Dementia is a growing concern in our society. With an ageing population, it’s projected that the number of people living with dementia will continue to rise. According to the World Health Organization, there are currently more than 50 million people living with dementia worldwide, and this number is expected to triple by 2050. Dementia is a comprehensive term used to describe a significant decline in mental capabilities that hinders one’s ability to function normally in everyday life. It’s a progressive disease that affects memory, thinking, and behaviour.

While the exact causes of dementia are not yet fully known, more pieces of evidence are emerging that suggest pollution may play a role. A recent report from the Committee on the Medical Effects of Air Pollutants (COMEAP) found growing evidence to support a link between pollution and cognitive decline.

The Mechanisms of Pollution-Induced Dementia

The precise mechanisms of pollution affecting the brain are not yet fully understood. However, researchers have identified several possible pathways that could explain the link between pollution and dementia. One potential mechanism is the disruption of the blood-brain barrier (BBB), a protective membrane that separates the brain from circulating blood.

Environmental exposure, such as PM 2.5, can weaken the BBB, allowing toxins and immune cells to enter the brain and cause damage. However, it remains unclear whether exposure to everyday particulate matter poses a significant risk of brain damage. Further investigation is needed to determine whether these particles are cleared from the brain over time.

A 2020 report from the British Heart Foundation states that a quarter of the UK population resides in areas where the air contains toxic particles exceeding 10 mcg/m3. In specific cities, such as London, the average concentration of PM2.5 particles is around 13 mcg/m3, while Birmingham experiences levels of approximately 14 mcg/m3, and Bristol exceeds 20 mcg/m3. Although pollution levels can vary daily, research suggests that the pandemic and subsequent reduction in car usage during lockdowns have saved tens of thousands of lives globally.

Types and Sources of Pollution

Air pollution is not a single entity but rather a complex mixture of gases, particles, and chemicals that differ in size, composition, and origin. In urban areas, the primary sources of air pollution are traffic, industry, and residential heating. Traffic-related pollution, which includes exhaust fumes from diesel and petrol vehicles, is particularly harmful due to its high levels of PM2.5 and NO2, which can penetrate deep into the lungs and circulatory system. In addition, indoor air pollution from cooking and heating with solid fuels, such as wood and coal, is a significant health risk for people in low- and middle-income countries.

Apart from air pollution, other environmental factors, such as exposure to lead, mercury, and pesticides, have also been associated with an increased risk of dementia. Lead, for example, can cause permanent brain damage and cognitive decline, while pesticides have been linked to Parkinson’s disease and other neurological disorders. Similarly, mercury exposure, commonly found in fish, can damage the nervous system and disrupt cognitive function.

Implications for Public Health

The evidence linking pollution and dementia is still emerging and needs to be further investigated. According to The National Library of Medicine, exposure to air pollution, particularly fine particulate matter, can lead to various grave health issues besides dementia. These include insulin resistance, oxidative stress, and stroke. However, the existing studies suggest that reducing exposure to air pollution and other environmental toxins could be an important strategy for preventing cognitive decline and improving brain health, especially among vulnerable populations, such as older adults, children, and people living in highly polluted areas.

Several measures could be taken to address the pollution problem and its impact on health. These include reducing emissions from vehicles and industry, promoting cleaner energy sources, improving public transportation, and promoting active travel, such as cycling and walking. Policies that reduce exposure to indoor air pollution and hazardous substances, such as lead and pesticides, could also have significant health benefits. Holding manufacturers accountable for diesel claims and cheating on emission tests is equally important. Individuals looking to file their emission claims can do so with the help of https://www.emissions.co.uk. The UK Government has set a target to reduce transport emissions to net zero by 2050, but much work still needs to be done.

The evidence supporting the link between pollution and dementia is growing, and the mechanisms by which pollution affects the brain are becoming more apparent. While more research is needed to establish causality and identify the most effective interventions, there is already enough evidence to suggest that pollution is a significant risk factor for cognitive decline and other neurodegenerative disorders. Protecting our environment and health should remain a top priority for individuals, governments, and organisations worldwide.