NHL Population-Based Case-Control Study

Principal Investigator: Brian C. - H. Chiu, PhD

The incidence of non-Hodgkin lymphoma (NHL) has increased about 80% since the 1970s, but risk factors are largely unknown. Higher risk of NHL has been linked to increased consumption of animal protein, fat, and meat, whereas higher intakes of fruits and cruciferous vegetables show an inverse association with NHL. There is growing evidence that SNPs in genes associated with metabolisms of meat, fat, antioxidants, and environmental carcinogens may alter risk of NHL. To investigate the possible gene-environment interactions, we recently completed a population-based case-control study of non-Hodgkin lymphoma in Nebraska. Extensive information on environmental/lifestyle factors, diet including cooking practices, and blood samples was collected from 389 cases and 535 controls between 1999 and 2002. Histologic subtypes of NHL were defined according to the WHO classification. Controls were selected by two-stage, random digit dialing with frequency matching by age (five-year age groups) and sex to cases using a 1.5 to 1 matching ratio. The non-dietary part of the questionnaire was administered by a telephone interview, whereas the dietary information was collected using a mailed questionnaire. Blood samples were collected using IsoCode cards (Schleicher & Schuell, Keene, NH). Genotyping is being conducted in collaboration with researchers at the University of Nebraska Medical Center and the Mayo Clinic. Data analysis is ongoing. We are also collaborating with researchers at the International Lymphoma Epidemiology Consortium (InterLymph) to investigate genetic and environmental determinants of rare subtypes of NHL.