IBS Center

Irritable Bowel Syndrome Causes and Risk Factors

What causes IBS?
It's not known exactly what causes irritable bowel syndrome. However, doctors are working on identifying triggers or possible causes of IBS. For reasons that still aren't clear, people diagnosed with IBS react strongly to stimuli that don't bother other people. Triggers for IBS can range from gas or pressure on the intestines to certain foods, medications or emotions. Possible IBS causes include:

Foods - Many people find that IBS signs and symptoms worsen when they eat certain foods. The role of food allergy or intolerance in irritable bowel syndrome has yet to be clearly understood.

Hormones - Because women are twice as likely to have IBS, researchers believe that hormonal changes play a role in this condition. Many women find that signs and symptoms worsen during or around menstrual periods.

Intestinal contractions - The walls of the intestines are lined with layers of muscle that contract and relax in a coordinated rhythm as they move food from the stomach through the intestinal tract to the rectum. It has been theorized that these contractions may be stronger and last longer than normal during IBS. Therefore, when food is forced through the intestines more quickly, it causes gas, bloating and diarrhea.

Nervous system problems - Doctors also think that abnormalities in the nervous system or colon may play a role, causing discomfort when the abdomen stretches from gas.

Other illnesses - Sometimes another illness, such as an acute episode of infectious diarrhea (gastroenteritis), can trigger IBS.

Stress - Stressful events, such as a change in your daily routine or family arguments can aggravate symptoms of IBS but have not been known cause them.

Risk factors
Some people naturally are at higher risk of non ulcer stomach pain than others are. However, some factors can put you at risk of developing IBS. In fact, IBS can occur at any age, but often begins in adolescence or early adulthood. Irritable bowel syndrome is also more common in women and may be more common in people predisposed to emotional stress or anxiety, in people who use laxatives, or who experience temporary bowel inflammation. Many people manifest occasional signs and symptoms of irritable bowel syndrome, but you're more likely to be diagnosed with IBS if you exhibit any of the following:

Age - IBS begins before the age of 35 for 50 percent of people.

Diet – Predisposing factors may include a low-fiber diet, overeating or eating too quickly. People who maintain a diet of greasy, spicy or fatty foods are also at risk of developing IBS. Alcohol, caffeine and carbonated beverages have been known to worsen symptoms of IBS.

Gender - Overall, about twice as many women as men are diagnosed with the condition.

Family history - Studies have shown that people with a parent or sibling diagnosed with IBS are at increased risk of developing the condition. Researchers are studying whether the influence of family history on IBS risk is related to genes, to shared factors in a family's environment, or both.

Lifestyle - Certain lifestyle factors can increase risk, including stress.

Medications - Taking certain medications, especially non steroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen (Advil, Motrin, others), and antibiotics can increase risk of IBS.

Other illnesses - Evidence exists of an increased risk of irritable bowel syndrome after an episode of bacterial gastroenteritis.


For some people IBS can be disabling. They may be unable to work, attend social events, or even travel short distances. But how do you know if abdominal pain is related to IBS? Continue reading here to learn more about the most common signs and symptoms of irritable bowel syndrome.

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