NCPA - National Center for Policy Analysis


April 15, 2005

Children whose grandmothers smoked during pregnancy are at twice the risk of developing asthma as other children, even if their mothers were non-smokers, according to researchers at the University of Southern California?s Keck School of Medicine.

The study, which will soon be published in the journal Chest, reveals that women who smoke during pregnancy not only run the risk of harming their children, but also their grandchildren.

  • The risk of asthma is 1.3 times greater for a child whose mother smoked, and 1.8 times greater for a child whose grandmother smoked.
  • The risk of asthma is 2.6 times greater for a child whose mother and grandmother smoked.
  • The amount of smoking done by mothers does not appear to increase the risk, although researchers say that the amount of smoking might have been underreported by respondents.
  • A child whose mother quit smoking before she became pregnant does not carry any increased risk.

Researchers speculate that smoking may change the DNA in a cell's mitochondria by "turning off" certain genes that help the immune system. Another possibility is that smoking may cause changes in the DNA of the fetus's eggs.

Although more research is needed, Dr. Frank Gilliland, senior author of the paper, recommend that women of childbearing age quite smoking.

Source: Nicholas Bakalar, "Child's Asthma Linked to Grandmother's Habit," New York Times, April 12, 2005 and Alicia Di Rado, "Smoking May be Harmful to Offspring," University of Southern California, April 12, 2005.

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For USC press release:


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