P3‐582: TOBACCO EXPOSURE AND CESSATION IS ASSOCIATED WITH INCIDENT DEMENTIA AND NURSING HOME PLACEMENT

Although tobacco cessation clearly reduces risk for mortality, the relationship between tobacco use and risk for dementia is less clear. Some studies show that tobacco use does not alter the risk for Alzheimer's disease dementia, whereas other studies show an increased risk with tobacco use. The goal of the present project was to determine the relationship between cigarette smoking, characterized as total tobacco exposure (pack-years) and smoking cessation, and incident dementia and nursing home placement. The dataset included 20,927 individuals age 45 or older enrolled in the National Alzheimer's Coordinating Center (NACC). Participants with inherited forms of dementia and those with a dementia diagnosis at baseline were excluded. Cox proportional hazard models, using delayed entry, were adjusted for race, education, and sex. Three models were used to examine incident dementia/nursing home placement in those with normal cognition or MCI at baseline: (1) cigarette smoking status (never versus ever), (2) total tobacco exposure (pack-years), and (3) tobacco (smoking) cessation. Cigarette Smoking Status: Smoking status and risk for incident dementia/nursing home placement was nonsignificant. Level of tobacco exposure (pack-years): Those with normal cognition at baseline and a 30-60 pack-year history had an increased risk of incident dementia/nursing home placement compared to those with a <30 pack-year history (HR 1.46; 95% CI 1.12-1.90; p=0.005). When adding death as an additional event, the pattern of greater risk with increased exposure remained. Models including individuals with MCI at baseline were nonsignificant. Smoking cessation: In those with MCI at baseline, current smokers had a higher rate of incident dementia/nursing home placement than those who had quit smoking (HR 1.70; 95% CI 1.30-2.22; p=0.000). Similar findings were obtained in individuals with normal cognition at baseline; current smokers had a higher rate of incident dementia/nursing home placement than those who quit smoking (Figure 1; HR 2.23; 95% CI 1.54-3.22; p=0.000). Within cognitively healthy current and former smokers, those with greater tobacco exposure had an increased risk of incident dementia and nursing home placement. Compared to current smokers those who quit smoking showed a reduced risk for incident dementia and nursing home placement.