Final answer:
Excessive alcohol consumption is the factor least associated with increased incidence of Alzheimer's disease.
Step-by-step explanation:
The factor that is least associated with increased incidence of Alzheimer's disease is C. Excessive alcohol consumption. While factors such as head trauma, advanced age, and family history of Alzheimer's disease have been shown to increase the risk of developing the disease, excessive alcohol consumption does not have a strong association with Alzheimer's.