Summary: A meta-analysis of research studies into the link between air pollution and incidences of clinical dementia has found a link at concentration levels of PM2.5 particles below the limits currently set by a number of country environmental agencies.
Why this is important: There are 55 million people with dementia globally and that is expected to rise to almost 153 million people by 2050. The estimated global cost of medical, social and informal care associated with dementia in 2019 was more than US$1.3 trillion with more than half attributable to care provided by informal carers.
The big theme: Air quality in general, and pollution in particular, have various significant investment and decision-making implications. Air pollution can be both naturally occurring or produced by human activity. Decreasing pollution with the aim of reducing human illness and suffering should be a goal unto itself. In practice it is also important to consider how such initiatives, that more often than not increase costs and dig into profits, will be beneficial to business and society in the long run, whether it be through decreased healthcare costs, increased health and productivity of the workforce, and reputational gains for such decisions.
Summary of a research paper published in the BMJ:
Researchers from the Harvard TH Chan School of Public Health (Wilker, Osman and Weisskopf) performed a systematic review of 51 studies and subsequent meta-analysis including 16 of those studies looking at potential links between ambient air pollution and dementia.
Their conclusion was that PM2.5 might be a risk factor for dementia. Interestingly the link between PM2.5 and clinical dementia seemed to exist below the current US Environmental Protection Agency (US EPA) annual standard of 12 mcg / m3 (micrograms per metre cubed) and well below the UK and EU limits of 20 mcg / m3 and 25 mcg / m3 respectively.
Nitrogen dioxide (NO2) and nitrous oxides (NOx) may also be risk factors but less data was available.
The findings support the importance of limiting PM2.5 and other air pollutants from a public health perspective.