APOE e4 genotype and cigarette smoking in adults with normal cognition and mild cognitive impairment: a retrospective baseline analysis of a national dataset.

BACKGROUND: APOE e4 genotype is known to be a risk factor for Alzheimer's disease and atherosclerosis. Recently, published evidence has shown that APOE e4 genotype may also be associated with the cessation of cigarette smoking.
OBJECTIVES: The aim of this retrospective analysis was to explore whether any past smoking outcomes differed based on APOE e4 genotype in a large national dataset.
METHODS: Data were extracted from the National Alzheimer's Coordinating Center's longitudinal Uniform Data Set study. We limited this retrospective baseline analysis to the normal cognition (n = 2995) and mild cognitive impairment (n = 1627) groups that had APOE genotype and smoking data. Because this was an exploratory retrospective analysis, we conducted descriptive analyses on all variables based on APOE e4 genotype. We controlled for demographic, clinical, medication and neurocognitive data in the analyses.
RESULTS: In both the normal cognition group and the mild cognitive impairment group, e4 carriers and e4 non-carriers did not significantly differ on total years smoked, age when last smoked and the average # of packs/day smoked during the years they smoked. In both groups, e4 carriers and e4 non-carriers differed on various neurocognitive measures.
CONCLUSION: These data do not support the recently published evidence of the association between APOE e4 genotype and smoking outcomes. SCIENTIFIC SIGNIFICANCE: Larger prospective clinical trials are needed to further explore the relationship between APOE genotype and smoking outcomes.