Cigarette Smoking Status, Cigarette Exposure, and Duration of Abstinence Predicting Incident Dementia and Death: A Multistate Model Approach

Article type: Research Article

Authors: Johnson, Adrienne L.^{a; b; *} | Nystrom, Naomi C.^{c; d} | Piper, Megan E.^b | Cook, Jessica^{a; b} | Norton, Derek L.^f | Zuelsdorff, Megan^{e; g} | Wyman, Mary F.^c | Flowers Benton, Susan^{e; h} | Lambrou, Nickolas H.^c | O’Hara, John^{i; k} | Chin, Nathaniel A.^{e; i} | Asthana, Sanjay^{c; e; i; j} | Carlsson, Cynthia^{c; e; i; j} | Gleason, Carey E.^{c; e; i}

Affiliations: [a] William S. Middleton Memorial Veterans Hospital, Madison, WI, USA | [b] Center for Tobacco Research and Intervention, University of Wisconsin, Madison, WI, USA | [c] VA Geriatric Research, Education and Clinical Center (GRECC), William S. Middleton Memorial Veterans Hospital, Madison, WI, USA | [d] Department of Human Services - State of Minnesota, Anoka, MN, USA | [e] Wisconsin Alzheimer’s Disease Research Center, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA | [f] Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA | [g] School of Nursing, University of Wisconsin, Madison, WI, USA | [h] College of Nursing and Allied Health, Department of Rehabilitation and Disability Studies, Southern University and A&M College, Baton Rouge, LA, USA | [i] Division of Geriatrics, Department of Medicine, University of Wisconsin School of Medicine & Public Health, Madison, WI, USA | [j] Wisconsin Alzheimer’s Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA | [k] Institute of Living/Hartford Hospital, Hartford, CT, USA

Correspondence: [*] Correspondence to: Adrienne L. Johnson, PhD, Center for Tobacco Research and Intervention, University of Wisconsin, Madison, WI 53711, USA. Tel.: +1 608 265 4797; Fax: +1 608 265 3102; E-mail: aljohnson43@ctri.wisc.edu.

Abstract: Background:To fully characterize the risk for dementia associated with cigarette smoking, studies must consider competing risks that hinder the observation of dementia or modify the chance that dementia occurs (i.e., death). Extant research examining the competing risks fails to account for the occurrence of death following dementia, limiting our understanding of the relation between smoking and dementia. Objective:Examine the impact of smoking status, lifetime smoking exposure, and duration of abstinence on incident dementia, death following dementia, and death without dementia. Methods:Multi-state models estimated hazard ratios (HR) for 95% confidence interval (CI) of 10,681 cognitively healthy adults for transition from baseline to dementia, baseline to death, and dementia to death based on smoking status, lifetime cigarette exposure, and abstinence duration. Results:Compared to never smokers, current smokers had increased risk of dementia (HR = 1.66; 95% CI 1.18– 2.32; p = 0.004), and death from baseline (HR = 2.98; 95% CI 2.24– 3.98; p < 0.001) and incident dementia (HR = 1.88; 95% CI 1.08– 3.27; p = 0.03). Pack years increased risk of death from baseline (HR = 1.01; 95% CI 1.00– 1.01; p < 0.001), but not dementia risk (HR = 1.00; 95% CI 1.00– 1.00; p = 0.78) or death following dementia (HR = 1.01; 95% CI 1.00– 1.01; p = 0.05). Recent quitters (quit < 10 years), compared to never smokers, had increased risk of death after baseline (HR = 2.31; 95% CI 1.55– 3.43; p < 0.001), but not dementia (HR = 1.17; 95% CI 0.73– 1.88; p = 0.52) or death following dementia (HR = 1.01; 95% CI 0.42– 2.41; p = 0.99). Conclusion:Current smoking increases the risk for dementia and death, but dementia is better attributed to smoking recency than lifetime exposure. Smoking cessation at any age might reduce these risks for cognitively healthy individuals.

Keywords: Cigarette smoking, dementia, mortality, smoking cessation, statistics

DOI: 10.3233/JAD-201332

Journal: Journal of Alzheimer's Disease, vol. 80, no. 3, pp. 1013-1023, 2021