Children exposed to air pollution are more likely to develop disease later in life
We have known for quite some time that the first years of life represent a unique “window of vulnerability”—exposures to environmental chemicals at this time influence cellular programming in ways that shape health and disease in later years.
For example, recent research shows that there is a significant association between multiple prenatal and early life exposures to indoor pollutants and the degree of allergic sensitivity in 2-year old children. In other words, babies exposed to air pollution during prenatal life and for the first several moths after birth, up to 2 years of age, are at higher risk of developing allergic sensitivity.
Now, results from a study published on February 18, 2021, show that children exposed to polluted air may develop heart disease and other conditions in adulthood. Researchers measured three types of air pollutants: fine particulate matter known as PM2.5, carbon monoxide and ozone. PM2.5 comes out of the tail pipes of cars and trucks, and is also contained in wildfire smoke.
The researchers studied a cohort of school-aged children (6–8 years) living in Fresno, California—the city is known for its elevated levels of air pollution resulting partially from industrial agricultural practices and wildfires. A New York Times article from last November clearly points out the gravity of the situation in that area: “The fires sweeping across millions of acres in California aren’t just incinerating trees and houses. They’re also filling the lungs of California’s children with smoke, with potentially grave effects over the course of their lives.”
Study lead author Mary Prunicki said: “I think this is compelling enough for a pediatrician to say that we have evidence air pollution causes changes in the immune and cardiovascular system associated not only with asthma and respiratory diseases, as has been shown before. It looks like even brief air pollution exposure can actually change the regulation and expression of children’s genes and perhaps alter blood pressure, potentially laying the foundation for increased risk of disease later in life.”
The researchers assessed the effects of exposure to pollutants on the immune and cardiovascular systems. Specifically, they assessed methylation and protein expression in different cell types of the immune system using a form of mass spectrometry that measured up to 40 cell markers simultaneously, thus providing a more in-depth analysis of the impacts of pollution exposure. They also studied cardiovascular outcomes by determining blood pressure levels.
Study results show that over time exposure to pollutants is linked to increased methylation in cells of the immune system, an alteration that can change the activity of DNA molecules without changing their sequence and can have long term effects. Furthermore, air pollution exposure may influence monocytes, white blood cells that play a key role in the buildup of plaques in arteries—and could possibly predispose children to heart disease in adulthood. Thus, even at a young age, the immune and cardiovascular systems could be negatively impacted by exposure to air pollution.
Kari Nadeau, study senior author, said: “This is everyone’s problem. Nearly half of Americans and the vast majority of people around the world live in places with unhealthy air. Understanding and mitigating the impacts could save a lot of lives.”
7 Comments
Abrham Amare
This is a fascinating article and raises some questions on how people can raise their children in the city. Infants are susceptible to different dangers, and most damages done during those years will have detrimental effects down the road. Growing up in suburban Ethiopia, I never really noticed air pollution as there were not many cars or factories around where I lived. I definitely noticed the change in the air whenever I go to the city. The one big difference I noticed in the way which cars are allowed on the road is that cars have to go through annual inspections. There are no emission tests where I grew up. All the vehicles had smoke that gave off a smell and a fogy gas that indicates that the fuel didn’t burn appropriately. This research definitely raises questions about raising kids in cities.
Our body is consistently being exposed to different stimulating factors that direct it to give the appropriate response. Inhalation of pollutant gases is one of those factors that stimulate our body defenses to orchestrate and come up with a response. In our body, Toll-Like Receptors (TLRs), reactive oxygen species (ROS) sensing pathway, and poly-aromatic hydrocarbon (PAH) sensing pathways are responsible for starting a cascade of reactions that are given against microbes, oxidative stressors, and noxious stimuli. Air pollutant chemicals put oxidative stress on the cells of the immune system like antigen-presenting cells. The increase in oxidative stress has been linked to the decrease of the co-stimulatory molecule of IL-12. This, in turn, affects T cell proliferation. Air pollution also affects the dendritic cell maturation and expression of CD4 and CD8 molecules. Macrophages and granulocytes are also the other cell types of the immune system that are affected by air pollution. Macrophages are affected as there will be more carbon loading and defective clearance which in turn affects phagocytosis. Granulocytes like neutrophiles are rich in oxidant enzymes. As there are a lot of transition elements in the pollutants, inhalation of these metals can activate these enzymes and cause oxidative damages.
Much research on the effect of air pollution on the immune system points out that air pollution can directly affect the immune system and start signaling pathways that cause the body to go into unnecessary immune response. These reactions can easily be observed with people showing symptoms of asthma. As a result, it is always important to keep in mind the things that we expose our bodies to. It is also good to note why suburban areas are usually chosen by people who are raising kids.
