Smoking, APOE Genotype, and Cognitive Decline: The Rotterdam Study

The association of smoking with preclinical cognitive decline remains unclear and may be modified by the APOE epsilon 4 genotype. In 5,705 participants (mean age: 63.9 +/- 9.1 years; 57.4% women) from the population-based Rotterdam Study, we investigated the relationship between smoking and cognitive decline over a 5.5-year period and examined potential effect modification by APOE epsilon 4 genotype. We found that current smoking was related to decline in global cognition [ difference compared to never smoking: -0.06 (95% C.I.-0.10;-0.01)],as well as decline on specific cognitive tests including the Letter Digit Substitution Task, the 15-Word Learning Test, and the Purdue Pegboard. We found no evidence for effect modification by APOE epsilon 4 genotype on this relation.