By the same authors

From the same journal

Childhood Acute Lymphoblastic Leukemia and Indicators of Early Immune Stimulation: A Childhood Leukemia International Consortium Study

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Published copy (DOI)


  • Jérémie Rudant
  • Tracy Lightfoot
  • Kevin Y Urayama
  • Eleni Petridou
  • John D Dockerty
  • Corrado Magnani
  • Elizabeth Milne
  • Logan G Spector
  • Lesley J Ashton
  • Nikolaos Dessypris
  • Alice Y Kang
  • Margaret Miller
  • Roberto Rondelli
  • Jill Simpson
  • Eftichia Stiakaki
  • Laurent Orsi
  • Eve Roman
  • Catherine Metayer
  • Claire Infante-Rivard
  • Jacqueline Clavel


Publication details

JournalAmerican Journal of Epidemiology
DateE-pub ahead of print - 1 Mar 2015
DatePublished (current) - 2015
Early online date1/03/15
Original languageEnglish


The associations between childhood acute lymphoblastic leukemia (ALL) and several proxies of early stimulation of the immune system, that is, day-care center attendance, birth order, maternally reported common infections in infancy, and breastfeeding, were investigated by using data from 11 case-control studies participating in the Childhood Leukemia International Consortium (enrollment period: 1980-2010). The sample included 7,399 ALL cases and 11,181 controls aged 2-14 years. The data were collected by questionnaires administered to the parents. Pooled odds ratios and 95% confidence intervals were estimated by unconditional logistic regression adjusted for age, sex, study, maternal education, and maternal age. Day-care center attendance in the first year of life was associated with a reduced risk of ALL (odds ratio = 0.77, 95% confidence interval: 0.71, 0.84), with a marked inverse trend with earlier age at start (P < 0.0001). An inverse association was also observed with breastfeeding duration of 6 months or more (odds ratio = 0.86, 95% confidence interval: 0.79, 0.94). No significant relationship with a history of common infections in infancy was observed even though the odds ratio was less than 1 for more than 3 infections. The findings of this large pooled analysis reinforce the hypothesis that day-care center attendance in infancy and prolonged breastfeeding are associated with a decreased risk of ALL.

Bibliographical note

© The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail:

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