study links birth month to certain diseases later in life

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From Northwest Herald today, Lifestyle section. www.northwestherald.com

Study links illness, birth month

By ERIKA NIEDOWSKI

The Baltimore Sun

Pisces (Feb. 19-March 20): Governed by Neptune and symbolized by the fish. =

Compassionate, introspective, artistic. Often dreamy and impractical. May be=

prone to schizophrenia, epilepsy or bipolar disorder.

It may sound like some kind of new, madcap astrology, but a number of scien=

tists are becoming convinced that our birth month may predispose us to parti=

cular diseases later in life.

Studies have shown that schizophrenia is more common among those born in la=

te winter or early spring. Multiple sclerosis is associated with births in A=

pril, May and June. And epilepsy occurs more frequently in those with birthd=

ays from December to March.

The findings may seem whimsical or – depending on which month you eat cake =

and unwrap presents – alarming. But researchers hope the emerging patterns w=

ill offer clues into the origins of a range of illnesses that, despite advan=

ces in treatment, have no known cause.

" It makes you think differently about disease, " said Dr. Emmanuel Mignot, p=

rofessor of psychiatry and behavioral sciences at Stanford University School=

of Medicine, who has studied the association between birth month and narcol=

epsy.

" Most people tend to think that disease is really something that is determi=

ned by your genes or what happens just before the disease occurs, " he said. =

" Maybe there are a number of things that can happen well before. "

In the latest study, published in the current edition of the journal Neurol=

ogy, scientists at the National Cancer Institute found that adults born in J=

anuary and February had the highest risk of brain cancer. Those with birthda=

ys in July and August had the lowest risk.

The paper's lead author, NCI epidemiologist Alina V. Brenner, is the first =

to offer a caveat: The findings could be the result of chance.

But separate studies in Britain and Norway have identified a similar correl=

ation between birth season and risk of brain tumors in children, with a stat=

istical " excess " of births in winter and a " deficit " in summer.

If the association turns out to be real, Brenner said, it suggests that exp=

osures early in a child's development – at any point from conception to the =

first few months after birth – could have a hand in the genesis of the disea=

se. Though it's not clear what those exposures are, they could include virus=

es, environmental toxins or even something as seemingly benign as the weathe=

r.

Seasonal birth patterns have been most firmly established in schizophrenia =

patients. Several years ago, a group of Danish researchers reported that the=

risk of developing the disorder was highest among those born in February an=

d March and lowest among those with birthdays in August and September.

For his part, Dr. E. Fuller Torrey, research psychiatrist at the Uniformed =

Services University of Health Sciences in Bethesda, Md., has ruled out the p=

ossibility that chance alone explains the findings.

" It could be chance if it were one study of 250 people, or a few dozen peop=

le here or a few dozen people there, " he said. " When you're dealing with a c=

ouple hundred thousand people and 200 studies, the chances of it being chanc=

e are zero-point-zero. It's remarkably consistent. "

The leading explanation implicates a seasonal infection that could be distu=

rbing the child's normal brain development, which may help explain why other=

central nervous system disorders are also more common in those with winter =

births.

" We know that infectious agents have a seasonality – influenza being the mo=

st striking, " Torrey said. " Therefore, you certainly have to think of infect=

ious agents infecting the mother late in pregnancy or infecting the newborn =

in the first few months of life. "

Stanford's Mignot and a group of colleagues from France published a paper i=

n the journal Sleep last year linking birth month with another disorder: nar=

colepsy. Patients with that condition are regularly seized with sleep during=

normal waking hours.

The researchers compared the birth dates of 886 narcoleptics being treated =

at sleep clinics in Montpellier, France; Montreal, and California to those o=

f more than 35 million people in the general population.

The distribution of births was strikingly uneven, with the number of narcol=

eptics born in March (11.9 percent) significantly exceeding the number expec=

ted in the general population (8.5 percent).

Conversely, the researchers found a significant drop in the number of narco=

leptics born in September (5.6 percent) compared with the number normally ex=

pected (8.7 percent).

CARPE