March 15, 2022

expert reaction to study looking at air pollution and autoimmune disease

A study published in RMD Open looks at long-term exposure to air pollution and immune mediated diseases.

Prof Felicity Gavins, Director of The Centre for Inflamation Research and Translational Medicine, Brunel University London, said:

“The press release accurately reflects the science. This is interesting study from Adami et al., who have used a large data set (a strength of the study) to investigate the association between ‘long-term’ exposure to air pollution and immune-mediated diseases (IMDs). There is certainly an unmet clinical need on a global level to understand the pathophysiology of IMDs to find novel therapeutic strategies to manage and treat patients with these diseases. This study further supports the mounting evidence suggesting a link between air pollution exposure and IMDs.

“We know that IMDs are characterised by uncontrolled activation and dysregulated of the immune system. Our own work focusing on inflammation and its resolution (www.gavins-lab.com) in IMDs has shown that neutrophils (the immune systems’ ‘first responders’) play a particularly important role. We also know that these first responders also play a role in air pollution pathogenesis, however, further studies are needed to discern whether neutrophil dysfunction is causative or symptomatic.

“Whether air pollution exposure specifically causes autoimmune diseases remains controversial, although there is no doubt that there is a link. With respect to this study, what may be more informative would be to ascertain why in certain areas of Italy there is a heightened increase in developing IMDs. The authors discuss the fact that exposure to air pollution was above average in northern Italy, Po Valley and other near-city areas, but why these areas in particular was not discussed e.g. are these areas associated with dumping of toxic waste in the ground that contributes to air pollution? Sites of industrial work (if so, what type of industry?)? Is this reflective of issues on a global scale or specifically in Italy? Are these areas ones in which industrial work and waste products are regulated?

“The term “long-term” is used, but strictly, data is collected from June 2016-November 2020, of which 91% of the study were women. 65 (+/- 11). “long-term” may not strictly be the correct terminology to use as the date of diagnosis and onset of autoimmune diseases were not available, so one cannot state with complete certainty that air pollution was the cause. In addition, as mentioned, 91% of the study were women (post-menopausal). This in itself raises several questions as to why such a high population of women show effects and men do not. The authors discuss the fact that post-menopausal women are more prone to some autoimmune diseases.”

“There is unequivocable evidence showing the direct effect of smoking on immune cell function and IMDs. There is no doubt that those that were included in the study that also smoked could have exacerbated (or potentially contributed) to their effects. The authors do discuss their limitations in the context of smoking, although I am less convinced by the conclusions (especially as they provide one reference as support, which is from 2004). In addition, this study is looking at the effect of air pollution through air monitoring, so the effect of passive smoking also plays a role and has not been discussed.”

‘Association between long-term exposure to air pollution and immune mediated diseases: a population-based cohort study’ by Giovanni Adami et al was published in RMD Open at 22:30 UK time on Tuesday 15^th March.

DOI: 10.1136/rmdopen-2021-002055

Declared interests

None received.