According to the International Foundation for Gastrointestinal Disorders, Inc., irritable bowel syndrome (also known as IBS) affects approximately 25 to 45 million Americans. Are you one of them? Who Gets IBS? While anyone can get IBS, there are some groups of people who are at a higher risk than others. Women, people under the age of 50 and those who have a family history of IBS are most at risk for the disease that affects ...