Good news for southern women: reduced risk of inflammatory bowel disease

A recent study presented at the annual meeting of the American College of Gastroenterology suggests that in the United States southern women are less likely than their northern counterparts to suffer from Crohn’s disease or ulcerative colitis. Researchers believe this is attributable to the extra time that southern women spend in the sun’s ultraviolet rays, thereby increasing their Vitamin D levels.

Vitamin D deficiencies have been linked to an increased risk of inflammatory bowel disease. Inflammatory bowel disease is a name given to a group of chronic digestive diseases of the small and large intestines, including colitis, proctitis, enteritis and ileitis. Typically, doctors divide IBD into two groups: ulcerative colitis and Crohn’s disease.

Ulcerative colitis causes ulcers and inflammation of the lining of the colon (large intestine). It almost always involves the rectum and usually causes a bloody diarrhea.

Crohn’s disease is an inflammation that extends into the deeper layers of the intestinal wall. In about 30 percent of cases the disease is limited to one or more segments of the small intestine, usually the ileum (ileitis); about 50 percent of the time it involves both the ileum and the colon (ileocolitis); and 20 percent of the time it is confined to the colon (Crohn’s colitis). Inflammation may also affect the mouth, esophagus, stomach, duodenum, appendix or anus.

Ulcerative colitis and Crohn’s disease are chronic conditions that may recur over a lifetime. Many people have long periods – sometimes years – when they are symptom-free. Unfortunately, doctors cannot predict with certainty when the disease will go into remission or when the symptoms will return.

There is good news for southerners, however.

In the study, a group of Boston researchers followed nearly 120,000 female nurses over a 20-year period. At the study’s inception none of the participants had inflammatory bowel disease. Over the course of the study, 284 participants developed Crohn’s disease and 332 developed ulcerative colitis.

Women who lived in southern latitudes at age 30 were about 50 percent less likely to have Crohn’s disease and about one-third less likely to have ulcerative colitis than those who lived in the north. Those born in the South or living in the South at age 15 also fared better, but the findings for that group were not as significant. Sunanda Kane, MD, a gastroenterologist with the Mayo Clinic in Rochester, Minn., said there is no reason to believe the findings would not also apply to men.

Researchers are working to determine cause and effect, and studies are underway to look at whether or not vitamin D supplements will help relieve symptoms of Crohn’s disease. In the meantime, southern women can bask in the knowledge that they have a reduced risk of inflammatory bowel disease.