Worldwide, cases of Parkinson’s disease are projected to double by 2040, according to recent research. Scientists who are investigating the causes of a disease they say is approaching pandemic proportions discuss ways to mitigate it.
Taking on a disturbing characteristic of certain infectious diseases, Parkinson’s is rapidly affecting growing numbers of people. That is likely to continue, according to a commentary published recently in JAMA Neurology.
Its authors, Bastiaan R. Bloem, MD, PhD, Professor of Neurology at Radboud University Medical Center in the Netherlands, and Ray Dorsey, MD, Professor of Neurology at University of Rochester Medical Center in New York, note that worldwide, cases of Parkinson’s disease more than doubled from 1990 to 2015. The “Global Burden of Disease Study 2015” estimated that well over 6 million people were living with Parkinson’s disease at the end of that period. And that may be a conservative figure.
“It’s hard to determine, and almost any way you do it, you undercount,” says Dr. Dorsey, a coauthor of the 2015 study. “The means by which we determine who has any condition is limited and especially difficult for people who are older and more disabled.”
The authors also note that the prevalence of Parkinson’s is expected to more than double again by 2040, when the number of people with the disease may reach 14.2 million globally.
“There’s a good likelihood that [healthcare providers] even outside the field of neurology and outside the field of Parkinson’s will somehow meet people with Parkinson’s in the near future because it is such a complex disease. On my last count, there were over 23 professional disciplines [involved in] the care of people with Parkinson’s. It’s not just neurologists.”
— Bastiaan R. Bloem, MD, PhD, Professor of Neurology at Radboud University Medical Center in Nijmegen, the Netherlands
Drs. Bloem and Dorsey attribute the sharp increase to four key factors — the first two related to longer lifespans.
“The incidence rises sharply with age around 65, and there are more people 65 and older in the U.S. and around the world than there were 25 years ago,” Dr. Bloem says. “Additionally, people are living longer, so the longer you live, the more likely you are to develop any condition, especially those that are associated with aging, like Parkinson’s disease.”
Environmental influences are the third factor driving the rapid increase of Parkinson’s.
In 1817 London, during the height of the Industrial Revolution, Dr. James Parkinson described the disease after treating a number of patients who reported symptoms of a condition that hadn’t previously been recognized. Since those initial reports, more than 1,000 studies have linked byproducts of the Industrial Revolution, such as heavy metals and solvents, as well as pesticides, to Parkinson’s. Individuals exposed to these chemicals are at two to five times higher risk of developing the condition than those who have not been exposed, according to Dr. Dorsey.
The fourth factor may be confounding to medical professionals and the general population alike. For uncertain reasons, smoking is associated with a 40 percent decreased risk of developing Parkinson’s disease. In recent years, smoking rates have steadily declined, especially in the U.S.
“That, by one estimate, will increase the number of people affected by Parkinson’s by about 10 percent to the extent that smoking and/or its factors are causally related to Parkinson’s,” Dr. Dorsey says. “It’s not just something that’s pure association.”
A Pressing Need
There is great urgency in combating the growing incidence of Parkinson’s, observers say.
“The increase of Parkinson’s disease, as well as other degenerative diseases, is crucial to be addressed now because it will have a major impact to the society economically and socially,” says Rodolfo Savica, MD, PhD, Consultant of Neurology at the Mayo Clinic Rochester and Associate Professor of Neurology and Epidemiology at the Mayo Clinic School of Medicine in Rochester, Minnesota. “Recent data on the costs of patients with Parkinson’s disease revealed how medical care costs more than doubled compared to patients without Parkinson’s.”
Key steps to address the prevalence of Parkinson’s during the coming years, according to Dr. Dorsey, include minimizing or eliminating the use of certain pesticides, such as paraquat, and industrial solvents, such as trichloroethylene. Encouraging individuals to exercise vigorously and regularly, especially during their 30s and 40s, is essential as well.
Drs. Dorsey and Bloem also emphasize the importance of advocating for increased funding and research to better understand causes and risk factors for the disease. They point out that HIV research gets roughly $3 billion annually from the National Institutes of Health, whereas less than $200 million goes to research on Parkinson’s disease — which affects about half as many Americans as HIV.
In addition, they stress the need to develop new vaccines, improve access to care and lower treatment costs.