Long-Term Use of Incense Increases Respiratory Cancer Risk

Exposure to burning incense over long periods of time may increase the risk of respiratory-tract cancers, a new study by researchers from Statens Serum Institute in Copenhagen, Denmark suggested Monday.

The study suggested that regularly inhaling the smoke could put people at risk of cancers of the respiratory tract. Based on data from a large Chinese cohort study, the findings are to be published in the October issue of Cancerdefine.

In order to determine a link between heavy incense use and various respiratory cancers, the researchers conducted interviews with more than 61,000 ethnic Chinese living in Singapore who were between the ages of 45 and 74 and were cancer-free at the beginning of the study.

After a 12-year follow up, Jeppe T. Friborg, M.D., Ph.D., of Statens Serum Institute in Copenhagen, Denmark, and formerly of the University of Minnesota, and colleagues noticed that incense users had an 80% increased risk of squamous-cell respiratory-tract cancers compared with nonusers.

Squamous cell carcinoma is a form of cancer of the carcinoma type that may occur in many different organs, including the skin, mouth, esophagus, prostate, lungs, and cervix. It refers to tumors that arise in the cells lining the internal and external surfaces of the body. This type of cancer is characterized by red, scaly skin that becomes an open sore.

During follow-up through 2005, 325 men and women developed cancer of the upper respiratory tract, such as nasal, oral or throat cancer, while another 821 developed lung cancer. The investigators found that burning incense almost doubled the risk of developing squamous cell upper respiratory tract carcinomas such as nasal or sinusdefine, tongue, mouth and laryngeal.

The study subjects who used incense in their homes throughout the day and night were 80 percent more likely to develop squamous cell carcinoma of the entire respiratory tract than their counterparts.

The study though found no connection between incense inhaled into the lungs and lung cancer, but noticed that incense did increase the risk of squamous cell carcinoma of the lung.

"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." Dr. T. Friborg said.

Past research has found that burning Incense, composed of aromatic organic materials can produce significantly dangerous cancer-causing substances, including benzene and polyaromatic hydrocarbons.

Incense, which releases fragrant smoke when burned, was used in ancient Egypt, Greece and Rome, and is also mentioned in the Old and the New Testaments. It is also found in the major religions of Asia, where many religious ceremonies use this aromatic substance.

Although, the findings pose a significant warning to incense-users worldwide, the researchers of the recent study say further studies are required to see whether different types of incense are associated with different degrees of cancer risk.

"Besides initiatives to reduce incense smoke exposure, future studies should be undertaken to identify the least harmful types of incense," they said.