Decades of daily incense use may culminate in limb-threatening condition

Burning incense in the home every day for decades appears to have deleterious consequences, with a Singapore study linking this practice to a heightened risk of chronic limb-threatening ischaemia (CLTI), the most severe form of peripheral arterial disease (PAD).

Analysis of data from the Singapore Chinese Health Study showed that current incense users were 22 percent more likely to have incident CLTI compared with never or former users (hazard ratio [HR], 1.22, 95 percent confidence interval [CI], 1.04–1.43). This risk further rose to 25 percent for those who had burned incense daily for over 40 years (HR, 1.25, 95 percent CI, 1.06–1.46). [Environ Health Perspect 2025;133:17009]

The findings were consistent across subgroups defined by sex, diabetes history, and smoking status.

In mediation analysis, a small but statistically significant indirect effect of diabetes history on CLTI risk was observed (HR, 1.05, 95 percent CI, 1.03–1.07). However, the direct effect of incense use on CLTI risk remained significant (HR, 1.20, 95 percent CI, 1.05–1.35), which was not so different from the total effect estimate (HR, 1.26, 95 percent CI, 1.10–1.42). This suggests that the association between incense and CLTI was largely independent of diabetes, as the authors noted.

These data have important public health implications, especially given the continued widespread use of incense despite growing awareness of its health risks, they said.

“The burning of incense at home is still a part of common practice in many parts of the world, not only for religious purposes but also for air freshening or therapeutic purposes,” the authors said, who cited studies wherein incense use was reported to range from 20 percent in Hong Kong to more than 70 percent in Taiwan.

In Singapore, the prevalence of current incense use in the present cohort was 76.9 percent. What’s more is that almost all of them (92.6 percent) burned incense at home daily, and 84.0 percent had been doing so for more than 40 years.

“This is concerning because incense smoke contains numerous harmful components, including particulate matter, various gases, VOCs, and PAHs, many of which are linked to cardiovascular disease,” including PAD, the authors said.

As an advanced stage of PAD, CTLI is marked by ischaemic rest pain, nonhealing ulcers, and/or gangrene. The authors stressed that CLTI is particularly worrying because it often requires surgical intervention, such as revascularization or amputation, and is associated with a disproportionately high 5-year mortality rate of more than 50 percent. [J Vasc Surg 2019;69:3S-125S; Arterioscler Thromb Vasc Biol 2020;40:1808-1817]

“It would be important to increase public awareness regarding the potential harmful effects of long-term incense exposure in order to reduce the risk of CLTI,” the authors said.

The present study included 63,134 Singaporean Chinese (mean age 56.5 years, 55.8 percent female). CLTI occurred in 1,097 participants over a mean follow-up of 18.8 years.