Wallace AD, et al. - Researchers assessed the link between allergies and acute lymphoblastic leukemia (ALL) in the California Childhood Leukemia Study (CCLS), a case-control study of 977 children diagnosed with ALL and 1,037 matched controls (1995-2015). Mothers were inquired about history of allergies in the first year of life and logistic regression analyses were performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs), controlling for birth order, day care attendance, and mode of delivery. They also examined this association via meta-analyses with data from the CCLS and 12 published studies. They used a new method to estimate between-study heterogeneity. Based on the findings, a clear association between allergy and childhood ALL was not supported.