- •Low BMD was highly prevalent in SMA patients, regardless of SMA subtype.
- •Lateral distal femur BMD declined over time for all SMA subtypes.
- •All SMA subtypes had high fracture frequency with predominance of femur fractures.
- •Time to first fracture was not different among SMA subtypes, although SMA1 patients tended to be younger.
- •Despite fractures and low BMD, few SMA patients met the criteria for osteoporosis.
Patients with Spinal Muscular Atrophy (SMA) are at risk for poor bone health. The prevalence of fractures, low areal bone mineral density (aBMD; Z-score ≤−2.0) of the lateral distal femur and of osteoporosis by SMA subtype is not known. We aimed to describe the natural history of bone health in patients with SMA prior to bisphosphonate treatment. We reviewed data from 85 eligible patients with SMA ages 12 months to 18 years, seen at a single institution between January 2005 and July 2016. Fracture history was reported at annual clinic visits. aBMD was obtained from dual energy x-ray absorptiometry scans of the lumbar spine, total body, and lateral distal femur. 85% of patients had aBMD Z-scores ≤−2.0 SD and were progressively lower with worsening SMA severity. Longitudinal aBMD Z-scores of the lateral distal femur decreased with age. Fractures occurred in 38% (32/85) of patients with the femur being the most common location (25 of 57 fractures). Thirteen percent of patients fulfilled criteria for osteoporosis. Low aBMD and femur fractures are highly prevalent in all SMA subtypes from a young age; however, few patients met the criteria for osteoporosis. Poor bone health may be an under-recognized comorbidity of SMA.
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- An update of the mutation spectrum of the survival motor neuron gene (SMN1) in autosomal recessive spinal muscular atrophy (SMA).Hum Mutat. 2000; 15: 228-237
- Identification and characterization of a spinal muscular atrophy-determining gene.Cell. 1995; 80: 155-165
- Spinal muscular atrophy.Orphanet J Rare Dis. 2011; 6: 71
- Consensus statement for standard of care in spinal muscular atrophy.J Child Neurol. 2007; 22: 1027-1049
- Pathophysiological insights derived by natural history and motor function of spinal muscular atrophy.J Pediatr. 2013; 162: 155-159
- Survival of patients with spinal muscular atrophy type 1.Pediatrics. 2013; 131: e1509-14
- Effects of weight-bearing activities on bone mineral content and density in children and adolescents: a meta-analysis.J Bone Miner Res. 2014; 29: 467-478
- Weight-bearing exercise and bone mineral accrual in children and adolescents: a review of controlled trials.Bone. 2007; 40: 14-27
- Time since onset of walking predicts tibial bone strength in early childhood.Bone. 2014; 68: 76-84
- Longitudinal changes in bone density in children and adolescents with moderate to severe cerebral palsy.J Pediatr. 2005; 146: 769-775
- Low bone mass in patients with motor disability: prevalence and risk factors in 59 Finnish children.Dev Med Child Neurol. 2010; 52: 276-282
- Factors associated with bone density in different skeletal regions in children with cerebral palsy of various motor severities.Dev Med Child Neurol. 2011; 53: 131-136
- Bone mineral density and fractures in boys with Duchenne muscular dystrophy.J Pediatr Orthop. 2000; 20: 71-74
- Osteoclast-stimulating factor interacts with the spinal muscular atrophy gene product to stimulate osteoclast formation.J Biol Chem. 2001; 276: 41035-41039
- Bone loss in survival motor neuron (Smn(−/−) SMN2) genetic mouse model of spinal muscular atrophy.J Pathol. 2009; 219: 52-60
- Association between bone mass and fractures in children: a prospective cohort study.J Bone Miner Res. 2006; 21: 1489-1495
- Childhood fractures are associated with decreased bone mass gain during puberty: an early marker of persistent bone fragility?.J Bone Miner Res. 2006; 21: 501-507
- Fractures in myopathies.Chir Organi Mov. 1991; 76: 39-45
- Fracture risk in patients with muscular dystrophy and spinal muscular atrophy.J Rehabil Med. 2001; 33: 150-155
- [Fractures in spinal muscular atrophy].Rev Neurol. 2013; 57: 207-211
- Fractures in proximal spinal muscular atrophy.Arch Orthop Trauma Surg. 2010; 130: 775-780
- The relationship between lean body mass and bone mineral content in paediatric health and disease.Bone. 2004; 35: 965-972
- Bone mineral density in a paediatric spinal muscular atrophy population.Neuropediatrics. 2004; 35: 325-328
- Bone and spinal muscular atrophy.Bone. 2015; 79: 116-120
- Low bone mineral density in spinal muscular atrophy.J Clin Neuromuscul Dis. 2008; 10: 11-17
- 2013 Pediatric Position Development Conference: executive summary and reflections.J Clin Densitom. 2014; 17: 219-224
- Fracture prediction and the definition of osteoporosis in children and adolescents: the ISCD 2007 Pediatric Official Positions.J Clin Densitom. 2008; 11: 22-28
- Pediatric reference data for dual X-ray absorptiometric measures of normal bone density in the distal femur.AJR Am J Roentgenol. 2002; 178: 439-443
- Revised pediatric reference data for the lateral distal femur measured by Hologic Discovery/Delphi dual-energy X-ray absorptiometry.J Clin Densitom. 2009; 12: 207-218
- Bone mineral content and density of the lumbar spine of infants and toddlers: influence of age, sex, race, growth, and human milk feeding.J Bone Miner Res. 2013; 28: 206-212
- Cross-sectional study of bone mineral density in adult survivors of solid pediatric cancers.J Pediatr Hematol Oncol. 2005; 27: 248-253
- Revised reference curves for bone mineral content and areal bone mineral density according to age and sex for black and non-black children: results of the bone mineral density in childhood study.J Clin Endocrinol Metab. 2011; 96: 3160-3169
- Fracture prediction and the definition of osteoporosis in children and adolescents: the ISCD 2013 Pediatric Official Positions.J Clin Densitom. 2014; 17: 275-280
- The relationship between fractures and DXA measures of BMD in the distal femur of children and adolescents with cerebral palsy or muscular dystrophy.J Bone Miner Res. 2010; 25: 520-526
- Bone mineral density in children with myelomeningocele.Dev Med Child Neurol. 2009; 51: 63-67
- Dual-energy X-ray absorptiometry interpretation and reporting in children and adolescents: the revised 2013 ISCD Pediatric Official Positions.J Clin Densitom. 2014; 17: 225-242
- The role of lean body mass and physical activity in bone health in children.J Bone Miner Metab. 2012; 30: 100-108
Published online: February 01, 2017
Accepted: January 23, 2017
Received: September 29, 2016
© 2017 Published by Elsevier B.V.