There's no effective treatment for dementia, and cases keep growing.
The best bet at the moment is to reduce your risk, which is higher for people with type 2 diabetes.
A new study based on national health registers in Denmark suggests starting statin treatment after a type 2 diabetes diagnosis could lower the risk of dementia, and it seems that the sooner patients did, the better.
The research, published in The Lancet Regional Health, is an observational study, meaning it can find statistically relevant patterns at the population level, but doesn't necessarily explain what caused those patterns.
The results, however, were interesting enough that the researchers, led by medical doctor Tummas Ternhamar of the Copenhagen University Hospital, are urging doctors to consider statin therapy when diagnosing type 2 diabetes patients.
"In individuals developing type 2 diabetes, statins were associated with a lower risk of dementia, most pronounced in those with early initiation," Ternhamar explains.
"Statins seem to be underused in patients with type 2 diabetes, despite their protective effects against cardiovascular disease."
If you're not familiar with statins, here's a quick run-down.
Doctors prescribe these drugs when a person has high levels of low-density lipoprotein cholesterol (LDL-C, also sometimes referred to as 'bad' cholesterol, though it's really only bad when there's too much of it built up in your arteries – otherwise it's just a normal part of your body). They can find out if that's the case with a blood test.
People with type 2 diabetes are even more prone to excessive LDL-C levels than the general population, in part because of the important role insulin plays in regulating the liver's production of fats like LDL-C.
Having a high level of LDL-C is also a modifiable risk factor to prevent dementia, according to the 2024 Lancet Commission on dementia.
The way these diseases cluster – type 2 diabetes, excessive LDL-C, and dementia – had Ternhamar and team wondering if statin therapy among people with type 2 diabetes could make a difference in their dementia outcomes.
They consulted a massive database from the national Danish health register to find 132,585 people who were diagnosed with type 2 diabetes between 2006 and 2019.
These people had never taken statins before their diagnosis.
People who were prescribed statin treatment early (less than a year after the initial type 2 diabetes diagnosis) had a 15 percent lower relative risk of dementia at 10 years of follow-up, compared to those with type 2 diabetes who were never prescribed statins.
For people who were prescribed statin treatment late (one to five years after diabetes diagnosis), the relative risk was 10 percent lower at 10 years, again compared to those who were not prescribed statins.
The researchers also estimated the absolute risk of dementia after 10 years, which is the chance that a person in each group developed dementia within that time (as opposed to the relative risk, which compares the difference in risk between two groups).
Absolute risk across 10 years was 3.9 percent for those with no statin therapy, 3.5 percent in the group that started statins late, and 3.3 percent in the group that started statins early.
"People with type 2 diabetes already have a higher risk of dementia and are advised to lower cholesterol to reduce their risk of heart attack and stroke," says cardiovascular disease researcher Isabel Goncalves from the European Society of Cardiology, who was not involved in the study.
"This study suggests that starting statins soon after a type 2 diabetes diagnosis may also be linked to a modest reduction in dementia risk, with greater benefit than delaying treatment."
Being an observational study, it's unclear exactly why these patterns emerged. We won't know the exact mechanisms at play without further research.
Related: A Painful Side Effect of Statins Explained After Decades of Mystery
Nonetheless, the findings are interesting given that many type 2 diabetes patients can benefit from statin therapy, even without dementia risk factored in.
It's another good reason to consider this kind of treatment when receiving a diagnosis – with appropriate medical consultation, of course.
"Because statins are widely available and inexpensive, the findings are potentially important," Goncalves says.
"Our findings suggest another potentially important reason to ensure that patients with type 2 diabetes and high LDL-C receive timely statin treatment," Ternhamar says.
The research was published in The Lancet Regional Health.
This article was fact-checked by Fiona MacDonald and edited by Fiona MacDonald. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.