Estimates suggest that about 50,000 Americans are diagnosed with PD each year, although some estimates are much higher. Getting an accurate count of the number of cases is difficult because many people in the early stages of the disease may assume their symptoms are the result of normal aging and do not seek medical attention. Diagnosis is sometimes complicated by the fact that other conditions may produce symptoms of PD and there is no definitive test for the disease. People with PD may sometimes be told by their doctors that they have other disorders, and people with PD-like diseases may be incorrectly diagnosed as having PD.
PD affects about 50 percent more men than women, and the reasons for this discrepancy are unclear. While PD occurs in people throughout the world, a number of studies have found a higher incidence in developed countries. Other studies have found an increased risk in people who live in rural areas with increased pesticide use. However, those apparent risks are not fully characterized.
One clear risk factor for PD is age. The average age of onset is 60 years, and the incidence rises significantly with advancing age. However, about 5 to 10 percent of people with PD have "early-onset" disease that begins before the age of 50. Some early-onset cases are linked to specific gene mutations such as parkin. People with one or more close relatives who have PD have an increased risk of developing the disease themselves, but the total risk is still about 2 to 5 percent unless the family has a known gene mutation for the disease. An estimated 15 to 25 percent of people with PD have a known relative with the disease.
In very rare cases, parkinsonian symptoms may appear in people before the age of 20. This condition is called juvenile parkinsonism. It often begins with dystonia and bradykinesia, and the symptoms often improve with levodopa medication.
Reference: National Institute of Neurological Diseases and Stroke
Last updated May 4, 2017
- Show All
- Causes & Risk Factors
- Signs & Symptoms
- Clinical Research