BACKGROUND: Previous studies suggested a protective effect of smoking on Alzheimer's disease, but most were case-control studies based on prevalent cases. The findings of prospective studies on the association between smoking and the risk of dementia are inconclusive. METHODS: We did a population-based follow-up study of elderly people who were initially free of dementia. 6870 people aged 55 years and older agreed to take part. Smoking history was taken at baseline and participants were classified as never smokers, former smokers, and current smokers. During follow-up, we recorded all incident cases of dementia. We used never smokers as the reference category to calculate relative risks of dementia and Alzheimer's disease by Cox proportional hazards regression, after adjustment for age, sex, education, and alcohol intake. We also examined modification of risk by age, sex, and the apolipoprotein E (APOE) genotype. FINDINGS: During mean follow-up of 2.1 (range 1.5-3.4) years, 146 incident cases of dementia were detected, of which 105 were Alzheimer's disease. Compared with never smokers, smokers had an increased risk of dementia (relative risk 2.2 [95% CI 1.3-3.6]) and Alzheimer's disease (2.3 [1.3-4.1]). Smoking was a strong risk factor for Alzheimer's disease in individuals without the APOEepsilon4 allele (4.6 [1.5-14.2]), but had no effect in participants with this allele (0.6 [0.1-4.8]). INTERPRETATION: Smoking was associated with a doubling of the risk of dementia and Alzheimer's disease. Our finding that carriers of the APOEepsilon4 had no increased risk of dementia suggests an interaction between smoking and the APOEepsilon4 genotype in the aetiology of Alzheimer's disease.
BACKGROUND: Previous studies suggested a protective effect of smoking on Alzheimer's disease, but most were case-control studies based on prevalent cases. The findings of prospective studies on the association between smoking and the risk of dementia are inconclusive. METHODS: We did a population-based follow-up study of elderly people who were initially free of dementia. 6870 people aged 55 years and older agreed to take part. Smoking history was taken at baseline and participants were classified as never smokers, former smokers, and current smokers. During follow-up, we recorded all incident cases of dementia. We used never smokers as the reference category to calculate relative risks of dementia and Alzheimer's disease by Cox proportional hazards regression, after adjustment for age, sex, education, and alcohol intake. We also examined modification of risk by age, sex, and the apolipoprotein E (APOE) genotype. FINDINGS: During mean follow-up of 2.1 (range 1.5-3.4) years, 146 incident cases of dementia were detected, of which 105 were Alzheimer's disease. Compared with never smokers, smokers had an increased risk of dementia (relative risk 2.2 [95% CI 1.3-3.6]) and Alzheimer's disease (2.3 [1.3-4.1]). Smoking was a strong risk factor for Alzheimer's disease in individuals without the APOEepsilon4 allele (4.6 [1.5-14.2]), but had no effect in participants with this allele (0.6 [0.1-4.8]). INTERPRETATION: Smoking was associated with a doubling of the risk of dementia and Alzheimer's disease. Our finding that carriers of the APOEepsilon4 had no increased risk of dementia suggests an interaction between smoking and the APOEepsilon4 genotype in the aetiology of Alzheimer's disease.
Authors: Bruce R Reed; Natalie L Marchant; William J Jagust; Charles C DeCarli; Wendy Mack; Helena C Chui Journal: Neurobiol Aging Date: 2011-11-10 Impact factor: 4.673
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Authors: Balenahalli N Ramesh; T S Sathyanarayana Rao; Annamalai Prakasam; Kumar Sambamurti; K S Jagannatha Rao Journal: J Alzheimers Dis Date: 2010 Impact factor: 4.472
Authors: Albert Hofman; Guy G O Brusselle; Sarwa Darwish Murad; Cornelia M van Duijn; Oscar H Franco; André Goedegebure; M Arfan Ikram; Caroline C W Klaver; Tamar E C Nijsten; Robin P Peeters; Bruno H Ch Stricker; Henning W Tiemeier; André G Uitterlinden; Meike W Vernooij Journal: Eur J Epidemiol Date: 2015-09-19 Impact factor: 8.082
Authors: Gjumrakch Aliev; Mark E Obrenovich; V Prakash Reddy; Justin C Shenk; Paula I Moreira; Akihiko Nunomura; Xiongwei Zhu; Mark A Smith; George Perry Journal: Mini Rev Med Chem Date: 2008-11 Impact factor: 3.862