Childhood vaccines have been blamed for many ills—most famously, autism. But thus far, research has failed to link vaccines to any particular disease. For a study published in this week's British Medical Journal, a statistician looked at another hypothesis—that the combined measles, mumps, and rubella (MMR) vaccine increases the risk of Crohn's disease, an often very painful disorder of the intestines.

What the researcher wanted to know: Did rates of Crohn's disease go up in England after the MMR vaccine was introduced in 1988?

What she did: The researcher used the United Kingdom's databases of health information to find out how many children ages 18 and under who had been admitted to the hospital with Crohn's disease in England between April 1991 and March 2003. Before 1988, almost no children were given the MMR vaccine; after the first few years of the program, at least 84 percent of children got the vaccine.

What she found: The rates of Crohn's disease hospital admissions by age did go up between 1991 and 2003. But there was no jump in Crohn's that coincided with the introduction of the MMR vaccine.

What the study means to you: It appears that parents deciding whether to have their children vaccinated with the MMR vaccine don't have to worry about Crohn's. The same issue of the British Medical Journal reports on a mumps epidemic in the United Kingdom, a reminder that the diseases vaccinations protect against are still a problem.

Caveats: The researcher didn't link each person's Crohn's diagnosis to whether that person had been given the MMR vaccine; instead, she relied on general information about how common the MMR vaccinewas before and after 1988. This doesn't absolutely prove that the vaccine and Crohn's disease aren't linked, but she says the method she used is good enough to detect anything but a very small increase in risk.

Find out more: Read about Crohn's disease from the National Institute of Diabetes and Digestive and Kidney Disorders.

Read the article: Seagroatt, V. "MMR Vaccine and Crohn's Disease: Ecological Study of Hospital Admissions in England, 1991 to 2002." British Medical Journal. May 14, 2005, Vol. 330, pp. 1120–1121.

Article online: http://bmj.bmjjournals.com