London, July 24 : A Southampton University research team says that boys who had low weight at the time of their birth are more likely to have poor health later in life.
The researchers say that blood vessel changes linked to poor health later in life may be spotted among boys born small within a few years of their birth.
Writing about their finding sin the European Heart Journal, the researchers say that their study showed that 8-year-olds who were smaller at birth were more likely to have "vascular resistance", which may contribute to high blood pressure decades later.
The researchers insist that they did not find any such problems in low birth weight girls.
They did not show any actual signs of heart disease, a condition which normally emerges far later in life, among the 140 eight or nine year olds tested during the study.
However, the researchers believe that, even at this age, the arteries of such children may show differences that may raise the risk of problems decades on.
The research team mainly tested for how a child's response to stress might affect vascular resistance, a property of blood vessels that makes it harder for the blood to be pumped through.
During the study, the children underwent a public speaking and mental arithmetic test designed to make them nervous, and increase their heart rate.
The researchers observed that boys at the lower end of the scale were more likely to have higher vascular resistance than those born bigger.
The difference in resistance levels between bigger and smaller birth weight boys was particularly strong half an hour after the test, suggesting some additional difference in the boys' ability to restore normal levels.
Although girls did not show this effect, they showed different levels of response in the part of their nervous systems linked to the "fight or flight" response.
"The sex differences in these relationships were striking and may eventually lead to a better understanding of why men and women tend to develop high blood pressure and heart or vascular disease at different times in their lives," the BBC quoted Dr. Alexander Jones, who led the project, as saying.
"It suggests that different underlying mechanisms for developing the same disorder may exist in the two sexes but have the same eventual result.
"My studies and future studies will focus more on childhood in an effort to better understand the processes that lead to disease and to seek to reverse them before it is too late to do anything about it," Jones added.
Many experts believe that these findings support large-scale studies that have already linked birth size to diseases in later life.
"That is beyond doubt now, in my view. There is plenty of evidence that chronic diseases start to develop pre-natally, or at least have their roots in pre-natal life," Professor Marjo-Riitta Jarvelin of Imperial College London said.
"We have supplied the proof that the association exists, now studies such as this one are beginning to look for the mechanism," she added.