ORIGINAL RESEARCH


https://doi.org/10.5005/jp-journals-10024-2791
The Journal of Contemporary Dental Practice
Volume 21 | Issue 3 | Year 2020

Patterns of Tobacco Use and its Relation to Oral Precancers and Cancers among Individuals Visiting a Tertiary Hospital in South India


Aarish Khan1, Ravikiran Ongole2, Joanna Baptist3, Natarajan Srikant4, Fatema Lukmani5

1Royal College of Surgeons, Dublin, Ireland
2,5Department of Oral Medicine and Radiology, Manipal College of Dental Sciences, Mangalore, Manipal Academy of Higher Education, Mangaluru, Karnataka, India
3Department of Oral and Maxillofacial Surgery, Manipal College of Dental Sciences, Mangalore, Manipal Academy of Higher Education, Mangaluru, Karnataka, India
4Department of Oral Pathology and Microbiology, Manipal College of Dental Sciences, Mangalore, Manipal Academy of Higher Education, Mangaluru, Karnataka, India

Corresponding Author: Joanna Baptist, Department of Oral and Maxillofacial Surgery, Manipal College of Dental Sciences, Mangalore, Manipal Academy of Higher Education, Mangaluru, Karnataka, India, Phone: +91 9480528512, e-mail: joanna.baptist@manipal.edu

How to cite this article Khan A, Ongole R, Baptist J, et al. Patterns of Tobacco Use and its Relation to Oral Precancers and Cancers among Individuals Visiting a Tertiary Hospital in South India. J Contemp Dent Pract 2020;21(3):304–309.

Source of support: Nil

Conflict of interest: None

ABSTRACT

Aim: The aim of this study was to evaluate the use of tobacco and its association with oral precancers and cancers.

Materials and methods: Medical records of 1,007 individuals were assessed for the patterns of tobacco abuse and the presence of tobacco-related oral mucosal alterations.

Results: This study comprised 1,007 individuals (M:F: 95.4%:4.6%). In the cohort, 60.1% had smoking habit and 56.1% had smokeless habit. Of the bidi smokers, 18.2% developed carcinoma, 14.3% developed leukoplakia, which is statistically significant (p < 0.001). A logistic regression analysis of the development of oral submucous fibrosis (OSMF) shows that habit of smokeless forms of tobacco has an odds ratio (OR) of 18+ when compared with smoking. Combination of bidi and gutkha had 12.3 times higher risk of developing oral cancer and 4.4 times risk of developing leukoplakia. A total of 33.3% betel quid and gutkha chewers presented with tobacco pouch keratosis, which is statistically significant.

Conclusion: Smoked and smokeless forms of tobacco were equally popular among the study population. The packeted form of smokeless tobacco (gutkha) was more prevalent. Oral submucous fibrosis was more common than leukoplakia, and oral cancer developed more frequently in elderly men smoking bidis.

Clinical significance: This study throws light on the fact that the use of both smoke and smokeless forms of tobacco is still prevalent, and the use of gutkha was most prevalent. These findings will help tobacco cessation and counseling centers to focus their effort in motivating people to stop gutkha chewing habit. This also brings to the forefront the need to create better treatment strategies to manage OSMF.

Keywords: India, Oral cancer, Oral precancers, Prevalence, Tobacco.

INTRODUCTION

India is considered the oral cancer capital of the world with 80,000 new, cases diagnosed annually and 52,000 oral cancer-related deaths registered per year.1,2 Thirty-eighty percentage of the malignancies of the oral cavity arise from premalignant lesions such as leukoplakia, erythroplakia, and oral submucous fibrosis (OSMF).3,4 Tobacco-related cancers are expected to increase the total cancer burden to 30% by 2020.5

