title: Childhood acute lymphoblastic leukaemia and indicators of early immune stimulation: the Estelle study (SFCE).
abstract: BACKGROUND
  Factors related to early stimulation of the immune system (breastfeeding, proxies for exposure to infectious agents, normal delivery, and exposure to animals in early life) have been suggested to decrease the risk of childhood acute lymphoblastic leukaemia (ALL).
  
  
  METHODS
  The national registry-based case-control study, ESTELLE, was carried out in France in 2010-2011. Population controls were frequency matched with cases on age and gender. The participation rates were 93% for cases and 86% for controls. Data were obtained from structured telephone questionnaires administered to mothers. Odds ratios (OR) were estimated using unconditional regression models adjusted for age, gender, and potential confounders.
  
  
  RESULTS
  In all, 617 ALL and 1225 controls aged ⩾1 year were included. Inverse associations between ALL and early common infections (OR=0.8, 95% confidence interval (CI): 0.6, 1.0), non-first born (⩾3 vs 1; OR=0.7, 95% CI: 0.5, 1.0), attendance of a day-care centre before age 1 year (OR=0.7, 95% CI: 0.5, 1.0), breastfeeding (OR=0.8, 95% CI: 0.7, 1.0), and regular contact with pets (OR=0.8, 95% CI: 0.7, 1.0) in infancy were observed.
  
  
  CONCLUSIONS
  The results support the hypothesis that conditions promoting the maturation of the immune system in infancy have a protective role with respect to ALL.
authors: 1] Epidemiology of childhood and adolescent cancers, CRESS, INSERM U1153, Villejuif, France [2] Paris-Sud University, Le Kremlin Bicêtre, France.
authors: R
authors: R
authors: Ajrouche
authors: 1] Epidemiology of childhood and adolescent cancers, CRESS, INSERM U1153, Villejuif, France [2] Paris-Descartes University, Paris, France [3] RNHE-National Registry of Childhood Hematopoietic Malignancies, Villejuif, France.
authors: J
authors: J
authors: Rudant
authors: 1] Epidemiology of childhood and adolescent cancers, CRESS, INSERM U1153, Villejuif, France [2] Paris-Descartes University, Paris, France.
authors: L
authors: L
authors: Orsi
authors: 1] AP-HP, Hôpital Armand Trousseau, Paris, France [2] Université Paris 6 Pierre et Marie Curie, Paris, France.
authors: A
authors: A
authors: Petit
authors: 1] AP-HP, Hôpital Robert Debré, Paris, France [2] Université Paris 7, Paris, France.
authors: A
authors: A
authors: Baruchel
authors: Hôpital Jeanne de Flandre, CHRU, Lille, France.
authors: A
authors: A
authors: Lambilliotte
authors: Hôpital des Enfants, Toulouse, France.
authors: M
authors: M
authors: Gambart
authors: AP-HM, Hôpital la Timone, Marseille, France.
authors: G
authors: G
authors: Michel
authors: Institut d'Hématologie et d'Oncologie Pédiatrique, Lyon, France.
authors: Y
authors: Y
authors: Bertrand
authors: Hôpital Pellegrin Tripode, Bordeaux, France.
authors: S
authors: S
authors: Ducassou
authors: CHU Hôpital Sud, Rennes, France.
authors: V
authors: V
authors: Gandemer
authors: Hôpital de Hautepierre, Strasbourg, France.
authors: C
authors: C
authors: Paillard
authors: Hôpital Arnaud de Villeneuve, Montpellier, France.
authors: L
authors: L
authors: Saumet
authors: Hôpital Mère-Enfant, CHU-Nantes, Nantes, France.
authors: N
authors: N
authors: Blin
authors: 1] Epidemiology of childhood and adolescent cancers, CRESS, INSERM U1153, Villejuif, France [2] Paris-Descartes University, Paris, France.
authors: D
authors: D
authors: Hémon
authors: 1] Epidemiology of childhood and adolescent cancers, CRESS, INSERM U1153, Villejuif, France [2] Paris-Descartes University, Paris, France [3] RNHE-National Registry of Childhood Hematopoietic Malignancies, Villejuif, France.
authors: J
authors: J
authors: Clavel
mesh_terms: D000293:Adolescent; D000328:Adult; D001942:Breast Feeding / Q000009:adverse effects; D016022:Case-Control Studies; D002648:Child; D002656:Child Day Care Centers; D002675:Child, Preschool; D005260:Female; D005602:France / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D009035:Mothers; D057805:Pets; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology* / Q000276:immunology* / Q000517:prevention & control; D012042:Registries; D012306:Risk; D012307:Risk Factors; D011795:Surveys and Questionnaires