The impact of early exposure to air pollution!

There have been many reports recently about the air pollution in our cities (for example this article here) and its damaging effects on human health. London is known to be particularly dreadful, with many headlines in recent times talking about how poor the air quality really is (and how it has broken legal limits). Air pollution is a relevant and serious topic, and there is much more that needs to be done to reduce the severe effects it has on our health.

Pollution is generated by different sources – natural sources, and manmade sources, such as factories and cars. The two people are most concerned about in cities are factories and vehicles. Most of the pollution from these sources comes from the burning of fossil fuels, a process which releases many harmful chemicals into the air. All of these contribute to the numerous health problems associated with pollution, many of which are well known. For a more detailed explanation of pollution, please see the video that I have linked at the bottom of the page!

Pollution has a wide range of effects on human health, and affects multiple organ systems. Many of these are well documented, and so the links are well known between pollution and respiratory (i.e. asthma and lung cancer), cardiovascular and neurological conditions.

However, the consequences of air pollution are wide reaching, with research suggesting that prenatal exposure poses risks to the developing fetus. The development of organs in the fetus can be easily modified depending on the intrauterine environment – and pollutants in the air (that then enter the blood) are no exception [5]. In fact, some studies show that pollutants are able to “impair the growth trajectory of major organs” [5]. One key issue is that there is a link between exposure to ozone (a pollutant) in the third trimester of pregnancy and low birth weight [4] in full term babies. This is a significant issue because “infants who are born low birthweight or small for their gestational age have a higher incidence of death and disabilities” [4]. However, the data on this issue is shown to vary between studies, so more research needs to be done before a definite conclusion can be drawn.

Firstly, lets look at how prenatal exposure to air pollutants is suggested to affect the developing lungs and their function. Some studies have shown that prenatal exposure to air pollutants can compromise the development by influencing “cellular differentiation, branching morphogenesis and vascularisation of the lung” [5], and thus, their function [5]. However, most of these studies are conducted in animal models and focus on specific pollutants, so no conclusive arguments can be drawn about the effects of prenatal exposure to general air pollution.
Some epidemiological studies have collected data that have shown a link between prenatal exposure to air pollutants and respiratory diseases [5] – however, more studies are needed.

Let’s now focus on how early exposure to a high level of pollutants at a young age affects cardiovascular health.
Studies were conducted to look at how prenatal exposure to pollutants would leave children more susceptible to developing cardiovascular disease as adults [2]. One study found that prenatal exposure to a certain level of pollution increased the risk of arterial stiffness in later life, which is a strong predictor of developing cardiovascular disease, or experiencing an acute event [2]. One suggested reason explaining why prenatal exposure to air pollution increases the likelihood of developing cardiovascular problems in adulthood is because it affects epigenetic mechanisms, which are crucial during fetal development and growth [3]. However, like with the studies on how pollution affects the developing respiratory system, more studies need to be conducted before conclusions can be drawn.

This is a very interesting area of research, especially since air pollution is such a pressing concern for all of us. As research continues, more epidemiological studies will be conducted, allowing us to draw more concrete conclusions. However, for now we can say that prenatal exposure to air pollution increases the probability of developing cardiovascular and respiratory problems.

References, full papers and further reading:

A great video explaining pollution:

Early life exposure to air pollution induces adult cardiac dysfunction
[1] http://ajpheart.physiology.org/content/ajpheart/307/9/H1353.full.pdf

Prenatal Air Pollution Exposure and Early Cardiovascular Phenotypes in Young Adults
[2] http://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0150825&type=printable

Prenatal Air Pollution Exposures, DNA Methyl Transferase Genotypes, and Associations with Newborn LINE1 and Alu Methylation and Childhood Blood Pressure and Carotid Intima-Media Thickness in the Children’s Health Study
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5132634/

Associations between prenatal exposure to air pollution, small for gestational age, and term low birthweight in a state-wide birth cohort
[4] http://www.sciencedirect.com/science/article/pii/S0013935114000875

Before the first breath: prenatal exposures to air pollution and lung development
[5] https://link.springer.com/article/10.1007/s00441-016-2509-4

Hello! This is my second article for TMS. I hope everyone enjoyed it. I appreciate that this area of research requires a lot of repeat studies and that the conclusions being drawn are only in their early stages, however, with all of the studies and news about pollution and climate change recently, I thought this would be an interesting area of research to focus on!

If anyone has any feedback on my article, I would be willing to hear it! Please just send us an email!

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