Invited Perspective: Incense Burning and Cardiovascular Risk—A Rising Concern

The burning of incense—a practice rooted in ancient religious, cultural, and even medicinal traditions—has persisted for thousands of years, with uses ranging from sacred rituals to modern-day aromatherapy.^1–4 Yet, while incense may impart an air of serenity, mounting evidence indicates that its fragrant smoke might pose major risks to human health. In the context of today’s rising awareness of environmental contributors to disease, it is essential to critically evaluate the impact of incense smoke on cardiovascular well-being and to consider whether its widespread use merits caution.

When incense burns, it releases a complex array of compounds, including particulate matter (PM), volatile organic compounds, polycyclic aromatic hydrocarbons, carbon monoxide, and other chemicals.^5–8 Many of these pollutants are also commonly found in cigarette smoke, which is well established as a potent cardiovascular hazard.⁹ Yet, the potential cardiovascular effects of burning incense, unlike those of cigarette smoking, remain largely underappreciated by both the public and health authorities.

Nevertheless, a growing body of epidemiological evidence is linking incense smoke exposure to adverse cardiovascular outcomes. In studies conducted in Asia, where incense use is prevalent,^10–12 associations between incense exposure and increased incidence of hypertension, coronary artery disease, stroke, kidney disease, and cancer have been reported.^13–18 Most recently, in this issue of Environmental Health Perspectives, Ying et al. demonstrate that daily exposure to incense smoke in the home environment for more than 40 years was associated with increased risk of developing chronic limb-threatening ischemia compared to never/former users.¹⁹

The World Health Organization has warned that indoor exposure to PM from sources such as cooking and heating with solid fuels can contribute to cardiovascular disease (CVD).²⁰ Given the composition and concentration of PM and other pollutants in incense smoke, it is reasonable to hypothesize that its long-term effects on cardiovascular health could be on par with other recognized indoor air pollutant sources, such as solid fuel emissions.

Incense smoke can contain PM at levels far above the National Ambient Air Quality Standards (NAAQS) of the US Environmental Protection Agency, particularly in indoor settings, where poor ventilation traps these particles.^8,21 In fact, recent research indicates that PM concentrations associated with incense burning can exceed those found in homes with frequent cigarette use.^22,23 Fine and ultrafine PM, like that found in incense smoke, can penetrate deep into the lungs, leading to systemic inflammation and oxidative stress, both of which are key pathways for CVD; exposure has also been associated with endothelial dysfunction or arterial stiffening, and with accelerated atherosclerosis.²⁴ Children, elderly individuals, and those with preexisting cardiovascular or respiratory conditions may be particularly vulnerable to incense smoke.¹²

The ritualistic nature of incense burning also contributes to its potential harm. Unlike other forms of smoke exposure, which may be intermittent, many individuals burn incense daily, sometimes several times a day, leading to cumulative exposure over time.²⁵ Individuals may be unknowingly exposing themselves and their families to hazardous pollutants. When combined with other risk factors, including age, genetics, and lifestyle, the cardiovascular toll of incense smoke may be significant.

Given the potential risks associated with incense smoke, we believe it is crucial to consider strategies to mitigate its impact on cardiovascular health:

• Public health education: As with other environmental risks, awareness is the first line of defense. Individuals who frequently use incense should be informed about the potential cardiovascular risks and encouraged to reduce exposure, particularly in enclosed or poorly ventilated spaces.

• Ventilation recommendations: Just as with other indoor air pollutants, effective ventilation can help disperse harmful compounds. Health guidelines should recommend ventilation strategies for households that use incense regularly, such as the use of exhaust fans or opening of windows.

• Regulatory oversight: Governments and health organizations might consider regulating the composition of incense products, setting standards to limit the emission of harmful compounds. Such regulation could mirror efforts made to reduce hazardous emissions from other indoor products, such as candles and household cleaners.

Despite the growing body of evidence, more research is needed to fully understand the cardiovascular effects of incense smoke. Longitudinal studies, in particular, would provide valuable insights into the long-term impact of incense exposure on heart health and help identify those most at risk.

As awareness of cardiovascular risks associated with environmental and lifestyle factors grows, it is crucial that incense smoke receive the scrutiny it deserves. Although its aromatic allure and cultural significance are undeniable, the potential cardiovascular hazards it poses warrant serious evaluation. For clinicians, researchers, and public health officials, incense represents an overlooked but actionable avenue for reducing CVD burden. Public health messaging and regulatory action are needed to ensure that individuals can make informed decisions about incense use and, ultimately, protect their cardiovascular health.

Conclusions and opinions are those of the individual authors and do not necessarily reflect the policies or views of EHP Publishing or the National Institute of Environmental Health Sciences.

Refers to https://doi.org/10.1289/EHP14674