People who have worked in jobs with high levels of lead exposure are up to 3.4 times more likely to develop Alzheimer’s disease. “Lead exposure remains a major public concern because of its adverse effects on brain development and health in general, even with low exposure levels,” said Elisabeth Koss, Ph.D., study lead author at Case Western Reserve University and University Hospitals of Cleveland, Ohio. “This study suggests that we also need to be concerned because of very long-lasting changes to the nervous system that may increase the risk for Alzheimer’s disease.”
The study compared the occupational histories of 185 people with Alzheimer’s disease to 303 people without Alzheimer’s. Utilizing hazard lists developed by the National Occupational Exposure Survey, researchers estimated the probability of toxic exposure to a variety of agents used in each occupation. That occupation exposure was then multiplied by the number of years a person worked at a job to determine lifetime exposure.
Although previous studies have raised concerns about possible relationships between Alzheimer’s and many of these metals, including aluminum and solvents, only lead exposure was found to increase the risk of Alzheimer’s. The researchers believe that these concerns may have been due to the unrecognized effect of lead as many occupations involve multiple exposures to numerous potentially toxic materials.
In the workplace, people are most often exposed to lead by either breathing lead dust, which is considered to be the most toxic, or by direct skin contact.
Activities that can expose workers to lead are:
- smelting or casting lead
- removing lead coatings (welding, brazing, cutting, sanding or blasting old paints)
- heating, machining or spraying lead products
- making lead products (lead acid battery manufacturing, lead glazing pottery making, cable production, ammunition manufacture, production of lead pipe, cable shielding, electronic components, paint and ink manufacture)
Earlier studies have shown that education has a protective effect against Alzheimer’s. As people with less education are more likely to work in blue-collar jobs where there is a greater chance of toxic exposure than white-collar jobs, the researchers statistically adjusted for participants’ education levels.
For more information about the American Academy of Neurology, visit its Web site at www.aan.com. For online neurological health and wellness information, visit NeuroVista at www.aan.com/neurovista.
From the Daily Regulatory Reporter