Reference: https://www.ncbi.nlm.nih.gov/pubmed/32007522/
Rafael Francis
I found your blog post elucidating because I had never considered the potential health effects that may be caused in young children due to poor air quality. However, it makes sense that children would be at a higher risk. From what I know about the immune system, and what I have learned in this class, the immune system develops over time, making children more susceptible to disease due to their less experienced immune system. When I was a child, I had little concern for my immediate health due to overall airborne pollution, however, I was wary about the danger of second-hand smoke. This may be due in part to the stress placed on the “Say No to Drugs” campaign emphasized by the health class curriculum of the public school system, but it led to me being disgusted by cigarettes and me, encouraging my family members who did smoke not to, especially around me. I did this yes out of concern for my own health, but also for the health of their lungs and preventive measures against cancer formation.
This post encouraged me to again look at the health effects of second-hand smoke on youth. After a little research, I found that smoking-related ailments are listed as the preeminent cause of preventable deaths worldwide leading to respiratory disease, heart disease, and lung cancer. This led me to articles detailing some lesser-known adverse effects of tobacco smoke. It is widely
known that smoking tobacco increases the risk of respiratory infection and lung cancer, however many are unaware of the effect that it has on the immune system. According to one article, I found, the cocktail of toxic chemicals present in tobacco smoke impairs the adaptive and innate immune response as well as causes inflammation in the lung tissues. The authors studied the influence of second-hand smoke on pulmonary inflammation and measured immune responses to respiratory infection by Haemophilus influenzae, a bacterium commonly present in patients with immune diseases. This was done using flow cytometry and ELISA to quantify Immune cell numbers and cytokines as well as identify antibodies. Their results concluded that long-term exposure inhibited the responses of antigen-specific B and T cells reducing the production
of antibodies, increased the numbers of neutrophils and inflammatory cytokines in the pulmonary tissue, and impaired overall immunity following vaccination or infection.
These potential long-term health effects for individuals exposed to second-hand smoke further illustrates the damage done directly to the smoker. This research serves to add to the large and ever-growing list of published information providing reasons not to smoke in general due to the detrimental effects on your own health as well as others. Due to this, it is imperative to further improve public health education to reduce smoking especially in proximity to those who fall in high-risk groups including children, babies, and pregnant women, those with respiratory conditions, and other immunocompromised individuals. Hopefully, improved awareness will reduce the smoking-related mortality rate as well as the occurrence of chronic lung diseases such as COPD, asthma, chronic inflammation, bronchitis, and pneumonia.
Similar to the known carcinogen of tobacco smoke, outdoor air pollution also causes cancer according to a 2013 study by WHO’s International Agency for Research on Cancer (IARC). While there are simple solutions to reducing one’s exposure to second-hand smoke, it is much more difficult to combat or alleviate local air pollution. For starters, most are unaware of their air quality in their area and the potential health risks, while it is easy to identify the smokers in your life. This lack of awareness stems from a lack of information as well as the nature of local air quality to vary seasonally and constantly throughout the day. Additionally, while eliminating second-hand smoke exposure can be eliminated relatively quickly through individual effort, controlling air pollution often requires a community effort or government intervention. These reasons are why air pollution presents a risk that can only be remedied with effective risk communication, periodic monitoring, and group collaboration.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5922268/
Jasmine Humphrey
This article was very interesting to read. It was very intriguing to read about ways in which the intake of excess pollution can affect components of the immune system. When I have heard stories about numerous individuals across the world getting sick just from living in an environment with poor air quality, I have always assumed those retained illness were respiratory-related, such as bronchitis or asthma. However, that is not the case at all!
It has been suggested that long-term exposure to air pollution can impact the immune system in a variety of ways, leading to numerous health effects. One method that I discovered after doing some thorough research is the alteration of telomere length in leukocytes of preschool children. I came upon an article about an investigation of telomere length in children being associated with exposure to air pollution. Telomeres are compound structures, consisting of protein and DNA, that are found at the ends of linear chromosomes. They protect the ends of chromosomes from incorrect recombination or chromosomal rearrangement. Their lengths shorten with each division, and this can in fact be modified by inflammatory reactions. The immune system is quite sensitive to the shortening of telomeres because it relies heavily on the immense population of T cells and B cells.
According to the article, the shortening of telomeres is linked to the exposure to fine particulate matter (PM) with a diameter of less than 1 micron, 2.5 microns, and 10 microns. The article also mentioned that children are especially vulnerable to these effects of air pollution because they are closer to the ground, spend lots of time playing outside, and have faster breathing. Children’s bodies are also rapidly developing, which is another reason why they are more prone to getting sick from air pollution. Telomere shortening was observed in numerous immune cells, such as CD4+ and CD8+ T cells, B cells, basophils, monocytes, and natural killer cells.
