The etiology of Parkinson's disease is complex and not fully understood, but it is believed to involve a combination of genetic, environmental, and age-related factors. -Aging is the most significant risk factor for Parkinson's disease, with the majority of cases diagnosed in individuals over the age of 60. As people age, there is a natural decline in the function and integrity of dopamine-producing neurons in the brain, which may contribute to the development of PD.