A number of predisposing factors for the development of oral precancers/cancers have been studied, some of which are region specific. In the western world, cigarette smoking and human papillomavirus are a major concern, whereas in Southeast Asia, various forms of smokeless tobacco (gutkha, paan, misri, mawa, etc.) apart from cigarette and “bidi” (hand-rolled thin cigarettes) are more relevant factors.1,2,58 Gutkha (commercially packeted) consists of a plethora of unknown substances, whereas paan (hand rolled) consists of betel leaf, areca nut, tobacco, and slaked lime. Studies have shown that these substances contain high levels of trace elements such as copper (known to cause fibrosis of the oral mucosa), magnesium, zinc, etc. which may, in turn, lead to the development of oral precancers and carcinoma.9 The use of smokeless tobacco may appear to be region specific; however, over the past decade, there has been an exponential rise in South Asian immigrants residing in the United Kingdom and Ireland. This has significantly affected the healthcare services, as patients are now entering the hospital with conditions, as well as habits, that are new to the region. A review of literature revealed a higher incidence of oral precancers and cancers amongst the South Asian immigrants in the United Kingdom and United States, when compared with the general population. A large percentage of these lesions are due to the consumption of smokeless tobacco, which have been imported from South Asia.10,11 Cigarette smoking has decreased over the past 20 years in contrast to an apparent rise in the consumption of smokeless tobacco products (chewing tobacco and snuff) particularly in the United States. Smokeless tobacco products vary considerably in composition and usage patterns across different regions of the world. Use of smokeless tobacco is found to be higher in rural than urban areas, in regions with small communities and where there is a tradition of smokeless tobacco use. Among the young population, the likelihood of using smokeless tobacco increases with age. Family members and peers are important influences on smokeless tobacco use by children and adolescents.12

Areca nut has been commonly used in the Asia Pacific region and is socially acceptable among all sectors of the society, including women, owing to its ceremonial value. Usually incorporated within a betel quid or pan, areca nut is the fourth most common psychoactive substance used in the world.13 The mouth is the only body site which permits viewing with the naked eye, the ravages caused by smoked and smokeless tobacco use. When compared with other body sites, the mouth offers a unique opportunity for defining biomarkers as it permits repeated, noninvasive examination in longitudinal cases of tobacco-associated acute and chronic diseases.4 Hence, it is extremely important for dental and medical professionals to be aware of various tobacco-related habits that are not indigenous to Europe/continental America. This awareness can be crucial in early diagnosis, intervention, and better prognosis of patients suffering from related conditions.

With an aim to evaluate the use of tobacco and its association with oral precancers and cancers, we set the following objectives for the study: to assess the prevalence of tobacco use (smoked and smokeless) and the prevalence of oral potentially malignant disorders and carcinoma among them; to evaluate the association between tobacco use and oral precancers; and to assess the association between chewable and non-chewable forms of tobacco with other oral mucosal lesions.

MATERIALS AND METHODS

After obtaining approval from the Institution Scientific and Ethics Committee, a retrospective review of the outpatient records of 1,007 individuals (out of a total of 45,000 patient records) with a history of tobacco use in various forms (smoked and smokeless) was performed, for the patterns of tobacco abuse and the presence of related oral mucosal alterations.

The study was conducted at a tertiary hospital in Mangaluru, India. Hospital records between the years 2013 and 2017 were chosen for the study. Individuals without any habit history or with lesions unrelated to tobacco use were excluded from the study. Individuals who consumed alcohol as the only habit without associated tobacco use were also excluded. Permission from the ethics committee of the dental hospital was obtained prior to the study.

Data obtained from the records included the individual’s age, gender, type of tobacco use, pattern, frequency and duration, combined habits (if any), and the presence of oral mucosal lesions (leukoplakia, lichen planus, OSMF, and malignancy). The presence of tobacco-related mucosal changes such as smoker’s melanosis, smoker’s palate, betel chewers’ mucosa, and tobacco pouch keratosis was also noted. Smokers were further categorized as those who smoke cigarettes or bidi and those who smoke both. Similarly, in the smokeless form of tobacco use, individuals were categorized based on the form of tobacco used such as gutkha, betel quid, snuff, or a combination of gutkha and betel quid.

