Oral cancer via the bargain bin: The risk of oral cancer associated with a smokeless tobacco product (Naswar)

In the wake of smokeless tobacco (SLT) being advocated as a mean of tobacco harm reduction, it is pertinent to establish individual health risks associated with each SLT product. This case-control study was aimed at assessing the risk of oral cancer associated with a smokeless tobacco product (Naswar). The study was conducted from September 2014 till May 2015 in Khyber Pakhtunkhwa, Pakistan. Exposure and covariate information was collected through a structured questionnaire. Conditional logistic regression was used to calculate odds ratios (OR) along with their 95% confidence intervals (CI). 84 oral cancer cases (62% males) and 174 age- and sex-matched controls were recruited. Ever users of Naswar had more than a 20-fold higher risk of oral cancer compared to never-users (OR 21.2, 95% CI 8.4-53.8). Females had a higher risk of oral cancer with the use of Naswar (OR 29.0, 95% CI 5.4-153.9) as compared to males (OR 21.0, 95% CI 6.1-72.1). Based on this result, 68% (men) and 38% (women) of the oral cancer burden in Pakistan is attributable to Naswar. The risk estimates observed in this study are comparable to risk estimates reported by previous studies on other forms of SLT use and the risk of oral cancer in Pakistan. The exposure-response relationship also supports a strong role of Naswar in the etiology of oral cancer in Pakistan. Although still requiring further validation through independent studies, these findings may be used for smokeless tobacco control in countries where Naswar use is common.