The PM levels were measured at both kindergarten classes and the children’s homes, and it demonstrated that exposure to PM1, PM2.5, AND PM10 all resulted in shorter leukocyte telomere length in children. Because of the poor air quality that these children are surrounded by, they are at a very high risk developing noninfectious diseases such as cancer, diabetes, as well as death. Cells of the immune system are unique compared to cells found elsewhere in the body. What is phenomenal about these cells is that they are also able to boost telomerase, an enzyme that extends telomeres, AND they can limit the weakening of telomeres’ role in the process of cell proliferation occurring in activated cells. So, that makes me wonder what exactly is causing the immune cells in these children to shortein their telomeres, and how the inhalation of polluted air affects their mechanisms.
As fascinating as it was to read about this and enhance my knowledge on the broad effects of air polltion in children, it is also quite saddening to know that these children are in a compromised living environment that can lead to lifelong effects of their health, all of which are completely out of their control. I believe their parents should start coming up with ways to limit the exposure to air pollution to their children while they are at school, such as maybe limiting or completely eliminating their outdoor playtime or convincing the authorities to temporarily close the schools and switch to an online learning environment.
https://pubmed.ncbi.nlm.nih.gov/32213432/
Taylor Nguyen
This article made me more wary about the side effects of air pollution. While I am glad that I never lived in an area with high pollution, I am aware of some of its respiratory effects in highly populated areas such as China. Throughout my education, I was taught that China produced the most smog due to their reliance on coal as an energy source. Inhalation of smog can irritate the lungs and cause disease. However, I was never aware of the cardiovascular and immune effects air pollution can cause to the body.
Looking more in depth into the air pollutant PM2.5, an article was found describing how the pollutant specifically harms the immune system. PM2.5 can affect the cytotoxic and inflammatory response through the NF-kB signaling pathway. NF-kB is a transcriptional factor that plays a role in the inflammatory response. It induces the expression of pro-inflammatory genes, such as cytokines and chemokines. In the case of PM2.5, exposure from pollution can cause inflammation in the lungs. Although inflammation is generally a good thing, excessive inflammation can be threatening. For instance, the activation of NF-kB can enhance inflammation in a tumor environment by secreting pro-inflammatory cytokines and chemokines, leading to the proliferation of tumor cells. Not only can excessive inflammation be threatening toward someone immunocompromised, but chronic inflammation can also cause a healthy individual’s inflammatory response to damage their healthy cells, tissues, and organs. This can eventually lead to damage in DNA, tissue death, and internal scarring which can be linked to diseases. There should be a balance in the body with enough inflammation without it being too much to keep homeostasis.
The role macrophages and NF-kB signaling play in the immune system are similar, but PM2.5 reduces the survival of macrophages and induces the expression of NF-kB, consequently affecting the inflammatory levels. Understanding how the particulate matter PM2.5 affects the immune system raises the question of: Why does PM2.5 reduce the survival rate of macrophages, but increases the expression of NF-kB? If they play a similar role in the inflammation process, why are only macrophages targeted by the particulate matter? PM2.5 has been proven to induce cell apoptosis in lung cells and NF-kB is a major anti-apoptosis transcription factor that plays a role in the apoptotic effect of PM2.5. However, the reduction in macrophages induced by PM2.5 is still uncertain due to interaction between different components.
In an action to reduce air pollution, energy can be conserved by investing in renewable energy sources, promoting shared mobility by carpooling or public transport, and reducing our overall energy consumption. In terms of energy consumption, children and adults alike should turn off the television or room lights if not in use. Spreading awareness of how to prevent and control air pollution can eventually reduce the overall effects it has on human health along with the environment altogether.
https://www.ncbi.nlm.nih.gov/pubmed/29396771/
Diane Guzman
I find this article to be an intriguing read and thought-provoking as it is a topic that significantly affects all humanity worldwide. Air pollution is becoming a more prominent issue. Greater demand for construction, a necessity for transportation, and spiking wildfires, among other pollutants, have been generated from our lifestyle and endless choices. During my various travels to Mexico City with my family, where the air pollution is a lot greater than here in Atlanta, a change in our breathing facility has always been evident. Air pollution clearly and directly impacts our respiratory system, but it is stunning to realize it also has lingering effects on our overall immune system.
