Allergy risk ‘depends on your month of birth’

New research at the University of Southampton claims that the likelihood of developing seasonal allergies depends on your month of birth.

Researchers found that babies born in winter have a higher risk of asthma, while those born in autumn are more likely to have eczema.

The study, which has been published in the journal Allergy, involved scanning DNA samples of a group of 18-year-olds from the Isle of Wight and comparing their known allergies with their date of birth.

Dr Holloway, the study’s lead author, said: ‘These are really interesting results. We know that season of birth has an effect on people throughout their lives. However, until now, we did not know that the effects can be so long lasting.

‘Epigenetic marks are attached on to DNA, and can influence gene expression for years, maybe even into the next generation. Our study has linked specific epigenetic marks with season of birth and risk of allergy.

‘However, while these results have clinical implication in mediating against allergy risk, we are not advising altering pregnancy timing.’

Instant analysis
This study looked at the markers for allergy at birth and compared this to when the subjects were aged 10 and 18. Epigenetic markers prominent at birth seemed to be associated with an increased amount of allergy.

However, the study offers various explanations for the link with the month of birth — for example, the increased incidence of infections in winter time, low levels of vitamin D, maternal health, and so on. It is not clear that birth month is really the causative issue.

A comparison might be made with schizophrenia. While more cases of the disease seem to occur in those who are born in the winter months, you cannot clearly state that timing of birth is a cause. The association is too broad.

The numbers, too, are small — a cohort size of 367, which splits down into about 30 patients a month. So it is difficult to make great deductions. However, the study does pave the way for more useful future research.
Research score: 2/5