MONDAY, July 19 (HealthDay News) -- People in an Alabama city
who had higher levels of the chemicals known as PCBs in their
bodies were much more likely to have high blood pressure, a recent
study found, but it's not clear if the PCBs actually caused their
If a direct connection does exist, the finding may indicate a
serious health threat to those exposed to PCBs, which were once
used in many products but have been banned in the United States
"We were surprised what a strong relationship we found," said study co-author Dr. David O. Carpenter, a public health physician and director of the Institute for Health and the Environment at the University at Albany in Rensselaer, N.Y.
The results could indicate trouble beyond Anniston, the city
where the study took place, Carpenter added. While the city housed
a plant that manufactured PCBs, the chemical levels linked to high
blood pressure were typical of those of many people living
elsewhere in the country.
PCBs -- polychlorinated biphenyls -- were used in hundreds of
industrial products during much of the 20th century. The U.S. ban
occurred amid fears about their adverse health effects, including
the belief that the compounds may cause cancer.
More than three decades later, PCBs still linger in air, water
and soil -- and in humans -- because the chemicals don't break
The study, published online recently in the
Journal of Hypertension, was funded by the U.S. Agency for Toxic Substances and Disease Registry, part of the U.S. Centers for Disease Control and Prevention.
Researchers tested the blood of 758 Anniston residents (407
whites, 351 blacks) and checked their blood pressure and
The researchers focused on 394 people who were not taking high
blood pressure medications. After adjusting the numbers for risk
factors like gender and obesity, they found that those with the
highest levels of PCBs in their bodies -- in the top third -- were
more than 3.5 times more likely to have high blood pressure than
those in the lowest third.
About a third of 98 people in the top third had elevated blood
pressure, which is a major risk factor for cardiovascular disease
If PCBs do contribute to high blood pressure in some way, it's
not clear how they might do so. Carpenter said the chemicals could
possibly disrupt genes that regulate blood pressure.
It's also possible that the chemicals could alter the way
hormones work, encourage inflammation and disrupt cell functioning
in the heart and blood vessels, added R. Thomas Zoeller, professor
of biology at the University of Massachusetts.
Carpenter cautioned that factors other than PCBs could explain
the higher rates of blood pressure in certain people. It's
possible, for example, that high levels of PCB are a sign of
exposure to other chemicals that actually may be at fault.
PCBs can still be found in animal fats, including fish, meat,
dairy products, eggs and breast milk, according to the study.
What to do? Carpenter advised people to eat fewer animal fats,
and Zoeller said the public should become more aware of the risks
of the chemicals around them. "There are invisible pollutants like
PCBs that can have very significant impact on our health," he
"These impacts are not trivial and should not be ignored," Zoeller said. "Because they are invisible, we don't have a choice but to be contaminated with them."
The U.S. Environmental Protection Agency has more details on