title: Low serum vitamin D is associated with higher cortical porosity in elderly men.
abstract: Bone loss at peripheral sites in the elderly is mainly cortical and involves increased cortical porosity. However, an association between bone loss at these sites and 25-hydroxyvitamin D has not been reported.
  
  
  
  To investigate the association between serum levels of 25-hydroxyvitamin D, bone microstructure and areal bone mineral density (BMD) in elderly men.
  
  
  
  A population-based cohort of 444 elderly men (mean ± SD age 80.2 ± 3.5 years) was investigated. Bone microstructure was measured by high-resolution peripheral quantitative computed tomography, areal BMD by dual-energy X-ray absorptiometry and serum 25-hydroxyvitamin D and parathyroid hormone levels by immunoassay.
  
  
  
  Mean cortical porosity at the distal tibia was 14.7% higher (12.5 ± 4.3% vs. 10.9 ± 4.1%, P < 0.05) whilst cortical volumetric BMD, area, trabecular bone volume fraction and femoral neck areal BMD were lower in men in the lowest quartile of vitamin D levels compared to the highest. In men with vitamin D deficiency (<25 nmol L-1) or insufficiency [25-49 nmol L-1, in combination with an elevated serum level of parathyroid hormone (>6.8 pmol L-1)], cortical porosity was 17.2% higher than in vitamin D-sufficient men (P < 0.01). A linear regression model including age, weight, height, daily calcium intake, physical activity, smoking vitamin D supplementation and parathyroid hormone showed that 25-hydroxyvitamin D independently predicted cortical porosity (standardized β = -0.110, R2= 1.1%, P = 0.024), area (β = 0.123, R2= 1.4%, P = 0.007) and cortical volumetric BMD (β = 0.125, R2= 1.4%, P = 0.007) of the tibia as well as areal BMD of the femoral neck (β = 0.102, R2= 0.9%, P = 0.04).
  
  
  
  Serum vitamin D is associated with cortical porosity, area and density, indicating that bone fragility as a result of low vitamin D could be due to changes in cortical bone microstructure and geometry.
authors.affiliation: Geriatric Medicine, Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Sundh
authors.affiliation: Geriatric Medicine, Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Mellström
authors.affiliation: Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
authors.forename: Ö
authors.initials: Ö
authors.lastname: Ljunggren
authors.affiliation: Clinical and Molecular Osteoporosis Research Unit, Department of Clinical Sciences, Lund University, Lund, Sweden.|Department of Orthopaedics, Skåne University Hospital, Malmö, Sweden.
authors.forename: M K
authors.initials: MK
authors.lastname: Karlsson
authors.affiliation: Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: C
authors.initials: C
authors.lastname: Ohlsson
authors.affiliation: Geriatric Medicine, Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Nilsson
authors.affiliation: Geriatric Medicine, Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.|Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: A G
authors.initials: AG
authors.lastname: Nilsson
authors.affiliation: Geriatric Medicine, Department of Internal Medicine and Clinical Nutrition, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. Mattias.Lorentzon@medic.gu.se.|Center for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden. Mattias.Lorentzon@medic.gu.se.
authors.forename: M
authors.initials: M
authors.lastname: Lorentzon
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D015519:Bone Density; D000071538:Cortical Bone / Q000000981:diagnostic imaging / Q000473:pathology*; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D016062:Porosity; D011446:Prospective Studies; D013977:Tibia / Q000473:pathology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000473:pathology / Q000503:physiopathology*
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D
keywords: cortical porosity; high-resolution peripheral computed tomography; vitamin D