Smoking as a risk factor for dementia and cognitive decline: a meta-analysis of prospective studies.
The authors assessed the association of smoking with dementia and cognitive decline in a meta-analysis of 19 prospective studies with at least 12 months of follow-up. Studies included a total of 26,374 participants followed for dementia for 2-30 years and 17,023 participants followed up for 2-7 years to assess cognitive decline. Mean study age was 74 years. Current smokers at baseline, relative to never smokers, had risks of 1.79 (95% confidence interval (CI): 1.43, 2.23) for incident Alzheimer's disease, 1.78 (95% CI: 1.28, 2.47) for incident vascular dementia, and 1.27 (95% CI: 1.02, 1.60) for any dementia. Compared with those who never smoked, current smokers at baseline also showed greater yearly declines in Mini-Mental State Examination scores over the follow-up period (effect size (beta)=-0.13, 95% CI: -0.18, -0.08). Compared with former smokers, current smokers at baseline showed an increased risk of Alzheimer's disease (relative risk=1.70, 95% CI: 1.25, 2.31) and an increased decline in cognitive abilities (effect size (beta)=-0.07, 95% CI: -0.11, -0.03), but the groups were not different regarding risk of vascular dementia or any dementia. The authors concluded that elderly smokers have increased risks of dementia and cognitive decline.
Anstey
Kaarin J
KJ
Centre for Mental Health Research, School of Psychology, The Australian National University, Canberra, Australia. kaarin.anstey@anu.edu.au
von Sanden
Chwee
C
Salim
Agus
A
O'Kearney
Richard
R
D000368:Aged; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology*; D003704:Dementia / Q000453:epidemiology / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*