title: Autonomic nerve fiber function and bone mineral density in individuals with type 1 diabetes: a cross-sectional study.
abstract: OBJECTIVE
  Experimental models support a role for the sympathetic nervous system in bone metabolism. Beta-adrenoreceptors have been demonstrated on osteoblast-like cells. Beta-blocker use is associated with higher bone mineral density (BMD) in some epidemiologic studies. The aim of this study was to determine if measures of the autonomic nervous system (ANS) were associated with reduced BMD in type 1 diabetes.
  
  
  METHODS
  We studied 66 individuals with type 1 diabetes. Dual-energy X-ray absorptiometry was used to measure BMD and bone mineral content (BMC). Measures of heart rate variability (HRV) (e.g., power spectral analysis, mean circular resultant) and circulating norepinephrine levels were used to evaluate autonomic function.
  
  
  RESULTS
  BMD/BMC were examined by gender for individuals with a normal versus elevated low-frequency (LF) band (expressed in normalized units). No significant differences in BMD/BMC were shown for individuals with an elevated LF band. Direct-entry linear regression models with BMD/BMC as the dependent variable were performed. Duration, gender, BMI, HbA(1c), insulin dose/kg, activity energy expenditure, and measures of HRV were entered as potential independent variables. No measures of HRV, or norepinephrine, were independently associated with BMD/BMC.
  
  
  CONCLUSIONS
  The ANS, as assessed by measures of HRV, does not appear to impact BMD/BMC in type 1 diabetes.
authors.affiliation: Department of Medical Technology, University of Delaware, Newark, DE 19716, United States. rmaser@udel.edu
authors.forename: Raelene E
authors.initials: RE
authors.lastname: Maser
authors.forename: John N
authors.initials: JN
authors.lastname: Stabley
authors.forename: M James
authors.initials: MJ
authors.lastname: Lenhard
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Provost-Craig
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D001341:Autonomic Nervous System / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001794:Blood Pressure; D015519:Bone Density; D001842:Bone and Bones / Q000000981:diagnostic imaging; D002112:Calcifediol / Q000097:blood; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D009412:Nerve Fibers / Q000502:physiology*; D009638:Norepinephrine / Q000097:blood; D018579:Patient Selection; D013564:Sympathetic Nervous System / Q000502:physiology / Q000503:physiopathology
chemical_list: D002112:Calcifediol; D006442:Glycated Hemoglobin; D009638:Norepinephrine