(SOLVED) Compare and contrast the differences in relative risk (RR) between red mea
Compare and contrast the differences in relative risk (RR) between red meat consumption and breast cancer risk in case-control studies and cohort studies.Expert preview solution
Globally, breast cancer is the most common cancer among women and the second leading cause of cancer death. Given the international variations in breast cancer rates and trends, the importance of identifying modifiable lifestyle risk factors is widely acknowledged as a means to reduce breast cancer. Red meat is hypothesized to be an important dietary risk factor for several cancer sites, and provides a source of animal fat, heme iron and chemical carcinogens that may accumulate during cooking and/or processing. The International Agency for Research on Cancer (IARC) concluded that consumption of red meat (unprocessed) was a probable human carcinogen, whereas processed meat was classified as “carcinogenic to humans.” This classification was largely based on the evidence for colorectal, pancreas and prostate cancers for red meat and colorectal cancer for processed meat. Using pooled data from eight cohort studies, Missmer et al. observed a null association of red meat and processed meat consumption with breast cancer risk. However, in a recent meta-analysis of studies, Guo et al. provided evidence that red meat and processed meat consumption was associated with higher risk of breast cancer. In contrast, Anderson et al. reported that only processed meat might increase risk of breast cancer. However, the meta-analysis by Guo et al. had several limitations such as including some studies twice in the analysis as well as including a case–control study
Epidemiological studies assessing red meat and processed meat intake with risk of breast cancer based on menopausal status are limited and inconsistent, with most of the studies including largely postmenopausal women. In previously meta-analysis, higher processed meat was associated with higher risk of postmenopausal breast cancer, but not breast cancer before menopause. Moreover, breast cancer is a heterogeneous disease, and estrogen receptor positive breast tumors (ER+) are more strongly associated with hormone-related factors than estrogen receptor negative tumors (ER−), therefore, hormone residues of the exogenous hormones used in beef cattle may increase risk of ER+ tumors. However, the association of red meat consumption in relation to tumor hormone receptor status is not well-established and, to our knowledge, no prior meta-analyses have reviewed this association.
Heterocyclic amines (HCAs) are carcinogenic compounds that form in meat when cooking for a long duration at high temperature. N-acetyltransferase 2 (NAT2), an important enzyme in the biotransformation of aromatics and HCAs, is a polymorphic enzyme that segregates individuals into biochemical phenotypes, ranging from slow to fast acetylators. It is hypothesized that higher levels of DNA adducts are formed by O-acetylation of HCAs among NAT2 fast acetylators than among slow acetylators. Therefore, these differences in enzyme activity may modify the carcinogenic effect of red meat. However, regarding the interaction between meat consumption and NAT2 polymorphisms on risk of breast cancer, evidence in epidemiological studies is sparse and conflicting, and it has not been evaluated in published meta-analyses
This systematic review and meta-analysis including prospective cohort studies of red meat and processed meat consumption provides evidence that higher consumption of processed meat is associated with higher risk of breast cancer. However, red meat was not a significant cause of breast cancer. Moreover, we did not find evidence for differing associations according to NAT2 genotypes. Further studies examining molecular subtypes of breast cancer are needed.
- The International Agency for Research on Cancer concluded that consumption of red meat is a probable human carcinogen, whereas processed meat was classified as carcinogenic. However, this classification was largely based on the evidence for colorectal, pancreas and prostate cancers. This systematic review and meta-analysis including prospective cohort studies of red meat and processed meat consumption provides evidence that higher consumption of processed meat, but not red meat, is associated with higher risk of breast cancer. These associations were independent of traditional breast cancer risk factors, and no evidence was found for differing associations according to N-acetyltransferase 2 (NAT2) genotypes