Does prolonged breastfeeding reduce the risk for childhood leukemia and lymphomas?

Aim. Prolonged breastfeeding was shown to reduce the risk of childhood acute leukemia. The aim of the study was to investigate the protective effect of longer breastfeeding on the risk of lymphoid malignancies in children and its dependent socio-economic factors. Methods. The study group comprised of 169 patients with acute lymphocytic leukemia (ALL), Hodgkin’s (HL) and non-Hodgkin’s lymphoma (NHL), age ≤15 years, and 169 healthy controls, matched to patients by age and sex. Mothers of all study subjects provided information via telephone about the history of breastfeeding and parameters seen as proxies for viral infection. Results. The mean age±SD of cases was 5.44± 3.29 years and of control subjects 5.51±3.62 years. The male/female ratio was 1.73. Overall, the mean number of months of breastfeeding in the male patients and controls was 9.1 (95% confidence interval [CI] 7.9-10.4) and 12.1 (95% CI 11.0-13.4), respectively (P<0.001), and in the female patients and controls 8.4 (95% CI 6.9-10.1) and 11.5 (95% CI 10.0-13.0), respectively (P