted a case-control study to evaluate the relationship between FHC and ESCC risk in Kashmir, India, with analysis of detailed epidemiological data and information on multiple gene polymorphisms. METHODS: We collected detailed information on FHC and a number of socio-demographic and lifestyle factors, and also obtained blood samples for genetic analysis from 703 histopathologically confirmed ESCC cases and 1664 individually matched controls. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). RESULTS: Participants who had FHC showed a strong association with ESCC risk, and the risk was stronger when first-degree relatives (FDRs) had FHC (OR=6.8; 95% CI=4.6-9.9). Having a sibling with a cancer showed the strongest association (OR=10.8; 95% CI=6.0-19.3), but having a child with a cancer was not associated with ESCC risk. A history of any cancer in the spouse was also associated with ESCC risk (OR=4.1; 95% CI=1.6-10.2). Those with two or more relatives with FHC were at a higher risk of ESCC. After restricting FHC to familial ESCC only, the above associations were strengthened, except when spouses were affected with ESCC (OR=2.5; 95% CI=0.7-8.9). When we examined the associations between several single-nucleotide polymorphisms and ESCC in those with and without FHC, the associations of variant genotypes in cytochrome P450 (CYP) 2C19 and CYP2D6 and the wild genotype of CYP2E1 with ESCC were much stronger in those with FHC. The FHC had an additive interaction with several risk factors of ESCC in this population. CONCLUSION: Our results showed that FHC was strongly associated with ESCC risk in Kashmir. It seems both genetic factors and shared environment are involved in this association.

Alcohol consumption and site-specific cancer risk: a comprehensive dose-response meta-analysis.

BACKGROUND: Alcohol is a risk factor for cancer of the oral cavity, pharynx, oesophagus, colorectum, liver, larynx and female breast, whereas its impact on other cancers remains controversial. METHODS: We investigated the effect of alcohol on 23 cancer types through a meta-analytic approach. We used dose-response meta-regression models and investigated potential sources of heterogeneity. RESULTS: A total of 572 studies, including 486 538 cancer cases, were identified. Relative risks (RRs) for heavy drinkers compared with nondrinkers and occasional drinkers were 5.13 for oral and pharyngeal cancer, 4.95 for oesophageal squamous cell carcinoma, 1.44 for colorectal, 2.65 for laryngeal and 1.61 for breast cancer; for those neoplasms there was a clear dose-risk relationship. Heavy drinkers also had a significantly higher risk of cancer of the stomach (RR 1.21), liver (2.07), gallbladder (2.64), pancreas (1.19) and lung (1.15). There was indication of a positive association between alcohol consumption and risk of melanoma and prostate cancer. Alcohol consumption and risk of Hodgkin's and Non-Hodgkin's lymphomas were inversely associated. CONCLUSIONS: Alcohol increases risk of cancer of oral cavity and pharynx, oesophagus, colorectum, liver, larynx and female breast. There is accumulating evidence that alcohol drinking is associated with some other cancers such as pancreas and prostate cancer and melanoma.

Alcohol drinking and cutaneous melanoma risk: a systematic review and dose-risk meta-analysis.

It has been suggested that alcohol intake increases sunburn severity, a major risk factor for cutaneous melanoma (CM). Several epidemiological studies have investigated the relationship between alcohol consumption and CM, but the evidence is inconsistent. Therefore, we aimed to quantify this relationship better, using a meta-analytical approach. The dose-risk relationship was also modelled through a class of flexible nonlinear meta-regression random effects models. The present meta-analysis included 16 studies (14 case-control and two cohort investigations) with a total of 6251 cases of CM. The pooled relative risk (RR) for any alcohol drinking compared with no/occasional drinking was 1·20 [95% confidence interval (CI) 1·06-1·37]. The risk estimate was similar in case-control (RR 1·20, 95% CI 1·01-1·44) and cohort studies (RR 1·26, 95% CI 1·19-1·35). The pooled RR was 1·10 (95% CI 0·96-1·26) for light alcohol drinking (≤ 1 drink per day) and 1·18 (95% CI 1·01-1·40) for moderate-to-heavy drinking. The pooled RR from 10 studies adjusting for sun exposure was 1·15 (95% CI 0·94-1·41), while the RR from six unadjusted studies was 1·27 (95% CI 1·20-1·35). No evidence of publication bias was detected. This meta-analysis of published data reveals that alcohol consumption is positively associated with the risk of CM. However, caution in interpreting these results is required, as residual confounding by sun exposure cannot be ruled out.

