People living further north appear to be more likely to develop dementia. Scientists mapped prevalence of dementia in Scotland among 37,000 people born in 1921. A second study involved over 26,000 Swedish twins living in different parts of that country. These two studies indicate that individuals living at higher latitudes tend to be more likely to suffer from dementia, perhaps due to environmental factors such as relative lack of sunlight (possibly implicating lower Vitamin D, which is a suspected risk factor previously identified) increasing the level of dementia risk.
Higher dementia rates found in northern countries. Edinburgh: BBC News (Edinburgh, Fife & East Scotland) / BBC Health News, January 19th 2015.
This relates to:
Full Text Link (Note: This article requires a suitable Athens password, a journal subscription or payment for access).
Russ, TC. Gatz, M. [and] Pedersen, NL. [et al] (2015). Geographical variation in dementia: examining the role of environmental factors in Sweden and Scotland. Epidemiology. January 8th 2015. [Epub ahead of print].