The research shows how genetic differences provide an important link between the biology that affects a person’s early growth and their chances of developing medical conditions such as type 2 diabetes or heart disease in later life.
The large-scale study, published today in Nature, could help to target new ways of preventing and treating these diseases.
The researchers analysed genetic information from nearly 154,000 people around the world – including 4,382 pairs of mothers and children from Children of the 90s.
They found that at least one-sixth of the difference in birth weight between babies is due to genetic differences. This is seven to eight times more variation than can be explained by other factors that influence birthweight, such as a mother smoking when pregnant or her body mass index before she is pregnant.
Babies who weigh well below or well above the average when they are born have a greater risk of developing diabetes later in life.
Until now, many researchers thought this was because events in early life can ‘programme’ a person’s body in ways that make them more prone to disease in later life.
What this new study shows is that there is substantial overlap between the ‘genetic regions’ linked to differences in birth weight and those connected to a higher risk of developing diabetes or heart disease.
Most of this crossover involves the baby’s genetic profile, but the researchers also found that the mother’s genes play an important role in her baby’s birth weight, most likely through the ways in which the genes alter the baby’s environment during pregnancy.
Professor Mark McCarthy at the University of Oxford, and co-lead author, said:
These findings provide vital clues to some of the processes that act over decades of life to influence an individual’s chances of developing diabetes and heart disease. These should highlight new approaches to treatment and prevention. Understanding the contributions of all of these processes will also tell us how much we should expect the many, wonderful improvements in antenatal care to reduce the burden of future diabetes and heart disease.
Dr Nicholas Timpson from the University of Bristol, and co-lead author, said:
The work does not necessarily show that birth weight itself is a direct target for potential therapeutic intervention, rather that there are likely to be shared mechanisms between the complex set of biological events contributing to birth weight and those to later life health. It was great that Children of the 90s was able to contribute to this work in such a substantial manner.