While attention is being drawn to the alarming rate of premature deaths in European Union countries owing to air pollution, little is said about the numerous terminal illnesses caused by rising cases of air pollution. Recent studies have linked air pollution to impaired cognitive performance particularly among senior with little education.
Dementia is a devastating condition but before that comes a phase characterized by accelerated cognitive decline and accumulation of neuropathology. Epidemiologic studies have over the years tried to figure out the link between air pollution and dementia. A recent review by a group of scientists found 18 credible publications that link at least one form of air pollution to one dementia-related outcome.
Problems With Studying Relationship Between Air Pollution And Dementia
The problem with linking air pollution to dementia is that not all cases of dementia are diagnosed or reported – and in some cases they are underdiagnosed. However, scientists conducting most of the studies on the incidence of dementia usually rely on health system records.
Most of the recent research also made use of the current air pollution exposures and statistics. Inasmuch as this is a reasonable approach, the validity of the research can be questioned if the exposure window varies over a few years. It is not always easy to establish sustained exposure since air pollution levels can vary significantly from one end of the street to another.
Again, since there are lots of pollutants in the air, it may be hard to associate a particular pollutant to the onset of dementia. This is because the degree of exposure varies among the different pollutants. Further research using improved methodological design may be needed to account for these shortfalls.
Men Are More Prone To Cognitive Decline Than Women
A team of Chinese researchers including Xiaobo Zhang of the National School of Development, Peking University, Beijing, China has been studying the mathematical and verbal skills of over twenty-five thousand Chinese residents for more than 4-years duration. According to their report, cognitive decline is more with worse air quality.
They also reported that cognitive decline is worse among older men compared to women, especially on verbal test scores. The negative effect of air pollution has long been established but from recent studies, investing in cleaner air will also improve cognitive capability.
How Pollutants Affect The Brain?
Zhang noticed that upon returning from the US to Peking he noticed a sharp headache which made it difficult for him to focus on his research. This was between 2012 and 2014 when air pollution was at its peak in China.
The researchers are suspecting the accumulation of pollutants in the white matter of the brain leading to its damage. The white matter of the brain is linked to verbal abilities. The damage of the white matter is likely the reason for the declined verbal functions in the test subjects. The researchers also noted that activated white matter is fewer in the brain of men and women which also explains why declined verbal functions are more among men compared to women.