Naturopathy

Of those children, those with daily exposure to incense in their homes were 78 per cent more likely than those with no exposure to currently have asthma -- a pattern that was not true of children with the gene variant.

Incense is usually derived from fragrant plant materials, like tree bark, resins, roots, flowers and essential oils. Previous research has found that burning these materials can produce harmful substances, including benzene and polyaromatic hydrocarbons. A 2008 study of more than 61,000 Chinese adults followed for up to 12 years found a link between heavy incense use and various respiratory cancers, including oral, nasal and lung cancers.


While neither that study nor the current one proves that incense is the reason for the greater disease risks, the more recent one raises the possibility that limited incense use at home could help curb asthma risk for some children, Lee told Reuters Health in an e-mail. Some studies in Asian countries have found connections between incense burning and respiratory symptoms in children, but others -- including one of schoolchildren in Hong Kong -- have not, Lee and his team said.
It is also not clear whether the most recent findings can be generalized to other countries, he added.

Of the children, 48 per cent carried no copies of a gene variant known as GSTT1, which helps regulate a family of enzymes that protect body cells from oxidative damage, including that caused by cigarette smoke or other toxic chemicals. People without this variant have been found to have higher risks of allergies and asthma. "Incense burning is a risk factor for asthma and wheezing, especially in GSTT1 genetically susceptible children," wrote Lee and his colleagues.