Air Pollution: Who's At Risk Of Heart Disease?

Air pollution is a major environmental health risk and a leading cause of cardiovascular disease, which is responsible for over 20 million deaths each year. While air pollution affects everyone, those with pre-existing cardiovascular conditions or who have previously experienced cardiovascular events are particularly vulnerable to the adverse health effects of air pollution. Research has shown that exposure to air pollution can trigger cardiovascular disease-related heart attacks and death, with fine particulate matter (PM2.5) being the air pollutant most closely linked to detrimental health effects. Vulnerable populations, including the elderly, children, and those with pre-existing cardio-respiratory diseases, are at an increased risk of serious cardiovascular events such as heart attacks, strokes, arrhythmias, and heart failure. Additionally, people who live or work near busy roads, urban areas, or industrial zones may be exposed to higher levels of air pollution, further exacerbating their risk of developing or exacerbating cardiovascular disease.

The elderly and children

Children

Children are more vulnerable to air pollution than adults for several reasons. Firstly, children breathe more rapidly and take in more air relative to their body weight. They also spend more time outdoors, playing and engaging in physical activities, which increases their exposure to outdoor air pollution. Their height also plays a factor, as they breathe air closer to the ground where pollutants from traffic exhausts and dust are emitted and become concentrated. This is especially true in urban areas.

Secondly, children spend a significant amount of time indoors, where they are exposed to household air pollution. This includes pollutants from cooking with polluting fuels, second-hand tobacco smoke, and mould. According to the 2024 State of Global Air report, air pollution was linked to approximately 709,000 deaths in children under 5 years old, with over 70% of these deaths attributed to household air pollution.

Thirdly, children are more vulnerable because their organs, including their lungs, brains, and immune systems, are still developing. Air pollution can hinder lung growth, inhibit brain development, and increase the risk of asthma, respiratory infections, allergies, and other chronic diseases later in life. Some air pollutants can even cross the placenta and affect developing babies in the womb, causing low birth weight and negatively impacting neurodevelopment and cognitive ability.

The Elderly

The elderly are also considered fragile and vulnerable to the harmful impacts of air pollution, especially those with pre-existing cardiovascular conditions or a history of cardiovascular events. While air pollution can affect people of all ages, the risk of developing heart disease and experiencing cardiovascular events, such as heart attacks, arrhythmias, and strokes, is higher in older individuals.

Particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), and ozone (O3) are some of the most common pollutants that have been linked to harmful effects on the health of older adults. Exposure to these pollutants can trigger cardiovascular disease-related events and increase the risk of mortality and decreased life expectancy.

Additionally, the elderly may be more susceptible to the harmful effects of air pollution during physical activities, as their bodies may have a reduced capacity to cope with the added stress of pollution while exercising.

People with pre-existing heart or lung conditions

Those with pre-existing heart or lung conditions are at a heightened risk of experiencing cardiovascular events such as heart attacks, arrhythmias, heart failure, strokes, and sudden cardiac death. This is especially true for those with chronic heart disease. Short-term exposure to air pollution can increase the risk of such cardiovascular events, while the risk of death is greater from long-term exposure.

Airborne particles, particularly fine particulate matter (PM2.5), have been identified as a major cause of the increased risk of cardiovascular events. These particles are commonly emitted from power plants, factories, automobiles, and wildfire smoke. They can remain in the atmosphere for days to weeks and can travel large distances, influencing the air quality of regions far from the original source. As a result, individuals who live or work near roadways, railyards, seaports, or industrial areas may be exposed to higher levels of PM2.5.

The American Heart Association has found that long-term exposure to air pollution is a significant risk factor for heart disease. Their studies have shown that healthy individuals exposed to air particle pollution over the long term experienced accelerated cases of atherosclerosis, or plaque buildup in the arteries, which can lead to an increased risk of heart attack. Furthermore, the higher the exposure level, the faster atherosclerosis tends to progress.

In summary, people with pre-existing heart or lung conditions are at a heightened risk of adverse cardiovascular events due to air pollution, especially from fine particulate matter (PM2.5). This risk is further exacerbated by long-term exposure to air pollution, which can lead to accelerated cases of atherosclerosis and an increased likelihood of cardiovascular events.

Those living in lower-income countries

While air pollution is a global issue, those living in lower-income countries are particularly vulnerable to the cardiovascular effects of air pollution. Lower-income countries often have a higher concentration of polluting industries, such as power plants and factories, which emit harmful pollutants like sulfur dioxide and nitrogen oxides. These countries may also have weaker environmental regulations, leading to higher levels of air pollution overall.

