Air pollution linked to heart disease, cancer risk, likely via shared risk factors
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Key takeaways:
- Air pollution contributed to CVD risk in patients with cancer and cancer incidence in those with CVD.
- The interaction may be due to its effects on common risk factors such as inflammation and oxidative stress.
Air pollution exposure may contribute to both CV and cancer risk by interacting with various common risk factors such as inflammation, oxidative stress and epigenetic modifications, according to a state-of-the-art review.
Xiaoquan Rao, MD, PhD, cardiologist at Tongji Hospital at the Tongji Medical College in Wuhan, China, and colleagues issued a state-of-the-art review on the effects of air pollution as a shared risk factor for both CVD and cancer, which was published in JACC: CardioOncology.
“The review underscores the critical need to consider environmental factors, especially air pollution, in cardio-oncology risk assessment and patient management,” Rao said in a press release. “By highlighting the significant role of air pollution in the cardiovascular health of cancer patients, our work aims to catalyze further research in this field and inform clinical practices and public health policies.”
Air pollution and risk for CVD and cancer
Exposure to particulate matter up to 2.5 µm (PM2.5) was associated with increased risk for hypertension, atherosclerosis, heart attacks and stroke, according to a prior study in Cardiovascular Research, as well as elevated risk for cancer — especially lung cancer — according to another study in Environmental Research.
Rao and colleagues then conducted a literature review of studies that evaluated the effect of air pollution on CVD risk within cohorts of patients with cancer and cancer risk in cohorts of patients with CVD. They observed that in patients with cancer, every 10 µg/m3 increase in PM2.5 exposure was associated with HRs for CVD and cardiopulmonary death ranging from 1.17 to 1.44.
Conversely, in patients with established CVD, exposure to nitrogen oxides — a proxy for traffic-related air pollution — was associated with cancer incidence, even when heavy smokers were excluded from the analysis (HR = 1.17; 95% CI, 1.01-1.36). This association between cancer incidence and air pollution in patients with CVD was especially strong for incident breast cancer, with an HR of 1.43 (95% CI, 1.12-1.83).
Inflammation and oxidative stress from air pollution
The researchers wrote that shared molecular and genetic pathways, such as inflammation and oxidative stress, may play a significant role in CVD and cancer risk in areas with high levels of air pollution.
Air pollutants, particularly PM2.5 and PM0.1, can breach the upper respiratory tract barrier and get deposited into the alveoli, leading to systemic inflammation that may contribute to inflammatory dysregulation, oxidative injury and ultimately CV damage and cancer risk, according to the review.
Moreover, a prior study in CA: A Cancer Journal for Clinicians showed that PM2.5 carried certain mutagens and carcinogens and could lead to gene instability, DNA methylation and transcriptional changes in microRNA and long noncoding RNA. Such changes can cause malignancy of somatic cells, CV dysfunction and exacerbate common CVD and cancer risk factors such as obesity and diabetes, Rao and colleagues wrote.
“This suggests that even temporary deteriorations in air quality can have immediate adverse effects on vulnerable populations such as cardio-oncology patients,” Rao said in the release. “This awareness is crucial for developing tailored air pollution exposure control measures and individualized patient management strategies aimed at mitigating cardiovascular disease risks among cancer patients.”
Rao and colleagues wrote that a better understanding of the effects of air pollution exposure will not only guide strategies for early prevention and personalized treatment in the setting of cardio-oncology, but could contribute to the appreciation of health disparities associated with air pollution.
References:
- Ciabattini M, et al. Environ Res. 2021;doi:10.1016/j.envres.2020.110440.
- Miller MR, et al. Cardiovasc Res. 2020;doi:10.1093/cvr/cvz228.
- Study finds air pollution can increase cardiovascular risk for cancer patients. https://medicalxpress.com/news/2024-06-air-pollution-cardiovascular-cancer-patients.html. Published June 18, 2024. Accessed June 18, 2024.
- Turner MC, et al. CA Cancer J Clin. 2020;doi:10.3322/caac.21632.
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