Stressful exit from the womb and risk of childhood leukaemia
A partir de données de 13 études cas-témoins conduites dans 9 pays, cette étude analyse l'association entre une naissance par césarienne et le risque de leucémie pédiatrique (10 112 cas et 23 459 témoins)
The cause of the most common cancer in children, acute lymphoblastic leukaemia (ALL), involves genetic and developmental aberrations that are probably modified by exposure and response to infectious agents. Early exposure to a variety of infections (via extensive childhood contacts) seems to decrease risk,1 and a vigorous response to infections (quantified by physician visits for infections) increases risk.2,3 Vaginal birth involves an early inoculation of the neonate with important commensal bacteria, which help to modulate immune development; indeed, children delivered vaginally have different gut microbiomes and T-cell reactivity persisting up to age 2 years compared with children born by caesarean.