The non-Hodgkin lymphomas (NHL) are a heterogeneous group of B-cell and T-cell neoplasms that arise primarily in the lymph nodes. NHL incidence rates in the US doubled between about 1970 and 1990, and stabilized during the 1990s. NHL accounts for approximately 3.4% of cancer deaths in the US. Although some of the observed patterns in NHL have been related to HIV/AIDS, these conditions cannot fully explain the magnitude of the changes; neither do changes in classification systems nor improved diagnostic capabilities. Studies of occupational and environmental exposures (e.g., pesticides, solvents) have produced no consistent pattern of significant positive associations. Inverse associations with ultraviolet radiation exposure and alcohol and fish intake, and positive associations with meat and saturated fat intake have been reported in several studies; additional studies are needed to confirm or refute these associations. Family history of NHL or other hematolympho-proliferative cancers and personal history of several autoimmune disorders are associated with increased risk of NHL, but are not likely to account for a large proportion of cases. HIV and other infectious agents, such as human herpesvirus 8 and Epstein-Barr, appear to be associated with differing types of NHL, such as some B-cell lymphomas. Future epidemiologic studies should evaluate associations by NHL type, enhance exposure information collected, and elucidate factors that may identify susceptible (or resistant) subpopulations because of genetic, immunologic or other characteristics. The extent to which the etiology of NHL types may differ is important to resolve in ongoing and future studies.
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EpidStat in the News
EpidStat presented "Survival Synthesis: Methods for Meta-analysis of Survival Rates and Aggregation of Survival Data" at a poster session for the International Conference on Health Policy Statistics on January 10, 2018 in Charlston, SC. The poster details the methods used in Bylsma et al. Arteriovenous Fistulae for Haemodialysis: A Systematic Review and Metaanalysis of Efficacy and Safety Outcomes. European Journal of Vascular and Endovascular Surgery, 2017. We discussed the process of digitizing survival curves from the published literature and simulating individual patient data to derive survival statistics that were not published with the article. We conclude that while labor-intensive, the methodology makes the best use of available study data.