WEDNESDAY, Dec. 1, 2010 (HealthDay News) -- Being exposed to pesticides over a long period of time might be linked to dementia, a new study of agricultural workers suggests.
The research effort included 614 vineyard workers in France who were in their 40s and 50s and had worked for at least 20 years in the agricultural sector. Their intellectual abilities were assessed twice, using nine tests designed to measure memory and recall, language retrieval, verbal skills and reaction time.
The workers' exposure to pesticides during the six-year span of the study varied. About 20 percent were never exposed to pesticides and more than half had been directly exposed, which included mixing or applying pesticides and cleaning or repairing spraying equipment. The rest had either been indirectly exposed by coming into contact with treated plants or possibly indirectly exposed through their work in buildings, offices, cellars and the like.
On seven of the nine tests, workers who had been exposed to pesticides were most likely to do worse the second time they were tested, the researchers found. The study also reported that pesticide-exposed workers were up to five times more likely than the others to have lower test scores on both occasions and were twice as likely to show a drop of two points in the Mini Mental State Examination (MMSE), which tests cognitive functioning and is frequently used to determine if a person has dementia.
The decline in MMSE score "is particularly striking in view of the short duration of follow-up and the relatively young age of the participants," Isabelle Baldi, of the Institute de Sante Publique d'Epidemiologie et de Developpement in Bordeaux, France, and colleagues wrote in the report published in the Dec. 2 online edition of Occupational and Environmental Medicine.
"The mild [cognitive] impairment we observed raises the question of the potentially higher risks of injury in this population and also of possible evolution towards neurodegenerative diseases such as Alzheimer's disease or other dementias," the study authors added.
The U.S. National Institute of Environmental Health Sciences has more about pesticides.