A review published in the journal Lancet Oncology says that oral and nasal snuff as well as chewing tobacco are harmful as they increase the risk of certain cancers, but on the reverse side these habits are considered safer thank smoking.
The risk of throat and pancreatic cancer is roughly 60 percent higher among users of smokeless tobacco products compared with non-users, it found.
Investigators in the United States and Asia also found a 260 percent increase in the risk of mouth cancer among smokeless tobacco users, compared with non-users, but a similar European investigation found no added risk, it said.
No conclusive evidence has emerged to suggest that these products enhanced the risk of lung cancer, the overview found.
More than 30 carcinogens, or cancer-causing ingredients, can be found in smokeless tobacco, a category that comprises oral products that are sucked or chewed or, in powdered form, inhaled through the nose.
"(The) cancer risk of smokeless tobacco users is probably lower than that of smokers, but higher than that of non-tobacco users," the paper says.
The study was lead-authored by Paolo Boffetta of the International Agency for Research on Cancer (IARC), based in Lyon, southeastern France.