BAD HABITS
If you were born in December, you've probably griped about your
birthday falling near Christmas or Hanukkah. But here's some news that
might put you m the holiday spirit: that birthday cut your odds of being
autistic in half.
It seems that people born in some months are less likely to wind up
with certain mental and cognitive disorders. Take autism. In Israel, 17
percent of babies are born in November and December-but only 8.5 percent
of autistic kids. March and August, however, are danger periods,
accounting for a third of autistic births, report Israeli researcher
Yoram Barak, M.D., and colleagues in the American Journal of Psychiatry
(Vol. 152, No. 5).
The season-of-birth effect doesn't stop at autism. Schizophrenia,
mental retardation, and Alzheimer's disease may all have high-risk
birthdays.
Don't blame the zodiac. The likely culprits are biological and
environmental factors that wreak havoc at particular times of the year.
"Viruses are the leading contender," says E. Fuller Torrey, M.D., guest
researcher at the National Institute of Mental Health. Other suspects
include extreme seasonal temperatures and winter vitamin
deficiencies.
Whatever the cause, it need not operate in the actual month of
birth. It just coincides with crucial periods of early development. So
the increase in autism among folks born in March might reflect exposure
to winter viruses late in pregnancy--or to some late-summer factor that
took place right after conception. "You may even be dealing with
something that's affecting children in the first three months after
birth," says Torrey.
Most birth-month fluctuations in these disorders are small:
schizophrenia is only 10 percent more common among the winter-born. But
figuring out why seasonal variations occur could help identify causes of
these disorders in everyone. Viruses, after all, invade us year round;
they're just more successful in winter. So it's possible the same agent
responsible for the rise in autism among the March-born also causes the
disorder in those with low-risk birthdays.
MONTH HIGHER RISK LOWER RISK
January Schizophrenia, Alzheimer's
February Schizophrenia, Alzheimer's
March Autism, Schizophrenia,
Alzheimer's
April
May
June Schizophrenia
July Autism, Schizophrenia
August Autism Schizophrenia
September Schizophrenia
October
November Schizophrenia
December Schizophrenia Autism
Tags:
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autism,
autistic kids,
bad habits,
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cognitive disorders,
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e fuller torrey,
environmental factors,
first three months,
hanukkah,
high risk,
mental retardation,
schizophrenia,
season,
seasonal variations,
virus,
vitamin deficiencies
