Parental smoking, CYP1A1 genetic polymorphisms and childhood leukemia (Québec, Canada).
OBJECTIVE
To evaluate the effect of parental smoking on childhood acute lymphoblastic leukemia and to determine if it is modified by child genetic polymorphisms.


METHODS
We carried out a case-control study in Quebec, Canada, including 491 incident cases aged 0-9 years and as many healthy controls matched on age and sex. Each parent was interviewed separately with respect to smoking habits during and after pregnancy. In addition, we carried out a case-only substudy with 158 cases classified according to presence or absence of the alleles *2A, *2B, and *4 in the CYP1A1 gene.


RESULTS
There were small risk increases with maternal smoking during the later trimesters. Interaction odds ratios were increased (although often not significantly) for the CYP1A1*4 allele at high levels of maternal smoking in the last trimesters and at low level of paternal postnatal smoking, and decreased for the CYP1A1*2B allele. The latter appeared to confer a protective advantage at low levels for maternal prenatal smoking and at high levels for paternal postnatal smoking.


CONCLUSIONS
Reported smoking habits showed no association with leukemia; risks for genetic polymorphisms lacked precision but indicated that the effect of parental smoking could be modified by variant alleles in the CYP1A1 gene.
Infante-Rivard
C
C
Joint Department of Epidemiology, Faculty of Medicine, McGill University, Montreal, Quebec, Canada. cirivard@epid.lan.mcgill.ca
Krajinovic
M
M
Labuda
D
D
Sinnett
D
D
D000483:Alleles; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics*; D005220:Fathers; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000201:enzymology / Q000209:etiology* / Q000235:genetics*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011792:Quebec / Q000453:epidemiology; D012907:Smoking / Q000453:epidemiology; D011795:Surveys and Questionnaires; D014028:Tobacco Smoke Pollution / Q000009:adverse effects
D014028:Tobacco Smoke Pollution; D019363:Cytochrome P-450 CYP1A1