Tobacco’s ill effects apparently can be passed down to future generations. A study looking at the link between smoking and childhood asthma shows for the first time that when a woman lights up during pregnancy, her children aren’t the only ones at risk. Her grandchildren are likely to suffer as well.
Preventive medicine researcher Yu-Fen Li and her colleagues at the University of Southern California found that smoking by a maternal grandmother during her own pregnancies doubles the risk that her daughters’ children will develop asthma. Li had planned on looking only at the effects of a mother’s smoking on children but included an additional question about the mother’s own exposure to maternal smoking. To the researchers’ surprise, if grandma had smoked, her grandchild’s risk of asthma went up—even when neither her daughter nor anyone else in the child’s home used tobacco.
Li’s group speculates that when a pregnant woman’s child is female, the tobacco damages the eggs developing in the fetus. Tobacco might also change markers on a certain type of the unborn baby’s DNA. That may affect the child’s immune system, increasing her susceptibility to asthma, which is passed to her children too.