The International Agency for Research on Cancer (IARC), an intergovernmental agency affiliated to World Health Organization (WHO) of the United Nations (UN) published its report on smokeless tobacco in 2007 in the form of a monograph (Vol. 89). Flavored / unflavored tobacco such as Zarda, Khiwam, loose tobacco leaves, khaini and flavored/ unflavored tobacco with additives such as betel quid/Pan, Gutka, Mawa etc. were considered as "smokeless tobacco" for the assessment. Altogether 19 experts drawn from 6 countries including India, called as “Working Group” deliberated on the issue in a week-long workshop held in Lyon, France in 2004 and brought out the manograph in 2007. The data on the exposure of the chewable tobacco to humans, data available on the cancer in humans due to the exposure, underlaying mechanism of cancer induction, experimental animal studies data, cell-line studies etc. published in reputed journals were reviewed by the working group.
The working group concluded the
following in their monograph.
·
Tobacco-specific nitrosamines, the most abundant
strong carcinogens in smokeless tobacco products have been detected in the
saliva of tobacco chewers in many studies around the world.
·
Smokeless tobacco products are associated with the
generation of reactive oxygen species, modulation of inflammatory mediators,
inhibition of collagen synthesis and impairment of DNA repair capacity.
· Smokeless tobacco products deliver nicotine in quantities and at rates that cause psychoactive effects, which eventually lead to tolerance and addiction.
·
There is sufficient evidence in humans for the
carcinogenicity of smokeless tobacco. Smokeless tobacco causes cancers of the
oral cavity and pancreas.
The overall conclusion was,
·
Smokeless tobacco is carcinogenic to humans (Group 1).
