Underweight babies and infants have a far greater risk of fracturing bones in later life, new research reveals.
Tests found the development of an infant even before it is born has a direct bearing on its chances of suffering potentially fatal fractures seven decades later.
Experts believe the findings will help to reduce fractures in Britain by tens of thousands, as well as saving the NHS hundreds of millions of pounds a year through early treatment.
'This is a very significant breakthrough, and if the knowledge is applied could reduce fracture rates by around a quarter,' said Professor Cyrus Cooper, who led the research team at the University of Southampton.
Researchers found that the hip bone of an underweight infant would be thinner, making it more susceptible to fracture in later life. 'If the bone is a cylinder like a can of baked beans, then its diameter would be more reduced in relation to its height, meaning it would be more slender,' said Cooper. In particular, the research found that people who grow slowly in childhood are significantly more susceptible to hip fractures - the most common breakage in the UK, with 70,000 cases a year.
Concern has been mounting that the number is increasing, with one in five older people who have a hip fracture dying within six months of the injury.
The UK has one of the highest rates of hip fractures in Europe - 14.4 per 1,000 of the population - with surgeons predicting the number of will double by 2020 as the population continues to age.
Cooper said the research - which will be unveiled later this month at a conference examining the foetal origins of adult disease - would help to relieve the burden on the NHS. Some 90 per cent of the £1.7 billion cost of treating orthopaedic fractures on the NHS is swallowed up by treating broken hips.
Experts from the Medical Research Council's Environmental Epidemiology Unit at the University of Southampton examined 178 men and 155 women aged between 60 and 75 who shared similar physical and lifestyle characteristics. They discovered that infant growth predicted the amount of bone at the hip in later life as well as its strength. Lower weight at birth and at the age of 12 months resulted in a significant reduction in the width of the hip bone for both men and woman in later life.
'The biological consequence of this geometric change at the hip area is to reduce bending strength at the hip and increase the risk of fracture', said Dr Kassim Javaid, who undertook the research.
'This information is crucial, as it will allow us to identify those people who are at a higher risk of osteoporosis early in life. We will be able to target them for dietary and other lifestyle interventions.'
Teenagers who developed slowly when in the womb or in infancy will in future be encouraged to take large amounts of calcium, to be supplemented with exercises when they reach their fifties.
Overall, three in 12 women and one in 12 men will develop osteoporosis after the age of 50 and many will suffer painful fractures. If left untreated, broken hips are fatal because they make elderly people immobile and vulnerable to conditions such as pneumonia.
New figures also reveal that the number of people with osteoarthritis - wear and tear of the joints - is also escalating and now stands at more than four million.
Previous research has suggested that poor foetal growth and small size at birth are associated with increased risk of coronary heart disease, stroke, diabetes and some neurological disorders in adult life.
Cooper will also unveil at the conference research revealing that mothers who smoke, have a poor diet and exercise intensively during late pregnancy run the risk of having children who grow slowly.
Analysts are hoping that the research will help to tackle NHS waiting lists. More than 265,000 people are currently awaiting hospital admission for orthopaedic treatment in England.