Air Pollution Makes Cancer Patients More Vulnerable To Cardiovascular Disease

Anuradha Varanasi, Contributor: Anuradha writes about environmental health disparities & epidemiology

A recent study reported that even short-term exposure to air pollutants known as fine particulate matter 2.5 (PM2.5) — which are microscopic particles or droplets with a width of less than two-and-a-half microns in width — is linked to a significantly greater risk of cancer patients suffering from and/or dying due to cardiovascular disease.

INNER MONGOLIA, CHINA – NOVEMBER 04: Smoke billows from a large steel plant as a Chinese labourer works at an unauthorized steel factory, foreground, on November 4, 2016 in Inner Mongolia, China. GETTY IMAGES

“This suggests that even temporary deteriorations in air quality can have immediate adverse effects on vulnerable populations such as cardio-oncology patients,” said Xiaoquan Rao, a senior author of the study and cardiologist at Tongji Medical College in Wuhan, China, in a press release. “The review underscores the critical need to consider environmental factors, especially air pollution, in cardio-oncology risk assessment and patient management.”

Previous studies have linked PM2.5 exposure to a higher risk of developing hypertension, atherosclerosis, heart attacks, and strokes. According to a 2019 Global Burden of Disease Study, air pollution contributed to 6.7 million deaths globally, and specifically, PM2.5 pollutants were attributed to 15.1% of lung cancer deaths worldwide.

In most parts of the world, air pollution levels have consistently exceeded the World Health Organization’s guideline for PM2.5. This type of air pollutant is emitted at extremely high levels, particularly in middle and low-income countries in South Asia, the Eastern Mediterranean, and Western Pacific regions. Urban populations experience the most severe exposure to PM2.5 pollutants compared to those who live in rural areas.

“Air pollution has long been overlooked in both cancer and cardiovascular disease, particularly in cardio-oncology care, despite robust evidence linking air pollution to both conditions. Although cardiovascular disease risk is recognized as an important consideration in cancer treatment according to the 2022 guideline on cardio-oncology, environmental factors are currently not adequately addressed because of insufficient awareness of this issue,” the researchers wrote in their study that was published in JACC: CardioOncology.

“This emphasizes the critical need to raise awareness about the impact of environmental factors, specifically air pollution, in cardio-oncology care. Increased awareness could lead to reduced risks through improved knowledge of personalized protection strategies against air pollution,” they added. “Preventative interventions such as using N95/N99 respirators; reducing outdoor activities during heavily polluted days; and improving indoor air quality with portable air cleaners or heating, ventilation, and air conditioning systems are recommended for vulnerable individuals residing in areas with high levels of pollutants.”

Rao and colleagues analyzed eight studies published from 2000 to 2023 which delved into how air pollutants like PM2.5 impact the cardiovascular health of cancer patients. They observed that exposure to PM2.5 was associated with higher rates of cancer patients being diagnosed with cardiovascular diseases and even higher rates of mortality due to cardiovascular disease.

“The co-occurrence of cancer and cardiovascular disease, along with their shared risk factors, suggests overlapping patho-physiological mechanisms. These mechanisms encompass a range of pathways, including inflammation, immune activation, metabolic pathways, neuro-hormonal mechanisms, and gut microbiome,” Rao and team explained in the study. “Within this intricate network, inflammation and oxidative stress play central and dominant roles, demonstrating not only a cause-and-effect relationship but also interacting with other pathological factors to collectively exert both cardiovascular and carcinogenic effects.”