Abstract
OBJECTIVES: Smokeless tobacco (SLT) use is common in South Asia and strongly associated with oral cancer. In Bangladesh, where SLT use is widespread, evidence remains limited. This study examined the association between SLT use and oral cancer among Bangladeshi adults and estimated the population-level burden. METHODS: This first hospital-based case-control study from Bangladesh examined the association between SLT use and oral cancer. Conducted in Dhaka between July and December 2015. A total of 169 newly diagnosed oral cancer cases and 338 frequency-matched controls were recruited. Structured interviews collected data on SLT use, smoking, alcohol, BMI, and socio-demographic variables. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression. Population attributable fractions (PAFs) were calculated based on national SLT prevalence. RESULTS: SLT use was strongly associated with oral cancer (adjusted OR: 8.78; 95% CI: 5.14-15.00). Risk was higher in women (OR: 14.33, 95% CI: 6.33-32.42) than in men (OR: 5.29, 95% CI: 2.62-10.67). Male dual users of SLT and smoked tobacco had the greatest risk (OR: 17.23, 95% CI: 5.70-52.01). Analysis by SLT type indicated significant independent associations with oral cancer for both Betel Quid (BQ) usage with tobacco (OR: 8.93, 95% CI: 5.23-15.27) and without tobacco (OR: 4.43, 95% CI: 1.94-10.10). A dose-response relationship was observed, particularly in women. SLT use accounted for an estimated 41% of male and 76% of female oral cancer cases in Bangladesh. CONCLUSION: SLT is a major, modifiable risk factor for oral cancer in Bangladesh, particularly among women and dual tobacco users. These findings support the need for stronger regulation, gender-sensitive education, and targeted SLT control strategies. Local evidence such as this is vital to shaping national and international oral cancer prevention policies.