Exposure to paints, degreasers, adhesives and glues
is common in some occupations, and has been linked to problems such
as memory loss, reduced cognitive processing speed and difficulty
“We do know that in the short term, certain chemicals at work –
solvents – are known to affect cognitive health, but there isn’t a
lot done that has looked at the long-term impact on cognitive
function, particularly after people retire,” said Erika Sabbath, of
the Harvard School of Public Health in Boston, who led the study.
Problems at older ages, things like memory, reasoning or
task-switching are very common, and we know surprisingly little
about what causes them or how to prevent them, she told Reuters
Generally, this is the same period of life when people begin to
experience cognitive decline, she added, so she and her colleagues
wanted to see if there were certain patterns of lifetime exposure to
solvents that predicted cognitive problems after retirement.
“When we looked at those where the exposure happened a long time
ago, 30 to 50 years before, we found that the effects of solvents on
cognitive function didn’t necessarily fade away,” she said.
The study also found that people who had the most exposure to
solvents and were also exposed most recently had cognitive problems
in areas classically associated with solvent exposure, but also
other areas of cognitive function.
The findings were published in Neurology.
The researchers used information from the GAZEL cohort – a large
study made up of workers with the French national utility company –
that began in 1989.
They analyzed data on 2,143 male retirees, but did not include women
because they were generally not exposed to high levels of solvents.
Using company records, they assessed the workers’ lifetime exposure
to fumes from chlorinated solvents, petroleum solvents, benzene and
non-benzene aromatic solvents.
The participants were categorized as having no exposure, moderate
exposure if they had less than the average amount and high exposure
if they had greater than the average amount of solvent exposure.
The research team also divided the participants according to whether
they were exposed 12 to 30 years prior to the cognitive testing –
the “recent exposure” group – or 31 to 50 years earlier, the
“distant exposure” group.
Overall, 26 percent of the men were exposed to benzene, 33 percent
to chlorinated solvents and 25 percent to petroleum solvents.
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When they were about 10 years into retirement, at an average age of
66 years old, they took eight tests that measured their memory and
A total of 59 percent of the participants had impairment on between
one and three of the eight tests, 23 percent had impairment on four
or more tests and 18 percent had no impaired scores.
The research found that retirees with high, recent exposure were at
greatest risk for memory and thinking deficits, but the risk still
remained somewhat elevated for those who were exposed more than 30
years before testing.
The findings didn’t change when the researchers took education, age,
smoking and alcohol consumption into account.
Sabbath explained that her study didn’t look at exact dosage of
solvent exposure, but previous studies indicate that solvents can
have a negative impact on health at legal limits.
The Occupational Safety and Health Administration, or OSHA, sets
U.S. standards on how solvents should be handled in the workplace
and what levels of exposure are safe.
Sabbath cautioned that only a person who is certified in industrial
hygiene can give detailed advice for workers currently exposed to
specific solvents on how to protect themselves, but she offered some
“In general using a respirator, ventilating the area and if possible
eliminating the exposure altogether, for example, people who use
paints to switch to versions that have no or lower levels of VOCS,
the volatile organic compounds,” she said.
Neurology, online May 12, 2014.
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