Association of statin use with cognitive decline in elderly African Americans

Background: Previously reported associations between statin use and incident dementia or cognitive decline have been inconsistent. We report the results from a 3-year prospective study on the association of statin use on cognitive decline and incident dementia in elderly African Americans. Methods: A community-based cohort of 1,146 African Americans aged 70 and older living in Indianapolis, Indiana, was evaluated in 2001 and 2004. The instrument used for cognitive assessment was the Community Screening Interview for Dementia (CSI-D). Cognitive decline was defined as CSI-D scores measured at 2001 minus scores at 2004. Measurements of low-density lipoprotein cholesterol (LDL-C) and C-reactive protein (CRP) were obtained from baseline blood samples. Results: Adjusting for age at baseline, gender, education, and the possession of ApoE ε4 allele, baseline statin use was associated with less cognitive decline (p = 0.0177). There were no significant interactions of statin use when LDL-C and CRP were included. Logistic regression with the four independent variables showed that statin use may be associated with a reduction in incident dementia (OR = 0.32; p = 0.0673). Association with cognitive decline was less clear when investigating statin use over time. Significance remained only for those who discontinued prior to follow-up compared to continuous users or users who started after baseline. Conclusions: The relationship between statin use and cognitive decline is complex and subjected to unknown confounders. This effect may not be associated with the cholesterol lowering or anti-inflammatory action of statins. GLOSSARY: AD = Alzheimer disease; ANCOVA = analysis of covariance; BMI = body mass index; CAMDEX = Cambridge Examination for Mental Disorders of the Elderly informant interview; CERAD = Consortium to Establish a Registry for Alzheimer’s Disease; CHIF = Clinician Home-based Interview to assess Function; CRP = C-reactive protein; CSI-D = Community Screening Instrument for Dementia; HDL = high-density lipoprotein; HMG-CoA = 3-hydroxy-3-methylglutaryl-coenzyme A; LDL-C = low-density lipoprotein cholesterol; LLAs = lipid-lowering agents; NSAIDs = nonsteroidal anti-inflammatory drugs.