RESULTS

This study comprised 1,007 individuals (M:F: 19:1). In the cohort, 60.2% had smoking habit and 56.1% had smokeless habit. Of the 1,007 patient records, 12.6% (n = 127) revealed a combination of smoking and smokeless tobacco habit. The oldest patient was 83 years of age and the youngest was 15 years. The mean frequency and duration of habits are summarized in Table 1. The analysis of duration of the habit showed longer duration of 11.3 ± 10.18 years of smoking habit followed by combination (10.68 ± 10.14 years) and least duration with smokeless habit (8.10 ± 7.74 years). The frequency was also higher among the smoking habit (7.73 ± 10.35 units per day) when compared with smokeless habit (4.49 ± 3.8 units per day).

Unsurprisingly, we found that cigarette smoking was the most prevalent habit among the study population (52%). The most commonly used smokeless product was gutkha (26%) followed by betel quid (24%) (Table 2). Betel quid was found to be the most used product among women (77%) (Fig. 1).

A review of oral lesions revealed that tobacco pouch keratosis was the most common lesion among patients with a habit history (7.8%). Patients with a habit history had a 7.2% prevalence in the development of OSMF, of which 13.2% were gutkha chewers. A binary logistic regression analysis with respect to all the habits involved in the development of leukoplakia showed that the two significant factors attending were bidi smoking, with an OR of 4.47, followed by gutkha (OR = 2.5). More than 5% of individuals with a habit history developed oral leukoplakia.

Smokeless habit presence increases the risk of developing OSMF. A total of 99.4% of individuals without habit did not have OSMF when compared with 13.2%, 13.9%, and 14.3% of gutkha, betel quid, and snuff habits showing the lesion (Table 3).

Oral submucous fibrosis caused by smokeless forms of tobacco was most prevalent in the study population. Snuff had an OR of 18.733 for developing OSMF followed by gutkha (OR: 17.704). Leukoplakia was most commonly associated with bidi smoking (OR of 4.469) followed by gutkha (OR of 2.506) (Tables 4 and 5). The majority of patients who only had a smokeless habit were found to have tobacco pouch keratosis (7.8%), whereas patients who chewed only gutkha had a 15.5% prevalence in the development of tobacco pouch keratosis.

Table 1: Mean duration and frequency of smoking, smokeless and combined habits
 
CountMeanStandard deviation
HabitCombinationDuration in years12710.682210.4105
  Frequency (cigarettes/day)127  6.70  6.96
 Smokeless habitDuration in years398  8.10  7.74
  Frequency (cigarettes/day)398  4.497  3.8
 Smoking habitDuration in years48211.328010.1897
  Frequency (cigarettes/day)482  7.7310.35
Table 2: Frequency distribution of the gender, habits and associated mucosal changes of the cohort
 CategoryCount (total n = 1,007)Prevalence
GenderMale96195.4
 Female  46  4.6
Smoking habitNo smoking habit40139.8
 Cigarette52452.03575
 Bidi  77  7.646475
 Cigarette and bidi    5  0.496524
Habit of smokeless tobaccoNo smokeless habit48247.9
 Gutkha26526.3
 Betel quid24424.2
 Snuff    7  0.7
 Gutkha + betel quid    9  0.9
 Leukoplakia  55  5.5
 OSMF  73  7.2
 Carcinoma  48  4.8
Other tobacco-related mucosal changesOthers85985.3
 Smoker’s melanosis  424.2
 Smoker’s palate  252.5
 Betel chewers’ mucosa    20.2
 Tobacco pouch keratosis  797.8

Fig. 1: Association of gender with type of smokeless tobacco use

Individuals with a habit of drinking alcohol, in addition to smoking, had a higher chance of developing smoker’s melanosis. Betel quid chewing led to a greater risk (10.3%) of developing carcinoma. Logistic regression for predicting the development of cancer led to correlated odds of multiple habits being present in an individual. The corrected odds of bidi smoking is 12.239 for the development of cancer (Table 6).

