PCBs May Affect Cognitive Performance in Seniors

Despite being banned in the US since 1979, PCBs are still affecting lives of the young and old alike, and new research on the chemical's impact on older people warns that the toxin could affect us throughout our lives.

New research from the University of Montreal and the Sainte-Justine University Hospital Center has linked PCB exposure to lower cognitive performance in seniors.

Writing in the journal Environmental Health Perspectives, researcher Maryse Bouchard reports a "significant association" between cognitive abilities in people aged 70 to 84 years and PCB levels in the blood. A similar association was also found between PCB levels and people aged 60 to 69 years, although the correlation was not as strong.

Bouchard found that the cognitive performance in men and women exposed to PCBs differed, with women in the higher age group showing the most diminution in cognition related to exposure.

"While most studies have looked at the impact of PCBs on infant development, our research shows that this toxin might affect us throughout our lives," Bouchard said.

Although PCBs have been phased out of the American supply chain for four decades, the chemicals are highly persistent and can be found in the blood of most older individuals, the researcher said.

For the research, Bouchard recruited 708 study participants to provide blood samples (to determine the levels of toxins in their body) and to complete memory tests and motor-skill tasks (to determine their cognitive ability).

The PCB levels found in the study population were consistent with PCB levels found in the overall US population.

"Aging persons could be at particular risk because of higher cumulative exposure built up across a lifetime, susceptibility due to underlying medical conditions, such as vascular disorders, and diminished cognitive reserve capacity," Bouchard said. "Our present findings suggest that PCBs, even at levels generally considered to pose low or no risk, may contribute to cognitive deficits."

PCBs wind up in the environment in a number of ways. In the past, deliberate dumping of the chemicals into municipal waterways was a common disposal method. The toxins readily accumulate in the lipids tissues of animal and marine lifeforms, biomagnifying across the food chain. There is a ubiquitous presence of PCBs in the tissues of human populations in North American and around the world.

Another recent PCB study linked the toxin to a change in birds' songs along the Hudson River.