The investigators, led by Walter Rocca, M.D., a Mayo Clinic epidemiologist, discovered the highest increase in Parkinson's risk in people with nine or more years of education. They also found that risk level rises as years of schooling increase. Occupationally, physicians had the greatest increased risk for Parkinson's compared to the general population, while those employed as construction and extractive workers (e.g., miners, well drillers), production workers (e.g., machine operators, fabricators), metalworkers and engineers had the lowest risk increase. The researchers also note that this study did not find farmers and other agricultural workers at increased risk for Parkinson's.

The Mayo Clinic investigators advise caution in interpreting this study. "Our findings for education and occupation are complex, and therefore they need to be interpreted with care," says Roberta Frigerio, M.D., the study's first author and former Mayo Clinic research fellow. "These factors may be surrogates for a variety of exposures, physical activity, personality or socioeconomic status. Further studies are needed to interpret our findings."

Demetrius (Jim) Maraganore, M.D., Mayo Clinic neurologist and study investigator, agrees. "We really can't say from this study that education and occupation are causal factors in Parkinson's disease; we can only say that they are associated," says Dr. Maraganore. "I don't think that schooling or wearing a stethoscope causes brain cells to degenerate or that digging holes with a digger protects your brain cells from atrophy, but I think that these are indirect indicators of factors that may
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Contact: Lisa Lucier
newsbureau@mayo.edu
507-284-5005
Mayo Clinic
21-Nov-2005