My father is 65 years old and is complaining of his hands trembling. Could it be the start of Parkinson's disease? At what age does Parkinson's disease usually start affecting a person?
It can start anytime after the age of 40. He should see a neurologist.
Parkinson's can affect even younger people. Michael Fox is an example...
It is variable and can be as early as late 30's to much later in life. Everyone is different. He should see a neurologist if you are worried.