Colorectal Diseases and Gut Microbiome

Irritable bowel syndrome (IBS) is characterized by repeated changes in the form of stool or defecation habits with abdominal pain or discomfort. The prevalence of IBS is 7–24% among women and 5–19% among men; women patients report a lower quality of life (QoL) and demonstrate more extraintestinal and psychological symptoms such as depression, anxiety, and somatization disorders. Inflammatory bowel diseases (IBDs) such as Crohn’s disease (CD) and ulcerative colitis (UC) are characterized by chronic, recurrent inflammation caused by dysregulation of the immune system. Significant sex differences are seen in symptoms, disease severity, and extraintestinal manifestations. Estrogen contributes to the development of IBDs through immune modulation, thrombosis formation, and intestinal microbiological alterations. Colorectal cancer (CRC) has sex-specific differences, about 1.5 times higher in males and 4–8 years later in females compared to males, suggesting the protective role of estrogen in the disease. In addition, female patients have a higher risk of developing right-sided colon cancer than male patients, which is more aggressive clinical character compared to left-sided colon cancer. Chromosomal instability (CIN) pathway is more common in left-sided colon cancer, while the microsatellite instability (MSI) and serrated pathways are more common in right-sided colon cancer. The factors that influence the composition of the gut microbiome are diet, ethnicity, antibiotics, stress, psychological factors, maternal health during pregnancy, the method of birth (i.e., vaginal birth versus cesarean section), environmental factors, and exercise. Estrogen and androgens influence the gut microbiome, which in turn influences the metabolism of estrogen and androgens, and the term “microgenderome” was created. Stress in pregnant women impairs vaginal immune activity and reduces the number of Lactobacillus, a component of the vaginal flora. The number of Enterococci spp. increases with age, that of Bacteroides spp. decreases, and the quantity of Lactobacilli and Bifidobacteria remain stable. Extensive research on sex/gender differences in IBS, IBD, CRC, and gut microbiome needs to be conducted.