Burning incense may create a sweet scent, but regularly inhaling the smoke could put people at risk of cancers of the respiratory tract, researchers reported on August 25.
In a study of more than 61,000 ethnic Chinese living in Singapore who were followed for up to 12 years, the investigators found a link between heavy incense use and various respiratory cancers. The findings are published in the medical journal Cancer.
Incense has been used for millennia in many cultures' religious and spiritual ceremonies. In Asia, people commonly burn incense in their homes - a practice that is becoming more popular in Western countries as well.
Incense is usually derived from fragrant plant materials, like tree bark, resins, roots, flowers and essential oils. Past research has found that burning these materials can produce potentially cancer-causing substances, including benzene and polyaromatic hydrocarbons. However, no studies until now had linked the practice of burning incense to an increased cancer risk over time, according to the researchers, led by Dr Jeppe T. Friborg of the Statens Serum Institute in Copenhagen.
For their study, the researchers followed 61,320 Singapore Chinese men and women between the ages of 45 and 74 from the Hokkien or Cantonese dialect group. All of the subjects were cancer-free at the outset. Over the next 12 years, 325 men and women developed cancer of the upper respiratory tract, such as nasal, oral or throat cancer. Another 821 developed lung cancer.