Long-term exposure to air pollution increases risk of dementia

Long-term exposure to air pollution is associated with an increased risk of dementia, according to research published in the journal JAMA Neurology. 

By 2050, 68% of the global population is expected to live in urban areas where they are continuously exposed to air pollution. Together with an ageing population, this poses a global challenge when it comes to preventive strategies for dementia. 

Researchers at the Karolinska Institutet in Sweden gathered data from 3,000 individuals aged 74 and over who live in central Stockholm, each individual was followed up for 11 years. During this period, 364 people developed dementia.  

The researchers then used dispersion methods to assess yearly pollution levels at residential addresses.

They found that long-term exposure to particulate matter (PM2.5) and nitrogen dioxide (NO2), was associated with a higher risk of dementia.

Heart failure and heart disease were also found to enhance the association between air pollution and dementia. 

According to the researchers, the biological mechanisms through which air pollution affects brain health are not completely understood, but it is likely that ultrafine particles may reach the brain via circulation and induce systemic inflammation, damaging the blood-brain barrier.

Giulia Grande, lead author of the study said: ‘Our findings suggest air pollution does play a role in the development of dementia, mainly through the intermediate step of cardiovascular disease.

‘Air pollution is an established risk factor for cardiovascular health and because cardiovascular disease accelerates cognitive decline, we believe exposure to air pollution might negatively affect cognition indirectly.

‘In our study, virtually all of the association of air pollution with dementia seemed to be through the presence or the development of cardiovascular disease, adding more reason to reduce emissions and optimise treatment of concurrent cardiovascular and related risk factors, particularly for people living in the most polluted areas of our cities.’

In related news, researchers at the University of British Columbia found that living near a major road increases the likelihood of developing a neurological disorder such as Alzheimer’s, Parkinson’s and multiple sclerosis (MS) 

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