Many teenagers increase their chances of fracturing their hips or other bones later in life because they don't eat enough dairy products and don't exercise, according to consultant geriatrician Dr Bernard Walsh of St James's Hospital, Dublin.
Dr Walsh was commenting on research which suggests that nearly half of all women over 50 in the United States have an early form of osteoporosis but don't know about it.
Half of all Irish women over 50 will suffer some sort of osteoporotic fracture - such as a fracture of hip, humerus (upper arm bone), wrist or vertebra - at some time, he said.
He was concerned that a lot of people who suffer fractures are not put on preventive therapy. This includes taking calcium and vitamin D. Medicines which dramatically reduced the rate of fracture could also be prescribed where appropriate, he said.
Teenagers who don't take milk or milk products such as cheese were increasing their chances of a future fracture because they were not getting enough calcium to build up their bones, he said. Young people with eating disorders were particularly at risk.
Some were also not getting enough exercise. Exercise which put a weight on the bones helped to increase mass, he said.
"Dancing is a great way to build up bones," he added.