This is the cause of child bone disease

Children who enter puberty earlier have the strongest bones, such as adults, and may face a lower risk of osteoporosis as they age.

Scientists at the University of Bristol studied thousands of British children, taking bone scans over 15 years. They discovered that the later a child enters the pubs, the weaker their bones were. The bone strength increases in early twenties, so those who entered puberty recently had weaker bones in years to come.

This could be a crucial factor if an adult begins to have problems such as osteoporosis later in life, experts said. Researchers collected data on 6,389 children who had bone scans aged 1025 as part of the children's study of the 1990s.

They calculated the age that the child entered puberty by seeing when they had their greatest growth- called age at the highest speed rate. Children entering puberty earlier .5 years ago in girls, and 12.5 years ago in boys, they had 12 percent more bone strength during puberty than those that puberty later emerged from 12.7 years to girls and 14.5 years in boys.

The largest development in size and bone strength occurs during adolescence because of hormones. But the bones continue to grow in strength even after puberty, reaching their maximum strength called bone roof, early 20 years of age. The peak bone mass at the end of teen growth is thought to be an indication of the subsequent risk of fractures and osteoporosis. A previous study found that a 10 per cent increase in bone density would delay osteoporosis by 13 years.

The situation is estimated to affect three million people in the United Kingdom, according to the International Osteoporosis Foundation. Growth rates are an accurate indicator of puberty, researchers said, but there are limits. Chief author Dr Ahmed Elhakeem said they also used the age at which girls began their period as an indicator of puberty's beginning, and received the same study findings.

Understanding the changes in bone density during puberty, and the measures people can take to the health of their bones now to prevent osteoporosis and future fractures, is an important step forward in finding a cure for this disease. )

Researchers said that teenagers who pass puberty later that their peers should exercise more to increase and maintain the density of their bones. The study has not been able to conclude any conclusions regarding fractures or bone disease later in life because the study was completed when participants were 25 years old.