The extent of current knowledge of risk factors for Alzheimer's disease (AD) is still limited. We conducted a case-control study of 98 AD patients and 98 age- and sex-matched controls. Light smoking had a decreased risk for AD (AD: 2.0%, controls: 21.4%, odds ratio = 0.10, p = 0.003), whereas daily smoking showed a trend to increase the risk for AD (AD: 45.9%, controls: 26.5%, odds ratio = 1.73, p = 0.08). After multivariable analyses factors associated with AD included the presence of apolipoprotein epsilon4 allele, and the duration of well water consumption.