Probability of Having Irritable Bowel Syndrome (IBS)

Irritable bowel syndrome (IBS) affects approximately 10-15% of the US population (about 25-45 million Americans), making it the most common gastrointestinal disorder seen by physicians. Despite its high prevalence, only about 50% of people with IBS symptoms seek medical care. IBS is about 2 times more common in women than men.

IBS is classified into subtypes: IBS-D (diarrhea-predominant, about 40% of patients), IBS-C (constipation-predominant, about 35%), IBS-M (mixed, about 25%), and IBS-U (unclassified). Symptoms include abdominal pain, bloating, altered bowel habits, gas, and urgency. IBS is diagnosed clinically using the Rome IV criteria after excluding other conditions.

The exact cause of IBS is not fully understood but involves altered gut motility, visceral hypersensitivity, gut-brain axis dysfunction, intestinal inflammation, and altered gut microbiome. Treatment includes dietary modifications (the low-FODMAP diet improves symptoms in about 70% of patients), stress management, fiber supplements, probiotics, and medications targeting specific symptoms (antispasmodics, loperamide, lubiprostone, linaclotide, rifaximin). The economic impact of IBS in the US is estimated at $28 billion per year, including direct healthcare costs and lost work productivity.