UC Davis study suggests link between obesity and autism The Sacramento Bee
April 10, 2012
In the scientific hunt for the causes of autism, researchers at
UC Davis may have just picked up a new trail: obesity during
Their study, published today in the journal Pediatrics, found
obese mothers were 70 percent more likely to have a child with
autism and twice as likely to have a child with other kinds of
developmental delays compared with normal-weight moms with normal
blood pressure and no diabetes.
That’s totally new,” said researcher Irva Hertz-Picciotto,
professor of epidemiology and chief of environmental and
occupational health at the UC Davis MIND Institute. “Nobody has
looked at obesity in relation to autism spectrum disorders that
I’m aware of.”
With obesity rocketing skyward in the United States, the findings
“raise serious public health concerns,” the authors wrote.
However, the results could also represent a step toward
uncovering causes of autism and a pathway for further research.
“Currently we really know very little about the causes of
autism,” Hertz-Picciotto said. “We have a few clues.”
Nearly 60 percent of women of childbearing age are overweight,
and one-third are obese, the researchers reported. Nearly 9
percent have diabetes.
The study, which involved more than 1,000 children from
California, also confirmed earlier findings that a mother’s
diabetes may play a role in cognitive disabilities in her
Diabetic moms were more than twice as likely to have a child with
developmental delays other than autism, compared with
non-diabetic moms with normal weight and blood pressure. The
diabetic moms showed a higher risk of having an autistic child,
but the difference wasn’t robust enough for scientists to
consider it reliable.
Whether they were autistic or not, kids whose moms had diabetes
scored lower on language tests than those with non-diabetic moms.
That held true even for children who seemed otherwise mentally
Obesity, diabetes and high blood pressure are all implicated in
problems with metabolism, the body’s processing of food into
energy. These metabolic conditions often come together.
So the researchers looked at all three conditions and found that
having any one of those significantly increased a mom’s risk of
having an autistic child – though obesity was the strongest
“It’s all about the obesity,” as it relates to full-fledged
autism in these findings, said Michael Greene, director of
obstetrics at Massachusetts General Hospital, who was not
involved in the study.
“Is diabetes the mechanism that caused the autism spectrum
disorder, or is it an innocent bystander (and oh, by the way,
it’s common in women with obesity)?” Greene asked. Scientists
will need more data to answer that question and ferret out the
disorder’s cause, he said.
“Obesity has been rising and autism has been rising, and people
might think, ‘Are they linked?’ ” Hertz-Picciotto said. It could
be that one causes the other, or that something else causes them
If a mom’s obesity does turn out to be causal, the likely trigger
for autism could be the chronic inflammation that obesity causes
in various systems in the body, Greene said. The UC Davis
researchers suggested possible triggers could also be low oxygen
levels or lasting exposure to high blood sugar while a fetus is
in the womb.
“We see pregnancy as a critical time window,” Hertz-Picciotto
said. “The brain is going through growth, it’s got cells that
need to migrate to the right place and connect with other cells.
… All those things are very delicately timed and require the
right amount of energy, and everything else about the
intrauterine environment has to be just right.”