Risk of Childhood Brain Tumors in Relation to Maternal Smoking during pregnancy by PAH Metabolism Genotype, West Coast Childhood Brain Tumor Study, Born 1978–1990.

aInteraction between genotype and smoking, using dichotomous genotype and exposure levels never and ever.bAdjusted for race, sex, age at diagnosis, mother’s education, birth year and center.cAdditionally adjusted for paternal smoking.dMicrosomal epoxide hydrolase (mEH) activity: low–0,1 or 2 stable alleles (HH/HH, HH/HR, HY/HH, HH/RR, HY/HR, YY/HH); high–3 or 4 stable alleles (HY/RR, YY/HR, YY/RR).eMissing gene information for 1 control.fMissing gene information for 1 case.