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Men who smoke pass on damaged DNA to their unborn children

Saturday, 07 July 2012

Unborn babies whose fathers smoked around the time of their conception can inherit damaged DNA, increasing their chances of developing diseases such as cancer in childhood and throughout their lives, according to new research published today.

The European study, published online in The FASEB Journal, was led by Professor Diana Anderson from the University of Bradford’s Division of Medical Sciences.

It shows—for the first time—a distinct correlation between DNA changes found in the sperm of male smokers and DNA changes in their newborn children. Genetic changes are the underlying cause of nearly all cancers in humans, and the research suggests that inheriting these may render children more susceptible to developing genetic diseases.

Studies in mice have suggested that paternal exposure to smoking may have reproductive consequences, in that alterations to the DNA might be passed on to the offspring; but until now, this effect of smoking has not been investigated in humans.

In humans it is very difficult to show whether heritable genetic changes are caused by the mother's or the father's exposure to cigarette smoke, and to separate whether these effects are influenced by other factors such as diet, alcohol or environment.

For this study, funded by the European Union, the researchers used two sensitive biomarkers to measure single and double strand breaks in the DNA of the paternal blood and semen in the period around conception, as well as maternal and umbilical cord blood at delivery.

The families in the study were drawn from two different European regions; the area of Bradford in the north of England and Heraklion on the Greek island of Crete. Information regarding the lifestyle, environmental and occupational exposures of these families, which can influence DNA, was taken from validated questionnaires.

They then used a combined analysis of exposures and DNA biomarkers to help differentiate the role of the various exposures before conception and during pregnancy, which could result in genetic changes in the developing embryo.

"Whilst our cohort size was small, the biomarkers were very sensitive, we were struck by the correlation between paternal smoking around the time of conception and DNA damage found in the newborns," said Professor Anderson.

"To be clear, this study does not show a direct causal link to any disease, but it’s evident that that the lifestyle of men before they try to conceive can directly affect the genetic information of their children."

She continued: "Anti-smoking campaigns are usually aimed at pregnant women, but couples planning their families – and public health policy-makers - need to know that the father must stop smoking before conception to avoid risking the health of the baby."

University of Bradford co-author, Dr Julian Laubenthal, added: "It's also important to know that a fertile sperm cell takes around three months to develop, so men should stop smoking well in advance of trying to conceive."