title: Longitudinal analysis of cartilage T2 relaxation times and joint degeneration in African American and Caucasian American women over an observation period of 6 years - data from the Osteoarthritis Initiative.
abstract: To investigate the change in cartilage T2 values and structural degeneration in knee joints over 72 months in women of African American (AA) vs Caucasian American (CA) ethnicity.
  
  
  
  Knee 3T magnetic resonance imaging (MRIs) from baseline, 24, 48 and 72 months visits of 100 AA and 100 CA women from the Osteoarthritis Initiative (OAI) were assessed for cartilage T2 values and whole-organ magnetic resonance imaging (WORMS) score. Subjects were pair-matched by age, body mass index (BMI), Kellgren-Lawrence (KL) score, clinical site and subcohort within the OAI. We compared the rate of change in whole knee cartilage T2 values and WORMS cartilage, bone marrow edema pattern (BMEP) and meniscus scores between the two ethnic groups using mixed random effects models.
  
  
  
  At 24 and 48 months 60 subjects and at 72 months 45 subjects per group were available for analysis resulting in 38 complete pairs with data of all time points. Compared to CA, cartilage T2 values in AA increased at a significantly faster rate at baseline (AA: 0.45 ms/y, CA: 0.35 ms/y, P = 0.029) and averaged over 6 years (AA: 0.36 ms/y, CA: 0.27 ms/y, P = 0.039) with changes in both groups reaching a plateau by 48 months. Cartilage, meniscus and BMEP scores tended to increase in both groups during follow up, but rates of change did not differ by ethnicity.
  
  
  
  Cartilage T2 values increased faster over 72 months in AA than CA, however changes in WORMS cartilage, meniscus and BMEP scores did not differ. T2 values may be able to distinguish ethnicity-related differences of cartilage degeneration at an early stage before differences in structural joint degeneration appear.
authors.affiliation: Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA. Electronic address: martin.kretzschmar@ucsf.edu.
authors.forename: M
authors.initials: M
authors.lastname: Kretzschmar
authors.affiliation: Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA. Electronic address: ursula.heilmeier@ucsf.edu.
authors.forename: U
authors.initials: U
authors.lastname: Heilmeier
authors.affiliation: Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA; Department of Radiology, Beijing Jishuitan Hospital, 4th Medical College of Peking University, Beijing, China. Electronic address: aihongy@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Yu
authors.affiliation: Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA. Electronic address: gabby.joseph@ucsf.edu.
authors.forename: G B
authors.initials: GB
authors.lastname: Joseph
authors.affiliation: Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA. Electronic address: fliu@psg.ucsf.edu.
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.affiliation: Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA. Electronic address: solka.martin@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Solka
authors.affiliation: Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA. Electronic address: cmcculloch@epi.ucsf.edu.
authors.forename: C E
authors.initials: CE
authors.lastname: McCulloch
authors.affiliation: Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA. Electronic address: mnevitt@psg.ucsf.edu.
authors.forename: M C
authors.initials: MC
authors.lastname: Nevitt
authors.affiliation: Musculoskeletal and Quantitative Imaging Research Group, Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA. Electronic address: thomas.link@ucsf.edu.
authors.forename: T M
authors.initials: TM
authors.lastname: Link
mesh_terms: D002357:Cartilage Diseases; D002358:Cartilage, Articular; D005260:Female; D006801:Humans; D007719:Knee Joint; D008279:Magnetic Resonance Imaging; D020370:Osteoarthritis, Knee; D014481:United States
keywords: Ethnicity; Knee cartilage; MRI; Osteoarthritis; Quantitative T2