Red and Processed Meat and Colorectal Cancer Incidence: Meta-Analysis of Prospective Studies

Abstract

BackgroundThe evidence that red and processed meat influences colorectal carcinogenesis was judged convincing in the 2007 World Cancer Research Fund/American Institute of Cancer Research report. Since then, ten prospective studies have published new results. Here we update the evidence from prospective studies and explore whether there is a non-linear association of red and processed meats with colorectal cancer risk.Methods and FindingsRelevant prospective studies were identified in PubMed until March 2011. For each study, relative risks and 95% confidence intervals (CI) were extracted and pooled with a random-effects model, weighting for the inverse of the variance, in highest versus lowest intake comparison, and dose-response meta-analyses. Red and processed meats intake was associated with increased colorectal cancer risk. The summary relative risk (RR) of colorectal cancer for the highest versus the lowest intake was 1.22 (95% CI = 1.11−1.34) and the RR for every 100 g/day increase was 1.14 (95% CI = 1.04−1.24). Non-linear dose-response meta-analyses revealed that colorectal cancer risk increases approximately linearly with increasing intake of red and processed meats up to approximately 140 g/day, where the curve approaches its plateau. The associations were similar for colon and rectal cancer risk. When analyzed separately, colorectal cancer risk was related to intake of fresh red meat (RR for 100 g/day increase = 1.17, 95% CI = 1.05−1.31) and processed meat (RR for 50 g/day increase = 1.18, 95% CI = 1.10−1.28). Similar results were observed for colon cancer, but for rectal cancer, no significant associations were observed.ConclusionsHigh intake of red and processed meat is associated with significant increased risk of colorectal, colon and rectal cancers. The overall evidence of prospective studies supports limiting red and processed meat consumption as one of the dietary recommendations for the prevention of colorectal cancer.

Correlation of Cancer Incidence with Diet, Smoking and Socio-Economic Position Across 22 Districts of Tehran in 2008

“…Trichopoulou proposed that approximately up to 25% of the incidence of CRC, could be prevented if the population diet could transfer to the Mediterranean diet (Trichopoulou et al, 2000). The combined consumption of vegetables and fruit, high intake of fiber, fish, unsaturated fat, vitamins and calcium decrease the risk and high consumption of red or processed meat, smoked or salted fish actually appears to be harmful, which increase CRC risk (Jacobs et al, 2003;MarquesVidal et al, 2006;Bravi et al, 2010;Gonzalez and Riboli, 2010;Randi et al, 2010;Chan et al, 2011). Our results indicate that CRC was correlated with meat, dairy products and fruits adjusted for total energy and reverse correlation with bread and fat.…”

Red and processed meat intake and risk of colorectal adenomas: a systematic review and meta-analysis of epidemiological studies

“…1.05, 1.31), although for processed meat the results for adenomas are stronger, summary RR=1.45 (1.10, 1.90, n=2) for colorectal adenomas vs. 1.18 (95% CI: 1.10, 1.28, n=9) for colorectal cancer, however, there were only 2 cohort studies in the analysis of colorectal adenomas, thus this difference might have been due to chance (9).…”

“…Screening for colorectal adenomas and removal of such adenomas by colonoscopy is an important strategy to reduce colorectal cancer risk (4). Although lifestyle factors are considered to be of major importance in colorectal cancer etiology (5)(6)(7)(8)(9), less is known about how such factors are related to risk of colorectal adenomas. Studying risk factors for colorectal adenomas could enhance our understanding of the early stages of colorectal carcinogenesis.…”

“…Red and processed meat intake were judged to be convincing risk factors for and processed meat intake and colorectal cancer in an updated meta-analysis of the evidence from prospective studies up to 2011 (9). However, the WCRF/AICR report did not find a significant association between red or processed meat intake and colorectal adenomas, but the number of studies assessed was modest (a total of 5 prospective studies, 4 case-control studies) (5).…”

From the Cover: PhIP/DSS-Induced Colon Carcinogenesis in CYP1A-Humanized Mice and the Possible Role of Lgr5+ Stem Cells

“…processed meat (American Cancer Society, 2014;Chan et al, 2011;Cross et al, 2010;Huxley et al, 2009). It is also one of the most serious complications of inflammatory bowel disease, such as ulcerative colitis and Crohn's disease (Eaden et al, 2001;van Hogezand et al, 2002).…”