In the first half of the 20th century, cigarette smoking was considered recreational, safe, and desirable. It was only when clinical studies demonstrated its irrefutable contribution to pulmonary diseases that the tobacco industry reluctantly, then openly, acknowledged the detrimental effects of cigarette smoking.
Today, many countries mandate cigarette boxes to be labeled with stern warnings on the potentially detrimental effects of cigarette smoking on human health (though, as many public health officials lament, some cigarette smokers eventually become desensitized to these warnings.)
A similar paradigm shift is happening with regards to general air pollution, which for the most part is invisible and covert. As the impact of the climate on human health gains interest, scientists are racing to test their hypotheses on the effects of air pollution on human health. Strikingly, many reports, as correctly assumed, identify air pollution as a risk factor in many human illnesses.
Is another Pandora’s box opening before our eyes? In other words, will we eventually discover that the majority of modern illnesses can be, at least in part, traced back to environmental pollution? Let’s get surgical for a moment and dare ourselves to ask the question: how many diseases are directly, or indirectly, caused by environmental pollution? Can we put a number on it? Can we put a human cost to the price of progress?
Tomos and colleagues carefully compiled evidence on the risk of long-term exposure to personal air pollution to acute exacerbations of idiopathic pulmonary fibrosis (IPF). Majewski and Piotrowski called air pollution “an overlooked risk factor for IPF.” We will explore the result of some of their findings in this article.
Invisible and Deadly
Environmentalists are in agreement that clean air is something to which every human being is entitled. After all, what could be more fundamental to being human than breathing? Unfortunately, official statistics demonstrate that this basic right is denied to millions.
“According to the World Health Organization (WHO), air pollution kills an estimated seven million people worldwide every year,” Majewski and Piotrowski wrote. ”The WHO data shows that 9 out of 10 people breathe air that exceeds WHO guideline limits containing high levels of pollutants, with low- and middle-income countries suffering from the highest exposures.”
The pathogenesis of IPF, as we understand it today, is due to “the chronic, repetitive, subclinical micro-injuries to the alveolar epithelium caused by the exposure to various noxious stimuli are leading in the predisposed individuals to subsequent dysfunction of the alveolar epithelium,” according to Majewski and Piotrowski.
Hence, even on a theoretical basis, it makes perfect sense that air pollution can injure the lungs and thus kick off the pathogenic pathways that lead to IPF. Air pollution has already been associated with COPD, asthma, lung cancer, and various respiratory illnesses. In fact, hardly a medical consultation on a pulmonary illness ends without the physician advising the patient to quit smoking, or at least consider signing up for a smoking cessation program. In other words, air pollution (that is both within one’s control and not) is just bad for one’s health.
A Clear Correlation
Tomos and colleagues conducted a clinical study to investigate the effects of long-term exposure of personal air pollution on patients. They did so by assigning long-term personal air pollution exposures to patients retrospectively: O3, NO2, PM2.5. To achieve this, they used maps with predicted annual averages of the air pollutants in Greece based on data provided by the Ministry of Environment and Energy. A total of 118 IPF patients were recruited for this study.
Read more about IPF etiology
The results were conclusive: there was a positive correlation between exposure to all of these air pollutants and acute exacerbations of IPF, independent of other factors such as age, gender, and lung function. The research team commented, “So far, the present study, to the best of our knowledge, is the first to investigate the association between long-term personal exposure to air pollutants and acute exacerbations of IPF as well as with changes in inflammatory mediators known to be involved in its pathogenesis.”
What could be the possible mechanisms in which air pollution causes acute exacerbations of IPF? Tomos et al have some theories.
“Ambient air pollution increases the morbidity in several chronic diseases through diverse mechanisms, such as inflammation, formation of reactive oxygen species, and oxidative stress,” they wrote. “Another potential mechanism by which air pollution could impact the progress of diverse diseases and that has been lately proposed is through oxidative stress-induced telomere erosion.”
Read more about IPF patient education
Majewski and Piotrowski agree on this point. In their study, they wrote, “Ambient air pollutants through several potential mechanisms may contribute to disease initiation, impact an individual’s disease severity, accelerate progression, trigger hospitalization and acute exacerbation, as well as affect mortality.”
Clean Air and General Health
What can clinicians do with these findings? First, they should continue to advise their patients to stop cigarette smoking, which is inhaled air pollution. Second, there should be pressure on councils and governments to ensure that local air quality remains at an acceptable level.
As Majewski and Piotrowski concluded, “Identification of the risk and approach towards its elimination or avoidance may result in meaningful benefits for the patients and global public health.”
Tomos I, Dimakopoulou K, Manali ED, et al. Long-term personal air pollution exposure and risk for acute exacerbation of idiopathic pulmonary fibrosis. Environ Health. Published online August 30, 2021. doi:10.1186/s12940-021-00786-z
Majewski S, Piotrowski WJ. Air pollution – an overlooked risk factor for idiopathic pulmonary fibrosis. J Clin Med. Published online December 28, 2020. doi:10.3390/jcm10010077