LOS ANGELES (January 27, 2011) – A team of researchers led by Vicente Gilsanz, MD, PhD, director of Clinical Imaging at The Saban Research Institute of Children's Hospital Los Angeles, determined that the onset of puberty was the primary influence on adult bone mineral density, or bone strength. Length of puberty did not affect bone density.
Reduced bone mineral density leads to osteoporosis, resulting in bones becoming increasingly brittle and at risk for fracture. Osteoporosis is a significant public health issue with the cost of treatment in 2010 estimated at $10 billion. This condition affects 55% of Americans aged 50 and older.
The Bone Mineral Density in Childhood Study is an ongoing multicenter study examining bone development in healthy children and teenagers of both sexes and ethnic groups in the United States. For this analysis, the investigators studied 78 girls and 84 boys who had just entered puberty, until they reached sexual maturity.
"Puberty has a significant role in bone development," explained Dr. Gilsanz. "During this time, bones lengthen and increase in density. At the end of puberty the epiphyseal plates close, terminating the ability of the bones to lengthen. When this occurs, the teenager has reached their maximum adult height and peak bone mass. We found that early puberty was associated with greater bone mass while later puberty resulted in less."
Adolescents with short stature sometimes undergo medical intervention to delay puberty in an effort to achieve greater height. This study indicates that prolonging the growth period by delaying puberty may have unexpected consequences in later life.
The 2000 National Institutes of Health Consensus Development Conference on Osteoporosis Prevention, Diagnosis, and Therapy identified bone mineral deposition during adolescence as a critical determinant of osteoporosis risk later in life. The care of patients with osteoporosis is difficult, and most therapies increase bone density by small amounts yet requires long periods of treatment. In contrast, during puberty large increases in bone density occur over a short period of time.
Given that the rate of decline of bone mass in adulthood is approximately 1% to 2% each year, a 10% to 20% increase in bone density resulting from a natural early puberty corresponds to an additional 10 to 20 years of protection against the normal age-related decline in bone strength.
Collaborators on this study included Tishya Wren, PhD, and James Chalfant, BS, Children's Hospital Los Angeles; John Shepherd, PhD, University of California, San Francisco; Heidi Kalkwarf, PhD, Cincinnati Children's Medical Center; Babette Zemel, PhD, Children's Hospital of Philadelphia; Joan Lappe, PhD, Creighton University; Sharon Oberfield, MD, Columbia University; and Karen Winer, MD, National Institute of Child Health and Development. The article was published in the Journal of Pediatrics.
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About The Saban Research Institute and Children's Hospital Los Angeles
Children's Hospital Los Angeles is one of the nation's best children's hospitals serving more than 97,000 patients each year with physicians specializing in more than 100 subspecialties. Children's Hospital is one of only eight children's hospitals in the nation – and the only one in the western United States – named to the national "Honor Roll" of children's hospitals in the 2010 U.S. News & World Report rankings. Children's Hospital is preparing to open a $636 million, 317-bed state-of-the-art facility in July 2011 that will further expand services and capabilities at its main campus on Sunset Boulevard in Hollywood, Calif., as well as increase the ability to provide family-centered care to residents throughout the region.
Children's Hospital offers care from some of the world's most prestigious physicians and surgeons, and is designated as a Magnet Hospital by the American Nurses Credentialing Center, an honor held by only five percent of all hospitals nationwide. Children's Hospital is home to The Saban Research Institute, ranked eighth in National Institutes of Health funding among children's hospitals in the United States; is one of America's premier teaching hospitals, affiliated with the Keck School of Medicine of the University of Southern California since 1932; is the only Level 1 Pediatric Trauma Center in L.A. County approved by the Committee on Trauma of the American College of Surgeons; and is one of the largest pediatric transport programs in the nation.
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The Journal of Pediatrics