Consumption of red and processed meat and breast cancer incidence: A systematic review and meta‐analysis of prospective studies

Abstract

Prior studies on red and processed meat consumption with breast cancer risk have generated inconsistent results. We performed a systematic review and meta-analysis of prospective studies to summarize the evidence regarding the relation of red meat and processed meat consumption with breast cancer incidence. We searched in MEDLINE and EMBASE databases through January 2018 for prospective studies that reported the association between red meat and processed meat consumption with incident breast cancer. The multivariable-adjusted relative risk (RR) was combined comparing the highest with the lowest category of red meat (unprocessed) and processed meat consumption using a random-effect meta-analysis. We identified 13 cohort, 3 nested case-control and two clinical trial studies. Comparing the highest to the lowest category, red meat (unprocessed) consumption was associated with a 6% higher breast cancer risk (pooled RR,1.06; 95% confidence intervals (95%CI):0.99-1.14; I = 56.3%), and processed meat consumption was associated with a 9% higher breast cancer risk (pooled RR, 1.09; 95%CI, 1.03-1.16; I = 44.4%). In addition, we identified two nested case-control studies evaluating the association between red meat and breast cancer stratified by N-acetyltransferase 2 acetylator genotype. We did not observe any association among those with either fast (per 25 g/day pooled odds ratio (OR), 1.18; 95%CI, 0.93-1.50) or slow N-acetyltransferase 2 acetylators (per 25 g/day pooled OR, 0.99; 95%CI, 0.91-1.08). In the prospective observational studies, high processed meat consumption was associated with increased breast cancer risk.

Association between meat consumption and risk of breast cancer: Findings from the Sister Study

“…To the best of our knowledge, four cohort studies 25,27,35,39,40 and one pooled case-control analysis 31 examined meat consumption and breast cancer risk by ER status with most finding no significant differences by ER status. 5 Our findings are consistent with past literature as we found that there was no significant heterogeneity in meat-associated breast cancer risk by ER status.…”

“…Anderson et al reported no association between red meat consumption and breast cancer risk in a meta-analysis of 11 prospective cohorts, whereas Farvid et al reported borderline significant positive associations between red meat consumption and breast cancer risk in a meta-analysis of 13 cohort, 3 nested case-control and 2 clinical trial studies. 4,5 An association between red meat and breast cancer may be due to dietary heme iron, fat and N-glycolylneuraminic acid as these compounds found in red meat are indicated to possibly increase tumor formation. 6 However, we did not find significant association between quartiles of heme iron and breast cancer risk in the present study (Table 4).…”

“…In 2015, the International Agency for Research on Cancer (IARC) evaluated the carcinogenicity of red meat consumption and announced that it is “probably carcinogenic to humans” (Group 2A) . Meat consumption has been indicated to increase the risk of breast cancer in ecological studies, but in several cohort studies, this association has not been consistent …”

“…3 Meat consumption has been indicated to increase the risk of breast cancer in ecological studies, but in several cohort studies, this association has not been consistent. 2,[4][5][6] Cooking methods and doneness of meat are likely to modify or mediate the magnitude of this association. 7 Certain cooking practices may be associated with higher risks of cancer, primarily through the exposure to mutagenic compounds such as polyaromatic hydrocarbons and heterocyclic amines related to meat preparation practices.…”

Reducing meat consumption by appealing to animal welfare: protocol for a meta-analysis and theoretical review

“…Excessive consumption of meat and animal products may be deleterious to human health (with meta-analytic evidence regarding cancer [1][2][3][4], cardiovascular disease [5][6][7], metabolic disease [8][9][10], obesity [11], stroke [12], and all-cause mortality [13], albeit sometimes subject to methodological limitations), promotes the emergence and spread of antibiotic-resistant pathogens [14], is a major source of greenhouse gas emissions and environmental degradation [15], and contributes to market demand for industry practices that cause the preventable suffering of more than one billion animals in the USA annually [16]. Therefore, developing simple, effective interventions to reduce meat consumption could carry widespread societal benefits.…”