Baby Siblings May Cut Multiple Sclerosis Risk

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Baby Siblings May Cut Multiple Sclerosis Risk

Exposure to Infections of Infant Siblings May Reduce MS Risk by

Strengthening Immune System

By Miranda Hitti

WebMD Medical News Reviewed By Brunilda Nazario, MD

on Tuesday, January 25, 2005

Jan. 25, 2005 -- Growing up with baby brothers or sisters may have a

protective effect against the development of multiple sclerosis (MS).

It's possible but not certain, says Anne-Louise Ponsonby, PhD. She works at

the Australian National University and has studied MS, a disease of the

brain and spinal cord. MS symptoms include problems with muscle control and

strength, vision, and balance.

No one knows what causes MS. Genetics might be involved, since people with

family members that have MS are at a higher risk for the disease.

Environmental factors such as viral illnesses and other infections may also

play a role in the development of the disease.

How might babies help protect their big brothers and sisters from MS? The

answer could be the infections infants often get during their first two

years of life. When babies become infected, their older siblings can also be

exposed, strengthening their immune systems, say the researchers.

It is thought that MS is an autoimmune-driven disease; people with this

disease have an altered immune system which mistakenly attacks nerve fibers

of the brain and spinal cord.

However, there is no clear proof that any specific infection triggers the

autoimmune disease to develop.

Ponsonby and colleagues studied more than 300 Australians, reporting their

findings in the Jan. 26 issue of The Journal of the American Medical

Association.

Participants were 136 adults with MS and 272 without MS. All were about 43

years old. Brain scans (MRI) confirmed MS cases by showing distinct lesions

seen in people with MS.

More Babies, Lower Risk

Those with at least one baby sibling before age 6 were less likely to have

MS as adults.

The more time participants spent before age 6 with baby brothers or sisters,

the less likely they were to have MS as adults.

For those with one to three years of infant contact before age 6, MS risk

was 43% lower. Those who were around baby siblings for three to five years

before age 6 had a 60% drop in MS risk. The greatest reduction in MS risk --

88% -- was among people with five or more years of exposure to baby siblings

before age 6.

For people with MS, infant exposure was linked to a delayed onset of the

disease.

Benefits were only seen with younger siblings less than 2 years old.

Researchers call for more studies to confirm the findings.

SOURCES: Ponsonby, A. The Journal of the American Medical Association, Jan.

26, 2005; vol 293: pp 463-469. WebMD Medical Reference from Healthwise:

" Multiple Sclerosis (MS) -- Topic Overview. " WebMD Medical Reference from

Healthwise: " Multiple Sclerosis (MS) -- Cause. " WebMD Medical Reference from

Healthwise: " Multiple Sclerosis (MS) -- What Increases Your Risk. " News

release, JAMA and Archives Journals.

http://my.webmd.com/content/Article/99/105349.htm?printing=true