Past research has associated exposure to solvents with liver and kidney damage, respiratory impairments, reproductive damage and even cancer. Now, a new study suggests that individuals exposed to solvents - such as paint, glue and degreasers - at work may be at increased risk of memory and thinking problems later in life.
The research team, including Erika L. Sabbath of the Harvard School of Public Health in Boston, MA, recently published their findings in the journal Neurology.
Health problems as a result of chemical exposure is something of a hot topic at present. Earlier this year, Medical News Today reported on a study associating low-level pesticide exposure with Parkinson's disease. Other research found that food packaging chemicals may impact long-term health.
For this latest study, researchers wanted to see how certain solvents impacted the health of workers who were frequently exposed to them.
They analyzed 2,143 retirees from the French national utility company Electricite de France/Gaz de France (EDF-GDF) and assessed their lifetime exposure to:
- Benzene - used in plastics, rubber, dye, detergents and other synthetic materials
- Chlorinated solvents - used in dry cleaning products, engine cleaners, paint removers and degreasers, and
- Petroleum solvents - used in carpet glue, furniture polish, paint, paint thinner and varnish.
Researchers say that high exposure to certain solvents at work, such as paint and glue, may increase the risk of cognitive decline later in life.
They found that 26% of the participants were exposed to benzene, 33% were exposed to chlorinated solvents, 25% were exposed to petroleum solvents and the remaining 16% had no solvent exposure.
An average of 10 years following retirement and when participants were an average age of 66 years, they were required to take eight memory and thinking skills tests. The team found that 59% of participants had impairments on up to three of the eight tests, 23% had impairments on four or more tests and 18% had no impairments.
The researchers calculated each participant's lifetime exposure to the solvents using company records. Subjects were then divided into three groups; no exposure, moderate exposure and high exposure.
Participants were also divided dependent on their last chemical exposure. Recent exposure was associated with those who had worked with the chemicals in the previous 12 to 30 years, while those who last worked with the chemicals 31 to 50 years previously were considered to have distant exposure.
High solvent exposure affects cognition 'regardless of time interval'
Results of the study revealed that participants with high, recent exposure to solvents were most likely to have impairments in all areas of memory and thinking - even areas that are not usually linked with such exposure.
They found that those with high, recent exposure to chlorinated solvents, for example, were 65% more likely to have impaired scores on memory, visual attention and task switching, compared with those with no solvent exposure.
However, the team notes they were surprised to find that even individuals with high, distant exposure to solvents showed some cognitive impairments. Sabbath says:
"This suggests that time may not fully lessen the effect of solvent exposure on some memory and cognitive skills when lifetime exposure is high."
She adds that the team's findings could have ramifications for workplace policies regarding solvent exposure levels. Protecting workers from such exposure may not only protect their cognitive health, Sabbath notes, but it could also reduce post-retirement health care costs and allow them to work longer.
She adds that individuals who have already experienced prolonged exposure to solvents throughout their career may benefit from "regular cognitive screening to catch problems early, screening and treatment for heart problems that can affect cognitive health or mentally stimulating activities, like learning new skills."
Medical News Today recently reported on a study from researchers at the University of Florida, which detailed the discovery of a drug that may reverse age-related cognitive decline.