DISCUSSION

Tobacco products are causally linked to a variety of cancers, including those of the oral cavity and aerodigestive tract, liver, pancreas, bladder, ureter, kidney, and cervix, and also to the development of myeloid leukemia. More than 60 carcinogens are present in cigarette smoke, and at least 16 in unburned tobacco have been identified.1 Among these, the most studied are tobacco-specific nitrosamines, such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N-nitrosonornicotine (NNN), polycyclic aromatic hydrocarbons (PAH), such as benzo[a]pyrene, and aromatic amines. In particular, NNK, NNN, and PAH have been causally linked to oral cancer.1 The association between tobacco smoking and oral cancer is dose dependent, with the risk for cancer development proportional to the number of daily smoked cigarettes and the duration of smoking.2 Tobacco’s popularity may be explained by its capacity to counter adverse conditions, which were frequent in the past-hunger, thirst, fatigue, fear, and cold. A widespread use of tobacco among ancient South American populations in the form of “pituri,” another nicotine-containing plant, can be attributed to its ability to assuage hunger and fatigue.1

According to the Global Adult Tobacco Survey India 2016–201714 (a nationally representative household survey of adult smokeless tobacco users, 15 years and older), 32% of the population are current users of tobacco. Of these, 10.6% are smokers, while 21.4% use a smokeless form of tobacco. Chockalingam et al. in their study comprising residents of Chennai, India, found a prevalence of 19.4% tobacco use. Among whom, 12.4% were smokers and 7.0% had a smokeless tobacco habit.15

Our study, which only involved individuals with a tobacco habit, showed that 60.2% of the study population were smokers, whereas 56.1% had a smokeless habit. Cigarettes were the most popular among smokers (52%), whereas gutkha was the preferred smokeless tobacco product (26.3%).16 Mehrotra et al. and Karthik and Mohan have found betel quid chewing to be more popular among females13,17 followed by reverse smoking.18 Our study showed similar results vis-a-vis betel quid chewing, but we did not find any subjects with a reverse smoking habit.

Association of tobacco smoking and leukoplakia has been established by several studies1922 with our study showing concurrent results, where 5.5% chance of developing leukoplakia is associated with a habit history. Tobacco pouch keratosis is the most common oral lesion associated with the use of smokeless tobacco;13,17,18,23,24 our study estimates its prevalence to be approximately 7.8% of all tobacco-associated oral mucosal lesions. Several studies, have found a near-equal prevalence of OSMF in individuals using smokeless tobacco12,13,23 although prevalence in rural populations may be as high as 25% as reported by Keluskar and Kale.25

Table 3: Logistic regression for precancerous leukoplakia
 
BSEWalddfp valueOR95% CI for OR
UpperLower
Step 1aNo smoking habit  12.0293  0.007   
 Cigarette    0.198        0.403  0.2421  0.6231.2190.554  2.683
 Bidi    1.497        0.500  8.9701  0.0034.4691.67811.902
 Cigarette and bidi−18.07717793.916  0.0001  0.9990.0000.000 
 No smokeless habit    4.9364  0.294   
 Gutkha    0.919        0.414  4.9121  0.0272.5061.1125.645
 Betel quid    0.702        0.454  2.3871  0.1222.0180.8284.917
 Snuff−17.55415185.822  0.0001  0.9990.0000.000 
 Gutkha + betel quid−18.10312812.011  0.0001  0.9990.0000.000 
 Alcohol (1)    0.620        0.350  3.1421  0.0761.8590.9373.690
 Constant  −3.679        0.45266.1321<0.0010.025  

a Variable(s) entered on step 1: smokers, smokeless, and alcohol; SE, standard error; CI, confidence interval

Table 4: Chi square test for testing association between the presence of oral submucous fibrosis (OSMF) with the smokeless tobacco habit
Crosstab
   OSMF
Total
NoYes
Smokeless tobacco habitNo smokeless habitCount4793482
  % within smokeless99.40.6100.0
 GutkhaCount23035265
  % within smokeless86.813.2100.0
 Betel quidCount21034244
  % within smokeless86.113.9100.0
 SnuffCount617
  % within smokeless85.714.3100.0
 Gutkha + betel quidCount909
  % within smokeless100.00.0100.0
Total Count934731,007
  % within smokeless92.87.2100.0

