Granny’s cigs can cause grandchild’s asthma

October 21, 2015 - 05:26

A Swedish study indicates that the risk of childhood asthma increases if a child’s maternal grandmother smoked while pregnant.

Smoking during pregnancy can have detrimental effects on the smoker’s children and perhaps even grandchildren. (Illustrative photo: Microstock)

The possible link between smoking and child asthma is widely known. But it could be that this connection stretches further back in the asthmatic child’s lineage.

A study at Umeå University shows that children with grandmothers who smoke(d) run a 10 to 20 percent higher risk of developing asthma. This applies to children with and without mothers who smoke.

The researchers behind the study think the cause could be genetic.

From 66,000 children

The researchers analysed information from about 66.000 children. This data was collected by midwives when the mothers visited hospitals. Bertil Forsberg, one of the researchers involved, thinks the method used boosts the credibility of the study.

“The structure made it impossible for women smokers, for example, to decline from being involved in the study.   And women with asthmatic children couldn’t be overrepresented,” points out Forsberg in a press release from Umeå University.

The study also showed that children ran this heightened risk throughout their preschool years.

Nature vs nurture

Child asthma cases have been on the rise in the past few decades. The cause of asthma is still not really understood. Second-hand smoking is one contributing cause, according to health authorities in most countries.  Another factor and a huge “no-no” is smoking during pregnancy.

Moreover, it is common for children to develop asthma if their parents are asthmatic.

The Swedish researchers take a step out of the nature versus nurture question and speculate as to whether epigenetics has a part in the development of respiratory ailments. Epigenetics means that molecular changes in a person’s gene material from external sources can have an impact on the gene’s function.

Recent research has shown that pregnant women who smoke can change the DNA of their babies.

“Smoking during pregnancy has dropped considerably in the past decades. But so far this hasn’t led to a reduction on child asthma. One explanation can be that the smoking habits of previous generations continue to affect incidents of asthma among grandchildren,” explains one the authors of the study, Lennart Bråbäck, in the same press release.

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Read the Norwegian version of this article at forskning.no

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Translated by
Glenn Ostling