Irritable bowel syndrome (IBS) is a common disorder of the intestines that leads to abdominal discomfort or pain, bloating and changes in bowel habits. The abdominal pain or cramping can be a dull ache over one area of the colon, or several areas and, for some women, it can be intolerable and without relief. It can also lead to a tired feeling and even low-grade depression. Some people with IBS suffer from constipation, others from diarrhea and some people experience bouts of both. If you have IBS, you may feel the urge (perhaps accompanied by cramps) to move your bowels but have to strain to do so. Sometimes, individuals with IBS pass mucus with their bowel movements.

According to the International Foundation for Functional Gastrointestinal Disorders (IFFGD), a nonprofit education and research organization founded in 1991, approximately 15 to 20 percent of all U.S. adults are affected by IBS, which involves an abnormality of the muscular action that passes food along the colon, as well as an increased sensitivity of the nerves in the colon. The syndrome can affect men and women of all ages, but it most often strikes the young and female. IBS generally first appears in people in their 20s to 40s, and women are roughly three times more likely than men to suffer from it. Women with IBS seem to have more symptoms during their periods, suggesting that reproductive hormones may play a role in this disorder.

IBS is a major women's health issue. Data reveals an increased risk of unnecessary surgery for extra-abdominal and abdominal surgery in IBS patients, according to the IFFGD. For example, hysterectomy or ovarian surgery has been reported in as many as 47 to 55 percent of female patients with IBS.

"Syndrome" refers to a collection of symptoms, not just one or two. In fact, IBS isn't a disease; it is considered a "functional disorder" because there is no sign of disease. It can strike otherwise healthy people. The causes are multiple: biologic, psychologic and social factors can all contribute to symptoms.

A small percentage (about 10 percent) of IBS patients report that their symptoms appear to have originated shortly after a bacterial infection, such as severe gastroenteritis. Clinicians have recognized this "post-infective IBS" for many years and there is increasing evidence that, in at least a subset of patients, infection and inflammation may play key roles.

IBS has been called by many names, including colitis, mucous colitis, spastic colon, spastic bowel and functional bowel disease. Some of these terms are inaccurate. Colitis, for instance, means inflammation of the large intestine. IBS, however, does not cause inflammation and should not be confused with another disorder, ulcerative colitis. There is no evidence that IBS leads to more serious medical problems such as colitis or cancer or that it affects life span in any way. However, left untreated, the symptoms will often persist, leading to pain and discomfort.

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