*Cognitive is a term that describes the process people use for remembering, reasoning, understanding, problem solving, evaluating, and using judgment. Cognition, more simply, is what a person knows and understands, or the process of knowing. It includes all aspects of perceiving, thinking, and remembering.

According to a large, multi-center study published in the March 23, 2004 issue of Neurology, the scientific journal of the American Academy of Neurology, smoking speeds up cognitive decline in the elderly.The rate of decline was found to be an average of five times higher per year in current smokers than those who never smoked.

Greater cognitive decline occurred with higher cigarette pack per year exposure, a calculation involving the number of years someone has smoked and the reported average daily number of cigarettes. This was significant mainly for the former smokers and not the current smokers. Former smokers showed twice the decline rate of those who never smoked.

Smoking could affect cognitive function through various mechanisms. Chronic tobacco use causes atherosclerosis and hypertension. This, and other effects of smoking, increase the risk of stroke and small, "silent" brain infarctions, according to study author Alewijn Ott, MD, of Erasmus Medical Center in Rotterdam, the Netherlands.

A family history of dementia did not influence the greater decline in cognition found among those who were smokers.

While more research is being planned, there are three very obvious lessons to be learned from this landmark study:
1. If you currently smoke, stop.
2. If you do not currently smoke, do not start.
3. How you feel is not a good indicator of health because all of the people experiencing cognitive decline did so slowly. Their health declined without symptoms for years.