Evaluating Bone Health of Children With Frequent Fractures
Evaluating Bone Health of Children With Frequent Fractures
Olney RC, Mazur JM, Pike LM, et al Pediatrics. 2008;121:890-897
The authors note that both pediatricians and orthopedists are often not sure whether to consider further evaluation in children with repeat fractures. Some previous reports suggested that low bone-mineral density (BMD) and/or a history of fracture were associated with risk for subsequent fracture in children.
The 68 subjects for this study were identified at one US institution. All were 3-17 years old with at least 2 "low-energy" fractures; this eliminated injuries incurred from motorized vehicles, skateboards and bicycles, climbing apparatus, and falls from more than standing height.
The 57 control subjects were a mixture of healthy siblings of fracture patients and unrelated controls, all with no history of fracture. Subjects with chronic medical conditions that might affect bone health were excluded. Subjects and controls underwent lumbar spine and whole-body "dexa" scans (DXA), and the authors also obtained height, weight, body mass index measurements.
The analyses also controlled for frequency of weight-bearing exercise, obtained by survey of the participants. Researchers also asked subjects to complete a 3-day food intake log. When comparing average z-scores of lumbar DXA scans, children with repeat fractures were lower than normal (average Z-score = -0.2) and control children were higher (average Z-score = 0.2). There was a similar difference for whole body DXA scan results. However, when looking at scores ≤ -2.0, the difference in rates between cases (4.4%) and controls (1.8%) was not significant.
The authors note that in a healthy population, approximately 2% of individuals will have z scores at or below -2.0. The study identified no differences between cases and controls in weight-bearing exercise or dietary intake. However, only 31% of all subjects met daily calcium intake goals and 41% met daily vitamin D intake goals.
The authors rather unexpectedly identified a high rate of hypercalciuria at > 20% in both groups. When subjects were divided into those with and without hypercalciuria, the cases with hypercalciuria did have significantly lower bone mineral density scores.
The authors conclude that at least 25% of the cases studied had an identifiable abnormality that is associated with bone density. The authors suggest that instead of completing DXA scans on everyone, clinicians should proceed as follows: First, take a dietary history for calcium and vitamin D intake. If results are low, check vitamin D, parathyroid hormone, and DXA. Second, assess for pubertal delay and evaluate accordingly if found. Third, screen for hypercalciuria and complete DXA scan for those with elevated urine calcium excretion.
The authors note that this diagnostic approach should be replicated in a prospective study, but their research also provides an outline for practitioners to follow until further data are available. The safest take-home message is for clinicians to continue to think about "bone health" in patients with more than 1 low-impact fracture, and to consider dietary or endocrinologic evaluation before going straight to studies of bone mineral density.
Abstract
Olney RC, Mazur JM, Pike LM, et al Pediatrics. 2008;121:890-897
The authors note that both pediatricians and orthopedists are often not sure whether to consider further evaluation in children with repeat fractures. Some previous reports suggested that low bone-mineral density (BMD) and/or a history of fracture were associated with risk for subsequent fracture in children.
The 68 subjects for this study were identified at one US institution. All were 3-17 years old with at least 2 "low-energy" fractures; this eliminated injuries incurred from motorized vehicles, skateboards and bicycles, climbing apparatus, and falls from more than standing height.
The 57 control subjects were a mixture of healthy siblings of fracture patients and unrelated controls, all with no history of fracture. Subjects with chronic medical conditions that might affect bone health were excluded. Subjects and controls underwent lumbar spine and whole-body "dexa" scans (DXA), and the authors also obtained height, weight, body mass index measurements.
The analyses also controlled for frequency of weight-bearing exercise, obtained by survey of the participants. Researchers also asked subjects to complete a 3-day food intake log. When comparing average z-scores of lumbar DXA scans, children with repeat fractures were lower than normal (average Z-score = -0.2) and control children were higher (average Z-score = 0.2). There was a similar difference for whole body DXA scan results. However, when looking at scores ≤ -2.0, the difference in rates between cases (4.4%) and controls (1.8%) was not significant.
The authors note that in a healthy population, approximately 2% of individuals will have z scores at or below -2.0. The study identified no differences between cases and controls in weight-bearing exercise or dietary intake. However, only 31% of all subjects met daily calcium intake goals and 41% met daily vitamin D intake goals.
The authors rather unexpectedly identified a high rate of hypercalciuria at > 20% in both groups. When subjects were divided into those with and without hypercalciuria, the cases with hypercalciuria did have significantly lower bone mineral density scores.
The authors conclude that at least 25% of the cases studied had an identifiable abnormality that is associated with bone density. The authors suggest that instead of completing DXA scans on everyone, clinicians should proceed as follows: First, take a dietary history for calcium and vitamin D intake. If results are low, check vitamin D, parathyroid hormone, and DXA. Second, assess for pubertal delay and evaluate accordingly if found. Third, screen for hypercalciuria and complete DXA scan for those with elevated urine calcium excretion.
The authors note that this diagnostic approach should be replicated in a prospective study, but their research also provides an outline for practitioners to follow until further data are available. The safest take-home message is for clinicians to continue to think about "bone health" in patients with more than 1 low-impact fracture, and to consider dietary or endocrinologic evaluation before going straight to studies of bone mineral density.
Abstract
Source...