If you live within a distance of 50m from a major road, then you are prone to suffer from dementia sooner or later, according to a new study.
Experts from Public Health Ontario, Toronto, ON, Canada have investigated the adverse effects of pollution on cognition and a striking relation had been found with increasing risk of dementia.
The study was recently published in The Lancet journal, which has given the world important insights to ponder upon.
The effect of road population has long been associated with worsening of respiratory conditions.
Previously, we had been well aware of the unfortunate fact which confirms that air pollution makes us increasingly susceptible to cardiovascular diseases, chronic respiratory conditions like asthma, chronic bronchitis or other lung diseases.
But now, a new unsettling linkage has come forth; which puts us at an appalling risk of developing a neurological disease.
In a population-based cohort study, over 6.6 million residents of Ontario were observed to establish a relation of pollution with three neurological diseases, which included dementia, Parkinson’s disease, and multiple sclerosis.
The study ran for over a decade, stretching from 2001 to 2012, which recruited adults from 20-85 years who were initially free of neurological diseases.
The distance of these residents from a busy road was stratified into three groups, people living less than 50m away from the road, people living at a distance between 50m-100m and people living at a distance between 101m-200m. Following this, the risk rate of these neurological diseases according to busy road proximity was recorded and analyzed.
According to the Centers of Disease Control and Prevention (CDC), in year 2013, about a 5 million Americans suffer from Alzheimer’s disease which is the most common form of dementia. This number doubles after every 5 years and the projected number of people to be suffering from this disease by year 2050 is 14 million.
The global disease burden of dementia is sky high, which in form of Alzheimer’s disease is 6th leading cause of death in the US alone. By the time, the US enters year 2040, the annual cost of providing medical help to the patients of dementia would rise between $379 and $500 billion, which is yet another alarming revelation.
During this study, 243,611 cases of dementia, 31,577 cases of Parkinson’s disease were identified, whereas 9,247 people suffered from multiple sclerosis. Interestingly, the link of proximity of the road with Parkinson’s disease and multiple sclerosis couldn’t be established.
On the contrary, the risk rate of dementia showed a plausible association with road proximity, as the distance from the road increased, the risk rate of developing dementia in an individual decreased.
In people living within the distance of 50 m from a busy road, the incidence rate of dementia was found as 7-11%, as the distance increased, there was a significant decrease in the dementia incidence rate.
From previous work of scientists, we have learned that car exhaust fumes have a negative impact on the cognitive development. Neurodegenerative pathology of these pollutants is multi-faceted in nature, contributing in a variety of forms to cause harm to the brain cells.
The traffic pollutants which remained the central focus of this study included close monitoring of nitrogen oxide and fine particulate matter.
Particulate matter includes the effects of air pollution which is composed of mixtures of liquid droplets and solid particles, involving fumes, aerosols, dust, ash, smoke and even pollen. The particulate matter which have a diameter of 2.5 microns or less, are often denoted as PM2.5.
According to the Ministry of Environment and Climate Change, the air of Ontario is composed of fine particulate matter which is largely contributed by organic and elemental carbon, nitrate particles, sulfate particles and soil.
This study however, also included the effects of ultrafine particles, heavy metals, volatile organic compound, polycyclic aromatic hydrocarbons and noise.
These factors collectively cause cognition problems attributed to increase oxidative stress in brain cells, activation of microglia, stimulation of neural antibodies and inflammation of neural cells.
These factors particularly are responsible for leading to cognitive decline and consequent cognitive impairment.
Similarly, the effect of traffic noise is also found to affect cognitive function adversely, however previously this effect had been demonstrated in rats only.
Now, that a decisive study has emerged which directly associates incidence rate of dementia with the proximity of a busy road, the leaders in global health sectors have to sit together and find a solution to this grave problem.
As these neurological diseases often have unknown underlying causes, the risk rate of increased dementia due to pollution has become scarier than ever.
While scientists will need to further learn about the precise effects of pollution on cognitive decline and find a treatment, the experts of environmental sciences and policy makers will also have to play an active role.
As this study has reached us, authorities who are responsible for urban development planning, road construction and land allotment for residential areas will also be required to step forward and devise policies where the distance of busy roads from residential area is far enough to help people stay healthier.