Can reducing air pollution prevent multimorbidity?

By Dr. Liji Thomas, MDReviewed by Benedette Cuffari, M.Sc.Jan 31 2023

Modern society is increasingly threatened by mounting air pollution, as well as the occurrence of multiple chronic illnesses in the same individual. Multimorbidity is defined as the co-occurrence of two or more long-term communicable and/or non-communicable diseases.

A new study published in the European Journal of Epidemiology argues for the need to frame studies that can identify a potential association between multimorbidity and air pollution, if it exists, and provide data on the effects produced by specific pollutants on multimorbidity.  

Study: The relationship between air pollution and multimorbidity: Can two birds be killed with the same stone? Image Credit: Zsolt Biczo/Shutterstock

Introduction

Tackling multimorbidity represents one of the greatest challenges for health systems worldwide, and a deeper and more comprehensive understanding of its determinants is urgently needed.”

Much more research is needed on the potential relationship between multimorbidity and air pollution. A greater understanding of how these two states interact with one another would help shape new guidelines and regulations about air quality that may reduce the incidence of multimorbidity and mitigate its burden.

Air pollution affects both indoor and outdoor air. According to both the World Health Organization (WHO) and the Organization for Economic Co-operation and Development (OECD), air pollution is the primary cause of premature death from environmental factors. In fact, between four and nine million people die too early every year, which is associated with a yearly economic cost of over $1.5 trillion USD.

Specific air pollutants, such as particulate matter (PM) with an average diameter of 10 µm or less (PM₁₀) and PM_2.5, as well as toxic gases like nitrogen dioxide or sulfur dioxide, are known to reduce the quality of life of people, as well as increase the prevalence and incidence of both acute and chronic illnesses. Since air pollution affects almost the entire world’s population, it is a top global public health priority.

The current study aims to examine how air pollution is linked to multimorbidity. The underlying factors for multimorbidity include biological aging, low-grade inflammation, a sedentary lifestyle, inadequate financial security or income, and poor social status.

Associations between air pollution and health

Air pollution could act synergistically with these factors by causing or aggravating “syndemics,” which are defined as epidemics of one illness on which the epidemic of multimorbidity has a synergistic effect. Since air pollution can cause both short- and long-term health effects, both of which may vary with the time of life of the individual, studies with different designs that cover different periods of time, as well as of the life span of the individual, are essential.

Air pollution is a complex topic to assess, as multiple air pollutants often occur in combination and in dosages proportional to each other. Furthermore, many of these pollutants produce a combination of effects that may mitigate or aggravate the harms of the individual chemicals.

Real-world data from large biomedical databases and electronic health records could help discern how air pollution impacts multimorbidity. However, such data may be limited by the number of records or missing key variables, as well as a narrow window of observation.

Pooled real-world data could offer one resolution to this challenge by allowing multiple data sets from different types of populations to be used to identify associations between air pollution and multimorbidity. One example is the European Study of Cohorts for Air Pollution Effects (ESCAPE) project, which is based on pooled data from over 30 cohort studies. This type of study could provide enriched and more reliable data that is capable of identifying relationships between these exposures and outcomes.

What are the implications?

[If] air pollution exposure affects multimorbidity risk, it presents an unusual opportunity for multimorbidity prevention.”

With the increasing number of multimorbidity patients in the world today, policies for healthcare and patient management should be framed concurrently with environmental guidelines and regulations that have been developed according to data-based linkages between multimorbidity and air pollution. These strategies would address the population at large and the environment, rather than attempting to treat patients on an individual basis for their numerous chronic conditions.

Such studies would also help assess the level of risk following the exposure of the population to a spectrum of pollutants, thus identifying those, whether individuals or groups, who are at a greater risk. This could also contribute to improved environmental policies that could prevent the generation of toxic levels of air pollutants and increase the success of already existing policies.

In turn, such forward-looking and holistic guidelines could reduce healthcare costs and the burden of multimorbidity by preventing its development.

Given the lack of evidence, the study of the long-term influence of air pollution on the accumulation of chronic diseases would be key to inform preventive measures and, ultimately, reduce the burden of multimorbidity.”