Where You Live Influences Risk for IBD

People in sunny regions are less likely to develop IBD

(RxWiki News) Living in a sunny region does more for your health than enhance your mood. Clear blue skies and lots of sun are associated with a lower chance of developing inflammatory bowel disease.

A new study finds that latitude – how close or how far you live from the equator – correlates to incidence of inflammatory bowel disease (IBD) in women who live in the US.

That means a woman who lives in Chicago or Detroit is more likely to develop Crohn's or ulcerative colitis than a woman who lives in Miami or San Diego.

"Environment can impact your health; talk to your doctor about IBD symptoms."

The study was led by Dr. Hamed Khalili at the Massachusetts General Hospital in Boston, a place that fits on the “higher risk” list for IBD. European researchers had found a similar correlation on their continent. The further north you live, the higher the incidence of IBD.

IBD is an umbrella term that includes Crohn's and ulcerative colitis, the most common IBDs. Both are chronic diseases that require lifelong treatment and in some cases, surgery. There is no known cause for IBD, but it's believed that both environmental and genetic factors play a role.

Dr. Khalili's team took their data from the Nurses' Health Study, a long-term study with phases that started in 1976 and 1989. The total number of participants was 238,000. The researchers looked at the women who had developed IBD over the past decades, and where they lived.

They found that women who lived in sunny areas in the southern United States were 52 percent less likely to have Crohn's disease by age 30, and 38 percent less likely to have ulcerative colitis. That's compared to women living in northern latitudes.

Researchers pointed to exposure to sunlight as the cause for their findings. People who live in sunnier climates get more sunshine on a daily basis.

Sunlight, or UV radiation, is the body's greatest source for vitamin D. The researchers say their findings add to the growing evidence that vitamin D plays a role in the development of IBD, and the body's immune response.

The study could point towards potential treatments or preventative measures for people living in northern latitudes.

The study was published in the journal Gut in January 2012.

Review Date: 
January 13, 2012