Poor oral hygiene and risk of esophageal squamous cell carcinoma in Kashmir.

BACKGROUND: Several studies have suggested an association between poor oral health and esophageal squamous cell carcinoma (ESCC). We conducted a case-control study in Kashmir, a region with relatively high incidence of ESCC in north India, to investigate the association between oral hygiene and ESCC risk. METHODS: We recruited 703 histologically confirmed ESCC cases, and 1664 controls individually matched to the cases for age, sex, and district of residence. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: We found an inverse association between teeth cleaning and ESCC risk. As compared with never cleaning teeth, the OR (95% CI) was 0.41 (0.28-0.62) for cleaning less than daily and 0.44 (0.25-0.77) for cleaning at least once a day (P for trend=0.026) in models adjusted for multiple potential confounders, including several indicators of socioeconomic status. This association persisted after we limited our analyses to never tobacco users. The inverse association between cleaning teeth and ESCC was stronger with using brushes than with using sticks/fingers. We also found an association between the number of decayed, filled, and missing teeth and ESCC risk, but the trend of the associations was not statistically significant. Avoiding solid food and cold beverages because of teeth and oral problems were also associated with ESCC risk. CONCLUSION: We found an association between poor oral hygiene indicators and ESCC risk, supporting the previous studies that showed the same associations.

Light alcohol drinking and cancer: a meta-analysis.

BACKGROUND: There is convincing evidence that alcohol consumption increases the risk of cancer of the colorectum, breast, larynx, liver, esophagus, oral cavity and pharynx. Most of the data derive from studies that focused on the effect of moderate/high alcohol intakes, while little is known about light alcohol drinking (up to 1 drink/day). PATIENTS AND METHODS: We evaluated the association between light drinking and cancer of the colorectum, breast, larynx, liver, esophagus, oral cavity and pharynx, through a meta-analytic approach. We searched epidemiological studies using PubMed, ISI Web of Science and EMBASE, published before December 2010. RESULTS: We included 222 articles comprising ∼92 000 light drinkers and 60 000 non-drinkers with cancer. Light drinking was associated with the risk of oropharyngeal cancer [relative risk, RR = 1.17; 95% confidence interval (CI) 1.06-1.29], esophageal squamous cell carcinoma (SCC) (RR = 1.30; 95% CI 1.09-1.56) and female breast cancer (RR = 1.05; 95% CI 1.02-1.08). We estimated that ∼5000 deaths from oropharyngeal cancer, 24 000 from esophageal SCC and 5000 from breast cancer were attributable to light drinking in 2004 worldwide. No association was found for colorectum, liver and larynx tumors. CONCLUSIONS: Light drinking increases the risk of cancer of oral cavity and pharynx, esophagus and female breast.

The contribution of molecular epidemiology to the identification of human carcinogens: current status and future perspectives.

