Dietary nitrate and nitrite intake and risk of non-Hodgkin lymphoma

Abstract

Although established risk factors such as immunodeficiency and viral infections may be responsible for a portion of cases of non-Hodgkin lymphoma (NHL), the vast majority of cases of NHL remain unexplained. The role of dietary nitrate and nitrite in NHL risk is of interest since they are precursors of N-nitroso compounds, and nitrosoureas have been shown to induce B- and T-cell lymphomas in animal studies. However, few studies have evaluated the potential association between consumption of nitrate and nitrite and NHL by subtype or chromosomal translocation status, and the results of these studies have been inconsistent. We estimated the dietary intake of nitrate and nitrite using a food frequency questionnaire in a population-based, case–control study of 348 cases and 470 controls conducted in Nebraska in 1999–2002. A non-significant excess risk of NHL was found among women who reported an intake of nitrite in the highest quartile compared to the lowest quartile (odds ratio [OR] = 1.6; 95% confidence interval [CI]: 0.8–2.9), particularly nitrite from animal sources (OR = 1.9; 95% CI: 1.0–3.4). No significant associations were observed for nitrate or nitrite by NHL subtype. Although there were some increases in risk that support the N-nitroso hypothesis, they were not significant and do not confer strong evidence of an association.

Keywords::

• Non-Hodgkin lymphoma
• nitrate
• nitrite
• diet

Acknowledgements

This research was supported by a grant 99B083 from the American Institute for Cancer Research and, in part, by grants CA94770 and CA100555 from the National Cancer Institute. The authors thank Mr. Martin Bast of the Nebraska Lymphoma Study Group Registry and Tissue Bank for coordinating the patient identification and physician consent. The authors would also like to thank Smrati Jain for her work on the FISH studies.

Potential conflict of interest: Disclosure forms provided by the authors are available with the full text of this article at www.informahealthcare.com/lal.