Sodiq Ojuroungbe
A new study has suggested that people exposed to fine particulate air pollutants are at higher risk of developing dementia.
It also indicated that air pollution can also contribute to a number of health conditions, including heart disease and respiratory conditions.
The new study also revealed that breathing in microscopic air pollutants also referred to as (PM2.5) in the research may raise the risk of developing dementia, adding that microscopic particles can cause serious health issues.
The study, which was a new analysis of existing research by public health scientists at Harvard and published in the British Medical Journal, examined 16 observational studies and found consistent evidence of a connection between PM 2.5 and dementia.
The World Health Organisation described dementia as a term used for several diseases that affect memory, thinking, and the ability to perform daily activities.
According to the global health body, more than 55 million people have dementia worldwide, and over 60 per cent of them live in low and middle-income countries.
WHO also projected that the number of people with dementia will increase to 153 million by 2050.
To ascertain how exposure to air pollutants can increase the risk for dementia, researchers from the Harvard T.H. Chan School of Public Health, scanned more than 2,000 studies and identified 51 that evaluated an association between ambient air pollution and clinical dementia, all published within the last 10 years.
The researchers assessed the studies for bias using ROBINS-E, and 16 of them met the criteria for the meta-analysis.
It was discovered that most of the research was about PM2.5, with nitrogen dioxide and nitrogen oxide being the next most common pollutants studied.
During the research, the team found consistent evidence of an association between PM2.5 and dementia, even when annual exposure was less than the current EPA annual standard of 12 micrograms per cubic meter of air (μg/m3).
Among the studies using active case ascertainment, the researchers discovered a 17 per cent increase in risk for developing dementia for every 2 μg/m3 increase in average annual exposure to PM2.5.
They further found evidence suggesting associations between dementia and nitrogen oxide (5 per cent increase in risk for every 10 μg/m3 increase in annual exposure) and nitrogen dioxide (2 per cent increase in risk for every 10 μg/m3 increase in annual exposure), though the data was more limited.
Speaking on the findings, the lead author and Professor of Environmental Epidemiology and Physiology, Marc Weisskopf said, “This is a big step in providing actionable data for regulatory agencies and clinicians in terms of making sense of the state of the literature on this hugely important health topic. The results can be used by organizations like the Environmental Protection Agency, which is currently considering strengthening limits on PM2.5 exposure.
“Our findings support the public health importance of such a measure. Air pollution’s estimated association with the risk of dementia is smaller than that of other risk factors, such as education and smoking. However, because of the number of people exposed to air pollution, the population-level health implications could be substantial.”
Continuing, he said, “Given the massive numbers of dementia cases, identifying actionable modifiable risk factors to reduce the burden of disease would have tremendous personal and societal impact.
“Exposure to PM2.5 and other air pollutants is modifiable to some extent by personal behaviours—but more importantly through regulation.”
Meanwhile, the head of policy at Alzheimer’s Research United Kingdom, Dr. Susan Mitchell called for stricter air pollution targets to tackle dementia risk.
The public health expert told The Guardian UK, “Poor air quality is a significant public health issue, and this new review helps to cement the relationship between certain types of air pollution and dementia risk.
“But as individuals, there’s little we can do about the air we breathe. So it’s vital the government leads from the front in reducing air pollution and the resulting harm to our brain health.
“But what we have seen so far has fallen disappointingly short. In December, the government missed a clear opportunity for decisive action on air pollution by setting an unambitious and inadequate target of 10 micrograms a cubic metre by 2040 – far less stringent than what Alzheimer’s Research UK and the World Health Organisation recommended.
“The government should now ensure brain health is central to its major conditions strategy and its wider ambitions for prevention, and invest in population-level interventions that have a significant impact on air pollution.
“What remains to be uncovered is the ‘how’ – there are several biological explanations that could be behind the link between air pollution and dementia, and we echo the authors’ call for more research to better our understanding in this area.”
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