Viagra may reduce the risk of Alzheimer's: Alzheimer's disease, a rapidly progressive brain disease, is considered the leading cause of Dementia. In the US, approximately 5.5 million (55 lakh) people are affected by the disease and more than 24 million patients are expected worldwide. This brain disease can cause memory loss, thinking problems, and confusion over time. If Alzheimer's is not treated on time, it can increase the risk of Dementia. Statistics show that the cases of this disease have increased in the last few years in India.