title: Socio-economic status and the risk of developing hand, hip or knee osteoarthritis: a region-wide ecological study.
abstract: OBJECTIVE
  To determine the association between socio-economic status (SES) and risk of hand, hip or knee osteoarthritis (OA) at a population level.
  
  
  METHODS
  Retrospective ecological study using the System for the Development of Research in Primary Care (SIDIAP) database (primary care anonymized records for >5 million people in Catalonia (Spain)). Urban residents >15 years old (2009-2012) were eligible.
  
  
  RESULTS
  Validated area-based SES deprivation index MEDEA (proportion of unemployed, temporary workers, manual workers, low educational attainment and low educational attainment among youngsters) was estimated for each area based on census data as well as incident diagnoses (ICD-10 codes) of hand, hip or knee OA (2009-2012). Zero-inflated Poisson models were fitted to study the association between MEDEA quintiles and the outcomes.
  
  
  RESULTS
  Compared to the least deprived, the most deprived areas were younger (43.29 (17.59) vs 46.83 (18.49), years (Mean SD), had fewer women (49.1% vs 54.8%), a higher percentage of obese (16.2% vs 8.4%), smokers (16.9% vs 11.9%) and high-risk alcohol consumption subjects (1.5% vs 1.3%). Compared to the least deprived, the most deprived areas had an excess risk of OA: age-sex-adjusted Incidence Rate Ratio (IRR) 1.26 (1.11-1.42) for hand, 1.23 (1.17-1.29) hip, and 1.51 (1.45-1.57) knee. Adjustment for obesity attenuated this association: 1.06 (0.93-1.20), 1.04 (0.99-1.09), and 1.23 (1.19-1.28) respectively.
  
  
  CONCLUSIONS
  Deprived areas have higher rates OA (hand, hip, knee). Their increased prevalence of obesity accounts for a 50% of the excess risk of knee OA observed. Public health interventions to reduce the prevalence of obesity in this population could reduce health inequalities.
authors.affiliation: Primary Health Care Department, Primary Health Care Center Eap Sardenya-Biomedical Resarch Institute Sant Pau (IIB Sant Pau), Barcelona, Spain; Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, Spain; Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain. Electronic address: carlenreyesreyes@gmail.com.
authors.forename: C
authors.initials: C
authors.lastname: Reyes
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, Spain; Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain. Electronic address: mgarcia@idiapjgol.info.
authors.forename: M
authors.initials: M
authors.lastname: Garcia-Gil
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, Spain; Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain. Electronic address: jmelorza@idiapjgol.info.
authors.forename: J M
authors.initials: JM
authors.lastname: Elorza
authors.affiliation: Primary Care Services Information System, Catalan Health Institute (ICS), Barcelona, Spain. Electronic address: lmendezboo@gencat.cat.
authors.forename: L
authors.initials: L
authors.lastname: Mendez-Boo
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, Spain; Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain. Electronic address: ehermosilla@idiapjgol.info.
authors.forename: E
authors.initials: E
authors.lastname: Hermosilla
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom; Oxford NIHR Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom. Electronic address: kassim.javaid@ndorms.ox.ac.uk.
authors.forename: M K
authors.initials: MK
authors.lastname: Javaid
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom; Oxford NIHR Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom. Electronic address: cc@mrc.soton.ac.uk.
authors.forename: C
authors.initials: C
authors.lastname: Cooper
authors.affiliation: Unitat de Recerca Musculo-esquelètica and RETICEF, IMIM Research Foundation, Parc de Salut Mar and Instituto de Salud Carlos III, Barcelona, Spain. Electronic address: ADiez@parcdesalutmar.cat.
authors.forename: A
authors.initials: A
authors.lastname: Diez-Perez
authors.affiliation: MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom; Oxford NIHR Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom; Arthritis Research UK (ARUK), Center for Sports, Exercise and Osteoarthritis, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, Nuffield Orthopaedic Centre, University of Oxford, Oxford, United Kingdom. Electronic address: nigel.arden@ndorms.ox.ac.uk.
authors.forename: N K
authors.initials: NK
authors.lastname: Arden
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, Spain; Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain. Electronic address: bbolibar@idiapjgol.info.
authors.forename: B
authors.initials: B
authors.lastname: Bolibar
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, Spain; Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain; Primary Health Care Department, Institut Català de la Salut, Barcelona, Spain. Electronic address: rramos.girona.ics@gencat.cat.
authors.forename: R
authors.initials: R
authors.lastname: Ramos
authors.affiliation: Institut Universitari d'Investigació en Atenció Primària Jordi Gol (IDIAP Jordi Gol), Barcelona, Spain; Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain; MRC Lifecourse Epidemiology Unit, University of Southampton, Southampton, United Kingdom; Oxford NIHR Musculoskeletal Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom; Unitat de Recerca Musculo-esquelètica and RETICEF, IMIM Research Foundation, Parc de Salut Mar and Instituto de Salud Carlos III, Barcelona, Spain. Electronic address: Daniel.prietoalhambra@ndorms.ox.ac.uk.
authors.forename: D
authors.initials: D
authors.lastname: Prieto-Alhambra
mesh_terms: D000328:Adult; D000367:Age Factors; D000428:Alcohol Drinking / Q000453:epidemiology; D016208:Databases, Factual; D005260:Female; D006225:Hand / Q000503:physiopathology*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology; D015207:Osteoarthritis, Hip / Q000453:epidemiology* / Q000503:physiopathology; D020370:Osteoarthritis, Knee / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D012907:Smoking / Q000453:epidemiology; D012923:Social Class; D013030:Spain / Q000453:epidemiology
keywords: Database; Osteoarthritis; Primary health care; Socioeconomic status