Relationship of Cigarette Smoking and Time of Quitting with Incident Dementia and Cognitive Decline

Jennifer A. Deal, Melinda C. Power, Priya Palta, Alvaro Alonso, Andrea L.C. Schneider, Kelly Perryman, Karen Bandeen-Roche, A. Richey Sharrett

Research output: Contribution to journalArticle

Abstract

OBJECTIVES: Understanding how dementia risk is impacted by timing of smoking cessation has public health implications for prevention efforts. We investigated the relationship of cigarette smoking and cessation with dementia risk and cognitive decline in the Atherosclerosis Risk in Communities (ARIC) study. DESIGN: Ongoing prospective cohort study. SETTING: Begun in 1987-1989, ARIC was conducted in four US communities. PARTICIPANTS: A total of 13 002 men and women (25% African American) aged 52 to 75 years. MEASUREMENTS: All-cause dementia was defined using standardized algorithms incorporating longitudinal cognitive data, proxy report, and hospital and death certificate dementia codes. Cognitive decline was measured using a composite cognitive score created from three tests measured at two time points (1996-1998 and 2011-2013). Smoking and cessation status were defined by self-report using data from 1987-1989 (visit 1) and 1996-1998 (visit 4). Incident dementia risk and differences in cognitive change by smoking status were estimated with Cox proportional hazards and linear regression models, respectively. To address smoking-related attrition, cognitive scores were imputed for living participants with incomplete cognitive testing. RESULTS: The proportion of never, former, and current smokers was 44%, 41%, and 14%; 79% of former smokers quit 9 years or more before baseline. A total of 1347 participants developed dementia. After adjustment, compared with never smoking, the hazard ratio for all-cause dementia for current smoking was 1.33 (95% confidence interval [CI] = 1.12-1.59) and for recent quitting (<9 y before baseline) was 1.24 (95% CI = 1.01-1.52). Quitting 9 years or more before baseline was not associated with dementia. We found no differences in rates of cognitive decline by smoking status. CONCLUSION: Although quitting at any time suggested benefit, dementia risk depended on time since smoking cessation. Our study highlights the importance of early midlife cessation to decrease dementia risk.

Original languageEnglish (US)
JournalJournal of the American Geriatrics Society
DOIs
StateAccepted/In press - Jan 1 2019

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Keywords

  • cessation
  • cognitive decline
  • dementia
  • smoking

ASJC Scopus subject areas

  • Geriatrics and Gerontology

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