BACKGROUND: The use of biological-based markers of exposure, intermediate effect, outcome, and susceptibility has become standard practice in cancer epidemiology, which has contributed to identification of several carcinogenic agents. Nevertheless, with the exception of biological agents, this contribution, in terms of providing sufficiently strong evidence as required by the International Agency for Research on Cancer (IARC) monographs, has been modest. MATERIALS AND METHODS: We discuss the overall contribution of molecular epidemiology to identification of carcinogens, with focus on IARC monographs. RESULTS: For many carcinogens, valid biological markers of exposure and mechanisms of actions are not available. Molecular markers are usually assessed in single biological samples, which may not represent the actual exposure or biological events related to carcinogens. The contribution of molecular epidemiology to identification of carcinogens has mainly been limited to the carcinogens acting through a genotoxic mechanism, i.e. when carcinogens induce DNA damage. A number of factors, including certain hormones and overweight/obesity, may show carcinogenic effects through nongenotoxic pathways, for which mechanisms of carcinogenicity are not well identified and their biomarkers are sparse. CONCLUSION: Longitudinal assessment of biomarkers may provide more informative data in molecular epidemiology studies. For many carcinogens and mechanistic pathways, in particular nongenotoxic carcinogenicity, valid biological markers still need to be identified.

A meta-analysis of alcohol drinking and oral and pharyngeal cancers: results from subgroup analyses.

AIMS: To quantify the magnitude of the association between alcohol and oral and pharyngeal cancer (OPC) by sex, smoking habits, type of alcoholic beverage and other factors. METHODS: We combined findings from all case-control and cohort studies published until September 2010 and present in this article the results classified by these factors, using a meta-analytic approach. Summary relative risks (RRs) were obtained using random-effects models; heterogeneity was assessed using the χ(2) test. RESULTS: The association between alcohol and OPC risk was similar in men and women, with similar dose-response relationships. No notable differences were found with respect to geographic area and other factors, both for drinking overall and heavy (≥4 drinks/day) drinking. Among never/non-current smokers, the pooled RRs were 1.32 (95% confidence interval, CI, 1.05-1.67) for drinking, and 2.54 (95% CI, 1.80-3.58) for heavy drinking. The corresponding RRs in smokers were 2.92 (95% CI, 2.31-3.70) and 6.32 (95% CI, 5.05-7.90). The pooled RRs for any drinking irrespective of smoking were 2.12 (95% CI, 1.37-3.29) for wine-, 2.43 (95% CI, 1.92-3.07) for beer- and 2.30 (95% CI, 1.78-2.98) for spirits-only drinking. The corresponding RRs for heavy drinking were 4.92 (95% CI, 2.80-8.65), 4.20 (95% CI, 1.43-12.38) and 5.20 (95% CI, 2.77-9.78). CONCLUSION: The alcohol-related RRs are similar with respect to sex, geographic area and type of alcoholic beverage. The association between alcohol and OPC is stronger in smokers than in non-smokers.

Hookah smoking, nass chewing, and oesophageal squamous cell carcinoma in Kashmir, India.

BACKGROUND: Although cigarette smoking is an established risk factor for oesophageal squamous cell carcinoma (ESCC), there is little information about the association between other smoking and smokeless tobacco products, including hookah and nass, and ESCC risk. We conducted a case-control study in Kashmir Valley, India, where hookah smoking, nass chewing, and ESCC are common, to investigate the association of hookah smoking, nass use, and several other habits with ESCC. METHODS: We recruited 702 histologically confirmed ESCC cases and 1663 hospital-based controls, individually matched to the cases for age, sex, and district of residence from September 2008 to January 2012. Conditional logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs). RESULTS: Ever-hookah smoking (OR=1.85; 95% CI, 1.41-2.44) and nass chewing (OR=2.88; 95% CI, 2.06-4.04) were associated with ESCC risk. These associations were consistent across different measures of use, including intensity, duration, and cumulative amount of use, and after excluding ever users of the other product and cigarette smokers. Our results also suggest an increased risk of ESCC associated with ever-gutka chewing and -bidi smoking. However, the latter associations were based on small number of participants. CONCLUSION: This study shows that hookah and nass use are associated with ESCC risk. As prevalence of hookah use seems to be increasing among young people worldwide, these results may have relevance not only for the regions in which hookah use has been a traditional habit, but also for other regions, including western countries.

Gastric atrophy and oesophageal squamous cell carcinoma: possible interaction with dental health and oral hygiene habit.

