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A US study has found that an adult with a blood
lead level of 20 to 29 micrograms per decilitre of blood is more likely to die earlier,
especially from circulatory disease or cancer, than adults with a level less than 10
micrograms per decilitre (10 µg/dL) Ten micrograms per declitre is the current US,
European and Australian "standard" for a maximum blood lead level.
Australia’s National Health and Medical Research Council recommends that all
Australians be below 10 micrograms. The US study, reported in the Archives of Internal
Medicine, found that the increase in all-cause mortality was 46%, from circulatory
disease, 39%, and 68% from cancer.
The authors of the study, Dr Mark Lustberg of the University of Maryland School of
Medicine, and Dr Ellen Silbergeld of Johns Hopkins University, call for efforts to reduce
exposure for anyone with a blood lead level of 20 micrograms per decilitre, or more, and a
reduction of the "acceptable blood lead level" for workers.
"We estimate that 29 million people (15% of the adult population older than 20
years) had blood lead levels of at least 20 µg/dL from 1976 to 1980", say the
authors. "A substantial number of Americans, then, are currently exposed to lead or
have a history of lead exposure."
"This study is hugely significant for Australia," says Elizabeth
O’Brien, National Coordinator of The LEAD Group, and Manager of the Lead Advisory
Service Australia. "The likelihood is that an even larger percentage of
Australians – more than 15% of the adult population - could be at risk of premature
death, given that the US started reducing lead in petrol in 1975 as compared to 1986
in Australia."
"The breadth of the study is remarkable, by Australian standards. It used
follow-up data for a US national survey carried out from 1976 to 1980, for participants
then aged 30 to 74 years."
"An Australia-wide blood lead level survey is vital, not only to establish blood
lead levels in the general population, but also to link blood lead levels with known risk
factors, and, potentially, uncover so-far unknown risk factors."
Australian doctors, says Ms O’Brien, have an inbuilt resistance to routinely
checking blood lead levels, especially in children. "Lead is notorious for not
producing clinical symptoms until you are, frankly, well on the way to being dead, or very
ill," she says. "Doctors are used to working from symptoms. They should be
working from risk factors, that is, from exposure to lead in the person’s work and
home life."
"A national survey in Australia would, one hopes, shake health professionals and
public health bureaucrats out of their complacency, which is based on the principle that
if you haven’t tested for a problem, it doesn’t exist. Australia has 3.7 million
dwellings built before 1970, when lead formed a now unacceptably high percentage of
paint."
"The US study gives the lie to the common belief that high blood lead levels are
only dangerous in childhood," says Ms O’Brien. "The present Australian
standard for maximum blood lead levels in adult workers exposed to lead is scandalously
high – 50 micrograms per decilitre" ### |
