The number of individuals with Parkinson's disease in 15 of the world's largest nations will double over the next generation, according to a study published in the January 30 issue of the journal Neurology. The study highlights the significant challenge facing countries with rapidly growing economies, particularly in Asia, many of which are ill prepared to meet this impending public health threat.
In recent years, a great deal of resources and energy have been focused on confronting infectious diseases such as HIV, malaria, and tuberculosis. This is highlighted by high-profile private investments in these areas by organizations such as the Gates Foundation. However, while infectious diseases have attracted the greatest attention from international donors, it is non-communicable chronic diseases, such as Parkinson's, that represent a far greater burden in terms of economic and social cost to developing nations.
University of Rochester neurologist Ray Dorsey, M.D., and a team of researchers examined the projected population growth in the five largest countries in Western Europe (France, Spain, Germany, the United Kingdom, and Italy) and the 10 most populous nations worldwide (China, India, Indonesia, the United States, Brazil, Pakistan, Bangladesh, Nigeria, Japan, and Russia). They then projected the prevalence of the disease by age group in each country. Their research estimates that the number of individuals with Parkinson's disease in these 15 countries will grow from 4.1 to 8.7 million by the year 2030. While the number of individuals with the disease will nearly double in the United States to 610,000, the greatest growth will occur in developing countries in Asia. By 2030, an estimated 5 million people in China will have the disease.
"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, where Parkinson's may not be viewed as a major public health problem," said Dorsey. "Moreover, 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."
Parkinson's disease is a degenerative disorder of the central nervous system that impairs motor skills and walking. Despite the fact that the disease is treatable with a combination of medications, therapy and exercise, many individuals in the developing world do not receive appropriate care and may not even be aware of their diagnosis. Dorsey and his colleagues noted that in door-to-door surveys in Bolivia, for example, none of the individuals who were found to have Parkinson's disease had ever seen a physician for their problem.
The growth in chronic diseases such as Parkinson's is one of the unfortunate byproducts of development. Economic growth and the corresponding improvements in health care and education are increasing the life expectancy of individuals in the developing world. In terms of the rise in chronic diseases, the key factor is not overall population growth but rather the number of people over age 65 and thus at risk of developing Parkinson's and other chronic conditions. Furthermore, as income grows, so too does health care spending which, in turn, increases the duration of illness and the overall number of people with a particular disease.
Without the proper systems of medical treatment and social support, chronic diseases can cause significant economic displacement in the form of lost productivity. According to the World Health Organization, China, India, and Russia could forego between $200 billion and $550 billion in national income over the next 10 years as a result of only three chronic diseases: heart disease, stroke and diabetes. Furthermore, 60 percent of deaths worldwide are the result of chronic disease, more than double all infectious diseases, maternal and infant conditions, and nutritional deficiencies combined.
"Understanding and predicting the burden of disease is critical to guiding future health, social and economic policy," said Dorsey. "The challenge for these developing countries that currently don't have the infrastructure in place to care for the small burden they have now is how they will develop this capacity over time recognizing that the costs will grow."