Dementia rates may vary with latitude

 
By Tom Nordlie • Published: April 7th, 2015
Category: Health in a Heartbeat
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Living way up North naturally carries an elevated risk of certain health problems — frostbite, for example.

Now it seems the risk of developing dementia might be greater for people at higher latitudes.

Dementia is a catch-all term for several conditions that impair mental functioning seriously enough to interfere with daily life, such as Alzheimer’s disease.

It’s well-established that genetics play a role in causing dementia. But there’s been little research on environmental factors that might be involved.

Public health officials generally assume that dementia is equally common everywhere you go. So, an international group of researchers decided to see if that assumption should be challenged.

Their findings were published in a recent issue of the journal Epidemiology.

The study involved health data on older people, including about twenty-seven-thousand older twins living in Sweden.

The results showed that if one twin lived further north than the other, the overall dementia risk was two or three times greater for that twin, compared with the one farther south.

One weakness of the study is that it didn’t look at any other environmental factors that might predispose people to dementia. Those factors might include air quality, local water chemistry, commonly available food and access to medical care in the area.

Bottom line, the findings only show a correlation between living farther north and dementia; they do not show that living at a higher latitude causes dementia. So there’s no need to panic on behalf of loved ones living up north.

Nonetheless, this study clearly shows that much more research is needed on the possibility that environmental factors promote dementia.

Even if latitude has nothing to do with dementia, scientists may eventually learn something that can be harnessed to lower the prevalence of this health problem.