title: Radiographically defined osteoarthritis of the hand and knee in young and middle-aged African American and Caucasian women.
abstract: Osteoarthritis (OA) has been characterized as a slowly evolving degenerative disease affecting cartilage and bone, with a multifactorial etiology that may differ depending on the joint site. Because OA has been considered a disease of the elderly, few population-based studies have examined its frequency and characteristics in persons under the age of 45.
  
  
  OBJECTIVE
  In this cross-sectional study, we examined X-rays of both knees and the dominant hand in a population of younger black and white pre- and perimenopausal women in southeastern Michigan (N = 1053) for evidence of osteoarthritis, and reported these outcomes according to the risk factors of age, body size, injury, and smoking behavior.
  
  
  METHODS
  Sixteen joints of the dominant hand as well as both knee joints (weight bearing) were evaluated using the Kellgren and Lawrence Atlas of Standard Radiographs of Arthritis.
  
  
  RESULTS
  By age 40, radiographically-defined osteoarthritis emerges in both the hands and knees. These age characteristics are observed in both black and white women, however prevalence of knee OA was higher in black females (23.1%) compared with white females (8.5%), and although prevalence of hand OA was more comparable between black (25.5%) and white females (19.2%), the joint sites affected differed. The major risk factors reported in studies of older populations are present in this younger population where OA is newly emerging.
  
  
  CONCLUSIONS
  This study provides strong evidence that primary prevention of OA must be implemented in young adulthood to curtail the emergence of radiographically-defined OA at the mid-life.
authors.affiliation: Department of Epidemiology, School of Public Health, University of Michigan, Ann Arbor 48109, USA.
authors.forename: M
authors.initials: M
authors.lastname: Sowers
authors.forename: L
authors.initials: L
authors.lastname: Lachance
authors.forename: M
authors.initials: M
authors.lastname: Hochberg
authors.forename: D
authors.initials: D
authors.lastname: Jamadar
mesh_terms: D000328:Adult; D000367:Age Factors; D001175:Arthrography; D044383:Black People; D001824:Body Constitution; D003430:Cross-Sectional Studies; D005260:Female; D006225:Hand / Q000000981:diagnostic imaging; D006801:Humans; D015994:Incidence; D007719:Knee Joint / Q000000981:diagnostic imaging; D008875:Middle Aged; D010003:Osteoarthritis / Q000000981:diagnostic imaging* / Q000208:ethnology* / Q000209:etiology; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging / Q000208:ethnology / Q000209:etiology; D012907:Smoking / Q000009:adverse effects; D014481:United States; D044465:White People; D001741:Black or African American