Current smoking and response to cholinesterase inhibitor therapy in Alzheimer's disease

Current smoking has been suggested as predicting poor response to cholinesterase inhibitor treatment. This observational study compares response in subjects with NINCDS-ADRDA 'probable' Alzheimer's disease who are current smokers and subjects who are non-smokers. Smoking status was not associated with response. Smokers were significantly more likely to improve Digit Symbol Substitution Test (DSST) scores following treatment. In non-smokers, improvement from baseline DSST scores was associated with good response but this was not the case in smokers. The change in the DSST is in keeping with smokers having increased numbers of nicotinic receptors. In smokers, the lack of association between improvement in DSST scores and good response may be representative of inhibitory properties of cigarette smoke that are unrelated to nicotine.