title: The association between hip bone marrow lesions and bone mineral density: a cross-sectional and longitudinal population-based study.
abstract: OBJECTIVE
  To describe the cross-sectional and longitudinal association between hip Bone marrow lesions (BMLs) and bone density.
  
  
  METHODS
  198 subjects with a right hip MRI and dual-energy X-ray absorptiometry (DXA) scans conducted at two time points, approximately 2.6 years apart were included. MR images were used to assess hip BML presence and size (cm(2)) while DXA scans were used to determine bone mineral density (BMD) of the total hip, spine and femoral neck.
  
  
  RESULTS
  Fifty-five subjects (28%) had either a femoral and/or acetabular BML. Cross-sectionally, acetabular BMLs were associated with 5-6% lower total hip [P = 0.01] and femoral neck BMD [P < 0.001]. Resolving acetabular BMLs were associated with a 1-2% increase in BMD at hip [P = 0.05] and femoral neck [P = 0.01]. In contrast, resolving femoral BMLs were associated with a 4% lower and incident femoral BMLs with 3% higher femoral neck BMD [P = 0.04, P < 0.001 resp.]. Finally, each 1 cm(2) change femoral BMLs was associated with increase in femoral neck BMD: +0.03 g/cm(2), 95% confidence intervals (CI): +0.00, +0.05, and enlarging acetabular BMLs was associated with decrease in hip: -0.01 g/cm(2), 95% CI: -0.03, -0.00 and femoral neck BMD: -0.01 g/cm(2), 95% CI: -0.03, -0.001.
  
  
  CONCLUSIONS
  Hip BMLs were associated with local BMD (hip and femoral neck) but not with spine BMD and these associations vary according to site. BML prevalence and change was low in this study, hence these findings need confirmation. However, we hypothesize that these associations represent a combination of changes related directly to the BML pathology or changes adjacent to the disease process.
authors.affiliation: Menzies Research Institute of Tasmania, University Of Tasmania, Hobart, Tasmania 7000, Australia. Electronic address: Harbeer.Ahedi@utas.edu.au.
authors.forename: H
authors.initials: H
authors.lastname: Ahedi
authors.forename: D
authors.initials: D
authors.lastname: Aitken
authors.forename: L
authors.initials: L
authors.lastname: Blizzard
authors.forename: F
authors.initials: F
authors.lastname: Cicuttini
authors.forename: G
authors.initials: G
authors.lastname: Jones
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods; D000077:Acetabulum / Q000503:physiopathology; D000368:Aged; D015519:Bone Density / Q000502:physiology*; D001855:Bone Marrow Diseases / Q000150:complications / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D005272:Femur Neck / Q000503:physiopathology; D006621:Hip Joint / Q000503:physiopathology; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000150:complications / Q000503:physiopathology; D013131:Spine / Q000503:physiopathology
keywords: Bone marrow lesions (BMLs); Bone mass; Bone mineral density (BMD); Dual-energy X-ray absorptiometry (DXA); Hip osteoarthritis (hip OA); Magnetic resonance imaging (MRI)