Nutritional factors and risk of non-Hodgkin lymphoma: The multiethnic cohort
Authors: Eva Erber, Gertraud Maskarinec, Jasmeet Gill, Song-Yi Park, Laurence Kolonel
Journal: Cancer Research (2008)

AACR Annual Meeting-- Apr 12-16, 2008; San Diego, CA

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Diet can affect hormonal and metabolic responses to cell growth and survival. Intake of meat, which is high in animal protein, may challenge the immune system; this chronic lymphoid stimulation might contribute to the development of Non-Hodgkin Lymphoma (NHL). On the other hand, the antioxidant effects of fruits and vegetables might lower NHL risk. Few cohort studies have examined the role of diet in the risk of NHL. The aim of this analysis was to identify dietary patterns as well as individual food items that are related to NHL incidence within the Multiethnic Cohort (MEC).    The MEC includes men and women from mainly five ethnic groups (Caucasians, African-Americans, Japanese, Native Hawaiians, and Latinos) aged 45-75 at baseline in 1993-1996. After excluding people for several reasons (13,992 not in main ethnic groups; 8,264 invalid diet; 513 prior NHL), 96,963 men and 118,868 women were part of the analysis. Between cohort entry and December 31, 2003, 937 NHL cases (512 men and 425 women) were identified through linkage with tumor registries. We applied Cox proportional hazards models using age as the time metric. Three previously identified dietary patterns, “Vegetables”, “Milk and Fruits”, and “Fat and Meat”, were examined using quintiles, whereas the food items (eggs, pasta, cereals, vegetables, tofu, fish, legumes, meat, fruits, and dairy products) were analyzed using quartiles. The models were performed separately for men and women and adjusted for age, ethnicity, education, alcohol and energy intake.    The “Vegetable” dietary pattern was associated with a lower NHL risk in men (RR = 0.86; 95% CI = 0.63-1.16) and in women (RR = 0.82; 95% CI = 0.58 - 1.16), comparing the highest quintile to the lowest. Among men, there was a similar reduction in risk for the “Milk and Fruits” factor, but this was not seen in women. The dietary pattern “Fat and Meat” showed no effect on NHL risk in either men or women. For the individual food items, a high intake of eggs was associated with a 30% increase in risk in both men (RR = 1.29; 95% CI = 1.00 - 1.67) and women (RR = 1.32; 95% CI = 1.00 - 1.73). Men also had a significantly elevated risk associated with high consumption of pasta (RR = 1.30; 95% CI = 1.01 - 1.67), but this food was inversely associated with risk in women (RR = 0.83; 95% CI = 0.62 - 1.12). In contrast, cereals showed a marginally elevated risk in women (RR = 1.23; 95% CI = 0.93 - 1.63), but not in men (RR = 1.09; 95% CI = 0.84 - 1.43). In women, vegetables, tofu, and fish were all associated with statistically non-significant reductions in risk of about 15%, whereas in men, legumes were associated with a statistically non-significant reduction in risk of 23%. No relation with NHL risk was found for meat, fruits, dairy products, or bread in either men or women. Because of the sample size, ethnic-specific associations could not be reliably assessed at the present time.    These preliminary results suggest that vegetables, fruits and legumes may have a protective effect on the risk of NHL.