Perinatal exposure to infection and risk of childhood leukemia.
BACKGROUND
A population-based case-control study was conducted to investigate the association between childhood leukemia and infectious exposures during pregnancy and early neonatal period.


METHODS
Children born and diagnosed with leukemia between 1973 and 1989 in Sweden (578 lymphatic, 74 myeloid) were selected as cases. One control was randomly selected for each case and individually matched by sex, month, and year of birth. Children with Down's syndrome were excluded. Exposure data were blindly abstracted from antenatal, obstetric, and other standardized medical records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by conditional logistic regression.


RESULTS
A history of maternal infection was not significantly associated with childhood leukemia, OR = 1.25 (95% CI 0.95-1.65). Maternal lower genital tract infection significantly increased the risk of childhood leukemia, OR = 1.78 (95% CI 1.17-2.72), and especially for children over 4 years of age at diagnosis, OR = 2.01 (95% CI 1.12-3.80). Neonatal infection was not associated with the risk of leukemia. The results remained unaltered after adjustment for potential confounders, and separate analyses for myeloid and lymphoid leukemia.


CONCLUSIONS
We could document an association between exposure to maternal lower genital tract infection in utero, and a subsequent risk for childhood leukemia, which indicate the importance of an early exposure.
Naumburg
Estelle
E
Department of Women's and Children's Health, Section for Pediatrics, Uppsala University, Akademiska Barnsjukhuset, Uppsala, Sweden. estelle.naumberg@kbh.uu.se
Bellocco
Rino
R
Cnattingius
Sven
S
Jonzon
Anders
A
Ekbom
Anders
A
D000208:Acute Disease; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D005831:Genital Diseases, Female / Q000150:complications; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007239:Infections / Q000150:complications; D007951:Leukemia, Myeloid / Q000209:etiology*; D016015:Logistic Models; D016017:Odds Ratio; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000209:etiology*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious; D011297:Prenatal Exposure Delayed Effects; D012307:Risk Factors; D014552:Urinary Tract Infections / Q000150:complications