Tobacco smoke and risk of childhood acute lymphoblastic leukemia: findings from the SETIL case-control study.
OBJECTIVE
Tobacco smoke could cause childhood acute lymphoblastic leukemia (ALL) through at least three pathways: (1) prenatal parental smoking; (2) fetal exposure through maternal smoking during pregnancy; and (3) childhood exposure to secondhand smoke (SHS). We tested these hypotheses in a large population-based case-control study (SETIL) primarily designed to evaluate the role of electromagnetic fields in childhood hematopoietic malignancies.


METHODS
From 1998 to 2003, we enrolled 602 incident cases of ALL from 14 Italian Regions, and 918 controls were individually matched by birthdate, sex, and area of residence. Cases (n = 557) and controls (n = 855) with complete information were analyzed; odds ratios (OR) and 95 % confidence intervals (95 % CI) were estimated with logistic regression models conditioned on matching variables and adjusted by birth order, birthweight, duration of breastfeeding, parental age at delivery, education, and occupational exposure to benzene.


RESULTS
No evidence associating paternal smoking in the conception period or maternal smoking during the pregnancy with ALL was found. An association of ALL with maternal exposure to SHS during pregnancy (adjusted OR for mothers exposed more than 4 h/day = 2.18, 95 % CI 1.39-3.42) was observed, but recall bias cannot be excluded. Exposure of the children to SHS was associated with ALL only in unadjusted analysis (unadjusted OR for highly exposed children = 1.64; 95 % CI 1.10-2.45).


CONCLUSIONS
This study does not support the hypothesis that parental active smoking is associated with ALL. We found very weak evidence of increased risk of ALL for children exposed to SHS. Maternal exposure to SHS was associated with ALL, but recall bias is likely to inflate our estimates.
Department of Medical and Surgical Sciences (DIMEC), UO Medicina del Lavoro, S Orsola-Malpighi University Hospital, University of Bologna, Via Pelagio Palagi 9, 40138, Bologna, Italy.
Andrea
A
Farioli
Patrizia
P
Legittimo
Stefano
S
Mattioli
Lucia
L
Miligi
Alessandra
A
Benvenuti
Alessandra
A
Ranucci
Alberto
A
Salvan
Roberto
R
Rondelli
Valentino
V
Conter
Corrado
C
Magnani
D016022:Case-Control Studies; D002648:Child; D005260:Female; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology* / Q000209:etiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology* / Q000209:etiology; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000009:adverse effects / Q000706:statistics & numerical data*
D014028:Tobacco Smoke Pollution