Are Teens Still Building Bone After Attaining Their Adult Height?

The findings:

Bone mineral accrual doesn’t keep pace with height growth prior to adolescence, according to a national study. After a teenager reaches adult height, bone mineral accrual tends to play catch-up: Roughly 10 percent of bone mass continues to accumulate after height growth is complete. The study findings also suggest that bone growth is site-specific, with bone mineral density developing at different rates in different parts of the skeleton.

Why it matters:

Overall bone health development is important during the late teen years; however, this is a period when teens typically pay less attention to healthy behaviors. They may not recognize that poor dietary choices and decreased physical activity can impair their bone development. Also, the “lag” in bone mineral accrual may help explain the high fracture rates among children and adolescents. Thirty to 50 percent of children experience at least one bone fracture prior to adulthood.

Who conducted the study:

CHOP researchers Shana McCormack, MD, MTR, an attending physician in the division of Endocrinology, and Babette Zemel, PhD, director of the Nutrition and Growth Laboratory, were leaders of the study team that included colleagues from CHOP, Nebraska, New York, California, and the National Institutes of Health.

How they did it:

The researchers analyzed data from 2,014 healthy children who participated in the Bone Mineral Density in Childhood Study, which included sophisticated bone and growth measurements via dual-energy X-ray absorptiometry at annual visits for up to seven years from 2002 through 2010. The participants were ages 5 to 19 when they joined the study.

Quick thoughts:

“We’ve known for a long time that maximizing bone health in childhood and adolescence protects people from osteoporosis later in life,” Dr. Zemel said. “This study reinforces that understanding and suggests that late adolescence may be an under-recognized period to intervene in this important area of public health.”

What’s next:

This study emphasizes that late adolescence is a foundation for lifelong health, especially because teens are still building bone. During this window of opportunity, families and physicians can encourage teens to engage in behaviors that promote bone strength, such as high-impact, weight-bearing exercise and healthy eating.

Where the study was published:

This study appeared in JAMA Pediatrics.

Who helped fund the study:

Multiple NIH grants and contracts supported the Bone Mineral Density in Childhood Study. Support for the current study came from the Pediatric Endocrine Society Clinical Scholars Award, institutional funds from CHOP, and the Daniel B. Burke Endowed Chair for Diabetes Research at CHOP.

Where to learn more:

Read about another CHOP study based on data from the Bone Mineral Density in Childhood Study that showed high-impact, weight-bearing exercise improves bone strength in children, even those with a higher genetic risk for bone fragility.