Originally Published Online

Understanding PD
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Living Well With PD
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Clinical Trials
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An estimated seven to ten million people wake up to face the challenge of Parkinson’s disease everyday. It is a disease that knows no boundaries on the basis of age, race, religion or geographical borders. But there are some trends – who is at risk for developing Parkinson’s disease?

Age: Getting older is a risk factor. Parkinson's disease ranks among the most common late-life neurodegenerative diseases, affecting approximately 1.5% to 2.0% of the population older than the age of 60 years. Young onset Parkinson’s (before age 40) occurs in 5-10% of people diagnosed while 20% of those affected are under the age of 50.

Sex: Men are more likely (approximately 1.5 times) to develop Parkinson’s disease than women.

Heredity: In Parkinson’s, the vast majority of people have no family history of the disease but approximately 14% of people affected with PD have a first degree relative (parent, sibling or child) that is also living with the disease. A recent large - scale NIH (National Institute of Health in the U.S.) study recently identified 26 genetic risk factors that increase an individual’s chance of developing Parkinson’s disease. But it’s important to keep in mind that just because you have the gene does not mean you will get Parkinson’s. 

Toxin Exposure: Exposure to a number of pesticides and herbicides including commonly used Paraquat and Rotenone have been shown to be toxic to the brain when an individual is exposed to them repeatedly and for a prolonged time, resulting in a higher risk of developing Parkinson’s disease. In those that are genetically susceptible, the chances of developing Parkinson’s may be increased two to six-fold. Industrial solvents such as TCE (Trichloroethylene) and PCBs (Polychlorinated biphenyls) have also been shown to be associated with the development of Parkinson’s disease in individuals who have had long-term exposure.

Head Trauma: Research studies support the observation that head injuries, particularly those that involve a concussion or loss of consciousness may increase
the incidence of Parkinson’s. This risk seemed sustained over several years meaning that in a patient with PD, their personal history of head injury could be years prior to their symptoms developing.

Geography: Globally the prevalence of Parkinson’s disease is lower in Asia and Africa compared to Europe and North America. A study conducted in the U.S. showed regional variation where the highest incidences of Parkinson’s were found in the Midwest and Northeastern U.S.

Ethnicity: Caucasians are more likely to develop Parkinson’s disease compared to individuals with African or Asian ancestry. Also people of two particular ethnic backgrounds, Ashkenazi Jewish and North African Arab Berbers have significantly high prevalence of this disease.

Although we still don’t know what causes Parkinson’s disease,
researchers are trying to figure out why certain characteristics or situations put people at risk for developing PD. If they are able to find out why one group of individuals gets this illness, it may be helpful for all those affected.

References Used:
Tanner, Caroline M., MD. "Environmental Factors and Parkinson's: What Have We Learned?" - Parkinson's Disease Foundation (PDF). Parkinson's Disease Foundation, 2011. Web. 12 Sept. 2014.
Willis, Allison Wright, Bradley A. Evanoff, Min Lian, Susan R. Criswell, and Brad A. Racette. "Geographic and Ethnic Variation in Parkinson Disease: A Population-Based Study of US Medicare Beneficiaries." Neuroepidemiology 34.3 (2010): 143-51. Web.
Harris, M. A., H. Shen, J. K. C. Tsui, and K. Teschke. "Head Injuries and Parkinson's Disease in a Case-control Study." Occupational and Environmental Medicine 70.12 (2013): 839-44. Web.
Nalls et al. “Large-scale meta-analysis of genome-wide association data identifies six new risk loci for Parkinson’s disease” Nat. Genetics, July 27, 2014. DOI: 10.1038/ng3043