Kids' Leukemia Risk Tied to Dads' Smoking

From Reuters Health Information By Kerry Grens NEW YORK (Reuters Health) Dec 15 - Children whose fathers smoked have at least a 15% higher risk of developing acute lymphoblastic leukemia, a new Australian study finds. "Paternal smoking seems to be real" as a risk factor, said Dr. Patricia Buffler, a professor at the University of California, Berkeley, who was not involved in the current analysis. "The importance of tobacco exposure and children's cancers has been overlooked until recently," Dr. Buffler told Reuters Health. "So I think this paper is important" in adding to the growing body of evidence. The research team, led by Dr. Elizabeth Milne at the Telethon Institute for Child Health Research in Australia, surveyed the families of nearly 400 children with ALL. Although ALL is the most common childhood cancer, it is still rare, affecting about three to five children out of every 100,000, according to the National Cancer Institute. The survey asked about the smoking habits of both parents. Dr. Milne and her colleagues compared these families to the families of more than 800 children of similar ages who did not have leukemia. They found that the mothers' smoking behavior had no impact on the kids' risk of developing the cancer. The researchers then added their results to those of nine earlier studies. When they did that, they found that kids whose fathers smoked at all around the time of their conception were 15% more likely to develop leukemia. Those whose dads smoked at least 20 cigarettes per day around that time were 44% more likely to be diagnosed with the cancer, according to a report published online December 5 in the American Journal of Epidemiology. Because of the toxins in tobacco smoke, Dr. Buffler said, "it's not unlikely that you'd have damage" in the cells that produce sperm. "Sperm containing DNA (damage) can still reach and fertilize an ovum, which may lead to disease in the offspring," Dr. Milne wrote in an email to Reuters Health. The study did not prove that DNA damage in the sperm caused by smoking is responsible for the children's increased risk of cancer. "The causes of ALL are likely to be multifactorial, and our findings relate to just one of the possible contributing factors," said Dr. Milne. Several other environmental factors are also tied to a greater chance of developing childhood leukemia, including ionizing radiation and the mother's exposure to paint or pesticides while pregnant. Dr. Milne said that many of the studies regarding these potential causes have been small, and not conclusive. Dr. Buffler is leading an international consortium of researchers tracking thousands of cases of childhood leukemia to determine the influence of environmental, genetic, and other biological factors on developing the disease. SOURCE: http://bit.ly/snq3sL