Hematological cancersInfections and the development of childhood acute lymphoblastic leukemia: a population-based studyHwee, Jeremiaha,,b; Sutradhar, Rinkua,,b,,c; Kwong, Jeffrey C.a,,b,,d,,e,,f; Sung, Lillianc,,g,,h; Cheng, Stephanieb; Pole, Jason D.a,,b,,iAuthor Information aDivision of Epidemiology, Dalla Lana School of Public Health, University of Toronto bInstitute for Clinical Evaluative Sciences cInstitute of Health Policy, Management and Evaluation, University of Toronto dDepartment of Family and Community Medicine, University of Toronto ePublic Health Ontario fToronto Western Family Health Team, University Health Network gDepartment of Paediatrics, Division of Haematology/Oncology, The Hospital for Sick Children hProgram in Child Health Evaluative Sciences, The Hospital for Sick Children, Peter Gilgan Centre for Research and Learning iPediatric Oncology Group of Ontario, Toronto, Canada Received 12 September 2019 Accepted 24 November 2019 The dataset from this study is held securely in coded form at ICES. While data sharing agreements prohibit ICES from making the dataset publicly available, access may be granted to those who meet pre-specified criteria for confidential access, available at www.ices.on.ca/DAS. The full dataset creation plan and underlying analytic code are available from the authors upon request, understanding that the programs may rely upon coding templates or macros that are unique to ICES. Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's website (www.eurjcancerprev.com). Correspondence to Jeremiah Hwee, PhD, MSc, Dalla Lana School of Public Health, University of Toronto, Health Sciences Building, 155 College St, Toronto M5T 3M7, Canada, Tel: +1 647 823 2604; e-mail: email@example.com European Journal of Cancer Prevention: November 2020 - Volume 29 - Issue 6 - p 538-545 doi: 10.1097/CEJ.0000000000000564 Buy SDC Metrics Abstract An infectious trigger for childhood acute lymphoblastic leukemia is hypothesized and we assessed the association between the rate, type, and critical exposure period for infections and the development of acute lymphoblastic leukemia. We conducted a matched case-control study using administrative databases to evaluate the association between the rate of infections and childhood acute lymphoblastic leukemia diagnosed between the ages of 2–14 years from Ontario, Canada and we used a validated approach to measure infections. In 1600 cases of acute lymphoblastic leukemia, and 16 000 matched cancer-free controls aged 2–14 years, having >2 infections/year increased the odds of childhood acute lymphoblastic leukemia by 43% (odds ratio = 1.43, 95% confidence interval 1.13–1.81) compared to children with ≤0.25 infections/year. Having >2 respiratory infections/year increased odds of acute lymphoblastic leukemia by 28% (odds ratio =1.28, 95% confidence interval 1.05–1.57) compared to children with ≤0.25 respiratory infections/year. Having an invasive infection increased the odds of acute lymphoblastic leukemia by 72% (odds ratio =1.72, 95% confidence interval 1.31–2.26). Having an infection between the age of 1–1.5 years increased the odds of acute lymphoblastic leukemia by 20% (odds ratio = 1.20, 95% confidence interval 1.04–1.39). Having more infections increased the odds of developing childhood acute lymphoblastic leukemia and having an infection between the ages of 1–1.5 years increased the odds of childhood acute lymphoblastic leukemia. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.