Effects of Parental Smoking on Occurrence of Childhood Acute Leukemia

We herein determined the effects of parental smoking on occurrence of childhood acute leukemia using the large volume of data accumulated in the Japan Children's Cancer Registry. Information on the smoking statuses of fathers was available for 4,802 acute leukemia cases diagnosed between 1985 and 2006 and that of mothers was available for 5,536 cases diagnosed between 1978 and 2006. We compared the smoking rates of parents whose children were diagnosed with leukemia with a control group of parents whose children were diagnosed with benign tumors or cancer-related diseases. The smoking rate of fathers was significantly larger than the control. The odds ratios were 1.284 for 1-9 cigarettes/day (c/d) before conception (p=0.127), 1.265 for 10-19 c/d (p=0.029), and 1.345 for more than 20 c/d (p=0.000). A logistic regression analysis controlling for sex, birth weight, paternal age at birth, and maternal smoking showed that the smoking rate of fathers whose children had acute leukemia was still significantly higher (OR 1.012, p=0.004). The difference of the smoking rate between mothers whose children had acute leukemia and the control mothers was not significant (OR 1.161, p=0.447).