Scientists have found out which terrain reduces the risk of dementia

In a new study, a team of scientists from Australia has revealed which factors in certain places where people live contribute to a reduced risk of dementia. One of them turned out to be the crime environment.

The work, published recently in the journal Preventive Medicine Reports, is based on data from the Healthy Brain Project. Within its framework, experts from Australia's Monash University study the circumstances affecting the development of Alzheimer's disease and other types of dementia.

Previously, scientists have noticed that residents of areas with low socioeconomic status are more susceptible to risk factors for dementia and have worse memory function. This prompted a more detailed analysis of area characteristics associated with dementia risk and cognitive decline.

In the new study, experts looked at several thousand Australian residents aged 40-70 who joined the Healthy Brain Project between 2016 and 2020. At the time of the start of observations, they did not suffer from dementia and did not take medications prescribed for Alzheimer's disease.

Researchers tracked how characteristics of the participants' neighbourhoods, such as the presence of green spaces, distance to the nearest park or public garden, number of intersections and crime rates (based on official crime statistics), correlated with scores on a dementia risk scale they had previously developed, as well as with the results of memory and attention tests. In analysing the data, the researchers applied linear regression techniques and made adjustments for distorting factors including age, gender, education and personal socioeconomic status.

In the end, it turned out that the remoteness of green spaces and higher crime rates correlated with a greater likelihood of experiencing Alzheimer's disease or similar disorders. Specifically, in terms of dementia risk, doubling the distance to the nearest park was equivalent to an additional 2.5 years to the participants' age. In addition, each double increase in crime was associated with the same deterioration in memory performance as if the person had suddenly aged three years.

Explaining the results, the authors noted that the proximity of parks can encourage people to be active and provide more opportunities to socialise. In addition, green spaces reduce the impact of environmental stressors like air pollution and noise.

The study also found that the short distance to parks is more important than the absolute amount of green space in a neighbourhood. In other words, in terms of reducing the risk of dementia, many small public gardens nearby are better than one large park somewhere in the distance.

As for the crime situation, its deterioration indirectly contributes to the lifestyle that leads to dementia. In particular, high crime rates may cause people to go out and be in public places less, experience psychological stress and sleep worse.

The authors stressed that their findings are worth considering when designing dementia prevention programmes. They also called on the authorities to improve accessibility of park areas and public safety to encourage people to adopt healthy lifestyles.