Study Says EMF May Be Linked to Alzheimer’s
Adding to growing evidence that electromagnetic fields may be linked to Alzheimer’s disease, USC researchers report today that the incidence of the disease is sharply higher among people occupationally exposed to the fields, popularly called EMF.
The results, published in the journal Neurology, indicate that people who are exposed to high EMF levels on the job--seamstresses in particular--have, on average, three to five times the normal risk of contracting the devastating disease of aging.
The results, from a study at Rancho Los Amigos Medical Center in Downey, follow on the heels of a September report from the Centers for Disease Control and Prevention indicating that a broad variety of neurodegenerative diseases, including Alzheimer’s, are more common among workers exposed to EMF on the job.
“We’re not talking about exposure in the home from [living near] high-power lines,” said Dr. Eugene Sobel of USC, the primary author. “These [occupational exposures] are much higher exposures than are usually found in residences.”
The greatest risk was for people who operate sewing machines. “Seamstresses are highly overrepresented among Alzheimer’s cases, and their exposure is the highest for all occupations,” Sobel said. The exposure is high because they work so close to the electrical motor in the machine.
Also at risk are carpenters and others who use electrically powered tools held close to the body, he said.
Many researchers are skeptical of the finding, however. “Our bottom line is that [the results] are really too preliminary to say anything,” said Dr. Neil Buckholtz, director of Alzheimer’s research at the National Institute on Aging, which sponsored the study. “It really needs to be reproduced by some other group before we can have a lot of confidence in it.”
“There are all kinds of other things, such as chemicals, in the work environment that could account for the relationship,” added Zavan Khachaturian, director of the Alzheimer Assn.’s Reagan Research Institute. “There is room [in the data] for all kinds of inadvertent biases.”
In contrast, EMF expert Louis Slesin, editor of Microwave News, calls the results “very important. . . . The thing about Sobel’s findings is that we now have four data sets, across different countries and different populations, with consistent results. . . . That points to the need to investigate this further.”
Sobel, Zoreh Davanipour and their colleagues studied 326 Alzheimer’s patients over the age of 65 who were hospitalized at Rancho Los Amigos and compared them to 152 non-Alzheimer’s patients at the medical center.
They found, primarily through interviews with family members, that males with Alzheimer’s were 4.9 times as likely to have had a high occupational exposure to EMF and females were 3.4 times as likely.
The results were similar to those in three earlier studies, involving a total of 386 Alzheimer’s patients and 475 controls in Finland and the United States, in which Sobel and his colleagues had also found an average threefold increase in risk.
The potential risks of EMF exposure have been a source of controversy for 17 years, since Colorado researchers first linked high EMF exposure in children living near power lines to an increased incidence of leukemia. Subsequent studies also showed an increased risk of brain tumors and other types of cancer.
Those studies, however, have typically shown relative risks of 1.5 to 1.7 times for exposure to EMFs, much lower than the threefold or greater risk increase found by Sobel.
Much of the interest in EMFs has abated, furthermore, since the National Academy of Sciences issued a report in October indicating that there is no clear and convincing evidence of a link between residential EMFs and cancer.
But biochemist Richard A. Luben of UC Riverside, a member of the committee that prepared the report, noted Tuesday that the committee had not considered either industrial exposures or a potential link to Alzheimer’s. There was not enough evidence about either topic for them to explore such links in detail, he said.
“If the data suggest that something is going on” in Alzheimer’s, Luben said, “we have to look at it in greater detail, especially when we are dealing with a disease that so many people contract.”
Alzheimer’s disease afflicts as many as 4 million Americans, most over the age of 65. It is characterized by memory loss, disorientation, depression and deterioration of bodily functions. It is ultimately fatal, causing about 100,000 deaths each year.
Its cause is still unknown. Although researchers have linked at least two different susceptibility genes to the disease, it is clear that as-yet unknown environmental factors also play a major role.
In a second paper in Neurology, Sobel and Davanipour outlined a potential biological pathway by which EMF could theoretically exert its effects. The bottom line, based on other researchers’ studies of brain cells grown in the laboratory, is that electric fields can disturb the normal concentrations of calcium ions within cells.
The increased concentration of calcium within the cells produced by EMFs, they speculate, triggers a well-known cascade of reactions that ultimately leads to the accumulation of damaging plaques and tangles in the brain.
The role of calcium in Alzheimer’s was originally postulated by the Reagan Institute’s Khachaturian, but he does not subscribe to the USC hypothesis. He believes that a calcium imbalance can be caused by biochemical reactions, “but we have never seen any relationship between that process and EMF. . . . To jump from cultured cells to humans is a very, very big jump.”
