The etiology of childhood brain tumors (CBTs) remains unknown. Tobacco smoke 
contains several known carcinogens and can induce DNA adducts in human placenta 
and hemoglobin adducts in fetuses. We present the results of an international 
case-control study to evaluate the association between CBTs and exposure of 
parents and children to cigarette smoke. The study was undertaken as part of the 
SEARCH program of the IARC. Nine centers in 7 countries were involved. The 
studies mainly covered the 1980s and early 1990s. Cases (1,218, ages 0-19 years) 
were children newly diagnosed with a primary brain tumor; there were 2,223 
population-based controls. Most mothers who agreed to participate were 
interviewed in person at home. Odds ratios (ORs) were calculated by 
unconditional logistic regression, adjusted for age, sex and center, for all 
types of CBT combined, 4 CBT histotypes, 5 age groups and each center. There was 
no association between the risk of brain tumors in the child and parental 
smoking prior to pregnancy, maternal smoking or regular exposure to others' 
cigarette smoke during pregnancy at home or at work, or passive smoking by the 
child during the first year of life. These results did not change considering 
the child's age at diagnosis, the histologic type of tumor or center.