Loss of sense of smell with age is likely correlated with the loss of other sensory neurons and is associated with aging.

“So, these neurons turnover throughout the lifespan and as we age, we actually can lose our sense of smell. And it's likely, I want to underscore likely, that that loss of sense of smell as we age is correlated with a loss of other neurons in the retina, in the ears, a loss of vision, loss of hearing, loss of smell, loss of the sense apparati which our neurons is correlated with aging.”