Inverse association between soy intake and non-Hodgkin lymphoma risk among women: a case-control study in Japan

Background: Non-Hodgkin lymphoma (NHL) is one of the common malignant tumors worldwide. Environmental factors, such as diet have an important association with the risk of cancer. Although soy intake has been associated with a reduced risk of several cancers, its association with NHL is not known. Patients and methods: We evaluated the association between soy consumption and risk of NHL by conducting a hospital-based case-control study in 302 patients with NHL and 1510 age-and sex-matched control subjects. Odds ratio (OR) and 95% confidence intervals (CIs) for groups with moderate (27-51 g/day) to high (>51 g/day) relative to low (<27 g/day) intake were calculated using multivariate conditional logistic regression model. Results: Soy intake was significantly associated with a reduced risk of NHL in women but not in men (OR [95% CI] for moderate and high intake: women, 0.64 [0.42-1.00] and 0.66 [0.42-1.02], respectively; men, 1.40 [0.87-2.24] and 1.33 [0.82-2.15], respectively; P-interaction = 0.02). This finding appeared consistent across NHL subtypes. Conclusion: These results indicate the potential importance of certain ingredients in soy for lymphomagenesis. Further studies to evaluate the mechanism behind the association between soy intake and lymphomagenesis are warranted.