title: Type 1 diabetes patients have lower strength in femoral bone determined by quantitative computed tomography: A cross-sectional study.
abstract: OBJECTIVE
  Previous studies have reported osteoporosis measured by dual-energy X-ray absorptiometry in younger patients with type 1 diabetes. Limitations of 2-D imaging, however, limit the precision of dual-energy X-ray absorptiometry for the measurement of bone mineral density and bone strength.
  
  
  METHODS
  Three-dimensional quantitative computed tomography was used to calculate volumetric-bone mineral density (vBMD) and strength in femoral bone subfractions. A total of 17 male type 1 diabetes patients and 18 sex-matched healthy controls aged from 18 to 49 years were investigated in the present cross-sectional study. Patients with overt nephropathy were excluded.
  
  
  RESULTS
  Type 1 diabetes patients had significantly lower cortical vBMD in the femoral neck, and significantly lower total vBMD, cortical thickness and cortical cross-sectional area (cortical CSA) in the intertrochanter. Bone strength estimated by the buckling ratio (an index of cortical instability) of the intertrochanter was significantly higher in type 1 diabetes patients. The following serum bone markers were comparable between the two groups: bone-specific alkaline phosphatase, N-terminal propeptide of type 1 procollagen, osteocalcin, pentosidine and homocysteine. Serum insulin-like growth factor-1 values were significantly lower in the type 1 diabetes patients than in controls. Serum insulin-like growth factor-1values were positively correlated with serum bone formation markers, and the total vBMD of the femoral neck and lumbar spine in type 1 diabetes patients.
  
  
  CONCLUSIONS
  The present study is the first investigation by quantitative computed tomography measurement to show cortical instability and lower vBMD in the intertrochanter of young and middle-aged type 1 diabetes patients. Low insulin-like growth factor-1 might be a causative factor for osteoporosis in type 1 diabetes.
authors.affiliation: Department of orthopaedic Surgery, Showa University School of Medicine Tokyo, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Ishikawa
authors.affiliation: Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine Tokyo, Japan.
authors.forename: Tomoyasu
authors.initials: T
authors.lastname: Fukui
authors.affiliation: Department of orthopaedic Surgery, Showa University School of Medicine Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nagai
authors.affiliation: Department of orthopaedic Surgery, Showa University School of Medicine Tokyo, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Kuroda
authors.affiliation: Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine Tokyo, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Hara
authors.affiliation: Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Department of orthopaedic Surgery, Showa University School of Medicine Tokyo, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Inagaki
authors.affiliation: Department of Medicine, Division of Diabetes, Metabolism and Endocrinology, Showa University School of Medicine Tokyo, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hirano
keywords: Insulin-like growth factor-1; Quantitative computed tomography; Type 1 diabetes