Neuropsychiatry and Memory Group, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205
We thank Drs. Kritz-Silverstein and Barrett-Connor for their observations (1). Edelstein et al. (2) reported that smoking is a confounding factor in the association between alcohol drinking and cognitive function. In our analysis (3), we used age, race, and education as covariates to adjust for the effect of variables other than alcohol use that might be associated with cognitive decline. We deliberately omitted drug use and cigarette smoking from the analysis because of previous reports, based on the Epidemiologic Catchment Area data set, of a lack of association between these factors and cognitive decline as measured by the Mini-Mental State Examination (4; K. Mehta, University of California, San Francisco, unpublished data). The use of the Mini-Mental State Examination may itself be a limiting factor in finding an association between smoking and cognitive decline using Epidemiologic Catchment Area data.
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