We examined the associations of four single nucleotide polymorphisms (SNPs) on aldehyde dehydrogenase (ALDH) and alcohol dehydrogenase (ADH) genes (i.e., ALDH2 rs671, ADH1B rs1229984, ADH1B rs1042026, and ADH1C rs1693482) and cognitive impairment among the oldest-old. The gene discussed is ALDH2; the disease is Cognitive impairment.