Meat subtypes and colorectal cancer risk: A pooled analysis of 6 cohort studies in Japan

Abstract

Red meat and processed meat have been suggested to increase risk of colorectal cancer (CRC), especially colon cancer. However, it remains unclear whether these associations differ according to meat subtypes or colon subsites. The present study addressed this issue by undertaking a pooled analysis of large population‐based cohort studies in Japan: 5 studies comprising 232 403 participants (5694 CRC cases) for analysis based on frequency of meat intake, and 2 studies comprising 123 635 participants (3550 CRC cases) for analysis based on intake quantity. Study‐specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using the Cox proportional hazards model and then pooled using the random effect model. Comparing the highest vs lowest quartile, beef intake was associated with an increased risk of colon cancer in women (pooled HR 1.20; 95% CI, 1.01‐1.44) and distal colon cancer (DCC) risk in men (pooled HR 1.30; 95% CI, 1.05‐1.61). Frequent intake of pork was associated with an increased risk of distal colon cancer in women (pooled HR 1.44; 95% CI, 1.10‐1.87) for “3 times/wk or more” vs “less than 1 time/wk”. Frequent intake of processed red meat was associated with an increased risk of colon cancer in women (pooled HR 1.39; 95% CI, 0.97‐2.00; P trend = .04) for “almost every day” vs “less than 1 time/wk”. No association was observed for chicken consumption. The present findings support that intake of beef, pork (women only), and processed red meat (women only) might be associated with a higher risk of colon (distal colon) cancer in Japanese.

An Overview of Gut Microbiota and Colon Diseases with a Focus on Adenomatous Colon Polyps

“…An unhealthy diet containing red meat, processed meat, fat, sugar, and alcohol is associated with an increased risk of colorectal cancer (CRC), which is, in most of cases, derived from ACPs [ 10 , 11 , 12 , 13 , 14 , 15 ]. Animal-based diets significantly contribute to changes in microbiota composition, development of inflammation, DNA damage, and impaired apoptosis when compared with plant-based diets [ 16 , 17 ].…”

Towards refining World Cancer Research Fund/American Institute for Cancer Research cancer prevention recommendations for red and processed meat intake: insights from Alberta’s Tomorrow Project cohort

“…A recent pooled analysis of six cohort studies in Japan explored differences in CRC risk across red meat and processed meat from red meat sources, and chicken. (17) The authors did not identify significant associations with high intakes of red meat and risk of CRC, however, processed meat from red meat sources was associated with an increased risk of CRC and colon cancer in women but not in men. Many studies evaluating processed meat have provided limited definitions of the source of processed meat, making it difficult to ascertain whether the observed associations are a result of intake of only processed red meat, or of processed meat from any source.…”

“…(1) There is a lot of variability in the way studies performing high vs. low intake risk analyses categorize intakes (ie., by tertiles, quartiles or quintiles), and as a result, associations with cancer may vary depending on the range of processed and red meat intake within the sample and the size of the study sample. (17)(18)(19) Other studies performing dose-response analyses have applied different increments of exposure which may also contribute to variability in cancer associations. (16) Studies utilizing larger intake cut-offs, such as adherence to the WCRF/AICR cut-off for red meat consumption (500 grams/per week) (5,54) may lack the sensitivity to identify associations, particularly with smaller numbers of events.…”

“…(15) The WCRF/AICR recommendations for red and processed meat consumption were not developed using evidence of a well-defined threshold exposure, but are intended to provide a balance between the advantages of consuming meat, which are sources of essential macronutrients and micronutrients, with the disadvantages of potential risk of carcinogenesis. (1) In effort to explore these relationships in greater detail, many epidemiological studies have examined dose-response relationships (16) and compared highest vs. lowest (tertiles, quartiles or quintiles) intakes (17)(18)(19) , adjusting for a varying range of known risk factors for cancer (20,21) , yet inconsistent associations across cancer subsites and between studies have prevented the refinement of current intake recommendations. Moreover, current evidence has yet to determine whether the carcinogenic effect of processed meat varies as a result of its origin.…”

Gastrointestinal Cancers: Racial and Ethnicity Differences

“…Also, gastric cancer incidence is usually highest among Asian/Paci c Islanders likely due to gene-environment interaction [1]. Many GI cancers present with higher risk within westernized countries, and the observed risk is suggested to originate from the more abundant availability of calories, red meat, and fat, and subsequent interaction with the gut microbiome [15].…”