Completing more research on this concern led me to an article that further analyses the effects of specifically traffic-related air pollution (TRAP) on newborns’ immune cells from pregnancy. According to that same article, traffic is the leading source of most harmful air pollutants. Outdoor air pollution exposure during prenatal development is associated with lung impaired function performance, allergic manifestations, asthma, and infections in the respiratory tract during childhood. In the same article, a study showed exposure to high particulate matter levels in the Czech Republic became associated with decreased T cells and an increasing amount of natural killer (NK) cells in a newborn’s cord blood. The article also provided information on similar studies done of expecting mothers exposed fourteen days before delivery to PM2.5 concentrations, which are considered a higher level of air pollutant, an increase in B cells was noted with a decrease in T cells. When expecting mothers exposed to greater amounts of NO2 concentrations were studied, it was revealed that there was a mean decrease of 15% of NK and a decrease in cytotoxic T cells. It became evident from the article’s research results that the cord blood developed disturbances in lymphocyte and leukocyte distributions as a result of exposure to TRAP during prenatal development.
According to this article, worldwide 4.2 million deaths in 2016 were caused by outdoor air pollution. Air is a fundamental necessity for all humans. The problematic growing pollution is an issue we need to consider making imperative changes. More efforts should be taken to inform parents of these effects as air pollution consequences initiate and are most susceptible during prenatal development and early childhood. Hopefully, as a result, more people will take an interest in influencing the government to make changes, such as in our choice of resources for energy.
https://pubmed.ncbi.nlm.nih.gov/33217431/
Summer Waters
This blog post is very interesting and definitely makes me rethink some of me and my friend’s experiences while living in big cities. I’ve lived in Atlanta and various urban areas for my whole life. In addition, this post reminds me of my friend who was in an environmental science course, and they did a test on the air quality of GSU’s downtown Atlanta campus. The results of that were surprising to me because the air quality here was incredibly bad according to the data they took! With this post and that data, it makes me wonder about how living here might have affected my health in the long term and my overall immune system.
With what some additional research shows, the effect of pollution of the overall immune system can be quite dramatic, even in the short-term! The paper I looked at called “Impacts of Air Pollution, Temperature, and Relative Humidity on Leukocyte Distribution: An epigenetic Perspective” focuses on the previously stated factors in a 28-day average on hundreds of participants over a course of years with DNA methylation data and leukocyte distribution. Here they conclude that in this short-term these factors have an effect on leukocyte numbers. For instance, more pollution and environmental conditions that maintain the pollution will mean less plasma cells, natural killer cells, and naïve CD8+ T Cells. But those conditions also led to higher numbers of CD4+ and CD8+ T Cells. They also concluded that this short-term effect on leukocyte distribution may be associated with recorded instances of inflammatory responses and other risks to human health. If even short-term effects can produce data like this, the effect of pollution on the immune system might be more damaging than we all may have previously expected.
With that research in mind towards children, the affects could possibly be much worse, but we will only know for sure if more research goes into studying the effects of pollution on the human body. Overall, in order to prevent such impairments to the human population, I suggest we should do something about the sources of said pollution! Maybe with more research it can convince governing bodies to adopt strict limits on the creation of pollution and aim to convert main energy sources to cleaner alternatives such as solar, wind, or water. Hopefully, we can all do something before this gets worse, but in the meantime we all need to press our representatives and convince them to start doing something about this issue.
Reference: https://pubmed.ncbi.nlm.nih.gov/30826618/
Samin A.
This article was a fantastic read and incredibly eye-opening. Growing up in Tehran, Iran, I would always hear about how harmful the city’s pollution was. Some days it would get so bad that the government would advise people, especially at-risk groups, to stay inside. Fortunately, I left Iran when I was nine-years-old but reading this post makes me feel like it might have been too late. I knew that pollution could have adverse effects on the respiratory system but never knew that it could affect the immune system.
Upon further research on the effects of pollution on the immune system, I came across an article that details the impact of ambient pollution on the immune system. According to the article, ambient pollution is composed of gases such as ozone, volatile organic compounds, carbon monoxide, nitrogen oxides, and particulate matter. The components found in air pollution can trigger many immune cells and cause adverse reactions. Toll-Like Receptors responsible for sensing pathogen-associated molecular patterns and toxic stimuli can also be triggered by pollution. Particulate matter can create reactive oxygen species, which can activate pro-inflammatory pathways and damage cellular proteins and DNA. Additionally, immune cells such as alveolar macrophages, neutrophils, and dendritic cells are shown to be triggered by air pollutants. The inappropriate response of the immune cells to air pollution instead of normal stimuli can lead to the overstimulation of the Th2 immune response and disturb the anti-microbial immune response. The combination of these can lead to asthma.
Understanding the impact of pollution on the immune system makes me wonder if pullulation is associated with autoimmune diseases and whether less pollution could help prevent them. Parents should be informed about the effects of pollution on children by their doctor and possibly be advised to keep their children out of polluted cities. Additionally, preschools and middle schools should be closed in polluted areas and relocated to ensure the children’s safety. These precautions should be taken to protect children as pollution is being dealt with and reduced to safe levels.
https://www.ncbi.nlm.nih.gov/pubmed/32007522/