1. Birth control pills are associated with a higher risk for Crohn’s disease: The most common symptoms of Crohn’s disease include abdominal pain (often in the lower right side), diarrhea, weight loss, rectal bleeding, and fever. Inflammation of the lining and wall of the large or small intestine, or both, may occur. The lining can become so inflamed it bleeds. Another complication of Crohn’s disease is blockage or stricture of the intestine. This occurs when the disease thickens the bowel wall with swelling and scar tissue. The intestinal passage becomes smaller and smaller, until it is completely closed.
2. Hormone replacement therapy (HRT) taken by some women after menopause is linked with ulcerative colitis: This disease of the colon (large intestine) or rectum is associated with abdominal cramping and pain, rectal bleeding and/or blood in the stool, ongoing bouts of diarrhea which do not respond to over-the -counter medications, and/or unexplained fever lasting more than a day or two.

Of the two findings, Khalili said the association with birth control pills and Crohn’s is the most relevant to patients and especially true for long-term users. “If you took oral contraceptives for more than five years, you have a threefold increased risk of Crohn’s disease,” he noted.

For the first study in younger women, Khalili and his colleagues analyzed data collected from approximately 233,000 women who had been enrolled in the large U.S. Nurses Health Studies I and II. Data from the beginning of the first study, 1976, through 2008 indicated 309 cases of Crohn’s disease and 362 of ulcerative colitis. Khalili’s analysis compared those who never used birth control pills to those who did. Current users had a nearly three times greater risk of Crohn’s disease. Those who used birth control pills had no increased risk of getting ulcerative colitis, compared with never-users.

In the second study, Khalili examined data collected from nearly 109,000 women past menopause who were enrolled in the Nurses Health Study that began in 1976 and followed through 2008. He found 138 cases of Crohn’s disease and 138 of ulcerative colitis. Those on hormone therapy had a 1.7 times higher risk of ulcerative colitis, compared to never-users. No link was found with Crohn’s disease.

While the studies uncovered an association between the hormone-based therapies and digestive problems, it did not prove a cause-and-effect relationship.

Although Khalili stated “We probably don’t have a clear mechanism,” he noted that animal studies have demonstrated that the colon is more vulnerable to inflammation when estrogen is given, and that estrogen alters permeability of the colon.

Dr. David Bernstein, a gastroenterologist and chief of hepatology at North Shore University Hospital in Manhasset, N.Y., indicated that the findings are probably of greater concern in younger women. According to Bernstein, the study of older women showed that “the risk may be present, but it seems to be quite small.” The link appears stronger for oral contraceptive use and Crohn’s disease. Older women on hormone therapy probably do not need to be concerned.

However, Bernstein noted that “younger women on oral contraceptives need to be told that there is an increased risk.”

Khalili agreed and advised that women on birth control pills who have a strong family history of IBD should be made aware of the research finding a link. A link is not a cause-and-effect relationship, but simply an association. Still, he said, they should be aware, in case they wish to choose another form of birth control.

The above findings should serve as a warning to all of us regarding the use of hormones by the meat and dairy industry, and the possibility of future use of growth hormones in the fish farming industry for salmon and tilapia, which is currently being discussed in Washington, D.C.

*Digestive Disease Week is jointly sponsored by the following four societies:

1. American Association for the Study of Liver Diseases
2. American Gastroenterological Association Institute
3. American Society for Gastrointestinal Endoscopy
4. Society for Surgery of the Alimentary Tract.

**Estrogen can increase cholesterol and reduce gallbladder motility. Women who are pregnant or who take birth control pills or hormone replacement therapy have higher levels of estrogen and may be more likely to develop gallstones.

A co-author on both studies reports consulting work for Pfizer, Millennium Pharmaceuticals and Bayer AG.

Because this research was presented at a medical meeting, the data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.