BACKGROUND: Gastric fundal atrophy has been hypothesised to increase the risk of oesophageal squamous cell carcinoma (OSCC), but studies have shown inconsistent results. METHODS: We measured serum pepsinogen I (PGI) and pepsinogen II (PGII) among 293 incident cases and 524 matched neighbourhood controls in a high-risk area of Northern Iran. Conditional logistic regression model was used to estimate odds ratios (ORs) and their 95% confidence intervals (CIs). RESULTS: After controlling for age, sex, residence area and other potential confounders, gastric atrophy (defined by a validated criterion, PGI <55 µg dl(-1)) was associated with a two-fold increased risk (OR=2.01, 95% CI: 1.18, 3.45) of OSCC in the absence of nonatrophic pangastritis (defined as PGII <11.8 µg dl(-1)). Stratification by PGII decreased the misclassification errors due to cancer-induced gastritis. Presence of both poor dental health, indicated by higher than median sum of decayed, missing, and filled teeth (DMFT score), and gastric atrophy further increased the risk of OSCC (OR=4.15, 95% CI: 2.04, 8.42) with relative excess risk due to interaction (RERI) of 1.47 (95% CI: -1.15, 4.1). Coexistence of poor oral hygiene habit with gastric atrophy elevated OSCC risk eight times (OR=8.65, 95% CI: 3.65, 20.46) and the additive interaction index was marginally statistically significant (RERI=4.34, 95% CI: -1.07, 9.76). CONCLUSION: Gastric atrophy is a risk factor for OSCC, and poor dental health and oral hygiene habit may act synergistically in increasing the risk.

Alcohol drinking and non-Hodgkin lymphoma risk: a systematic review and a meta-analysis.

BACKGROUND: Whether an association between alcohol drinking and non-Hodgkin lymphoma (NHL) risk exists is an open question. In order to provide quantification of the issue, we carried out a meta-analysis of published data. METHODS: We identified 21 case-control and 8 cohort studies, including a total of 18,759 NHL cases. We derived meta-analytic estimates using random-effects models, taking into account correlation between estimates. RESULTS: The overall relative risk (RR) of NHL for drinkers versus non-drinkers was 0.85 [95% confidence interval (CI) 0.79-0.91]. Compared with non-drinkers, the pooled RRs were 0.88 for light (≤1 drink per day), 0.87 for moderate (1 to <4 drinks per day), and 0.84 for heavy (≥4 drinks per day) alcohol drinking. There was no association for light drinkers in cohort studies, whereas for moderate and heavy drinkers, the RRs were similar in case-control (0.85 for moderate, 0.92 for heavy) and cohort (0.89 for moderate, 0.79 for heavy) studies. The inverse relation with alcohol consumption (drinkers versus non-drinkers) was similar in men (RR = 0.83) and women (RR = 0.86), but apparently stronger in studies from Asia (RR = 0.69) than other world areas (RR = 0.88). CONCLUSION: This meta-analysis provides quantitative evidence of a favourable role of alcohol drinking on NHL risk, though the lack of a biological explanation suggests caution in the interpretation of results.

Alcohol drinking and bladder cancer risk: a meta-analysis.

BACKGROUND: We aimed at investigating the risk of bladder cancer at different levels of alcohol consumption by conducting a meta-analysis of epidemiological studies. PATIENTS AND METHODS: In October 2010, we carried out a systematic literature search in the Medline database, using PubMed. We identified 16 case-control and 3 cohort studies, including a total of 11 219 cases of bladder cancer, satisfying the inclusion criteria for this meta-analysis. Moderate alcohol intake was defined as <3 drinks per day (i.e. <37.5 g of ethanol per day) and heavy intake as ≥3 drinks/day. Pooled estimates of the relative risks (RR) and the corresponding 95% confidence intervals (CI) were calculated using random effects models. RESULTS: Compared with non-drinkers, the pooled RRs of bladder cancer were 1.00 (95% CI 0.92-1.09) for moderate and 1.02 (95% CI 0.78-1.33) for heavy alcohol drinkers. When we excluded four studies that did not adjust for tobacco smoking, the corresponding estimates were 0.98 (95% CI 0.89-1.07) and 0.97 (95% CI 0.72-1.31). CONCLUSIONS: This meta-analysis of epidemiological studies provides definite evidence on the absence of any material association between alcohol drinking and bladder cancer risk, even at high levels of consumption.

