Journal: International journal of cancer
Study type and population
- Multicenter hospital-based case–control study from five cancer centers in India.
- Participants: 2,320 buccal mucosa cancer cases and 2,302 frequency-matched controls.
- Data collected: Detailed histories of smoking and smokeless tobacco chewing, including duration, products, and quitting.
Key exposures
- Cigarette/bidi smoking
- Chewing tobacco (with and without areca nut)
- Status: current use vs former use, with time since quitting
Main findings
- Strong associations: Both smoking and chewing tobacco were strongly associated with buccal mucosa cancer.
- Impact of cessation: Risk dropped substantially after quitting.
- Smoking: Quitting for ≥10 years was associated with a 61% lower odds of buccal mucosa cancer vs continued smokers (OR 0.39; 95% CI 0.28–0.54).
- Chewing tobacco: Quitting for ≥10 years was associated with a 42% lower odds vs continued chewers (OR 0.58; 95% CI 0.43–0.81).
- Timing of risk reduction: The risk of cancer decreased notably after about 5 years of quitting for both smoking and chewing.
- Areca nut products: Chewing products that included areca nut carried higher risk than chewing without areca nut (OR 1.86; 95% CI 1.53–2.26), but the relative benefit of quitting (rate of risk reduction with time) was similar regardless of areca nut.
Clinical and public health implications
- Risk reduction: Cessation of both smoking and smokeless tobacco chewing meaningfully reduces buccal mucosa cancer risk, with clear benefits observable within a few years and increasing over time.
- Policy relevance: Given the high prevalence of chewing tobacco (often with areca nut) in India, cessation-focused interventions and policies targeting these products are strongly supported by the data.