While we've known for some time that along with diabetes and high blood pressure smoking is one of the major vascular risk factors that increases one's risk of Alzheimer's disease, a recent study gives us an idea of just how high that risk is with smoking. The study, published online yesterday in the Archives of Internal Medicine, analyzed data from over 20,000 members of a health care system who participated in a survey between 1978 and 1985. Over a quarter of those people ultimately developed dementia, and compared with nonsmokers those who smoked more than 2 packs per day in middle age were more than twice as likely to develop Alzheimer's disease. Those heavy smokers were also more than twice as likely to develop Vascular Dementia.
Those who smoked one to two packs per day had a 44% greater risk of developing dementia compared with nonsmokers, while even those who smoked just half a pack of cigarettes daily had a 37% increased risk. Even these findings are likely underestimates of the true risk of smoking, since some of the smokers likely died before dementia even developed.
The good news was that those people who had quit smoking by the start of the study didn't have an increased risk of dementia. But the bottom line remains that even if the lungs find a way to escape the damage of smoking cigarettes,the brain may not.