Table 65Tobacco use and risk of cognitive decline – recent cohort studies

StudySample (n)FollowupExposureCase definitionConfounding adjustmentResults
Barnes et al., 2007271Community cohort (9704)6 to 15 years (median, 10)Self-report smoking historyCognitive decline on a 26-point version of MMSE
Grouped as “maintain cognition,” “minor decline,” or “major decline”
Age
Educational level
Baseline cognitive status
Study site
Risk of maintaining optimal cognitive function versus minor cognitive decline related to lack of smoking: OR 1.73 (95% CI 1.30 to 2.30)
Reitz et al., 2005361Community cohort (791)5-year intervalSelf-report smoking historyDecline on cognitive testsAge
Educational level
Race
Sex
HTN
Heart disease
DM
APOE
Estimated beta coefficient (SE):
Abstract/visuospatial
≤ 75 years: No significant interaction between time x current smoking (beta = 0.1[0.5]; p = 0.9)
> 75 years: No significant interaction between time x current smoking (beta = −0.4 [0.5]; p = 0.5)

Memory
≤ 75 years: No significant difference between time x current smoking (beta = −1.1 [1.6]; p = 0.5)
> 75 years: Significant interaction between time x current smoking (beta = −4.0 [1.8]; p = 0.02)

APOE −/−
Memory
≤ 75 years: Time x current smoking (beta = −1.3 [1.9]; p = 0.5)
> 75 years: Time x current smoking (beta = −5.5 [2.3]; p = 0.016)

Abstract/visuospatial
≤ 75 years: Time x current smoking (beta =0.4 [0.6]; p = 0.5)
> 75 years: Time x current smoking (beta= −0.3 [0.7]; p = 0.7)
Among individuals with one or more APOE e4 alleles
Memory
≤ 75 years: Time x current smoking (beta =−0.1 [2.7]; p = 0.9)
> 75 years: Time x current smoking (beta = −0.9 [2.8]; p = 0.7)

Abstract/visuospatial
≤ 75 years: Time x current smoking (beta = −0.6 [1.0]; p = 0.5)
> 75 years: Time x current smoking (beta = −0.4 [1.2]; p = 0.7)
Solfrizzi et al., 2004266Community cohort, including institutionalized subjects (1566)3.5 yearsSelf-report smoking historyVariation of Petersen MCI criteriaAge
Educational level
Total cholesterol
HTN
Coronary artery disease
RR
Pack years: 0.94 (95% CI 0.62 to 1.42)
Yaffe et al., 2009258Community cohort (2509)8 yearsSelf-reported information on current smokingLongitudinal performance on the 3MS.
Maintainers: Predicted slopes of 0 or greater (indicating no change or improvement in cognitive scores over time)
Minor decliners: Predicted slopes less than 0 decline in cognitive score over time) but no more than one SD below the mean of the slopes
Major decliners: Predicted slopes more than 1 SD below the mean
Age
Rac
Educational leve
APOE genotype
When controlling for about 20 other factors associated with being a maintainer or decliner, risk of being a cognitive maintainer vs. a minor decliner for individuals who did not currently smoke vs. current smokers: OR 1.84 (95% CI 1.14 to 2.97)

Risk of being a major decliner vs. a minor decliner: OR 1.15 (95% CI 0.72 to 1.84)
Cherbuin et al., 2009257Community cohort (2082)4 yearsSelf-report information about current and past smokingPublished criteria for MCI, AAMI, AACD and other cognitive disorderAge
Sex
Educational level
Incident MCI: Past smoking was associated with higher risk of MCI compared to never smoking (OR 3.22; 95% CI 1.05 to 9.87, p = 0.04)

Incident any MCD: Past smoking was associated with higher risk of MCD compared to never smoking (OR 1.97; 95% CI 1.12 to 3.44, p = 0.03)

Abbreviations: 3MS = Modified Mini-Mental State Examination; AACD = aging-associated cognitive decline; AAMI = age-associated memory impairment; APOE = apolipoprotein E gene; APOE e4 = e 4 allele of the apolipoprotein E gene; CI = confidence interval; HTN = hypertension; DM = diabetes mellitus; MCD = mild cognitive disorder; MCI = mild cognitive impairment; MMSE = Mini-Mental State Examination; NS = not statistically significant; OR = odds ratio; RR = relative risk; SD = standard deviation; SE = standard error

From: 3, Results

Cover of Preventing Alzheimer's Disease and Cognitive Decline
Preventing Alzheimer's Disease and Cognitive Decline.
Evidence Reports/Technology Assessments, No. 193.
Williams JW, Plassman BL, Burke J, et al.

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