Findings from different studies suggest that people who use smokeless tobacco products are at a high risk of developing different types of cancers including head and neck cancers, specifically oral cancer, pharyngeal cancer, laryngeal cancer, esophageal cancer; and pancreatic cancer. Smokeless tobacco is not a safer alternative to smoking cigarettes. Irrespective of the type, form and intake routes, all tobacco products (whether taken alone or with betel leaf, areca nut/betel nut and slaked lime) should be considered harmful and their use should be strongly discouraged.
Tobacco consumption is one of the leading causes of cancer. According to the World Health Organization, tobacco consumption kills more than 8 million people a year around the world. There are around 1.3 billion tobacco users worldwide with more than 80% of them living in low and middle income countries. People usually use tobacco products for nicotine, a highly addictive chemical compound present in the tobacco plant.
Apart from nicotine, tobacco smoke also consists of over 7000 chemicals including 70 carcinogens that can lead to cancer, with many damaging the DNA. Some of these chemicals include hydrogen cyanide, formaldehyde, lead, arsenic, ammonia, benzene, carbon monoxide, nitrosamines and polycyclic aromatic hydrocarbons (PAHs). The tobacco leaves also contain certain radioactive substances such as Uranium, Polonium-210 and Lead-210 which are absorbed from high-phosphate fertilizers, soil and air. Tobacco use can lead to many types of cancer, including lung, laryngeal, mouth, esophageal, throat, bladder, kidney, liver, stomach, pancreatic, colon, rectal and cervical cancers, as well as acute myeloid leukemia.
This leads to the question of whether smokeless tobacco use is a safer alternative to smoking cigarettes and other tobacco products? Let us find out!
What is Smokeless Tobacco?
Smokeless tobacco and tobacco products are used either orally or through the nasal cavity, without burning the product. There are many types of smokeless tobacco products including chewing tobacco, snuff, snus and dissolvable tobacco.
Chewing, Oral or Spit tobacco
These are loose leaves, plugs, or twists of dried tobacco possibly flavored, which are chewed or placed between the cheek and gum or teeth, and the resulting brown saliva is spitted out or swallowed. The nicotine present in the tobacco is absorbed through the mouth tissues.
Snuff or Dipping tobacco
These are finely ground tobacco, sold as dry or moist forms, and may have flavorings added. Dry snuff, available in powdered form, is sniffed or inhaled through the nasal cavity. Moist snuff is placed between the lower lip or cheek and gum and the nicotine is absorbed through the tissues of the mouth.
A type of moist snuff flavored with spices or fruit, which is held between the gum and mouth tissues and the juice is swallowed.
These are flavored, dissolvable, compressed, powdered tobacco that dissolve in the mouth and require no spitting of tobacco juices.
Like cigarettes, cigars and other tobacco products, smokeless tobacco use is also addictive due to nicotine content.
Are there Cancer Causing chemicals in Smokeless Tobacco Products?
Many of us also have a misconception that smokeless tobacco products are safer alternatives to cigarette smoking as they may not be linked to lung cancer. However, the risk of developing cancers is not limited to those who “smoke” tobacco. People who use smokeless tobacco products are also prone to developing different types of cancers. In fact, there is no safe form of tobacco or safe level of tobacco use.
There are 28 different cancer causing agents or carcinogens identified in smokeless tobacco products. Of these, the most harmful cancer-causing substances are tobacco-specific nitrosamines (TSNAs). In addition to TSNAs, other carcinogens present in smokeless tobacco include N-nitrosoamino acids, volatile N-nitrosamines, volatile aldehydes, polynuclear aromatic hydrocarbons (PAHs) and radioactive substances such as polonium-210 and uranium-235 and -238. (International Agency for Research on Cancer (IARC), World Health Organization)
Health Hazards Associated with Smokeless tobacco
Due to the presence of harmful chemicals and carcinogens, the use of smokeless tobacco products is also associated with a variety of health issues. Some of these are listed below:
- Risk of different types of cancers
- More exposure to nicotine as smokeless tobacco products are usually used more constantly compared to tobacco smoking which is done periodically in a day.
- Risk of Heart diseases
- Prone to gum diseases, tooth cavities, tooth loss, receding gums, abrasion of teeth, bad breath, bone loss around roots and staining of teeth.
- Precancerous Oral lesions such as leukoplakia
- Candy-like appearances of certain smokeless tobacco products may attract children and lead to nicotine poisoning.
Smokeless Tobacco Use and Cancer Risk
Different studies and systematic reviews have been conducted by researchers across the world to evaluate the association between use of smokeless tobacco and cancer. Findings from some of these studies are collated below.
