Processed meat and colorectal cancer: a quantitative review of prospective epidemiologic studies

Abstract

A tremendous amount of scientific interest has been generated regarding processed meat consumption and cancer risk. Therefore, to estimate the association between processed meat intake and colorectal cancer (CRC), a meta-analysis of prospective studies was conducted. Twenty-eight prospective studies of processed meat and CRC were identified, of which 20 represented independent nonoverlapping study populations. Summary relative risk estimates (SRREs) for high versus low intake and dose-response relationships were calculated. The SRRE for high (vs. low) processed meat intake and CRC was 1.16 [95% confidence interval (CI): 1.10-1.23] for all studies. Summary associations were modified considerably by sex; the SRRE for men was 1.23 (95% CI: 1.07-1.42) and the SRRE for women was 1.05 (95% CI: 0.94-1.16), based on nine and 13 studies, respectively. Sensitivity analyses did not indicate appreciable statistical variation by tumor site, processed meat groups, or study location. The SRRE for each 30-gram increment of processed meat and CRC was 1.10 (95% CI: 1.05-1.15) based on nine studies, and the SRRE for each incremental serving of processed meat per week was 1.03 (95% CI: 1.01-1.05) based on six studies. Overall, summary associations were weak in magnitude (i.e. most less than 1.20), processed meat definitions and analytical comparisons were highly variable across studies, and isolating the independent effects of processed meat intake is difficult, given the likely influence of confounding by other dietary and lifestyle factors. Therefore, the currently available epidemiologic evidence is not sufficient to support a clear and unequivocal independent positive association between processed meat consumption and CRC.

Colorectal cancer in India: controversies, enigmas and primary prevention

“…There was little evidence of association between the food groups examined and risk for colorectal cancer: Odds ratios (95% confidence intervals) for a 50 g/day increase were 1.01 (0.84-1.22) for red meat and 0.88 (0.68-1.15) for processed meat [23]. Two other meta-analysis published recently have failed to show any significant association between red meat or processed meat and CRC [24,25]. A very recent systematic review of diet and cancer by Professor Key from Oxford University created a lot of media headlines because of the conclusion that overall, the data do not show a clear association between fruits and vegetables and the risk for colorectal cancer, although they are compatible with a small reduction in risk [26].…”

Comparison of Diets of Urban American Indian and Non-Hispanic Whites: Populations with a Disparity for Biliary Tract Cancer Rates

“…The AI consumed significantly more processed meat than NHW women. Processed meat consumption has been reported to increase the risk of development of other gastrointestinal tract cancers such as colorectal cancer, however a recent report showed that this may not be a strong association (Alexander et al, 2010;Miller et al, 2010). The AI had significantly higher BMI than NHW.…”

Red Meat Intake and Colorectal Cancer Risk: A Summary of Epidemiological Studies

“…This conclusion was received with some criticisms [15,16]. Two meta-analyses of prospective studies concluded that the available epidemiologic data were not sufficient to support an independent and unequivocal positive association [17,18]. The controversy concerned the possible presence of confounding from other lifestyle and dietary factors in the weak magnitude of association and the inconsistency of effect by cancer subsite and gender.…”