Dementia disorders are still a problem of interest to many doctors. One reason for this is the number of dementia cases - the World Health Organisation estimates that nearly 50 million people worldwide may be affected. Certain risk factors for dementia are known, some of which (e.g. genetic load) are unfortunately beyond the control of patients, while others, such as appropriate treatment of hypertension, can definitely be influenced. It is this second group of factors that is of most interest to physicians - knowledge of modifiable dementia risk factors allows them to be avoided, thus lowering the patient's risk of the disease.

Dementiarisk factors have become an aspect of interest to researchers in Canada. Well, in past, other studies, it was shown that a certain factor - to which quite a significant number of people are exposed - could be linked to neurodegeneration phenomena. This factor was living near a busy road and the associated air or noise pollution. Canadian researchers decided to test whether the distance of a house from a busy road affects the risk of dementia.

Dementia risk versus living near a busy street

The observations were conducted from 2001 to 2012. 6.6 million citizens of Ontario were included; patients ranged in age from 20 to 85 years. In an ongoing follow-up of the stated range, doctors focused on the prevalence of three conditions: dementia, Parkinson's disease and multiple sclerosis.

For multiple sclerosis and Parkinson's disease, no association was seen between the risk of disease and living near a busy road. It turned out to be slightly different for dementia - up to 1 in 10 cases of this disease could have some connection with living near a road frequently used by cars. It also appeared that the closer the patient lived to the road, the higher the risk - where the patient's home was a maximum of 50 metres from a busy road, the risk increased by 7%. When the distance difference was 50 to 100 metres, the risk in such patients was increased by 4%, while when it reached more than 200 metres, the risk was no longer increased.

The cited study was not perfect, which is due, among other things, to the fact that exposure to harmful substances (emitted by vehicles) was assessed according to general information for a given location, and not on the basis of an analysis of the individual patient's exposure to such factors. Nevertheless, the study is important; moreover, it could be the start of wider analyses. After all, both dementia and the fact that we live close to crowded streets are becoming more common - so the problem may be growing.