Case-control Study of Risk Factors for Non-Hodgkin Lymphoma in Mumbai, India

Background: In the year 2010, it is estimated that nearly 0.36 million new cases and 0.19 million deaths with Non-Hodgkin lymphoma occurred. In India, among males, NHL incidence rates vary across the country which has encouraged us to conduct a case-control study to study risk factors. Materials and Methods: The present unmatched hospital-based case-control study conducted at Tata Memorial Hospital included subjects registered between the years 1997-99. There were 390 'lymphoma cases' and 1,383 'normal controls. Results: Data on age, tobacco habits, occupational history, dietary factors, tea, coffee were collected by the social investigators. Univariate and multivariate methods were applied for obtaining the odds ratios for risk factors. Conclusions: In the study, cigarette smoking (OR=2.0) and bidi smoking (OR=2.8), were associated with excess risk of lymphoma. Among the dietary items, only consumption of mutton showed 7.3-fold significant excess risk for lymphoma. Consumption of milk showed a 6-fold excess risk (OR=1.5); while coffee showed a 50% reduction in risk for lymphoma. Among occupational exposure, exposure to use of pesticides showed 3-fold excess risk for lymphoma.