title: High plasma osteocalcin is associated with low blood haemoglobin in elderly men: the MrOS Sweden Study.
abstract: BACKGROUND
  It has been suggested that osteoblasts are involved in the regulation of haematopoietic stem cells. Whether osteocalcin, which is derived from osteoblasts and is metabolically active, influences blood haemoglobin (Hb) levels is not known.
  
  
  OBJECTIVE
  To determine whether plasma osteocalcin is a determinant of Hb in elderly men.
  
  
  METHODS
  A total of 993 men (mean age 75.3 ± 3.2 years) participated in the population-based MrOS (osteoporotic fractures in men) study. Plasma osteocalcin concentration was evaluated in relation to Hb and adjustments were made for potential confounders (i.e. age, body mass index, erythropoietin, total oestradiol, fasting insulin, adiponectin, ferritin and cystatin C).
  
  
  RESULTS
  Hb correlated (age adjusted) negatively with osteocalcin in the total study group (r = -0.12, P < 0.001) as well as in the subgroup of nondiabetic men (r = -0.16, P < 0.001). In nondiabetic men with higher osteocalcin levels, it was more likely that Hb would be in the lowest quartile (odds ratio per SD decrease in osteocalcin 1.32, 95% confidence interval 1.13-1.53). Quartiles of Hb were negatively associated (age adjusted) with osteocalcin (P < 0.001). Anaemic men (47/812) (Hb <130 g L(-1) ) had significantly higher mean osteocalcin levels than nonanaemic men (33.9 vs. 27.1 μg L(-1) , P < 0.001). In multiple stepwise linear regression analyses (adjusted for age, body mass index, total oestradiol, adiponectin, erythropoietin, fasting insulin, cystatin C, leptin, ferritin and holotranscobalamin), osteocalcin was an independent predictor of Hb concentration in nondiabetic men (P < 0.05).
  
  
  CONCLUSIONS
  These data add further support to the evidence indicating that the bone-specific protein osteocalcin has several endocrine functions targeting the pancreas, testes, adipocytes, brain. An additional novel finding is that osteocalcin may also have a paracrine function as a regulator of haematopoiesis.
authors.affiliation: Section of Hematology and Coagulation, Department of Internal Medicine and Clinical Nutrition, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. catharina.lewerin@vgregion.se.
authors.forename: C
authors.initials: C
authors.lastname: Lewerin
authors.affiliation: Center for Bone and Arthritis Research (CBAR), Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Johansson
authors.affiliation: Department of Clinical Sciences and Orthopaedics, Lund University, Malmö, Sweden.
authors.forename: M K
authors.initials: MK
authors.lastname: Karlsson
authors.affiliation: Center for Bone and Arthritis Research (CBAR), Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Department of Geriatric Medicine, Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Lorentzon
authors.affiliation: Center for Bone and Arthritis Research (CBAR), Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Molecular Periodontology, Umeå University, Umeå, Sweden.
authors.forename: U H
authors.initials: UH
authors.lastname: Lerner
authors.affiliation: Center for Bone and Arthritis Research (CBAR), Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: J M
authors.initials: JM
authors.lastname: Kindblom
authors.affiliation: Center for Bone and Arthritis Research (CBAR), Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Ohlsson
authors.affiliation: Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Smith
authors.affiliation: Center for Bone and Arthritis Research (CBAR), Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. dan.mellstrom@vgregion.se.|Department of Geriatric Medicine, Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. dan.mellstrom@vgregion.se.
authors.forename: D
authors.initials: D
authors.lastname: Mellström
mesh_terms: D000367:Age Factors; D000368:Aged; D000740:Anemia / Q000097:blood; D006410:Hematopoiesis / Q000502:physiology*; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood; D015675:Osteocalcin / Q000097:blood*; D010976:Platelet Count; D011446:Prospective Studies; D012044:Regression Analysis
chemical_list: D006454:Hemoglobins; D015675:Osteocalcin
keywords: elderly; haemoglobin; male; osteocalcin