Secondhand smoke appears to heighten risk of oral cancer

That's according to a review of existing research published online in the journal Tobacco Control.

Oral cancers – lip, oral cavity and oropharynx cancers – account for 447,751 new cases of cancer and 228,389 deaths every year globally. Significant risk factors for these forms of cancer include tobacco smoking and use of smokeless tobacco, consumption of alcohol, and betel quid chewing.

Tobacco smoke forms the largest exposure of humans to chemical carcinogens and it causes one out of five cancer-related deaths in the world.

However, it is not only active smokers affected as, according to data from 192 countries, 33% of male non-smokers, 35% of female non-smokers and 40% of children were exposed to involuntary smoking during one year by inhaling secondhand tobacco smoke.