A recent study conducted and presented by the researchers of the department of epidemiology from Copenhagen’s Statens Serum Institut, shows that there is a connection between the exposure to burning incense and airway cancers. The study was led by Dr. Jeppe T. Friborg and demanded a long term involvement from the entire research team.

"This association is consistent with a large number of studies identifying carcinogens in incense smoke," Friborg's team writes, "and given the widespread and sometimes involuntary exposure to smoke from burning incense, these findings carry significant public health implications." According to the results, the long-term exposure to the incense smoke leads to certain respiratory tract, lung, tongue and mouth cancers.

The incenses are usually made from a series of plant materials such as tree bark, roots, resins, flowers or essential oils. While burning, these materials are known to produce potentially carcinogen substances such as carbonyls, benzene and hydrocarbons (PAHs).

This is not the first study targeting the effects of inhaled incense, but so far none of them managed to provide conclusive information. What sets this research apart from the others is the long term observation process on healthy people, which provided all the needed data to help the researchers reach the firm conclusion.

The study involved the careful observation of about 60,000 Chinese residents of Singapore. They were recruited between 1993 and 1998 and followed until 2005. At the time of their selection they were all cancer-free and had to answer several questions about their diet, lifestyle habits and offer details about their exposure to incense – close to 75 percent were frequent incense users.

The results after more than eight years of tests listed 325 upper respiratory tract cancers and 821 lung cancers, and the frequent incense users appeared twice as exposed to developing squamous cell upper respiratory tract cancers including nasal/sinus, tongue, mouth and laryngeal. The risk appears to be the same for smokers and non-smokers. There are still many more aspects of the issue that demand attention, such as the upcoming analysis which will be focused on whether different types of incense are associated with different degrees of cancer risk.

"Given that our results are backed by numerous experimental studies showing that incense is a powerful producer of particulate matter and that incense smoke contains carcinogenic substances, I believe incense should be used with caution," said Dr. Jeppe Friborg.

The news were quickly acknowledged by many, and Dr. Norman Edelman, chief medical officer of “The American Lung Association” explained for US News & World Report that incense exposure will be added as a risk factor on its lists.

Even though is it considered far less dangerous than smoking, people should try to avoid it as much as possible, as there are many more ways of keeping the house perfumed without worrying about these risks. The problem is that the incense burning trend is extremely popular all over the world and it might take a while for everyone to understand the risks and keep their places incense-free.