title: Hyperuricemia protects against low bone mineral density, osteoporosis and fractures: a systematic review and meta-analysis.
abstract: BACKGROUND
  Serum uric acid (SUA) accounts for about 50% of extracellular antioxidant activity, suggesting that hyperuricemia may have a protective role in diseases characterized by high levels of oxidative stress, such as osteoporosis. We aimed to meta-analyse data regarding bone mineral density (BMD), osteoporosis and fractures in people with higher SUA vs. lower SUA concentrations.
  
  
  METHODS
  Two investigators conducted a literature search using PubMed and Scopus, without language restrictions. Standardized mean differences (SMDs) and 95% confidence intervals (CIs) were used for BMD; risk ratios (RRs) and adjusted odds ratios (ORs) for cross-sectional data. Most possible adjusted hazard ratios (HRs) were used to assess the association between baseline SUA and incident fractures.
  
  
  RESULTS
  Of 1405 initial hits, 19 studies were eligible including a total of 55 859 participants. Subjects with higher SUA levels had significantly higher BMD values for the spine (six studies; SMD = 0·29; 95% CI: 0·22-0·35; I2= 47%), total hip (seven studies; SMD = 0·29; 95% CI: 0·24-0·34; I2= 33%) and femoral neck (six studies; SMD = 0·25; 95% CI: 0·16-0·34; I2= 71%). Simple correlation analyses substantially confirmed these findings. An increase of one standard deviation in SUA levels reduced the number of new fractures at follow-up (three studies; HR = 0·83; 95% CI: 0·74-0·92; I2= 0%). No significant differences between men and women emerged, although data about women were limited.
  
  
  CONCLUSIONS
  Hyperuricemia was found independently associated with BMD and fractures, supporting a protective role for uric acid in bone metabolism disorders.
authors.affiliation: Geriatrics Section, Department of Medicine, University of Padova, Padova, Italy. ilmannato@gmail.com.|Institute for Clinical Research and Education in Medicine (IREM), Padova, Italy. ilmannato@gmail.com.
authors.forename: Nicola
authors.initials: N
authors.lastname: Veronese
authors.affiliation: Geriatrics Section, Department of Medicine, University of Padova, Padova, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Carraro
authors.affiliation: Geriatrics Section, Department of Medicine, University of Padova, Padova, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Bano
authors.affiliation: Geriatrics Section, Department of Medicine, University of Padova, Padova, Italy.
authors.forename: Caterina
authors.initials: C
authors.lastname: Trevisan
authors.affiliation: Institute for Clinical Research and Education in Medicine (IREM), Padova, Italy.|Department of Neurosciences, University of Padova, Padova, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Solmi
authors.affiliation: Department of Neurosciences, University of Padova, Padova, Italy.|Department of Pathology and Diagnostics, Verona University and Hospital Trust, Verona, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Luchini
authors.affiliation: Geriatrics Section, Department of Medicine, University of Padova, Padova, Italy.|National Research Council, Aging Branch, Institute of Neuroscience, Padova, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: Manzato
authors.affiliation: Nutrition and Dietetics Service, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Caccialanza
authors.affiliation: Geriatrics Section, Department of Medicine, University of Padova, Padova, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Sergi
authors.affiliation: Azienda Provinciale per i Servizi Sanitari (APSS) Trento, Trento, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Nicetto
authors.affiliation: Nutrition and Dietetics Service, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Cereda
mesh_terms: D015519:Bone Density / Q000502:physiology*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D033461:Hyperuricemia / Q000503:physiopathology*; D008297:Male; D010024:Osteoporosis / Q000503:physiopathology*; D058866:Osteoporotic Fractures / Q000503:physiopathology*; D014527:Uric Acid / Q000378:metabolism
chemical_list: D014527:Uric Acid
keywords: Bone mineral density; fractures; hyperuricemia; osteoporosis; uric acid