Colorectal cancer is a major cause of cancer mortality and is considered to be largely attributable to inappropriate lifestyle and behavior patterns. The purpose of this review was to undertake a comparison of the strength of the associations between known and putative risk factors for colorectal cancer by conducting 10 independent meta-analyses of prospective cohort studies. Studies published between 1966 and January 2008 were identified through EMBASE and MEDLINE, using a combined text word and MESH heading search strategy. Studies were eligible if they reported estimates of the relative risk for colorectal cancer with any of the following: alcohol, smoking, diabetes, physical activity, meat, fish, poultry, fruits and vegetables. Studies were excluded if the estimates were not adjusted at least for age. Overall, data from 103 cohort studies were included. The risk of colorectal cancer was significantly associated with alcohol: individuals consuming the most alcohol had 60% greater risk of colorectal cancer compared with non-or light drinkers (relative risk 1.56, 95% CI 1.42-1.70). Smoking, diabetes, obesity and high meat intakes were each associated with a significant 20% increased risk of colorectal cancer (compared with individuals in the lowest categories for each) with little evidence of between-study heterogeneity or publication bias. Physical activity was protective against colorectal cancer. Public-health strategies that promote modest alcohol consumption, smoking cessation, weight loss, increased physical activity and moderate consumption of red and processed meat are likely to have significant benefits at the population level for reducing the incidence of colorectal cancer. ' UICCKey words: meta-analysis; colorectal cancer; lifestyle; smoking; alcohol Cancers of the colon and rectum (colorectal) constitute a significant proportion of the global burden of cancer morbidity and mortality, particularly in developed countries where these malignancies rank second in terms of both incidence and mortality, compared with fifth in less developed countries. 1 Annually, approximately 1 million new cases of colorectal cancer are diagnosed, and more than half a million people die from colorectal cancer, equivalent to approximately 8% of all cancer-related deaths worldwide. The occurrence of colorectal cancer varies at least 25-fold between countries 1,2 with the highest incidence rates for colorectal cancer seen in certain areas and ethnic groups in the United States, Canada, Japan and New Zealand.3 The wide geographical variation in incidence rates for colorectal cancer, and data from migrant studies, 4 suggest that lifestyle risk factors, including diet, 5,6 physical activity, 7 obesity 8 and diabetes, 9 play a pivotal role in the aetiology of the disease. 10 A high consumption of different processed foods and alcohol intakes have also been associated with a higher colorectal cancer risk. 11 The proportion of colorectal cancer attributed to dietary factors has been estimated to be about 50%.12 Further, approxim...

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BackgroundRecently, some US cohorts have shown a moderate association between red and processed meat consumption and mortality supporting the results of previous studies among vegetarians. The aim of this study was to examine the association of red meat, processed meat, and poultry consumption with the risk of early death in the European Prospective Investigation into Cancer and Nutrition (EPIC).MethodsIncluded in the analysis were 448,568 men and women without prevalent cancer, stroke, or myocardial infarction, and with complete information on diet, smoking, physical activity and body mass index, who were between 35 and 69 years old at baseline. Cox proportional hazards regression was used to examine the association of meat consumption with all-cause and cause-specific mortality.ResultsAs of June 2009, 26,344 deaths were observed. After multivariate adjustment, a high consumption of red meat was related to higher all-cause mortality (hazard ratio (HR) = 1.14, 95% confidence interval (CI) 1.01 to 1.28, 160+ versus 10 to 19.9 g/day), and the association was stronger for processed meat (HR = 1.44, 95% CI 1.24 to 1.66, 160+ versus 10 to 19.9 g/day). After correction for measurement error, higher all-cause mortality remained significant only for processed meat (HR = 1.18, 95% CI 1.11 to 1.25, per 50 g/d). We estimated that 3.3% (95% CI 1.5% to 5.0%) of deaths could be prevented if all participants had a processed meat consumption of less than 20 g/day. Significant associations with processed meat intake were observed for cardiovascular diseases, cancer, and 'other causes of death'. The consumption of poultry was not related to all-cause mortality.ConclusionsThe results of our analysis support a moderate positive association between processed meat consumption and mortality, in particular due to cardiovascular diseases, but also to cancer.

Background-Excess weight is an established risk factor for several cancers but there are sparse data from Asian populations in whom overweight and obesity is increasing rapidly and adiposity can be substantially greater for the same body mass index (BMI) compared to Caucasians.