Exercising youth can "bank" bone mass to fight osteoporosis


CORVALLIS, Ore. - A new study at Oregon State University has found that children as young as 7-8 years old can significantly increase bone mass through a brief, yet specific weekly exercise regimen that may help them "bank" extra bone to fight osteoporosis in adulthood.

The critical component, researchers say, is for youth to engage in "impact loading" exercises that boost bone mass in a targeted area - especially the hips.

In the OSU study, youth volunteers who were asked to jump off two-foot boxes 100 times, three times a week for seven months had 5 percent more bone mass than a control group of classmates who used the time for stretching and non-impact exercise.

"A 5 percent increase may not sound like a lot, but it translates into a 30 percent decrease in the risk of a hip fracture at adulthood," said Christine Snow, director of the Bone Research Laboratory at Oregon State University and principal investigator in the study.

The findings are the result of a pilot study done last year and should be considered preliminary, Snow cautioned. She has received a major three-year, $400,000 grant from the National Institutes of Health to follow up that pilot study with a more comprehensive research project that will begin this fall.

The research is significant, Snow said, because there was only one published study in the world that details how children can increase bone mass. That study, conducted in Australia, showed similar gains of 5-8 percent in bone mass, but it required children to maintain a rigid schedule of weight lifting and jumping activities for 50 minutes, three times a week for 10 months. And it was unclear whether the weight lifting or the jumping improved the bone mass.

"Our study is particularly valuable because it only takes 10 minutes to do the 100 jumps - and you can easily incorporate that into a school's physical education schedule three times a week," Snow said. "We also used the opportunity to teach the kids about their skeletal systems, the importance of exercise, fitness and nutrition."

During the last 10 years, OSU has developed a nationally recognized program in the study of bone research and exercise. Much of the research has pointed to the same conclusion - that the best way to increase bone mass in the hips is through high-impact exercise.

This latest study by Snow and OSU master's student Robyn Fuchs was even more specific - looking at increasing bone mass in children, especially in the hard-to-influence hip area. Each year, some 300,000 elderly Americans suffer hip fractures, leading to hospitalization, incapacitation and even death.

Studies nationally have found that bone mass decreases with age and can only be slowed at adulthood, not reversed.

"Over the last five years, it has become increasingly evident that the best method for preventing osteoporosis is to put bone mass in the bank at childhood, and maintain as much as you can through your adult years," Snow said. "Early intervention is not as evident for other chronic diseases."

The National Institutes of Health grant will enable Snow to recruit 300 to 400 children for a more comprehensive look at the effects of the jumping protocol on bone density. The OSU researchers hope to determine if the young volunteers maintain or lose that 5 percent edge when the jumping activity ceases, and to discover whether there is any increase in bone mass in the spine.

Snow said the project was approved by the university's Institutional Review Board for human subjects and contains little risk for the volunteers. During the pilot study, there were no injuries and none of the children reported pain associated with the jumping activity. The researchers consulted with a pediatrician and an orthopedics specialist in designing the exercise protocol.

The pilot study was conducted at Harding School in Corvallis. This fall, student volunteers from Garfield Elementary and Mountain View Elementary - also in Corvallis - will take part in the second phase of the project. Each school will receive a $2,500 stipend.

"We would also like to evaluate the bone density of parent volunteers to find out the contribution of genetics to bone mass," Snow said.