Common Workplace Solvents Linked To Long-Term Cognitive Problems
Those who work around paint, glue, or degreaser fumes on a regular basis may be at high risk of experiencing memory and thinking problems for years or even decades after exposure according to a recent study published in the journal Neurology.
“Our findings are particularly important because exposure to solvents is very common, even in industrialized countries like the United States.” Erika L. Sabbath, study author and researcher from the Harvard School of Public Health in Boston, said in a statement. “Solvents pose a real risk to the present and future cognitive health of workers, and as retirement ages go up, the length of time that people are exposed is going up, too.”
The researchers examined more than 2,143 retirees from the French national utility company. The participants were evaluated on their lifetime exposure to chlorinated solvents, petroleum solvents, and benzene, including questions such as the timing of last exposure and lifetime dosage.
Benzene is used in the manufacturing of rubber, plastics, dye, detergents, and other synthetic materials, while chlorinated solvents are common in dry cleaning solutions, engine cleaners, paint removers, and degreasers. Petroleum solvents are used in carpet glue, furniture polishes, paint, paint thinner, and varnish.
Of the participants, 26 percent were exposed to benzene, 33 percent to chlorinated solvents, and 25 percent to petroleum solvents.
The participants were given eight tests of their memory and thinking skills an average of 10 years after retiring, when the individuals were an average age of 66.
The researchers noted 59 percent of the participants had impairment on one to three of the eight tests, while 23 percent had impairment on four or more tests, and 18 percent had no impaired scores.
The average lifetime solvent exposure was determined by the researchers based on historical company records, and the participants were grouped as having no exposure, moderate exposure if they had less than the average, and high exposure if they had higher than the average. They were also categorized by when the last exposure occurred. Those last exposed from 12 to 30 years prior to the testing were considered as recent exposure, while those last exposed 31 to 50 years prior to testing were considered as more distant exposure.
According to the findings, people with high, recent exposure to solvents were at greatest risk for memory and thinking deficits.
“The people with high exposure within the last 12 to 30 years showed impairment in almost all areas of memory and thinking, including those not usually associated with solvent exposure,” Sabbath said. “But what was really striking was that we also saw some cognitive problems in those who had been highly exposed much longer ago, up to 50 years before testing. This suggests that time may not fully lessen the effect of solvent exposure on some memory and cognitive skills when lifetime exposure is high.”
It is important to note that the researchers did not directly measure whether these chemicals cause brain damage, as participants were not tested before exposure to the chemicals. However, there was a statistical association between impairment on tests and exposure to chemicals, indicating there is good reason for further research.