Dementia & Air Pollution: Study Links Breathing to Disease
Air Pollution Linked to Increased Dementia Risk, New Study Reveals
central London, UK – Long-term exposure to outdoor air pollution is a significant risk factor for the onset of dementia, according to groundbreaking new research. The study, which analyzed epidemiological evidence, highlights the urgent need for policy interventions to combat air pollution and protect cognitive health.
the findings suggest that for every 10 μg/m³ increase in PM2.5, the relative risk of dementia rises by 3%. In Central London in 2023, the average roadside measurement for PM2.5 was 10 μg/m³. Similarly, for every 10 μg/m³ of NO2, the relative risk increased by 3%, with average roadside measurements in Central London reaching 33 µg/m in 2023. Moreover, each 1 μg/m of soot within PM2.5 was associated with a 13% increase in relative risk. London recorded annual mean soot concentrations of 0.93 μg/m at select roadside locations in 2023, compared to 1.51 μg/m in Birmingham and 0.65 μg/m in Glasgow.Dr. Haneen Khreis, senior author from the MRC Epidemiology Unit, emphasized the crucial role of epidemiological evidence in quantifying the impact of air pollution on dementia.”Our work provides further evidence to support the observation that long-term exposure to outdoor air pollution is a risk factor for the onset of dementia in previously healthy adults,” she stated. “Tackling air pollution can deliver long-term health, social, climate, and economic benefits.It can reduce the immense burden on patients, families, and caregivers, while easing pressure on overstretched healthcare systems.”
The study proposes several mechanisms through which air pollution may contribute to dementia, primarily involving inflammation in the brain and oxidative stress. these processes, known to play a role in dementia’s onset and progression, are thought to be triggered by air pollutants entering the brain directly or through pathways similar to those underlying lung and cardiovascular diseases. Air pollution can also enter the bloodstream from the lungs, leading to widespread inflammation.
While the research indicates that exposure to these pollutants increases the risk of Alzheimer’s disease, the effect appeared stronger for vascular dementia, a condition caused by reduced blood flow to the brain. Approximately 180,000 people in the UK are estimated to be affected by vascular dementia.However, the researchers noted that this difference was not statistically significant due to a limited number of studies examining this specific aspect.
The researchers also highlighted a critical gap in current research: the majority of participants in published studies were white and resided in high-income countries.This is notably concerning given that marginalized groups frequently enough experience higher exposure to air pollution. Studies suggest that reducing air pollution exposure may yield greater benefits for these communities in terms of reducing the risk of early death. Consequently, the study calls for urgent future research to ensure better and more adequate depiction across ethnicities and low- and middle-income countries and communities.
Clare rogowski, joint first author from the MRC Epidemiology Unit, stressed the need for robust policy changes. “Efforts to reduce exposure to these key pollutants are likely to help reduce the burden of dementia on society,” she commented. ”Stricter limits for several pollutants are likely to be necessary, targeting major contributors such as the transport and industry sectors. Given the extent of air pollution, there is an urgent need for regional, national, and international policy interventions to combat air pollution equitably.”
Dr. Christiaan bredell, joint first author from the University of Cambridge and North West anglia NHS Foundation Trust, underscored the interdisciplinary nature of dementia prevention. “These findings underscore the need for an interdisciplinary approach to dementia prevention,” he stated. “Preventing dementia is not just the duty of healthcare: this study strengthens the case that urban planning, transport policy, and environmental regulation all have a significant role to play.”
The research was supported by funding from the European Research Council under the Horizon 2020 research and innovation program and the European Union’s Horizon Europe Framework Program.