Hormonal Influences on the Gastrointestinal Tract and Irritable Bowel Syndrome

62 IBS: CLINICAL SYMPTOMS IBS is a disorder in which abdominal pain or discomfort is a primary symptom. It is accompanied by a change in bowel habit and abnormal stool frequency (defined as >3 bowel movements per day [diarrhea] or <3 bowel movements per week [constipation]) (1). IBS patients also commonly report hard or loose/watery stools, a feeling of incomplete evacuation after bowel movement, bloating and/or abdominal distension, and the passage of mucus. IBS: EPIDEMIOLOGY Reported prevalence rates range from 3% to 20%, with most estimates concentrated between 10% and 15% (2). Although IBS affects individuals of all races and both sexes, women are more commonly affected than men in Western nations at a ratio of approximately 2:1, a phenomenon that has yet to be completely explained (3–6). In North American studies, the female predominance is greater among individuals who seek medical attention (3–4:1) as compared with those who do not (<2:1) (7); however, it is unclear if this reflects underreporting in men or a true predominance in women. Sex differences in presentation of symptoms have been described, including more IBS with diarrhea among men and more IBS with constipation and bloating among women (8). IBS is one of the most common disorders seen in the primary care setting. Women often present to their gynecologist first, as this may be Hormonal Influences on the Gastrointestinal Tract and Irritable Bowel Syndrome TREATMENT OF IRRITABLE BOWEL SYNDROME, SERIES #7