Burning incense at home could increase cancer risk, UAE study finds

A study of Emiratis reveals that regular exposure to incense smoke reduces bacteria in the mouth needed to fight off disease

A sales clerk drops a piece of oud into an incense burner at Ibn Battuta Mall in Dubai. More than 90 per cent of Emiratis burn incense at home and more than a third do so every day, researchers found.Show more

Burning incense could increase the chance of developing cancer and cardiovascular disease, according to a study of Emirati households.

Research by NYU Abu Dhabi revealed that people exposed to incense smoke are at greater risk of disease.

The pilot study, part of NYU's long-term UAE Healthy Future Study, was carried out on 303 Emiratis and published in the international journal Scientific Reports.

Participants filled out a questionnaire on incense usage and supplied a mouthwash sample.

The findings showed people who burnt incense and were exposed to the smoke regularly have a different composition in the bacteria in their mouth than those who do not. These crucial bacteria are needed to fight off infections and diseases, researcher Yvonne Valles told The National.

One example is Streptococci, which commonly lives in the mouth but was found in low numbers in Emiratis exposed to incense smoke.

“The changes are significant. This is one of the most important bacteria found in the mouth and it has significantly decreased in people exposed to incense," Dr Valles said.

"What we have shown is that there is a change and the next step is to now show what it can lead to."

Incense burning is part of Gulf culture. It is frequently used at special occasions and in hotels, among other public places. Oud comes from the bark of trees and can cost thousands of dirhams per gram.

According to the research results, 36.6 per cent burnt incense daily (5 to 7 times a week) and 33.7 per cent did so frequently (2 to 5 times a week).

Just over 24 per cent of subjects burnt incense once a week or less and 6.6 per cent did not use incense at all.

A major misconception, Dr Valles said, is a belief that the oud used for incense burning is natural because it comes from the bark of a tree.

“It is natural but you are not taking it in a natural way; you are burning it and when you burn it, it changes the natural structure of the product," she said.

The research will continue for generations and the 303 subjects in this study are part of 5,000 people who are already signed up for future UAE health projects. It is hoped that 20,000 Emiratis will volunteer in total.

“We cannot safely say that there is a causation at this point," Dr Valles said. "We know from other studies that in China and the US there is a link between lung cancer and incense burning but this research is new and has just started."

“The most important thing is to continue this type of study. I would like for people to be aware of the possibility that they could develop cardiovascular diseases.

"I understand that incense burning is traditionally so important, but if we continue this study and continue seeing such results then a policy should be put in place for when and where to burn it."

Researchers said that although incense is regarded as an "indoor air pollutant, guidelines for control of incense use have yet to be developed" by the government.

"For example, I would not burn it around babies," Dr Valles said. "I will not say stop burning incense, but I will say be careful."

The study used a complex formula to mark the fall in good bacteria in the mouth.

There was a -0.24 per cent reduction in bacteria in those who burnt incense once or twice a week, a -0.32 per cent reduction in those who frequently burnt incense and -0.51 per cent in those who are exposed to the smoke every day.

“It is an important finding and it is important for people to be aware," Dr Valles said. "In the UAE, incense is burnt in the mall, at homes and everywhere. We do not want to create panic because that is not the case yet. It is a finding that is important for people to be aware of."

Raghib Ali, director of the Public Health Research Centre at NYU Abu Dhabi, said that because incense smoke is inhaled, the likely effect would be on the lungs and heart.

“As far as we know there is no previous study done on the health effects of incense burning. This study did not look at the health effects directly but it looked the bacteria in the mouth collected from participants," he said.

"By looking at bacteria in the mouth, we compared to those who have been exposed to incense smoke and those who have not. The fact that there is a difference is important.”