BPA May Be Linked to Heart Disease Risk

Jan. 12, 2010 - Nearly everyone in the U.S. carries the plastics chemical
BPA in their bodies. But those with the highest BPA levels have the highest
risk of heart disease, new data confirm.
BPA -- bisphenol A -- is one of the world's most heavily produced chemicals.
More than 2.2 metric tons of BPA are used each year to make PVC pipes, epoxy resins that line
food cans, food packaging, and drink containers. It can be detected in the
bodies of more than 90% of Americans.
Animal studies suggest BPA can have a wide range of health effects. But it's
not at all clear whether these animal studies are relevant to humans. In
response to calls for data, the CDC in 2003-2004 began testing a representative
sample of Americans for BPA as part of the huge NHANES data-collection
study.
In 2008, University of Exeter researcher David Melzer, MB, PhD, led a U.K.
research team that analyzed the CDC's 2003-2004 data. They found that high BPA
levels were linked to a higher risk of heart disease, diabetes, and elevated
liver enzymes.
Critics pointed out that the NHANES study looked at so many things,
something was bound to seem risky just by chance. Was the BPA finding such a
statistical blip?
No, Melzer says. His team analyzed a new set of CDC data collected in
2005-2006. Surprisingly, average BPA levels were 30% lower in the new study.
Yet people with the highest BPA levels still had a significantly higher risk of
heart disease.
"It is very clear that the connection is still there," Melzer tells WebMD.
"It underlines the question mark we found between BPA and human health."
To estimate the size of the risk they found, Melzer calculates that a
60-year-old man in the top third of BPA levels (over 3.5 nanograms/milliliter
urinary concentration) has a 10.2% chance of having heart disease. A
60-year-old man in the lowest third of BPA levels (under 1.4 ng/mL urinary
concentration) has a 7% chance of having heart disease.
"As urinary concentrations of BPA are an approximate marker of longer-term
BPA exposure, we expect these figures underestimate the true effect size. We
can’t say by how much, as no long-term exposure data are available," Melzer
says.
It's not clear why BPA levels were lower in 2005-2006 than in 2003-2004.
Melzer notes that public awareness of possible BPA health effects may have
contributed to the decline, though nobody really knows.
But at these lower overall BPA levels, there was a trend but no significant
association between BPA and diabetes or liver enzymes. However, when data from
both years was pooled, these links were highly significant.
While the Melzer study shows a link between BPA and heart disease, it in no
way proves that BPA causes heart disease. Such proof may be hard to come by, as
definitive studies would mean giving people BPA to see what happens. But
longitudinal studies that track people with high BPA levels over time might
provide clearer answers.
 
http://www .webmd.com/heart-disease/news/20100112/bpa-link-to-heart-disease-confirmed?src=RSS_PUBLIC