title: Bone fracture in severe small-for-gestational-age, extremely low birth weight infants: A single-center analysis.
abstract: Bone fracture is a complication of extremely low birth weight infants (ELBWIs). This study aimed to analyze risk factors for bone fracture in a population of severe small-for-gestational-age (SGA) ELBWIs.
  
  
  
  We retrospectively studied data from ELBWIs with a birth weight <1000g and <-2 standard deviations (SDs) born at the National Center for Child Health and Development, Japan, from 2013 to 2015. Infants were divided into fracture and control groups. Serum calcium (Ca) and phosphorus (P) levels, perinatal factors, and previously reported risk factors were analyzed.
  
  
  
  Of 25 cases of severe SGA ELBWIs, 5 cases of bone fracture were identified. Gestational age was 27.7±2.2, 29.1±2.6weeks (mean difference [MD] -1.4, 95% confidence interval [CI]: -4.0, -1.2, p=0.280), birth weight (BW) 448±105, 673±216g (MD -225, 95% CI: -433, -17, p=0.036) and BW-SD -4.1±0.1, -3.4±0.8 (MD -0.8, 95% CI: -1.5, -0.02, p=0.045) in the fracture and control groups, respectively. Minimums of serum Ca and P were 6.6±1.4, 8.1±0.8mg/dl (MD -1.5, 95% CI: -2.5, -0.6), p=0.003) and 2.3±0.6, 3.5±1.1mg/dl (MD -1.2, 95% CI: -2.2, -0.1, p=0.027) in the fracture and control groups, respectively.
  
  
  
  Lower BW and BW-SD were possible risk factors for bone fracture. Hypocalcemia and hypophosphatemia may also contribute to the condition.
authors.affiliation: Division of Neonatology, Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Japan. Electronic address: maruyama-h@ncchd.go.jp.
authors.forename: Hidehiko
authors.initials: H
authors.lastname: Maruyama
authors.affiliation: Division of Neonatology, Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Amari
authors.affiliation: Division of Neonatology, Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Japan.
authors.forename: Hideshi
authors.initials: H
authors.lastname: Fujinaga
authors.affiliation: Division of Neonatology, Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Fujino
authors.affiliation: Division of Neonatology, Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Nagasawa
authors.affiliation: Division of Neonatology, Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Wada
authors.affiliation: Division of Neonatology, Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Tsukamoto
authors.affiliation: Division of Neonatology, Center for Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Japan.
authors.forename: Yushi
authors.initials: Y
authors.lastname: Ito
mesh_terms: D002118:Calcium / Q000097:blood; D002675:Child, Preschool; D005260:Female; D050723:Fractures, Bone / Q000097:blood / Q000453:epidemiology*; D006801:Humans; D006996:Hypocalcemia / Q000097:blood / Q000453:epidemiology*; D017674:Hypophosphatemia / Q000097:blood / Q000453:epidemiology*; D007223:Infant; D052577:Infant, Extremely Low Birth Weight / Q000097:blood* / Q000254:growth & development; D007231:Infant, Newborn; D008297:Male; D010758:Phosphorus / Q000097:blood
chemical_list: D010758:Phosphorus; D002118:Calcium
keywords: Bone fracture; Extremely low birth weight infant; Hypocalcemia; Hypophosphatemia; Small for gestational age