Year: 2021
Type: preprint
Study design: Observational Study
Abstract: Smoking is associated with dementia, but causality has not been well-established. Given smoking has a strong genetic component, we used genetic predisposition to smoking, based on a genome-wide association study (GWAS) from the GWAS & Sequencing Consortium of Alcohol and Nicotine use, as an instrumental variable. In a Mendelian randomization framework, we assessed the relationships between smoking and impaired cognitive status using the 2010 wave of the Health and Retirement Study. Cognitive status was assessed using cognition tests and categorized in three levels (normal cognition, cognitive impairment-non dementia, dementia). Smoking status was self-reported and classified into never, former, and current smoking. We used multivariable logistic regressions, Wald-type ratio estimators, and two-sample Mendelian randomization methods to examine associations and infer causal relationships. Among European genetic ancestry participants (n = 8741), current smoking was associated with cognitive impairment (OR = 1.62, 95%CI: 1.29, 2.01) relative to normal cognition. Two-sample Mendelian randomization results showed an inferred causal effect of smoking initiation on late-onset Alzheimer’s type dementia (MR-Egger: OR = 1.021, 95%CI: 1.017, 1.025). We observed no association between current smoking and dementia, or between former smoking and any cognitive status. No associations between smoking status and cognitive status were observed in the African genetic ancestry sample (n = 2501). Smoking behavior can give rise to cognitive impairment; therefore, promotion of smoking cessation is also important for brain health. Studies on dose and duration of smoking on cognition are critically needed, as well as continued research in non-European genetic ancestry study samples.
Source: Research Square
Authors: Mingzhou Fu, Jessica D. Faul, Yuan Jin, Erin B. Ware, Kelly M. Bakulski
Institution: University of Michigan
Language: English
Subfield: Psychiatry and Mental health
Field: Medicine
Domain: Health Sciences
Open Access status: green
Awards: Michigan Alzheimer's Disease Core Center, G1908904451, G2639381427, G319086767, G4428411940, Racial inequalities in health throughout adulthood: The cumulative impact of neighborhood chemical and non-chemical stressors on epigenomic pathways, G5442798412, G6449351383, G6975118844, Characterizing disparities in late-onset Alzheimer's disease risk through polygenic risk and epidemiologic factors in the Health and Retirement Survey, G8018240826, G8907452884, DNA Methylation,Genetics, and Modifiable Risk Factors of Dementia in a Nationally Representative, Multi-Ethnic Cohort, Michigan Center on the Demography of Aging
OpenAlex ID: W3164493566