Exposure to benzene and non-Hodgkin lymphoma, an epidemiologic overview and an ongoing case-control study in Shanghai

To further investigate the relationship between benzene exposure and NHL, we are conducting a hospital-based case-control study in Shanghai, China. Cases are newly diagnosed NHL patients at 29 hospitals in Shanghai. For each case, two matched controls are selected among patients without any lymphatic or hematopoietic diseases at the same hospital. Demographic, employment, medical and lifestyle information is obtained through questionnaires (primary and secondary). Sources for benzene exposure information include a database of 50,000+ benzene measurements maintained by the Shanghai Municipal Institute of Public Health Supervision (IPHS), Shanghai District IPHS, walk-through surveys at factories, additional measurements at factories and reports in Chinese medical journals. Patient enrollment started in 2003 and it is estimated that the study will have 400-450 NHL cases by December 2006. Some of the occupations or industries reported among enrolled study subjects (cases and controls) with potential exposure to benzene include shoe workers, painters, mechanics or machinists, and printers. Some of the unique features of the study are discussed.