The population in lower-income countries may also be more susceptible to the health impacts of air pollution due to a variety of factors. For instance, individuals in these countries may have limited access to healthcare services, making it more difficult to manage pre-existing cardiovascular conditions or to receive treatment for pollution-related health issues. Additionally, lower-income populations may have a higher prevalence of risk factors for cardiovascular disease, such as smoking, high blood pressure, and high cholesterol, which can be further exacerbated by air pollution exposure.

Furthermore, the effects of air pollution on heart health in lower-income countries can be compounded by other social and economic factors. For example, individuals in these countries may have limited access to healthy and nutritious food options, which can contribute to the development of cardiovascular disease. They may also face challenges in accessing education and awareness programs about the risks of air pollution, as well as the importance of monitoring air quality and taking protective measures.

The impact of air pollution on heart disease in lower-income countries is a serious concern. Research has shown that exposure to fine particulate matter, such as PM2.5, can trigger cardiovascular events and increase the risk of mortality. This is particularly true for those with pre-existing cardiovascular conditions or risk factors. Therefore, it is crucial to address the issue of air pollution in lower-income countries through policy interventions, improved industrial regulations, and the promotion of cardiovascular health and awareness among vulnerable populations.

Males

Several factors contribute to males being more vulnerable to heart disease from air pollution. Firstly, males tend to develop heart disease earlier in life than females. This may be attributed to the protective effects of estrogen and progesterone in premenopausal women, which enhance blood vessel health and regulate cholesterol levels. After menopause, however, the risk of heart disease in women increases significantly due to the loss of these hormonal benefits.

Secondly, biological factors play a role in the gender disparity. Men have larger hearts and blood vessels, making them more susceptible to cholesterol accumulation and plaque formation in the major arteries. Men also tend to store excess fat around their abdomen, which is associated with visceral fat accumulation. Visceral fat is linked to increased inflammation, insulin resistance, and higher levels of LDL ("bad") cholesterol, all of which contribute to a heightened risk of heart disease. Additionally, research indicates that men are more prone to developing high blood pressure at an earlier age, further increasing their vulnerability to cardiovascular issues.

Behavioural factors also come into play. Smoking is a significant risk factor for heart disease, and according to the World Health Organization (WHO), 40% of men smoke compared to only 9% of women. Smoking damages arteries, exacerbates blood pressure, and diminishes oxygen levels in the blood, placing a greater burden on the heart. Furthermore, while both genders experience stress, men are more likely to externalize their stress through anger or aggression. Evidence suggests that in the two hours following an angry outburst, an individual's risk of a heart attack increases significantly.

The combination of these biological, behavioural, and lifestyle factors places males at heightened vulnerability to heart disease, with air pollution acting as a contributing factor. Air pollution, particularly fine particulate matter (PM2.5), has been linked to an increased risk of cardiovascular events, including heart attacks, arrhythmias, and heart failure. It is important to recognize that while males may be more susceptible to certain risk factors, heart disease is a significant concern for both genders, and maintaining heart health is crucial for everyone.

Smokers

Smoking is one of the leading causes of cardiovascular disease. Smokers are consistently at a higher risk of metabolic syndrome and cardiovascular mortality due to air pollution. Research has shown that smokers, who already inhale smoke, are unaffected by dirty air. This indicates that bad air can cause heart attacks, as smokers seem less affected by additional external pollutants.

Myocardial infarction was found to be significantly more common on days with high nitric oxide concentrations, with a 1% higher incidence for every 10 µg/m3 increase. Myocardial infarction was also more likely to occur when there was a high average PM10 concentration over the previous three days, with a 4% higher incidence for every 10 µg/m3 increase. However, the incidence of myocardial infarction in smokers was found to be unaffected by nitric oxide and PM10 concentrations.

Additionally, air pollution is associated with an increased risk of heart attacks, especially in smokers. This is because smoking already introduces pollutants into the body, and when coupled with external pollutants, it can have adverse effects on heart health. Smokers are also more likely to experience plaque buildup in their arteries, which can lead to atherosclerosis and an increased risk of heart attack.

Furthermore, air pollution is linked to higher cardiovascular mortality rates in urban cities in Asia, such as New Delhi, Hong Kong, and Beijing, compared to urban cities in Europe and North America. This is due to the higher air pollution levels in these regions, which disproportionately affect vulnerable subgroups, including smokers.

Overall, smokers are a vulnerable group when it comes to the effects of air pollution on heart disease. The combination of smoking and exposure to air pollution can increase the risk of cardiovascular events and mortality. Quitting smoking and reducing exposure to air pollution are crucial for improving heart health and lowering cardiovascular risk.

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