Final answer:
The prevalence of Parkinson's disease increases with age, most commonly diagnosed after 50. It leads to motor symptoms due to dopaminergic neuron loss in the substantia nigra. The provided prevalence options do not match the information presented.
Step-by-step explanation:
Parkinson's Disease Prevalence in the Older Population
When analyzing the prevalence of Parkinson's disease among various age groups, it is predominantly diagnosed in individuals after 50 years of age. Parkinson's disease is a neurodegenerative disorder characterized by symptoms such as muscle tremor, rigidity, slowness of movement, and postural instability. These primary symptoms arise due to the loss of dopamine neurons in the substantia nigra, which plays a crucial role in motor control. While both primary and secondary forms of the disease exist, with secondary Parkinson's disease sometimes linked to factors like toxin exposure or head trauma, the exact cause of neuronal death in most cases remains unclear. However, the presence of Lewy bodies is associated with this cell death. Medications can mitigate motor disturbances early in the disease, but they lose effectiveness and cause side effects as Parkinson's progresses.
Based on the provided information, none of the choices A through D accurately reflect the prevalence of Parkinson's disease in adults over specific ages. The data does not support the percentages given in the multiple-choice options.