Babies who are heavier at birth may have a higher risk of childhood allergies

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New Australian research has found that babies who are heavier at birth may have a higher risk of a food allergy or eczema later in childhood.

Carried out by researchers at the University of Adelaide’s Robinson Research Institute, the new study looked at 42 studies including data on more than 2.1 million people with allergic dermatitis, commonly known as eczema, nearly 70,000 people with food allergies and over 100,000 people with allergic rhinitis or hay fever.

The team analyzed the studies to see if there was an association between birth weight, relative to its gestational age, and rates of allergies in both children and adults.

The findings, published in the Journal of Allergy and Clinical Immunology, showed that for each kilogram increase in a baby’s birth weight there was a 44% increased risk of developing a food allergy and a 17% increased risk of developing eczema in childhood.

However, there was no link between a higher birth weight and the risk of childhood hay fever.

“Allergic diseases including eczema, hay fever, food allergies, anaphylaxis and asthma are estimated to affect 30-40% of the world’s population,” said lead author Dr. Kathy Gatford.

“It is increasingly clear that genetics alone do not explain risks of developing allergies, and that environmental exposures before and around birth can program individuals to increased or decreased risk of allergies,” said Gatford.

“Although restricted growth before birth — intra-uterine growth restriction (IUGR) — is associated with increased risks of many diseases in later life, it appears to protect a child against the risk of developing allergic responses.”

“The main message for moms is that big babies are at increased risk of allergy, so mothers with big babies should seek advice on modifying environmental factors to reduce those risks.”

As most of the allergies in these studies were assessed in young children, the researchers note that further studies are now needed to investigate the association between IUGR and the rate of allergies among older children, adolescents and adults. IB/NVG

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