An analysis of traditional and commercial tobacco use and lung cancer risk in Nepal

Recent statistics suggest lung cancer to be the top contributor to cancer deaths in the developing world and tobacco use is the leading risk factor for this disease. Limited information is available on the role of specific local tobacco products that are commonly used in the low income countries. In this study, we compared the role of local tobacco products commonly used in Nepal on lung cancer risk. We recruited a total of 606 lung cancer cases and 606 controls from the B.P. Koirala Memorial Cancer Hospital in Nepal between 2009 and 2012. All lung cancer cases were either histologically or cytologically confirmed. We computed odds ratios (ORs) and 95% Confidence Intervals (CI) using unconditional logistic regression, adjusting for demographic and socioeconomic variables (age, race, income level, education, and region of the country) as well as household air pollution (HAP) from solid fuels. Overall, the highest risk of lung cancer was observed in the groups that smoked multiple types of tobacco, with the highest risk of those who smoked bidi (local tobacco rolled in a leaf) and cigarettes without filters. Among those who only smoked one type of product, bidi users had the highest risk (OR 5.33; 95% CI 3.1-9.06) followed by cigarettes without filters (OR 5.32; 95% CI 3.5-7.1) and cigarettes with filters (OR 2.8; 95% CI 1.7-4.7). A clear dose-response relationship was observed between increased frequency of smoking and lung cancer risk, for all products considered. These results highlight the important role of local tobacco products on lung cancer risk in the low income countries.