Paediatric acute lymphoblastic leukaemia and caesarean section: A report from the United Kingdom Childhood Cancer Study (UKCCS)

Abstract

Background:Reports have suggested that children born by caesarean initiated before labour onset may be at increased risk of developing acute lymphoblastic leukaemia (ALL). However, with most data being derived from case-control study interviews, information on the underpinning reasons for caesarean section is sparse, and evidence is conflicting. Objectives:Use clinical records compiled at the time of delivery to investigate the association between childhood ALL and caesarean delivery; examining timing in relation to labour onset, and reasons for the procedure.Methods: Data are from the UK Childhood Cancer Study, a population-based casecontrol study conducted in the 1990s, when caesarean section rates were relatively low, in England, Scotland, and Wales. Children with ALL were individually matched to two controls on sex, date of birth, and region of residence. Information on mode of delivery and complications was abstracted from obstetric records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression models adjusted for matching variables and relevant covariates.Results: Around 75% of the 1034 cases and 1914 controls were born through unassisted vaginal delivery. Caesarean delivery was as frequent in cases and controls (OR 1.07, 95% CI 0.84, 1.36). No association was observed between ALL and caesarean delivery either during or before labour, with adjusted ORs of 1.08 (95% CI 0.78, 1.48) and 1.09 (95% CI 0.78, 1.53), respectively. For B-cell ALL, the ORs were 1.14 (95% CI 0.81, 1.59) for caesarean during labour and 1.21 (95% CI 0.85, 1.72) for prelabour. The underpinning reasons for caesarean delivery differed between cases and controls; with preeclampsia, although very rare, being more common amongst cases born by caesarean (OR 8.91, 95% CI 1.48, 53.42). Conclusions:Our obstetric record-based study found no significant evidence that caesarean delivery increased the risk of childhood ALL, either overall or when carried out before labour. K E Y W O R D S caesarean, childhood leukaemia, delivery, epidemiologyThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Association of cesarean section with risk of childhood leukemia: A meta‐analysis from an observational study

“…Thirty studies were excluded due to the following reasons: a lack of relevant data ( n = 16); a non‐original article ( n = 8); basic science ( n = 3); data source duplication ( n = 2); and data unavailability ( n = 1). Finally, 16 relevant articles 1,6,9–22 included ten case‐control studies, five cohort studies, and one pooled analysis. The data from the original study were excluded in this pooled analysis to avoid double counting.…”

“…Different studies have found a link between CS and leukemia, with contradictory results. Several studies 6,9–15 established a relationship between CS and leukemia, particularly for elective CS 1,12,16–19 . In contrast, some studies found no overall link between CS and leukemia 1,17,19–21 .…”

“…Several studies 6,9–15 established a relationship between CS and leukemia, particularly for elective CS 1,12,16–19 . In contrast, some studies found no overall link between CS and leukemia 1,17,19–21 . Simultaneously, articles have performed subgroup analyses of the child's age at diagnosis 1,15,19,20,22 and the type of leukemia 1,10,12,15,18,22 .…”

“…1,12,[16][17][18][19] In contrast, some studies found no overall link between CS and leukemia. 1,17,[19][20][21] Simultaneously, articles have performed subgroup analyses of the child's age at diagnosis 1,15,19,20,22 and the type of leukemia. 1,10,12,15,18,22 To further and thoroughly investigate this association, we analyzed relevant observational studies.…”

Cohort profile: the United Kingdom Childhood Cancer Study (UKCCS) – a UK-wide population-based study examining the health of cancer survivors

“…Thus far, over 90 peer-reviewed articles containing UKCCS data have been published, and a full list is available on the study website (www.UKCCS.org). Assembling data from multiple sources, key reports include ALL genome-wide association studies (GWAS),14 20 and those examining the potential aetiological roles of a wide range of biological (eg, infections/markers of infectious exposure),21–23 physical (eg, ionising/non-ionising radiation)12 13 24 25 and chemical (eg, prescription drugs/smoking) agents acting on parents before the child’s conception and the child during pregnancy/early life,10 26 27 as well as relationships with other illnesses (eg, allergy) and birth characteristics (eg, birth weight) 21 28 29. Importantly, the UKCCS accessed medical records to help answer key questions relating to prescription drugs, illness histories and comorbidities; such contemporaneously recorded information, which by its nature is free from differential recall bias, often producing very different results from that obtained by self-report 11 22 30 31…”