Chi-square value of 62.910 and p value of < 0.001

Our study found a 12-fold increase in risk of oral cancer in bidi smokers, similar to the study by Madani et al.26

This could be a result of higher nicotine content, tar, and particulate matter present in bidis.27,28 Additionally, most bidis are unfiltered; therefore, a greater amount of these carcinogens may be delivered to the oral cavity during smoking.

In recent times, use of smokeless tobacco has garnered attention among clinicians and researchers alike owing to a vast majority of the population using these products and the occurrence of various associated mucosal lesions, which may be precancerous in nature. The smokeless tobacco products are available in myriad forms and follow no standard packaging or labeling of their contents. This exposes the oral cavity to a plethora of unknown substances which may pose new threats to oral and overall health. Smokeless tobacco products, though banned in a lot of states, continue to be manufactured and sold widely.

CONCLUSION

Our study revealed that both the forms of tobacco use (smoke and smokeless) are very common. Gutkha use is more prevalent than betel quid use. The study also shows that oral cancer was seen more frequently in elderly men who had the habit of smoking bidis. Leukoplakia was relatively rare when compared with OSMF.

The limitation of our study was that it was retrospective in nature. Hence, larger population studies examining their association with oral lesions prospectively and a longitudinal study may be imperative in acquiring the magnitude of the health concern posed by smokeless tobacco products in the Indian subcontinent.

Table 5: Logistic regression for oral submucous fibrosis
 BSEWalddfp valueOR95% CI for OR
LowerUpper
No smoking habit    2.5743  0.462   
Cigarette  −0.322        0.336  0.9151  0.339  0.7250.375    1.401
Bidi−17.746  4184.579  0.0001  0.997  0.0000.000 
Cigarette and bidi    1.542        1.293  1.4231  0.233  4.6750.371  58.916
No smokeless habit  19.8194  0.001   
Gutkha    2.874        0.66018.9421<0.00117.7044.853  64.583
Betel quid    2.924        0.66919.1361<0.00118.6235.024  69.035
Snuff    2.930        1.262  5.3911  0.02018.7331.579222.244
Gutkha + betel quid−16.35213177.356  0.0001  0.999  0.0000.000 
Alcohol (1)    0.158        0.433  0.1341  0.715  1.1710.502    2.735
Constant  −4.680          .66948.9321<0.001  0.009  

Variable(s) entered on step 1: smokers, smokeless, and alcohol; SE, standard error; CI, confidence interval; p values < 0.05 are considered significant and are marked in bold

Table 6: Logistic regression for oral cancer
Variables in the equation
  BSEWalddfp valueOR95% CI for OR
LowerUpper
Step 1aSmokers  32.1773<0.001   
 Cigarette smokers    0.182        0.436  0.1741  0.677  1.1990.510  2.818
 Bidi smokers    2.505        0.52322.9141<0.00112.2394.38934.130
 Cigarette + bidi smokers−17.08517919.727  0.0001  0.999  0.0000.000 
 Smokeless tobacco  23.1364<0.001   
 Gutkha    0.459        0.533  0.7401  0.390  1.5820.556  4.499
 Betel quid    2.049        0.47518.6301<0.001  7.7603.06119.678
 Snuff−16.80615183.901  0.0001  0.999  0.0000.000 
 Gutkha + betel quid−17.78512251.049  0.0001  0.999  0.0000.000 
 Tobacco + alcohol    0.513        0.389  1.7431  0.187  1.6710.780  3.580
 Constant−4.424        0.51075.1371<0.001  0.012  

a Variable(s) entered on step 1: smokers, smokeless, and alcohol; SE, standard error; CI, confidence interval; p values < 0.05 are considered significant and are marked in bold

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