Large body size and sedentary lifestyle during childhood and early adulthood and esophageal squamous cell carcinoma in a high-risk population.

BACKGROUND: Little is known about the association of obesity and physical activity at young ages with subsequent risk of esophageal squamous cell carcinoma (ESCC). PATIENTS AND METHODS: Between 2003 and 2007, we conducted a case-control study in a high-risk population in northeastern Iran. Three hundred ESCC cases and 571 matched controls were recruited. Each individual was shown a standard pictogram, to report body size at ages 15 and 30. Demographic and health-related information, including physical activity at these ages was also collected. RESULTS: In the fully adjusted models, very obese body size (last two pictograms) at age 15 [odds ratio (OR) 3.2, 95% confidence interval (CI) 1.3-7.7] and age 30 (OR 3.1; 95% CI 1.1-8.5) were associated with ESCC in women, but not in men. Sedentary work at age 15 (OR 3.3, 95% CI 1.3-8.3) and 30 (OR 18.2, 95% CI 3.9-86.2) were also associated with ESCC risk in women only. The increased risk in women at age 15 remained high after later reduction in body size, while women who became very obese only at age 30 did not show a significantly increased risk. CONCLUSION: These results highlight the importance of early lifestyle modifications in the context of cancer prevention, particularly in women.

A meta-analysis on alcohol drinking and esophageal and gastric cardia adenocarcinoma risk.

BACKGROUND: In order to provide a precise quantification of the association between alcohol drinking and esophageal and gastric cardia adenocarcinoma risk, we conducted a meta-analysis of available data. PATIENTS AND METHODS: We identified 20 case-control and 4 cohort studies, including a total of 5500 cases. We derived meta-analytic estimates using random-effects models, taking into account correlation between estimates, and we carried out a dose-risk analysis using nonlinear random-effects meta-regression models. RESULTS: The relative risk (RR) for drinkers versus nondrinkers was 0.96 [95% confidence interval (CI) 0.85-1.09] overall, 0.87 (95% CI 0.74-1.01) for esophageal adenocarcinoma and 0.89 (95% CI 0.76-1.03) for gastric cardia adenocarcinoma. Compared with nondrinkers, the pooled RRs were 0.86 for light (≤ 1 drink per day), 0.90 for moderate (1 to < 4 drinks per day), and 1.16 for heavy (≥ 4 drinks per day) alcohol drinking. The dose-risk model found a minimum at 25 g/day, and the curve was < 1 up to 70 g/day. CONCLUSIONS: This meta-analysis provides definite evidence of an absence of association between alcohol drinking and esophageal and gastric cardia adenocarcinoma risk, even at higher doses of consumption.

A meta-analysis on alcohol drinking and gastric cancer risk.

BACKGROUND: Whether an association between alcohol drinking and gastric cancer risk exists is an open question. In order to provide a definite quantification of the association between alcohol drinking and gastric cancer risk, we conducted a meta-analysis of available data. PATIENTS AND METHODS: We carried out a PubMed search of articles published up to June 2010 and identified 44 case-control and 15 cohort studies, including a total of 34 557 gastric cancer cases. We derived meta-analytic estimates using random-effects models, taking into account correlation between estimates. We carried out a dose-risk analysis using nonlinear random-effects meta-regression models. RESULTS: Compared with nondrinkers, the pooled relative risk (RR) was 1.07 [95% confidence interval (CI) 1.01-1.13] for alcohol drinkers and 1.20 (95% CI 1.01-1.44) for heavy alcohol drinkers (≥4 drinks per day). The pooled estimates were apparently higher for gastric noncardia (RR for heavy drinkers=1.17, 95% CI 0.78-1.75) than for gastric cardia (RR=0.99, 95% CI 0.67-1.47) adenocarcinoma. The dose-risk model estimated a RR of 0.95 (95% CI 0.91-0.99) for 10 g/day and 1.14 (95% CI 1.08-1.21) for 50 g/day. CONCLUSIONS: This meta-analysis provides definite evidence of a lack of association between moderate alcohol drinking and gastric cancer risk. There was, however, a positive association with heavy alcohol drinking.

