In a recent study published in the journal Nutrients, The researchers investigated associations between consumption of red and processed meat and the subsequent risk of colon neoplasms. This important research contributes to the limited body of evidence by focusing on the joint effects of meat consumption and genetic predisposition on disease risk. Screening colonoscopy data from 7,291 participants and genotype information from a subset of 4,774 participants were used for the study.
The study’s findings revealed that while red meats were not statistically associated with an increased risk of colon neoplasms, processed meats significantly increased the subsequent risks of developing the condition. Specifically, eating processed meats more than once a week was associated with an increased risk of colon neoplasms, equivalent to a 19 percentage point higher polygenic risk score (PRS). This highlights the importance of limiting processed meat intake as a health behavior that can offset the genetic predisposition to colorectal neoplasms.
Study: Red and Processed Meat Intake, Polygenic Risk and Colorectal Neoplasm Prevalence: Results from a Screening Colonoscopy Population. Image credit: Hakase_420 / Shutterstock
Background
Colorectal cancer (CRC), also called colon cancer, is the abnormal growth of tissue (“polyps”) in the inner lining of the large intestine or rectum. It is a serious and often fatal condition, ranking as the second most common cause of cancer-related mortality worldwide. Worryingly, the incidence of CRC is increasing at an unprecedented rate, with approximately 2 million new cases and 1 million deaths recorded each year.
Encouragingly, CRC usually begins as benign polyps and their development into malignant tumors can take ten years or more, emphasizing the life-saving potential of early detection and frequent screening.
Previous research has identified genetic predisposition and diet as two major factors contributing to the risk of breast cancer. The International Agency for Research on Cancer has classified red and processed meats in particular as carcinogens. However, despite existing studies of independent risks, evidence regarding the joint effects of genetic predisposition and meat consumption on CRC risk has been limited.
About the study
The present study aims to bridge this gap in the literature by elucidating whether meat consumption (as a function of frequency per week) can enhance or offset the risks of genetic predispositions using the ‘genetic risk equivalent (GRE)’ metric.
Data for the study were collected from the non-invasive German large cohort screening study Begleitende Evaluierung innovativer Testverfahren zur Darmkrebsfrüherkennung (BliTz) for men and women over 50 between 2002 and 2019 (n = 11,104). Study inclusion criteria included completed socioeconomic, lifestyle, demographic, medical, and family CRC histories (obtained from medical records and participant-completed questionnaires).
All participants underwent routine colonoscopy and relevant histology. CRC (or precancerous lesions) were identified using the presence and progression of adenomas. Participants with confirmed CRC (or its precursors) were genotyped, along with a random subset of healthy subjects for comparison. Genotyping data were used to calculate polygenic risk scores (PRS). Questionnaires were used to record the participants’ diet in the year preceding the study, focusing on the frequency of consumption of red or processed meat.
“Frequency was initially categorized into 2 levels: ≤1 time/week and >1 time/week and frequency >1 time/week was further divided into 2 levels: >1 time/week and <1 time/day and ≥ 1 time/ day to assess the individual association of processed meat intake and risk of colorectal neoplasia."
Statistical analysis included Chi-square tests to compare participants with and without CRC or its precursors. Multiple logistic regressions were adjusted for education level, age, sex, body mass index [BMI]Smoking and alcohol consumption, chronic disease and level of physical activity were then used. The regression coefficients and adjusted odds ratios (ORs) derived from these models were used to calculate the GREs, which serve as the outcome of interest in this study.
Study findings
Of the 11,104 participants from the BliTz study, 7291 met the inclusion criteria of the present study and were included for further analyses. Histological examinations revealed that 2,427 participants had colorectal neoplasms, of which 877 had advanced precancerous lesions and 68 had CRC. All these participants were genotyped. In addition, 2,559 participants without colorectal neoplasms were genotyped for study comparisons.
The results showed that processed meats and genetic predisposition were independently associated with higher GRE scores and, in turn, the likelihood of colon neoplasms. When analyzed together, consumption of processed meat higher than once per week increased GRE scores equivalent to 19% higher PRS (GRE = 19.0, aOR = 1.28), indicating a profound effect of dietary choices on subsequent CRC risk. In people in the highest PRS risk quartile, this risk increased by 2.3- to 3.8-fold.
Surprisingly, the association between red meat consumption and CRC risk did not reach statistical significance, regardless of frequency of consumption.
conclusions
The present study is a valuable contribution to the literature as it is the first to evaluate the joint associations of genetic predisposition and meat consumption on subsequent risk of CRC or its precursors. Study findings in a group of more than 7,000 German adults revealed that eating processed meat higher than once/week increased GRE scores equivalent to a 19 percentile higher PRS. Contrary to previous research, red meat consumption was not associated with an increased risk of cancer.
Together, these findings highlight the role of diet in colorectal neoplasms and highlight the potential for interventions against processed meat as a countermeasure for the high predisposition to the fatal disease.
