Low birth weight children are at a greater risk of hip fractures when they are pensioners, warn scientists.
Hip fractures cost the NHS around £1bn annually
They say this can now be used to give them early advice on reducing their risk of osteoporosis in later life.
The study from the University of Southampton's Centre for the Fetal Origins of Adult disease, showed evidence of a new link between the way a baby grows in the womb and as an infant and their risk of hip fracture later in life.
Dr Kassim Javaid studied 178 men and 155 women aged 60-75.
He quizzed them about their birth weight and weight aged one as well as their diet and lifestyle.
Dr Javaid carried out his research under the supervision of Professor Cyrus Cooper, professor of rheumatology at the university, who had already found an indication that growth in early life influences bone mass, although the effect on the hip was not known.
It is important that we put as much 'bone in the bank' as possible in early life
Emma Burrows spokesperson for the National Osteoporosis Society
Because hip fractures are the most common site for osteoporotic fracture Dr Javaid wanted to investigate the relationship between growth in the womb and early postnatal growth and the state of the hip bone.
He found that poor growth in early life and a year later could have an affect on the mechanical strength of the hip seven decades later.
Both males and females with the lower weight in early life had a significant reduction in the width of their hip bones in later life.
Dr Javaid said: "The biological consequences of this geometric change at the hip area is to reduce bending strength at the hip and increase the risk of fracture.
"This information is crucial as it will allow us to identify those people who are at a higher risk of osteoporosis early in their life and we will then be able to target them for dietary and other lifestyle interventions, and hopefully, reduce their risk of osteoporosis in later life."
A spokeswoman for the Arthritis Research Campaign, which funds Dr Javaid's Clinical Research Fellowship, agreed that it ould enable experts to target the people most at risk for special treatment.
Emma Burrows, spokesperson for the National Osteoporosis Society, said the research highlighted the importance of bone health at an early age.
"As we reach our peak bone mass in our mid-twenties, it is important that we put as much 'bone in the bank' as possible in early life.
"A well-balanced, calcium-rich diet and regular weight-bearing exercise is the best way to build strong, healthy bones. This research shows that parents need to think about the bone health of their children from a very early age, and make lifestyle changes now in order to reduce the risk of a fracture later."
Dr Javaid's research will be presented at the Second World Congress on Fetal Origins of Adult Disease in Brighton, from June 7-10.