Dec. 3--Do 3M-made chemicals in water cause high cholesterol?
Or is the opposite true -- that high cholesterol causes the chemicals to accumulate?
Three new studies link cholesterol with 3M-manufactured chemicals found in drinking water, without saying whether one might cause the other.
State experts on pollution say the studies have not changed their minds about acceptable levels of the chemicals -- called perfluorochemicals, or PFCs.
"From a public health perspective, we are always concerned about cholesterol levels and heart disease," said Jean Johnson, a public health scientist for the state Department of Health. "But there is no evidence that PFCs cause a change in cholesterol."
In 2004 and 2005, traces of PFCs were discovered in groundwater in a 15-mile swath of Washington County from Oakdale to Hastings.
One of the new studies, by the Boston University School of Public Health, split a sample group of 860 Americans into quarters according to the levels of PFCs in their blood.
The top quarter, with the highest levels of PFCs, had cholesterol about 7 percent higher than the lowest quarter.
The test is significant because it considers the effects of small amounts of PFCs in the blood of the general population. Most previous studies involved higher exposures to workers in PFC plants, or groups known to be exposed to PFCs, as about 69,000 Washington county residents have been.
The study follows two others that came to similar conclusions.
One involved about 46,000 people in West Virginia, exposed to PFCs in groundwater from a DuPont Corp. plant. The other involved more than 12,000 children living in the same area.
If trace amounts of PFCs cause high cholesterol, it would be a major health worry. High cholesterol leads to heart disease and shortens lives.
Yet experts are not alarmed -- because of the confusing and apparently contradictory nature of such studies.
Earlier studies also have not shown that PFCs cause increases in cholesterol or any other harmful effects, even in ultra-high doses. Several studies of PFCs hinted that the chemicals might cause cancer or other ailments -- only to be refuted by more thorough studies later.
And in the Boston study, one kind of PFC was actually associated with lower cholesterol.
"The findings are totally inconsistent," said Geary Olsen, a 3M staff scientist who has spent years studying the effects of PFCs.
In biology, the effect of any chemical increases with the dose -- just as the effect of two aspirin is stronger than one. So if there are no health effects from high PFC doses in factory workers, no one should expect to see effects from tiny doses in drinking water, said Larry Zobel, 3M medical director.
The idea that PFCs could cause high cholesterol, Zobel said, "just makes no sense to us."
PFCs attach to proteins -- and cholesterol is a fatty material that does the same thing. Therefore, Zobel speculates, it could be that people with high cholesterol tend to have more blood proteins for PFCs to cling to.
In other words, the high cholesterol may cause PFCs to stay in the body longer -- instead of PFCs causing high cholesterol.
Either way, the connection will have to be studied further, Olsen said.
The authors of the Boston study agreed. While saying the study shows that PFCs might cause cholesterol to spike, "it is possible that PFCs behave differently in the bodies of people who have higher cholesterol levels."
The chemicals have been manufactured by 3M since the 1940s, for use in household products including Teflon, Scotchgard stain repellent and fire extinguishers. The company legally dumped some PFCs into landfills, ending in the 1970s.
In the 1990s, scientists began to detect PFCs in animals and people worldwide. Megadoses of PFCs were shown to cause cancer, thyroid problems and birth defects in mice.
In 2004, tiny traces -- measured in parts per billion -- were discovered in drinking water from Lake Elmo and Oakdale, having leached from the dumpsites. Later, a less worrisome form of PFC was found in a 15-mile swath that reached as far south as Hastings.
Even though the chemicals have never been shown to hurt people -- at any dose -- scientists were worried because PFCs can accumulate in the human body. If a body does contain PFCs, it can take 3 1/2 to eight years to reduce that amount by half.
State officials set maximum standards for PFC consumption. It's now considered safe, for example, to drink water daily with 0.3 parts per billion of the most common types of PFCs for a lifetime.
"We don't see anything (in the new studies) that points to a reconsideration," said Tannie Eshenaur, health educator with the Health Department.
"We build in a lot of precautions," she said, allowing for pregnant women, children or anyone with an illness.
Department scientist Johnson was asked if the new studies were cause for worry.
"I never like to tell people what they should and should not worry about," Johnson said. "But the big risk factors for high cholesterol are diet and heredity. We need to tell people to pay attention to those. They are much more important than PFCs."
Bob Shaw can be reached at 651-228-5433.
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