Smokeless Tobacco Use and Oral Cancer Risk
- Researchers from the ICMR-National Institute of Cancer Prevention and Research, India did an analysis of 37 studies published between 1960 and 2016, to evaluate the association between smokeless tobacco use and oral cancer. The studies were obtained through literature search in the Pubmed, Indmed, EMBASE, and Google Scholar databases/search engines. The researchers found that smokeless tobacco use was associated with a significantly increased risk of oral cancer, especially in the Southeast Asia regions, Eastern Mediterranean Regions, and among women users. (Smita Asthana et al, Nicotine Tob Res., 2019)
- In a meta-analysis of 25 studies carried out by the researchers from India, they found that smokeless tobacco use was associated with a significant increase in oral, pharyngeal, laryngeal, esophageal and stomach cancers. They also found that when compared with men, women had a higher risk of oral cancer, but a lower risk of esophageal cancer. (Dhirendra N Sinha et al, Int J Cancer., 2016)
- Researchers from Leibniz Institute for Prevention Research and Epidemiology-BIPS in Germany and Khyber Medical University in Pakistan, carried out a systematic review of 21 publications to assess the risk of oral cancer with the use of different forms of smokeless tobacco. The data was obtained through literature search in Medline and ISI Web of Knowledge, for observational studies published in South Asia from 1984 till 2013. They found that chewing tobacco and use of paan with tobacco was associated with an increased risk of oral cancer. (Zohaib Khan et al, J Cancer Epidemiol., 2014)
- A meta-analysis of 15 studies was carried out by the researchers of Griffith University in Australia to evaluate the association between the use of oral smokeless tobacco in any form, betel quid (containing betel leaf, areca nut / betel nut and slaked lime) without tobacco and areca nut, with the incidence of oral cancer in South Asia and the Pacific. The studies were obtained through literature search in Pubmed, CINAHL and Cochrane databases till June 2013. The study found that chewing tobacco is significantly associated with an increased risk of squamous-cell carcinoma of the oral cavity. The study also found that the use of betel quid (containing betel leaf, areca nut / betel nut and slaked lime) without tobacco also resulted in an increased risk of oral cancer, possibly due to the carcinogenicity of areca nut.
The findings of these studies suggest a strong association between the use of various forms of smokeless tobacco (with or without betel leaf, areca nut / betel nut and slaked lime) and increased risk of oral cancer.
Smokeless Tobacco Use and Head and Neck Cancer Risk
Researchers from the National Institute of Environmental Health Sciences, North Carolina analyzed data from 11 US case-control studies (1981-2006) of oral, pharyngeal, and laryngeal cancers involving 6,772 cases and 8,375 controls, in the International Head and Neck Cancer Epidemiology (INHANCE) Consortium. They found that people who never smoked cigarettes but used snuff were strongly associated with an increased risk of head and neck cancer, especially oral cavity cancers. Additionally, they found that tobacco chewing was also strongly associated with an increased risk of oral cancers, though the association was found to be weak when all other sites of head and neck cancers were collectively evaluated. (Annah B Wyss et al, Am J Epidemiol., 2016)
The study concluded that smokeless tobacco may be associated with an increased risk of head and neck cancers, especially oral cancers, with the risk more elevated when using snuff compared to chewing tobacco.
Alcohol and Tobacco Chewing and Risk of HPV Infection in Head and Neck Cancer Patients
Researchers from India analyzed the results from samples taken from 106 head and neck cancer patients obtained from the Head and Neck oncology surgery unit of Dr. Bhubaneswar Borooah Cancer Institute (BBCI), Regional Cancer Center, Guwahati, India to investigate high risk HPV (hr-HPV) infection and its association with lifestyle habits including tobacco and alcohol consumption. The patients were enrolled between October 2011 and September 2013. (Rupesh Kumar et al, PLoS One., 2015)
High risk HPV infections were found in 31.13% of the head and neck cancer patients. The study found that alcohol consumption and tobacco chewing were significantly associated with an increased risk of hr-HPV infection in head and neck cancer cases. They also added that when compared to HPV-18 infection, HPV-16 was found to be more significantly associated with tobacco chewing.
Smokeless Tobacco Use and Esophageal Cancer Risk
In a study done by the researchers of Kuwait University, they evaluated the association between chewing areca nut, betel quid (containing betel leaf, areca nut / betel nut and slaked lime), oral snuff, cigarette smoking and the risk of esophageal squamous-cell carcinoma in South Asians.The study used data from 91 cases of esophageal squamous-cell carcinoma and 364 matched controls from 3 tertiary-care hospitals in Karachi, Pakistan.
Their analysis found that people who chewed areca nut, chewed betel quid (containing betel leaf, areca nut / betel nut and slaked lime) with tobacco, practiced snuff dipping or smoked cigarettes were associated with an increased risk of esophageal squamous-cell carcinoma. The risk of esophageal squamous-cell carcinoma was further increased in those who smoked cigarettes as well as chewed betel quid (containing betel leaf, areca nut / betel nut and slaked lime) with tobacco, or in those who smoked cigarettes as well as practiced snuff dipping. (Saeed Akhtar et al, Eur J Cancer., 2012)
Smokeless Tobacco Use and Pancreatic Cancer Risk
Researchers from the ICMR-National Institute of Cancer Prevention & Research, Noida and School of Preventive Oncology, Patna, India studied the relationship between smokeless tobacco and the risk of different types of cancers. They used data from 80 studies, which included 121 risk estimates for various cancers, obtained through literature search in PubMed and Google Scholar databases based on studies published from 1985 till January 2018 on smokeless tobacco and cancer. (Sanjay Gupta et al, Indian J Med Res., 2018)
The study found that smokeless tobacco use was associated with an increased risk of oral, esophageal and pancreatic cancers; with the risk of oral and esophageal cancers more predominant in the South-East Asian Region and Eastern Mediterranean Region, and pancreatic cancer in the European Region.
Different studies demonstrated that people who use smokeless tobacco products are also at a high risk of developing different types of cancers including head and neck cancers, specifically oral cancer, pharyngeal cancer, laryngeal cancer, esophageal cancer; and pancreatic cancer. This provides evidence that regardless of the type, form and intake routes, all tobacco products (whether taken alone or along with betel leaf, areca nut/betel nut and slaked slime) are harmful and can cause different types of cancers and other health issues. Hence, the use of all tobacco products including smokeless tobacco should be strongly discouraged.
Cancer patients often have to deal with different chemotherapy side effects which affect their quality of life and look out for alternative therapies for cancer.Taking the right nutrition and supplements based on scientific considerations (avoiding guesswork and random selection) is the best natural remedy for cancer and treatment related side-effects.