Statins not linked to cognitive decline shows study
MELBOURNE: Statins were not linked to any greater decline in cognition or memory over 6 years, a longitudinal study of elderly adults in Australia showed.
People, ages 70 to 90, showed no difference in the rate of decline in either memory or global cognition regardless of whether they ever used statins, reported Katherine Samaras, MBBS, PhD, of St. Vincent’s Hospital in Sydney.
Several longitudinal studies have shown no adverse association between statins and cognition, but many of them have limitations including short observation periods. Case reports of cognitive decline in statin users have concerned some people, and up to half of people prescribed statin therapy do not fill their prescription largely due to this concern, Samaras noted.
“We carried out the most comprehensive analysis of cognition in elderly statin users to date, and found no results to support that cholesterol-lowering statins cause memory impairment,” Samaras said in a statement. “There was also no difference in the change in brain volumes between the two groups.”
“Many factors can contribute to the cognitive symptoms that isolated case reports describe,” she added. “What we’ve come away with from this study is a reassurance for consumers to feel more confident about their statin prescription.”
The study used data from the Sydney Memory and Aging Study, an observational study of older community-dwelling Australians that started in 2005 to research the effects of aging on cognition over time. The Mini Mental State Examination (MMSE) was used to screen participants and exclude people with a score <24. In this analysis, researchers followed 1,037 people with an average age of 79, including 395 statin never-users and 642 ever-users (including 99 people who started statins during the study period), to follow changes in memory and global cognition over 6 years. Complete data were available for 573 participants (55%) over the study period. In a subgroup of 526 people, the researchers also looked at brain volume on MRI. To measure memory, the researchers developed a comprehensive assessment that incorporated a battery of tests evaluating new learning, short- and long-term recall, and visual and verbal retention. To measure global cognition, the researchers incorporated memory tests and assessments of processing speed, language, visuospatial ability, and executive function. Over the 6-year follow-up period, psychologists and nurses conducted neuropsychological testing every 2 years. The average duration of statin use was 9.1 years at baseline and 68% of statin users were continuous users. Statin users were slightly younger, had higher BMI, more vascular disease, and more cardiovascular risk factors. At baseline, statin ever-users and never-users showed similar total brain volume, hippocampal, and parahippocampal brain volumes. They demonstrated no significant differences on MRI 2 years later. Memory and global cognition scores also were similar between statin ever-users and never-users at baseline after adjusting for covariates, and there was no significant difference in the rate of decline in either memory or global cognition 6 years later. In the 99 people who started statins during the study period, statin initiation was associated with a lessening in the rate of decline of memory (B=0.066, P=0.038), at the test-wise significance level. Participants who took statins continuously had significantly higher baseline performance in memory and global cognition compared with never-users but over 6 years, the rate of decline in memory and global cognition was similar between continuous statin users and never-users. In exploratory analyses, ever-user patients with heart disease displayed a slower rate of decline on a learning memory test than never-users. Similarly, ever-users who carried the APOE-4 genotype showed a slower rate of decline in long-delayed recall performance (B=0.157, P=0.005). In an accompanying editorial, Costantino Iadecola, MD, and Neal Parikh, MD, both of Weill Cornell Medicine in New York City, wrote: "These data support the view that worries about cognitive impairment should not limit statin use and raise the possibility that statins may favorably alter cognitive trajectories in a group of elders at high risk of Alzheimer's disease." The last point is of great interest and requires additional clarification and validation, they added. But the study has significant limitations, Iadecola and Parikh noted, including the loss of 45% of participants to follow-up, the small sample size especially for new statin users, and likely unmeasured confounding. Last month, the NIH's National Institute on Aging (NIA) announced that it has funded a trial to look at benefits and risks of statins in adults, ages ≥75, without cardiovascular disease. The Pragmatic Evaluation of Events and Benefits of Lipid-Lowering in Older Adults (PREVENTABLE) study will help determine whether statins can help prevent dementia and disability in older adults while not increasing other risks.
