title: Osteoporosis and osteoarthritis: shared mechanisms and epidemiology.
abstract: OBJECTIVE
  Osteoporosis and osteoarthritis are different diseases, with differences in risk factors, bone mineral density (BMD), BMI, phenotype, morbidity and mortality. We review new data on the role of bone metabolism in osteoporosis and osteoarthritis.
  
  
  RESULTS
  The insights in the common convergent and divergent risk factors between osteoarthritis and osteoporosis have resulted in new findings on the role of BMD, BMI, falls, genetics and epigenetics in the pathophysiology of both diseases and on the increased fracture risk in osteoporosis and osteoarthritis. The relation between BMD, BMI and fracture risk in osteoarthritis is dependent on the stage, definition and location of the osteoarthritis and method of BMD measurement. It has been suggested that osteoarthritis should be further specified in terms of bone involvement.
  
  
  CONCLUSIONS
  These new findings open the way to better understand the bone subtypes of osteoarthritis (osteoporotic, bone forming and erosive) and the common and different ways bone is involved in osteoporosis and osteoarthritis. Much can be expected from further prospective studies, when taking into account the heterogeneous nature of both osteoporosis and osteoarthritis.
authors.affiliation: aInternal Medicine, Subdivision of Rheumatology, Maastricht UMC and CAPHRI, Maastricht, The Netherlands bRheumatology, University of Hasselt, Hasselt, Belgium cInternal Medicine, Subdivision of Rheumatology, Maastricht UMC and NUTRIM, Maastricht dInternal Medicine, VieCuri Medical Center, Venlo, The Netherlands.
authors.forename: Piet P
authors.initials: PP
authors.lastname: Geusens
authors.forename: Joop P
authors.initials: JP
authors.lastname: van den Bergh
mesh_terms: D000058:Accidental Falls; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology; D044127:Epigenesis, Genetic; D006801:Humans; D010003:Osteoarthritis / Q000453:epidemiology / Q000209:etiology*; D010024:Osteoporosis / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D058866:Osteoporotic Fractures / Q000209:etiology / Q000503:physiopathology; D012307:Risk Factors