Fewer cigarettes smoked does not reduce the risk of dementia.

Study participants who quit smoking completely had an 8% lower risk of developing dementia, a 6% lower risk of Alzheimer's disease, and a 16% lower risk of vascular dementia. And those who simply reduced the number of cigarettes they smoked per day even had increased risks. One explanation could be compensatory smoking among people who cut back on cigarettes. The feeling of nicotine withdrawal can cause people to inhale deeper, negating any potential health benefits.