This longitudinal study conducted by Steenland et al explored the effects of statins on cognitive decline in healthy elderly adults. Over 5000 research volunteers were evaluated in the minimum requirement of at least 3 annual visits with an average follow-up of 3 years. The effect of statins on cognitive decline in subjects with normal cognition at baseline and subjects with mild cognitive impairment (MCI) at baseline were evaluated separately.
Cognitive performance was assessed according to 10 neuropsychological indices and the Clinical Dementia Rating Sum of Boxes (CDR-SOB). Repeated-measures analysis were conducted and adjusted for age, sex, comorbidities, education and a family history of dementia. The inclusion criteria required that participants have a diagnosis of normal cognition or MCI from the clinicians at each center.
Longitudinal linear regression analyses were conducted to determine whether there was a difference in cognitive change over time between statin users and nonusers. Of participants with normal cognition at baseline, statin users performed significantly better across all visits and had significantly slower annual worsening in CDR-SOB scores (P = .006). For participants with MCI, statin users performed significantly better across all visits on attention measures, verbal skills, and executive functioning, but there were no differences in cognitive decline between users and nonusers. Thus the authors postulate that statins exert an effect only before significant deterioration is observed. Supplemental stratified analyses considered the approximately 60% of the population in the study with data on apolipoprotein E (APOE). The data were stratified according to APOE4 status (variant, present or absent). A stronger protective effect of statins against the Mini-Mental State Examination (MMSE) decline was found in participants with normal cognition at baseline in those without the APOE4 variant, although this protective effect was not significant (P = .08); no suggestion of a protective effect was found for those with the variant (P = .95). In sum, this study demonstrated a modest but positive effect of statin use for those with normal cognition but not for those with MCI.
- Elderly adults with normal cognition at baseline who used statins had a slower rate of annual cognitive decline.
- Statin users performed significantly better across all visits on attention measures, verbal skills, and executive functioning in participants with MCI.
- For participants with MCI, there were no differences in cognitive decline between users and nonusers.
Journal of the American Geriatrics Society, September 2013