Life-time tobacco consumption and oral cancer among citizens of a high incidence metropolis

Objective:To analyse dose-response relationship between the common risk factor of tobacco consumption and oral lesions like squamous cell carcinoma and pre-cancerous lesions. Methods: The cross-sectional case-control study was conducted at Ziauddin University, Karachi from 2011 to 2016, and comprised histologically-confirmed cases of oral squamous cell carcinoma in group A, clinically-diagnosed oral pre -cancerous lesions in group B, and habit-matched controls in group C. The subjects were enrolled from 2011 to 2016. Life-time tobacco exposure was calculated using chewing index and smoking index for comparison between cases and controls. Data was analysed using SPSS 20. Results: Of the 358 subjects, 150(42%) were in group A with a mean age of 47.1 +/- 12.22 years, 100(28%) were in group B with a mean age of 34.17 +/- 13.78 years, and 108(30%) were in group C with a mean age of 41.6 +/- 14.58 years. Of all the group A patients, 125(83.33%) and 96(96%) in group B had a positive history of tobacco use, with tobacco-chewers being the most in numbers 172(68.8%). Exclusive smoking was seen in 11(4.4%) cases, 38(15.2%) patients were both tobacco-chewers and smokers, and 29(11.6%) were tobacco-free. Group A and B patients had life-time tobacco exposures either equal or lower compared to group C controls (p>0.05). Conclusion: Life-time tobacco exposure indices were either comparable or lower in patients compared to the controls.