Intended for healthcare professionals

Rapid response to:

Practice Guidelines

Secondary prevention of cardiovascular disease, including cholesterol targets: summary of updated NICE guidance

BMJ 2024; 384 doi: (Published 28 March 2024) Cite this as: BMJ 2024;384:q637

Rapid Response:

The Impact of Air Pollution on Cardiovascular Health: An important Non-Traditional Risk Factor

Dear Editor

We congratulate Wonderling & colleagues for this welcome update and agree on the increasing number of individuals now surviving with diagnosed cardiovascular diseases (CVD). These patients persist in facing an elevated risk of further cardiovascular incidents and increased mortality rates. Interventions geared towards secondary prevention, particularly those aimed at reducing low-density lipoprotein cholesterol (LDL-C), have been identified as effective strategies in diminishing this risk and enhancing patient outcomes.

We aim to underline the importance of one of the nontraditional risk factors that should be addressed: air pollution, particularly fine particles (<2.5 µm; PM2.5) because of their negative effect on lipoprotein cholesterol metabolism.

Both short-term and chronic exposure to PM2.5 has been found to increase the relative risk of cardiovascular events such as heart failure hospitalizations, cardiac arrest, arrhythmias, ischemic stroke, and, most significantly, myocardial infarction (MI). High levels of PM2.5 have been linked to the enhancement of coronary atherosclerosis and plaque destabilization, while randomized studies have demonstrated that exposure to PM2.5 increases blood pressure within hours. Recent evidence also suggests that individuals with recurrent acute coronary syndrome and higher long-term PM2.5 exposure may experience impaired plaque healing.

Human studies have shown that plasma oxidized low-density lipoprotein (LDL) concentration is positively associated with chronic air pollution exposure, independent of traditional cardiovascular risk factors or lipid-lowering drugs. Furthermore, exposure to higher levels of PM2.5 has been linked to impairments in high-density lipoprotein functionality, increased levels of oxidized LDL, elevated levels of systemic inflammation markers like C-reactive protein, and oxidative stress.

Individuals who require secondary prevention of CVD and reside in highly polluted areas face an increased risk of worsening their condition. While traditional risk factors such as smoking, obesity, high blood pressure, and high cholesterol are commonly targeted in CVD prevention strategies, the impact of air pollution on cardiovascular health should not be overlooked.

One suggestion for individuals with existing CVD or those at high risk is to consider relocating to less polluted areas. By moving to a cleaner environment with reduced levels of air pollution, individuals can decrease their exposure to harmful particles and potentially improve their cardiovascular health. Because, for several reasons, moving may not be a viable option for many individuals, those who benefit more from secondary prevention of CVD should be informed of the potential risk reduction of residing in a less polluted area and take adequate measures to minimize their exposure to air pollution to enhance their cardiovascular health.

Bonanni A, Basile M, Montone RA, Crea F. Impact of the exposome on cardiovascular disease. Eur Heart J Suppl. 2023 Apr 21;25(Suppl B):B60-B64. doi: 10.1093/eurheartjsupp/suad069. PMID: 37091631; PMCID: PMC10120942.

Competing interests: No competing interests

03 April 2024
Giovanni Ghirga
Paola Ghirga, MD
International Society of Doctor for the Environment ( ISDE, Italy )