Smoking, dementia and cognitive decline in the elderly, a systematic review.
BACKGROUND
Nicotine may aid reaction time, learning and memory, but smoking increases cardiovascular risk. Cardiovascular risk factors have been linked to increased risk of dementia. A previous meta-analysis found that current smokers were at higher risk of subsequent dementia, Alzheimer's disease, vascular dementia and cognitive decline.


METHODS
In order to update and examine this further a systematic review and meta-analysis was carried out using different search and inclusion criteria, database selection and more recent publications. Both reviews were restricted to those aged 65 and over.


RESULTS
The review reported here found a significantly increased risk of Alzheimer's disease with current smoking and a likely but not significantly increased risk of vascular dementia, dementia unspecified and cognitive decline. Neither review found clear relationships with former smoking.


CONCLUSIONS
Current smoking increases risk of Alzheimer's disease and may increase risk of other dementias. This reinforces need for smoking cessation, particularly aged 65 and over. Nicotine alone needs further investigation.
Peters
Ruth
R
Experimental Medicine and Toxicology Imperial College Faculty of Medicine, Hammersmith Campus, Du Cane Road, London, UK. r.peters@imperial.ac.uk
Poulter
Ruth
R
Warner
James
J
Beckett
Nigel
N
Burch
Lisa
L
Bulpitt
Chris
C
D000368:Aged; D000375:Aging / Q000502:physiology / Q000523:psychology; D003072:Cognition Disorders / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D003704:Dementia / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000503:physiopathology / Q000523:psychology