Longest observational study to date finds no association between statin use and decline in memory or cognition
New research has found no association between statin use and memory change in older Australians.
A prospective observational study published this week in the Journal of the American College of Cardiology followed community-dwelling elderly aged 70-90 (n=1037) over six years, measuring at two-yearly intervals.
Researchers found no significant difference in the rate of decline in memory or global cognition between statin-users and never-users.
“This was in people who had ever used statins, people who used statins continuously over the six-year mark and between the different types of statins – so we couldn’t find that there was for example, a difference between the lipophilic versus the hydrophilic statin medication,” explains lead author Professor Katherine Samaras from the Garvan Institute of Medical Research.
“There is a commonly held consumer concern that statins cause memory loss,” she says.
“Overall these are very reassuring results for not only people who take statins but also people who prescribe them, like myself.”
Participants were recruited from the Sydney Memory and Ageing Study and those with a diagnosis of dementia, major neurological or psychiatric disease were excluded.
Researchers measured memory and global cognition through neuropsychological testing every two years across all participants.
“We had five distinct measures of memory, measured on four occasions over the six years. We didn’t just do a Mini-Mental State Examination, there were hours of neurocognitive assessments that our participants undertook,” Prof Samaras tells AJP.
A battery of five memory tests were used including total learning (the Rey Auditory Verbal Learning Test–total [RAVLT]); short-delayed recall (RAVLT-6 item); long delayed recall (RAVLT-7 item); the Benton Visual Retention Test recognition; and delayed recall (Logical Memory story A).
The study also measured brain volumes through magnetic resonance imaging in a subgroup (n=526).
There were no significant differences in the changes in brain volumes between statin ever-users and never-users over two years. Similar null results were found when examining continuous-statin use compared to never-use.
Prof Samaras says the research is the “most detailed and comprehensively measured study” of memory and the other cognitive domains related to statins to date.
“We’re one of the longest observational studies, and we’re one of the few studies to comprehensively include all of the covariates that also affect memory – not only age, sex and BMI but level of education, all the cardiovascular risk factors, and Alzheimer’s disease gene carriage. No study to date has done that to that extent.”
She says pharmacists can help to reassure patients who are taking statins that evidence shows the drugs do not contribute to cognitive decline.
“Pharmacists can be first point of contact for a lot of people and may have a role here when people say to them, ‘these [pills] make me stupid’, to suggest overall our data and other studies don’t support that statins have an impact,” she says, adding that patients who have further concerns should be referred to speak with their GP.
So what actually impacts memory and cognition in older people?
Dementia risk factors include heart disease, stroke, diabetes and family history, says Prof Samaras. There is also an Alzheimer’s dementia susceptibility gene.
“It’s the vascular side of cardiovascular risk factors that we can manage that do impact on dementia development. Anything that slows down cardiovascular disease and slows down vascular disease in the brain is important,” says Prof Samaras.
“It means appropriate diabetes management, it means appropriate hypertension management, appropriate management of vascular risk factors like hyperlipidaemia.
“Cognitive activity, physical activity, social engagement are all factors that help maintain cognitive health as we age.”
Meanwhile secondary analyses in the study revealed statins appeared to have protective effects in people with cardiovascular risk factors such as hypertension and a history of heart disease.
Additionally brain volume declined at a much slower rate in people who had diabetes and took a statin compared to people with diabetes who weren’t on a statin.
However Prof Samaras says these results should be interpreted with caution.
“These are interesting findings but they have to be taken with a measure of limitation, as it’s observational data and not a randomised controlled trial,” she says.
“We did find these effects that might be beneficial but I think we have to be quite conservative in how we interpret that.”
See the full study here (login required)