The development of colorectal cancer is associated with social environment, lifestyle (especially dietary habits, lack of physical activity), and genetic factors. Age, history of colorectal polyps, ulcerative colitis and history of cholecystectomy are also high risk factors for colorectal cancer. 1. Dietary factors Although tumors are influenced by genetic factors, 80% of tumors are related to environmental factors including diet. At present, it is believed that high intake of animal fat and protein and insufficient intake of dietary fiber are the main risk factors for colorectal cancer, especially colon cancer; while other nutrients in the diet including vitamin A, C, D and calcium are beneficial factors. And folic acid and methionine can reduce the risk of colon cancer. Current research suggests that the incidence of colorectal cancer is positively associated with total protein, especially animal protein, and negatively associated with plant protein. Some animal experiments also found that soy can reduce the risk of colorectal cancer. 2. Physical indicators Physical activity, obesity
Energy intake, metabolic rate, physical activity and various measures of body size or obesity are closely related and affect each other. If they are not taken as a whole, it is difficult to determine or express the role of each factor in the risk of cancer by quantity. Epidemiology suggests that long years of sedentary office work with little physical activity is a risk factor for colorectal cancer, and physical activity reduces the risk of colorectal cancer and is one of the most important protective factors. No significant correlation was found between BMI and the risk of rectal cancer. 3, genetic factors Research has confirmed that people with a family history of colorectal cancer have a higher risk of colorectal cancer than the general population, and people with first-degree relatives suffering from colorectal cancer have a two-fold higher risk of the disease than the general population, and the age of the disease is significantly earlier. Colorectal cancer caused by family genetic factors accounts for about 10%-20% of these genetic families, mainly familial adenomatous polyposis, Gardner syndrome and hereditary nonpolyposis colon cancer syndrome. In addition to these, there are some sporadic colorectal cancers with genetic background. Hereditary colorectal cancers are broadly divided into two categories, namely polyposis (multiple polyps) and nonpolyposis. This type of colorectal cancer has autosomal dominant genetic characteristics. 4.Disease factors History of colorectal polyps, chronic inflammatory colon diseases and history of cholecystectomy are also related to the occurrence of colorectal cancer. Patients with chronic colitis such as ulcerative colitis and Crohn’s disease have a higher chance of intestinal cancer than the general population, and inflammation in the process of proliferative lesions is often accompanied by chronic ulcers or formation of inflammatory polyps, etc. According to statistics, the incidence of colon cancer in patients with colon polyps is 5 times higher than that in patients without colon polyps. And personal tumor history, infection, schistosomiasis, diabetes, etc. also have some correlation. 5.Drug factors Modern research has more and more evidence suggesting that hormone replacement therapy (HRT) is related to reducing the risk of colorectal cancer, but further research is still needed to clarify the role of HRT. Meanwhile, studies have shown that non-steroidal anti-inflammatory drugs (NSAID) have obvious anti-tumor effects, and experiments have shown that NSAID has obvious inhibitory effects on tumors induced by chemical carcinogens, and can inhibit the proliferation of cell lines such as colon cancer in vitro. 6.Other factors: (1)Age factor: Colorectal cancer can occur at any age, but 90% of them occur above 50 years old, and the older the age, the higher the risk of colorectal cancer. (2) Smoking: Smoking is a major source of many carcinogens, including heterocyclic amines and nitrosamines. Consider the biological relationship between smoking in some respects and the risk of colorectal cancer. (3) Alcohol consumption: Many cohort and case-control studies have associated alcohol intake with the risk of colorectal cancer. In addition, alcohol is associated with an increased risk of colorectal adenoma. (4) Occupational exposure: Some studies have found that people in occupations related to asbestos exposure are susceptible to colorectal cancer. Animal experiments have also confirmed that asbestos is able to penetrate the intestinal mucosa as it passes through the digestive tract.