Parkinson's disease is a degenerative central nervous system disorder that commonly causes a breakdown in muscle function and speech.
The study, published in January 30 issue of "Neurology," used projections of population growth and current prevalence of the disease to predict how many people in 2030 will have Parkinson's disease. The greatest predictor is the number of people in a society over the age of 65, the population at highest risk for chronic diseases such as Parkinson's.
The study looked at data from Bangladesh, Brazil, China, France, Germany, India, Indonesia, Italy, Japan, Nigeria, Pakistan, Russia, Spain, the UK and the United States, and concluded that the number of people with Parkinson's in these countries will rise from 4.1 to 8.7 million. This includes 610,000 in the United States (twice the current number) and 5 million in China.
Researchers expressed concern that the greatest growth in the disease is expected in countries that are ill-prepared to cope with the social costs of such an epidemic.
"The bulk of the growth in Parkinson's disease in the next 25 years will not be in the United States and Europe but in other places, namely China," said lead researcher Ray Dorsey, M.D. "This growth will occur in societies where there is very limited infrastructure in place to diagnose individuals, much less address their medical needs or the societal impact."
The report noted that according to door-to-door surveys conducted in Bolivia, none of the people who researchers determined to have Parkinson's disease had ever seen a doctor for their symptoms.
The study takes into account only the growth in Parkinson's due to a growing and aging world population. It does not factor in potential causes of Parkinson's such as exposure to pesticides and other industrial toxins, or how exposure to these risk factors may change in the coming decades.