A WIDESPREAD HABIT
Betel quid generally consists of
betel leaf (from the Piper betle vine), areca nut (from the Areca
catechu tree), and slaked lime (predominantly calcium hydroxide), to
which tobacco is often added. Other ingredients and flavouring agents
can be included according to local preferences and practices.
Betel-quid and areca-nut chewing are widely practiced in many parts of Asia and in Asian-migrant communities elsewhere in the world, with hundreds of millions of users worldwide. Betel quid is chewed for many reasons, including for its stimulant effects, to satisfy hunger, to sweeten the breath, and as a social and cultural practice. Traditional as well as commercially packaged products are now freely available in pan shops in many cities outside Asia. The United Kingdom is the number one importing country outside of Asia, with imports having doubled since the early 80's. In some immigrant communities a large majority is using these products. Young children start using sweetened areca-nut products, often adding tobacco later in their adolescence.
A CANCER-CAUSING HABIT
The expert working group has
determined that betel quid with tobacco causes oral cancer, cancer of
the pharynx, and cancer of the oesophagus in humans. Betel quid without
tobacco is now known to cause oral cancer in humans. Areca nut, a common
component of all betel quid preparations, has been observed to cause
oral submucous fibrosis (a pre-cancerous condition that can progress to
malignant oral cancer), leading to the determination that areca nut
itself is carcinogenic to humans. Studies among Asian migrant
communities have demonstrated a significantly higher risk for oral
cancer compared with natives of countries where they have settled.
The new evaluation of betel quid without tobacco was made possible by recent epidemiologic studies from parts of the world where tobacco generally is not added to the betel quid. In addition, recent epidemiologic studies in South Asia have been able to separate the effects of betel quid use with and without tobacco.
Oral cancers are more common in parts of the world where betel quid is chewed. Of the 390,000 oral and oro-pharyngeal cancers estimated to occur annually in the world, 228,000 (58%) occur in South and South-East Asia. In some parts of India, oral cancer is the most common cancer. Striking evidence has emerged from Taiwan, China, where the incidence of oral cancer in men has tripled since the early 1980s, coinciding with a steep rise since the early 1970s and predominantly among men, in the practice of chewing betel quid. Tobacco generally is not added to the betel quid in that region.
A NEW CAUSE FOR CONCERN
In recent years, a variety
of mass-produced, pre-packaged areca-nut products have become available
in many countries around the world. Aggressive advertising, targeted at
the middle class and at children, has enhanced the sales and use of
these products. In some parts of India, almost one out of three children
and teenagers regularly or occasionally chew these products. Some have
viewed such products without tobacco (for example, pan masala) as a safe
alternative to betel quid with tobacco. The evidence shows that these
products have led to oral disease, even among children, and that use of
these products cannot be considered safe. Several states in India have
begun to regulate these products, and reductions in oral disease and
oral cancer can be expected to follow from reductions in their use.
THE IARC MONOGRAPHS
The IARC Monographs Programme
publishes authoritative, independent evaluations of carcinogenic risks
to humans caused by a variety of agents, mixtures and exposures. Each
evaluation is the product of deliberations by an international working
group of scientific experts. Since its inception in 1971, the series has
evaluated nearly 900 agents, and the IARC Monographs have become known
for their thoroughness, accuracy, and integrity.
For general information on the Monographs Programme visit our website and for further information on this release, please direct your questions to Dr. Kurt Straif straif@iarc.fr
For more general information, contact Dr Nicolas Gaudin, Chief, IARC Communications (com@iarc.fr). If you wish your name to be removed from our press release e-mailing list, please write to the same address.