The Johnston County OA Project: Arthritis and Disability

Research project


In accordance with RFA-DP11-005, this study will provide long-term outcome data for the prevalence, incidence and progression of radiographic and symptomatic knee and hip OA in African Americans and Whites, aged 45 years and older. It will additionally examine the occurrence and timing of concomitant obesity, diabetes mellitus, and cardiovascular disease, and their interactive effects, upon OA outcomes, and extend the timeline for examination of risk (leg length inequality) and potentially protective factors (weight maintenance) upon these outcomes. This proposal requests process and technical support to complete the 3rd follow-up (T3) of the Johnston County Osteoarthritis Project, an average of 4 - 7 years after the 2nd 5-year follow-up (T2), approximately 10 – 15 years after the 1st follow-up, and 20-25 years after the baseline examination (T0). The effect of some risk factors may take longer time periods to exert their effects than are commonly observed in most OA studies. This study with its long follow-up time is poised to fill that knowledge gap. This study of risk factors for incidence and progression of radiographic and symptomatic knee and hip osteoarthritis, knee and hip symptoms, and disability in AAs and Whites in a rural, Southern county has included extensive radiographic, clinical, interview, and functional data on over 4,300 individuals (approximately 1/3 African American, 40% men) throughout these past 20 years. The current sample eligible for T3 includes individuals from the original T0 baseline time point as well as individuals from a cohort enrichment conducted in 2003-2004. The protocol and data collection instruments for T3 are now in development, and we are on schedule to begin the T3 data collection in the 2nd quarter of 2011 under the current grant funding cycle (2007-11). Thus, T3 will already be underway at the time that this proposal, if successful, would be funded. All individuals will complete radiographic examinations of the knees, hips, patellofemoral joints, hands, and lumbar spine, physical and functional examination, DEXA, and contribute urine and blood for storage of serum, plasma, DNA and RNA. Stratified analysis and multiple logistic and polytomous logistic regression, with generalized estimating equations when appropriate, will be used to assess ethnic differences in the roles of risk factors assessed at T0, T1, and T2, and their timing, in the incidence and progression of the above outcomes at T3. The proposed study will thus define objectively the burden of knee and hip OA in these groups over time, increase knowledge about factors associated with the incidence and progression of OA of these joints, identify potentially modifiable risk factors for these outcomes, and identify high risk subgroups. By examining these unique factors in multiple aspects of the OA process in both ethnic groups within one study, efficiency and significant impact upon the public health can be maximized.
Effective start/end date9/30/119/29/16


  • Centers for Disease Control and Prevention (CDC)


Hip Osteoarthritis
Knee Osteoarthritis
African Americans
Leg Length Inequality
Competitive Bidding
Patellofemoral Joint
Organized Financing
Hip Joint
Ethnic Groups
Physical Examination
Diabetes Mellitus
Appointments and Schedules
Cardiovascular Diseases