 The disease is more common as we age, and as we'll probably discuss, it has numerous environmental factors that contribute to its rise. Is there a typical age when Parkinson's is first diagnosed? It's rare, but not unheard of before age 50. About 4% to 5% of people have it before age 50, maybe a little bit more. It increases to about 1% of people at 65 and 3% of people at 85 have the disease. And again, it's the fastest growing brain disorder in the world.