The findings, published yesterday, caused concern among health professionals as the number of larger babies has increased in the past 30 years because of better nutrition. At the same time there has been a rise in asthma, with one child in seven now developing it, a 21 per cent increase in 10 years.
The researchers said the data suggests over-nutrition is increasing the risk for asthma and allergies in later childhood. In the study published in the journal Thorax, scientists studied 730 children whose health had been assessed every two or three years since they were born in April 1972. They compared the children's birth statistics to asthma and allergies reported when they were aged 11 and 13.
The researchers found that children with a large head at birth, greater than 37cm (14.5in), were over three times as likely to have asthma by the age of 11. Children born with a body length of 56cm (22in) or longer were six times more likely to have reported recent asthma symptoms than those who were born shorter.
The findings also revealed that babies born under 3kg (6.6lb) had a reduced risk of asthma and allergic potential.
"The reason for the association between increased foetal growth and the subsequent risk of asthma are unclear," said Dr Philip Leadbitter, from the Wellington School of Medicine, New Zealand, and co-author of the study.
"However, it is known that foetal growth is determined by many factors including maternal health and nutrition, placental function and foetal growth potential. The factors may also interact to influence the developing respiratory and immune system and programme the foetus to be at greater risk of developing asthma and allergies in later childhood."
British asthma experts said they thought it was unlikely that increased nutrition alone was responsible for the increasing prevalence of asthma in bigger babies.
"The diet in Western countries has changed in the last few decades," said a spokesman for the National Asthma Campaign. "It is more likely that the increase in allergic potential in bigger babies is due to this increasing consumption of food additives and junk food."Reuse content