As an antimicrobial agent found in many household products, triclosan may play a role in changing the micro-organisms to which we are exposed in such a way that our immune system development in childhood is affected.
"It is possible that a person can be too clean for their own good," said Aiello, who is also a visiting associate professor of epidemiology at Harvard.
Previous animal studies indicate that BPA and triclosan may affect the immune system, but this is the first known study to look at exposure to BPA and triclosan as it relates to human immune function, Aiello said.
One surprise finding is that with BPA exposure, age seems to matter, said Rees Clayton. In people 18 or older, higher amounts of BPA were associated with higher CMV levels, but in people younger than 18 the reverse was true.
"This suggests the timing of the exposure to BPA and perhaps the quantity and length of time we are exposed to BPA may be affecting the immune system response," Rees Clayton said.
This is just the first step, she said, but a very important one. Going forward, researchers would like to study the long-term effects of BPA and triclosan in people to see if they can establish a causal relationship.
One limitation of the study is that it measured disease and exposure simultaneously and thus shows only part of the picture, Aiello said.
"It is possible, for example, that individuals who have an allergy are more hygienic because of their condition, and that the relationship we observed is, therefore, not causal or is an example of reverse causation," Aiello said.
|Contact: Laura Bailey|
University of Michigan