Introduction
Irritable Bowel Syndrome_Disease BackgroundIrritable bowel syndrome (IBS) is a chronic, relapsing functional bowel disorder characterized by recurrent abdominal pain and bloating with altered bowel habits that may affect the patient’s quality of life. There are no identifiable physical, radiologic, or lab abnormalities indicative of organic disease. Irritable bowel syndrome is currently considered to be a disorder of gut-brain interaction that affects gastrointestinal (GI) motility, sensation, and secretion.
Epidemiology
The global prevalence of irritable bowel syndrome is between 4.1-12%. The occurrence of irritable bowel syndrome varies among different countries and demographic groups, with prevalence rates reported at approximately 7.1% in North America and 12.6% in Asia. The Rome Foundation Global Epidemiology Study found that the prevalence rates in Europe and the United States were similar, whereas slightly lower rates were observed in Asia and Australia. Irritable bowel syndrome is most common in women and younger individuals (ie 20-39 years old). The prevalence is decreased with advancing age.
Pathophysiology
The pathogenesis of irritable bowel syndrome is multifactorial, including environmental, psychologic, and physiologic factors (eg altered gut motility, visceral hypersensitivity, brain-gut interactions, gut microbiome, intestinal barrier dysfunction, and mucosal immune dysregulation).
Disturbances in the hypothalamic–pituitary–adrenal axis, altered serotonergic activity, bile acid dysregulation, and compromised intestinal barrier function collectively promote disordered gut motility, enhanced visceral pain perception, and ongoing inflammation. The gut microbiome plays a central role in these pathways by shaping neurotransmitter balance, regulating immune activity, and maintaining epithelial integrity, thereby acting both as a contributor to disease manifestations and a potential focus for therapeutic intervention.
Risk Factors
Risk factors for irritable bowel syndrome may include a history of childhood sexual abuse, domestic abuse in women, personality disorders, and anxiety or depression. Other risk factors include chronic pain, sleep disorders, diabetes mellitus (DM), and restless leg syndrome.
The symptoms may be exacerbated by stress, alcohol, food, abdominal and/or pelvic surgery, a sequela of GI infection, and/or a difficult life-changing event in the patient’s life. It has no known association with the development of cancer, mortality, or inflammatory bowel disease (IBD).