Red and processed meat consumption and colorectal cancer risk: a systematic review and meta-analysis

Abstract

The associations between red and processed meat consumption and the risk of colorectal cancer types have not been conclusively defined. We performed a systematic review and meta-analysis to analyze these associations. We searched PubMed and EMBASE to identify studies published from inception through September 2016. Dose-response, subgroup and subtype analyses of colorectal cancer (colon cancer, proximal colon cancer, distal colon cancer and rectal cancer) were performed. We ultimately selected 60 eligible studies. Positive associations were observed for colorectal cancer in case-control studies (red meat, P<0.01; processed meat, P<0.01) and cohort studies (red meat, P<0.01; processed meat, P<0.01). However, subtype analyses yielded null results for distal colon cancer in case-control studies (P=0.41) and cohort studies (P=0.18) for red meat and null results for proximal colon cancer in case-control studies (P=0.13) and cohort studies (P=0.39) for processed meat. Additionally, although the results of case-control studies were positive (red meat, P<0.01; processed meat, P=0.04) for rectal cancer, there were no positive associations between red (P=0.34) and processed meat (P=0.06) consumption and the risk in cohort studies. In a systematic review and meta-analysis, we found consumption of red and processed meat was associated with the risk of overall colorectal cancer but not rectal cancer. Additionally, there were no associations between the consumption of red meat and distal colon cancer risk and between the consumption of processed meat and proximal colon cancer risk.

Consumption of meat, traditional and modern processed meat and colorectal cancer risk among the Moroccan population: A large‐scale case–control study

“…No association between intake of red meat and risk for rectal cancer was observed. These findings are in line with a recent meta‐analysis published in 2017, in which a positive association between red and processed meat intake and the risk of overall CRC risk, has been reported, but not with rectal cancer risk …”

“…With regard to red meat consumption, the results of our study are aligned with several previous epidemiological studies showing a significant association between red meat and CRC risk and have been confirmed by the IARC and WCRF…”

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

“…We found an increased risk of CRC or colon cancer with the frequent intake (almost every day) of processed red meat and risk in women but not in men. Accumulating evidence from meta‐analyses consistently reported an increased risk of CRC with higher intake of processed red meat, although these studies did not present the association by sex. Our findings were also compatible with a recent meta‐analysis of 2 large cohorts (the Nurses’ Health Study and Health Professional Follow‐Up Study), which reported an increased risk of CRC associated with higher intake of processed red meat (>5 vs ≤1 serving/wk) .…”

“…In contrast, a recent prospective study in the Swedish population reported that pork intake was associated with an increased risk of colon cancer, whereas beef intake was associated with a decreased risk of colon cancer . Additionally, few studies examined meat‐CRC risk association by subsites of the colon …”

“…18 Additionally, few studies examined meat-CRC risk association by subsites of the colon. 19,20 In Japan, CRC is the third most common cancer type in men and the second in women. 21 In spite of westernization of lifestyle and diet, 22 the amount of red meat intake is still much lower than that of populations in Europe and America.…”