The children of women who give birth in later life are less likely to develop asthma than those born to younger mothers, researchers have found.

“There is some evidence that maternal age at delivery may be related to asthma in childhood and young adulthood,” explain Dr Birger Laerum, from Haukeland University Hospital in Bergen, Norway, and team in the journal Respiratory Medicine.

To investigate further, the researchers surveyed 16,190 people, aged between 23 and 54 years, who were participating in a European respiratory study.

The volunteers were asked to give the age of their mothers when they were born, and whether they had ever suffered from asthma, hayfever or other respiratory symptoms.

Analysis revealed that the participants were 8% less likely to suffer from asthma and 6% less likely to suffer from breathlessness and wheezing for every 5-year increase in their mother’s age at delivery.

However, participants born to the youngest and oldest mothers were more likely to develop hayfever than those born to mothers of intermediate ages.

The findings remained true after taking into account maternal smoking habits, body mass index and other asthma risk factors.

Dr Laerum and team conclude: “In this large, population based, multi-centre study of North-European adults, younger maternal age at delivery was consistently and significantly associated with increased risk for asthma.

“The effect on asthma was similar in men and women, independent of hayfever status and consistent between centres.”

They suggest: “This could possibly reflect a biological effect of ageing of the mother.”

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First Publishd June 2007

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