Objective: Oral cancer is the leading malignancy in India, with tobacco playing a major role in the etiology.The aim of the present study was to quantify nitrate+nitrite (NO2+NO3) in tobacco products as well as to studytobacco exposure related biomarkers in controls, patients with oral precancers (OPC) and oral cancer patients.Materials & Methods: Healthy individuals (n=90) were grouped into without habit of tobacco (NHT, n=30) andhealthy individuals with habit of tobacco (WHT, n=60). Oral cancer patients with a tobacco habit were classifiedinto abstinence (n=62) and non-abstinence (n=64) groups according to status at the study time. Urinary nicotineand cotinine levels were analyzed by modified high-pressure liquid chromatography (HPLC) using a UV detector.Levels of NO2+NO3 in tobacco and urine, and urinary thioether levels were estimated by spectrophotometry. Results: NO2+NO3 levels in different types of tobacco product ranged between 0.13 to 3.39 mg/g. The OddsRatio (OR) analysis indicated positive associations of both smoking and chewing habits of tobacco with highrisk of development of oral cancer. Urinary nicotine, cotinine and NO2+NO3 levels were significantly elevatedin WHT, patients with OPC and oral cancer patients as compared with the NHT group. This was also the casefor urinary thioether levels. Levels of urinary nicotine and cotinine were also higher in the non-abstinencegroup with oral cancers. Conclusion: The results confirmed that tobacco chewing and smoking habits areprominent risk factors for development of oral cancer in the western part of India (Gujarat). Urinary nicotine,cotinine, NO2+NO3 and thioether levels can be helpful for screening programs for oral cancer
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