Widely
used PVC plastic chemical spurs obesity,
prediabetes: Study
Mice
exposed in the womb to a chemical used in PVC plastic, door and window frames,
blinds, water pipes, and medical devices were more likely to suffer from
prediabetes and obesity, according to a study released this week.
The
chemical also increased fat accumulation in human stem cells.
The
research suggests that the widely used chemical— organotin dibutyltin (DBT)—could
be spurring obesity and diabetes and scientists say we should monitor people's
exposure since we know so little about the compound.
"We don't really know how exposed we are [to DBT]," lead author of the new study, Raquel Chamorro-García told EHN. García is a postdoctoral researcher at University of California Irvine's Department of Developmental and Cell Biology.
"But
it's in so many materials in our houses and we believe most people are exposed
and the chemical could be impacting our current diabetes problem," she
added.
There
have been dramatic increases in both obesity and diabetes rates over the past
few decades. About 38 percent of adults in the US—and about 17 percent of
children—are now considered obese. More than 30 million people in the US now
suffer from diabetes—if you include prediabetes that number jumps to more than
100 million people.
And,
while poor diets and not enough physical activity remain the leading causes,
scientists increasingly say this problem goes beyond these obvious culprits.
The new study —published this week in
Environmental Health Perspectives—is the latest evidence that
chemicals in our environment may contribute to these problems—by activating
certain receptors, triggering oxidative stress or promoting tissue dysfunction.
Researchers have
previously linked certain flame retardant chemicals, BPA, some pesticides,
PCBs, and tributyltin (another chemical used in PVC piping) to obesity. DBT,
which was tested in the new study, is formed when tributyltin degrades, and it
also used on its own in manufacturing.
Scientists at the
University of California, Irvine exposed pregnant female mice to DBT. The
exposure led to more fat and decreased glucose tolerance in male mice. It's not
clear why the link was so profound in male mice but "males and females are
metabolically different, we speculate that differences in fat storage might
become evident at older ages in females," the authors wrote.
They also examined what
effect the chemical had on human stem cells and found increased fat
accumulation in exposed cells.
While scientists haven't
tested humans for DBT, previous studies found the chemical in house dust and
seafood. In addition, a 2009 study estimated humans are exposed to DBT via
leaching from PVC water pipes as well.
"The concentrations
we used in this study are in the realm of what we'd expect people to be exposed
to," García said.