Linoleic acid, vitamin D and other nutrient intakes in the risk of non-Hodgkin lymphoma: an Italian case-control study

Background: Dietary habits have been suggested as a factor related to the increase of non-Hodgkin lymphoma (NHL) incidence in western populations, but the role of individual nutrients is still unclear. Patients and methods: A hospital-based case-control study was conducted in Italy, 1999-2002. Cases: 190 incident, histologically-confirmed NHL cases aged 18-84 years. Controls: 484 subjects admitted to hospital for acute, non-neoplastic diseases unrelated to diet. Dietary habits were assessed by a validated food-frequency questionnaire; nutrient intakes were computed using the Italian food composition database. Odds ratios (ORs) and corresponding 95% confidence intervals (CI) for tertiles of intake of nutrient were computed using the energy-adjusted residual models. Results: Inverse association emerged for polyunsaturated fatty acids (OR=0.6; 95% CI: 0.4-0.9), linoleic acid (OR=0.6; 95% CI: 0.4-0.9), and vitamin D (OR=0.6; 95% CI: 0.4-0.9). The protective effect for linoleic acid (OR=0.3; 95% CI: 0.2-0.7) and vitamin D (OR=0.4; 95% CI: 0.2-0.9) was stronger in women; no differences emerged according to age. Linoleic acid was inversely related to follicular and diffuse large B-cell lymphoma; the protective effect of vitamin D emerged most clearly for follicular subtypes. Conclusions: Our study suggests that a diet rich in polyunsaturated fatty acids and vitamin D is associated with a reduced risk of NHL.