Hi. Has anyone seen this article below?
Just when I thought this is not at all an issue for us nmr lab
manager types, here's a story at UCLA website:
http://www.ucla.edu/Templates/NewsItem1.html
(A rather vaguely worded article, but thought I should pass it on.)
John Chung
The Scripps Research Institute
================================================================
Magnetic Fields, Leukemia Countered
Date: October 27, 2000
Contact: Dan Page (dpage_at_support.ucla.edu)
61458
Investigation Finds Association in Homes With High and Uncommon
Exposures
A new UCLA/Loma Linda University investigation of the original data from 12
studies of magnetic field exposure and childhood leukemia, including those with
the largest numbers of heavily exposed leukemia cases, counters earlier claims
of inconsistencies among the results.
The new investigation, published in the November edition of the peer-review
journal Epidemiology, found a high degree of consistency across the studies,
and an association between the rare childhood disease and households with
high and uncommon magnetic field exposures. The analysis found no
association with typical household exposure levels.
A combined analysis of the 12 studies estimated a 70 percent elevation in
childhood-leukemia incidence among households with residential magnetic
fields stronger than 0.3 microtesla, compared with levels below 0.1 microtesla.
(A microtesla is a unit of magnetic field strength.) The analysis found no
association between childhood leukemia and magnetic fields below 0.3
microtesla.
Nonetheless, because such a small percentage of households is highly exposed,
the new analysis concluded that the fraction of childhood leukemia actually
attributable to household magnetic field exposures was probably small, if not
zero. Leukemia strikes about five out of every 100,000 children in the United
States each year. According to U.S. survey data used in the new analysis, the
average household magnetic-field strength is 0.09 microtesla, and less than 5
percent of homes have fields above 0.3 microtesla.
"Our analysis indicates that earlier reports of inconsistency among studies
arose because the association of magnetic fields with childhood leukemia is
concentrated among homes with relatively high and uncommon exposures,"
said Sander Greenland, principal author and a professor in the Department of
Epidemiology in the UCLA School of Public Health. "Some studies did not have
enough subjects at high exposures to allow them to statistically detect the
association. No study exhibited an association of leukemia with typical
household magnetic fields."
Asher Sheppard, the study's principal investigator and an assistant research
professor in the Department of Physiology and Pharmacology at Loma Linda
University, also cautioned that while the new analysis exhibits an association
between elevated magnetic fields and childhood leukemia, more research is
needed to determine if a causal relationship exists. "To confirm the association,
there would have to be studies of highly exposed populations, which might be
found in densely settled areas of some industrialized countries," Sheppard said.
Considerable uncertainty remains about the source of the association of
leukemia with high magnetic field exposures. "There could be some problem
shared by all the studies," Greenland said. "For example, other factors related
to both magnetic fields and childhood leukemia may be responsible for the
association."
Magnetic fields originate from everything with an electrical current. A field
spreads from a source in a manner analogous to a ripple emanating from a
pebble thrown in a pool of water, but penetrates objects in its path. Elevated
field levels can occur in homes close to power lines. Improper household wiring
occasionally can increase exposure to these fields as well.
The National Institute of Environmental Health Sciences funded the study, with
initial support from Southern California Edison. In addition to Greenland and
Sheppard, researchers involved with the study included William T. Kaune of
EM Factors in Richland, Wash.; Charles Poole of the Department of
Epidemiology at the University of North Carolina School of Public Health,
Chapel Hill; and Michael A. Kelsh of Exponent Health Group in Menlo Park,
Calif.
-UCLA-
DP520
chung_at_scripps.edu
Received on Mon Oct 30 2000 - 19:30:57 MST