Association of thromboangiitis obliterans with cigarette and bidi smoking in Bangladesh: A case-control study

Background. In addition to cigarettes, bidi, made of unprocessed and low- grade tobacco, is being smoked widely in Bangladesh and in other south Asian countries. The cause-and-effect relationship is established between thromboangiitis obliterans (TAO) and smoking. However, type of smoking material(s) most strongly related to TAO is not yet determined. Methods. We conducted a hospital-based case-control study in Rajshahi, Bangladesh, to examine the relationship of type of smoking materials (cigarette versus bidi) with TAO on 103 pairs of cases and controls matched by age and sex during the period 1995 to 1996. The inclusion criteria for cases were newly diagnosed TAO and current smoker, while those for controls were current smokers admitted to the hospital due to non-cardiovascular diseases. Results. Among the cases 35.0% and 65.0% were cigarette and bidi smokers, while among the controls 69.9% and 30.1%, respectively. Using logistic regression approach, considering cigarette smoking ~10 per day as reference, bidi smoking >20 per day (odds ratio [OR] = 34.76, 95% CI: 6.11-197.67) and 11-20 per day (OR = 7.12, 95% CI: 2.35-21.63) had greater risk of TAO after adjusting confounding factors. Respective OR for bidi smoking ~10 per day, cigarette smoking 11-20 per day and cigarette smoking >20 per day, were 2.18 (95% CI: 0.64-7.51), 3.81 (95% CI: 1.37- 10.57) and 6.88 (95% CI: 1.87-25.30). Conclusion. Within the limits inherent to case-control study, our findings suggest that bidi smoking may well play a more important role in causing TAO than cigarettes. It leads to the speculation that unprocessed and low-grade tobacco used for producing bidi might play a more potent role to initiate TAO than cigarettes.