Alcohol drinking and colorectal cancer risk: an overall and dose-response meta-analysis of published studies.

BACKGROUND: The International Agency for Research on Cancer (IARC) concluded that alcohol consumption is related to colorectal cancer (CRC). However, several issues remain unresolved, including quantification of the association for light (≤1 drink/day) and moderate (2-3 drinks/day) alcohol drinking, investigation of the dose-response relationship, and potential heterogeneity of effects by sex, colorectal site, and geographical region. METHODS: Twenty-seven cohort and 34 case-control studies presenting results for at least three categories of alcohol intake were identified from a PubMed search of articles published before May 2010. The summary relative risks (RRs) were estimated by the random effects model. Second-order fractional polynomials and random effects meta-regression models were used for modeling the dose-risk relation. RESULTS: The RRs were 1.21 [95% confidence interval (CI) 1.13-1.28] for moderate and 1.52 (95% CI 1.27-1.81) for heavy (≥4 drinks/day) alcohol drinking. The RR for moderate drinkers, compared with non-/occasional drinkers, was stronger for men (RR = 1.24, 95% CI 1.13-1.37) than for women (RR = 1.08, 95% CI 1.03-1.13; P(heterogeneity) = 0.02). For heavy drinkers, the association was stronger in Asian studies (RR = 1.81, 95% CI 1.33-2.46; P(heterogeneity) = 0.04). The dose-risk analysis estimated RRs of 1.07 (95% CI 1.04-1.10), 1.38 (95% CI 1.28-1.50), and 1.82 (95% CI 1.41-2.35) for 10, 50, and 100 g/day of alcohol, respectively. CONCLUSIONS: This meta-analysis provides strong evidence for an association between alcohol drinking of >1 drink/day and colorectal cancer risk.

Gastric atrophy and risk of oesophageal cancer and gastric cardia adenocarcinoma--a systematic review and meta-analysis.

BACKGROUND: Several studies have reported an association between gastric atrophy and upper gastrointestinal cancers. Our aim was to summarise the available information and calculate the relative risks (RRs) associated with gastric atrophy for gastric cardia adenocarcinoma (GCA), oesophageal squamous cell carcinoma (OSCC), and oesophageal adenocarcinoma (OAC) by conducting a systematic review and meta-analysis. METHODS: We searched the PubMed and ISI-Web of Science databases, as well as the reference lists of the relevant articles. Summary RRs and 95% confidence intervals (95% CI) were calculated using random-effects models for the association between gastric atrophy, defined histologically or by serum pepsinogen markers, and OSCC, OAC, and GCA. RESULTS: Eighteen articles were included in the meta-analysis; 13, 7, and 3 studies reported on GCA, OSCC, and OAC, respectively. The overall RRs (95% CI) for the three cancer types were: GCA, 2.89 (2.09-3.98); OSCC, 1.94 (1.48-2.55); OAC, 0.51 (0.19-1.37). Several subgroup analyses showed the robustness of the results. In the majority of the analyses, there was low to moderate heterogeneity. CONCLUSIONS: This study found two- to threefold increased risk of OSCC and GCA but a possible reduced risk of OAC in people with gastric atrophy. Further studies are needed to establish the association with OAC and causal association with OSCC, and mechanisms of the increased risk need to be investigated for GCA.