5 Unexpected Things That Seem to Lower Dementia Risk

Strange as it might seem, our eyes are essentially an extension of the brain. So maintaining the health of our eyes may have an added effect in keeping the brain healthy, too. And that maintenance might include the treatment of cataracts, a condition where the lens of our eyes start to cloud up, obscuring our vision.

A study out this month found that people over 65 who had their cataracts surgically removed were nearly 30% less likely to develop dementia than those who didn’t. This lowered risk was seen even after other risk factors for dementia were controlled for, and the effect seemed to last at least a decade later.

This reduction in risk might happen because people’s improved vision post-treatment helps keep the brain active, the researchers theorize. It could also be the result of the treatment specifically improving people’s ability to process blue light, which could reawaken cells in the retina associated with healthy sleep and cognition. As further evidence for that theory, it’s suspected that people with other eye disorders involving the retina are at higher risk for dementia as well.

The eyes aren’t the only window to the brain—our ears, too, are thought to influence cognitive health. Many studies have found a link between hearing loss and an increased risk of dementia. And some have found that hearing aids may help to mitigate that risk.

With both the eyes and ears, it’s possible that preventing the brain from losing sensory input can help stave off the degradation that leads to dementia. But there may be more indirect benefits involved, too. A 2019 study, for instance, found that people who received hearing aids soon after their diagnosis were not only less likely to be diagnosed with dementia but also less likely to suffer depression and falling injuries—both of which could contribute to dementia risk themselves.

The theory that some infections can raise the risk of dementia had long been seen as fringe. But in recent years, newer studies have started to reverse that perception. Researchers have found traces of herpesviruses in the brains of Alzheimer’s patients, as well as evidence that these infections can somehow contribute to the development of plaques and tangles, the damaging clumps of amyloid and tau proteins definitively linked to Alzheimer’s. It’s possible, though still very speculative, that infections from SARS-CoV-2, the coronavirus, could also raise the risk of dementia.

There is still much disagreement about exactly how (and how often) these germs contribute to Alzheimer’s disease, and not all recent studies have been supportive of the theory. But there have been recently launched trials testing out whether antiviral treatments for older people with herpes can reduce their dementia risk down the road. So we may have more answers soon enough.

It’s no surprise that exercise is good for you. But these positives extend beyond keeping your legs and lungs strong. Numerous studies have shown that people who regularly exercise are less likely to develop dementia. Exercise may in fact be the most impactful lifestyle choice you can make to reduce your risk of dementia, even if it isn’t widely advertised as such.

Of course, the type of person who exercises regularly can be different in other important ways relevant to dementia. They might eat healthier food in general, or simply have more resources and free time, which then allows them to exercise in the first place. But exercise does seem to inherently improve our brain’s health. Among other things, exercise can boost our cardiovascular health and circulation, which can reduce dementia risk directly and indirectly by preventing strokes. It also appears to help slow down the shrinking of the brain as we age. And even people with mild cognitive impairment seem to benefit from exercise.

Any amount of regular exercise helps your health, though aerobic exercise seems to be best, and you can see the benefits no matter how old you are when you first start.

This is the most speculative thing on the list, but it’s one that could have some important implications.

Just this week, Cleveland researchers published a study claiming to show that sildenafil, the active ingredient in the erectile dysfunction drug Viagra, may help prevent or treat Alzheimer’s disease. In brain tissue collected from Alzheimer’s patients, they found evidence that high doses of sildenafil can boost the growth of brain cells and reduce the expression of amyloid and tau proteins. And when they looked at insurance claims data, they also found that people prescribed Viagra were 69% less likely to be later diagnosed with Alzheimer’s.

One of the main ways that sildenafil affects the body is by relaxing our blood vessels, and it’s already used to treat certain forms of high blood pressure. So it’s plausible that its effects on circulation could also reduce dementia risk. Even before this study, there had been evidence in animals that sildenafil could reduce the risk of vascular dementia, a condition closely linked to blood clots and circulation problems.

For the time being, though, not even the authors of this study are claiming that sildenafil should be taken for dementia. But given these findings, and the relatively low cost of sildenafil now that it’s become generic, it’s certainly worth studying further.