date : 5/5/2003
media contact : Amy Austell , (919) 684-4148 or (919) 660-1303
editor's note : "Duke Health Briefs" contains consumer health information and is distributed every Monday by the Duke University Medical Center News Office. To hear an audio clip of this Health Brief, visit Duke MedMinute.

Even though many osteoporosis-prevention messages are targeted at older women, grandmothers aren't the only ones who should be concerned about this major health threat. Girls as young as pre-teens are at an age when they can reduce future bone loss through regular, moderate exercise.

This window of opportunity to "load our skeleton," or increase bone mass, is brief -- starting right around puberty and continuing through it, according to Kenneth Lyles, M.D., professor of medicine in the division of geriatrics at Duke University Medical Center.

"It is possible -- and there's pretty clear data -- that weight-bearing exercise for girls as they just start going into puberty is a very useful way to help them achieve their full skeletal potential," says Lyles.

"We now realize that not only do you need dense bones, but the structure of your bones is also important," he explains. "Exercise can have a profound effect on bone strength. There have been some very effective studies that show, if you have girls jump off a box that's two feet high and land on both feet 100 times, three times a week, this can have a very positive effect on bone density and especially on bone structure."

Advertising that shows pre-teens exercising or drinking a glass of milk can help make this age group aware of healthy habits that can reduce their risk of developing osteoporosis when they grow older.

"There are a number of programs to try to convince young women to be more physically active," says Lyles. "I think habits should be lifelong. Trying to get someone to do it who's never done it before is a real problem. I think people should be encouraged to be physically active almost from the time they can walk. And it needs to be set by families."

As for diet, Lyles says calcium and vitamin D are key needs for osteoporosis prevention. "Almost everyone, from childhood through the start of menopause, needs 1,000 milligrams of calcium a day," he says. "The easy way to remember this is that the average diet with no dairy products provides between 400 and 600 milligrams of calcium. A glass of milk adds 250 milligrams; a cup of yogurt is 200 milligrams. You want that daily intake, along with 800 international units of vitamin D."