Abstract

Background of the Study: Oral cancer is estimated to be 16^th most common cancer for both sexes and the third most common cancer in developing nations. In India, Oral cancer is found to be 2^nd leading site in males (10.1/100,000 persons) and 4^th leading site in females (4.3/100,000persons, hence there is an urgent and intense need to study its health consequences in general population and particularly, the risk of development of oral cancer necessitates taking up epidemiological case-control study to identify risk factors for Oral cancer.

Methodology: All cases reporting to Kidwai Memorial Institute of Oncology (KMIO), clinically diagnosed and microscopically confirmed cases were only included. Those diagnosed through X-ray and others imaging techniques are excluded from the study. Smokers often start with bidi, shift to cigarette or vice versa. Similarly, with tobacco chewing and alcohol usage in the above study, the patients who used for long duration (> 1year) are retained. Separate groups were made to analyze the data to find out association of different habits. The direct personal interview of the Cases and Controls was carried out from January 2015 to June 2018. A total of 370 microscopically confirmed Oral cancer cases and 370 healthy individuals were interviewed during a four-year period, on an average 2 to 3 per working day.

Results: TheIncome status and education status were strongest association with Oral cancer among demographic factors, even after adjusting for the effect of smoking, chewing and alcohol consumption. Ever smokers showed 2.5-fold (95% CI 1.6342, 4.026) oral cancer risk without adjusting any other probable risk factors. After adjusting for chewing tobacco and alcohol, the risk increased to 3.4-fold (95% CI 1.371, 8.475) the analysis was not carried out for female group due to very less ever smokers in women. The risk in ever beedi smoker after adjusting (chewing and alcohol), the OR was 3.1. (CI 95% 1.239, 7.970). Ever smokers of both (Cigarette and Beedi) 4.0-fold (95% CI 1.6271, 10.2810) compared to never smokers of both habits.

Ever chewing group showed 7.4 folds higher risk of Oral cancer compared to never chewer group (95% CI 4.8523, 11.3062) after adjusting with smoking and alcohol. In males, ever chewers showed 6.7 folds oral cancer risk after adjusting for smoking and alcohol. For males, alcoholic ever users, OR is 0.4 (95% CI, 0.104, 1.142). The OR was not found to be significant for wine and beer users. For ever hot drink users, OR (4.0) was found to be significant (95% CI 2.437, 6.44) with 95% confidence interval.

Conclusions: The present study indicates that exposure to smoking in any form, either by Cigarette or Beedi increases the chances of developing oral cancer.The association between Beedi smoking and oral cancer is found to be statistically significant after adjusting cigarette, chewing and alcohol. Beedi smoking exhibited higher risk of getting Oral cancer compared to cigarette smoking.

A significantly increased risk for Oral cancer was seen by chewing tobacco in males and females. Chewing tobacco is significantly and independently associated with an increased risk of squamous-cell carcinoma of the oral cavity. Synergistic risk (combined effect) of all the above products on Oral cancer was observed.

Keywords: Oral cancer, Cigarette smoking, Tobacco chewing, Cancer Registry, Odds ratio.