Multicenter Osteoarthritis Study logo and title      
 
 

Multicenter Osteoarthritis Study Overview and Objectives

Osteoarthritis (OA) is the most common form of arthritis and the major cause of activity limitation and physical disability in older people. More than half of those over the age of 65 have radiological evidence of osteoarthritis in at least one joint. By 2030, approximately 20 percent of Americans (about 70 million people) will have passed their 65th birthday and will be at increased risk for the disease. Today, 39 million people (13 percent of the U.S. population) are 65 and older, and more than half have developed OA.

The Multicenter Osteoarthritis Study (MOST) is a longitudinal, prospective, observational study of knee OA in older Americans with OA disease or at increased risk of developing it. The study is comprised of two clinical centers, a data coordinating center, and an analysis center.

MOST enrolled 3,026 study participants and has conducted five follow-up contacts at 15, 30, 60, 72, and 84 months. At each time point, clinical assessments were conducted and radiological data (x-ray and MRI) collected, as well as other measures and instruments, with the exception of the 72-month follow-up, which was a Telephone Interview only.

The overall aims of MOST are to identify novel and modifiable biomechanical factors (including physical activity-related factors), bone and joint structural factors (including those assessed by MRI of the knee), and nutritional factors that affect the occurrence and progression of OA-related knee symptoms and radiographic knee OA. Additionally, MOST investigators aim to determine whether risk factors for new disease differ from those for OA progression. The MOST cohort has been followed through 84 months with three investigative themes: mechanical risk factors, causes of knee symptoms and pain, and the long term disease trajectory of knee OA.

To achieve these aims, we recruited a community-based sample of 3,026 (101% of our goal) men and women aged 50 to 79 and drawn from the general population but selected so as to be likely to either have preexisting OA or be at high risk as indicated by weight, knee symptoms, or a history of knee injuries or operations. Approximately 15% of the cohort are African Americans and 60% are women. Baseline exams began in 2003 and included an assessment of risk factors and disease characteristics, knee radiographs and knee MRIs, and a musculoskeletal examination to identify knee symptoms that do not emanate from the knee or hip joint. Knee MRIs were acquired with a 1.0 T dedicated extremity MR scanner (GE Healthcare).

MOST participant retention is excellent, as summarized in the tables below.


    Retention success in MOST: Follow-up Data Collected by Time Point, Gender, and Racial Background


 

Total (All)

Enrolled1

Data collected2

Baseline

3026

3026 (100%)

15 months

3018

3007 (100%)

30 months

2993

2969 (99%)

60 months

2882

2768 (96%)

72 months

2778

2715 (98%)

84 months

2721

2638 (97%)

 

Female

Male

White

Non-white

White

Non-white

Enrolled

Data collected

Enrolled

Data collected

Enrolled

Data collected

Enrolled

Data collected

Baseline

1501

1501 (100%)

319

319 (100%)

1018

1018 (100%)

188

188 (100%)

15 months

1500

1495 (100%)

319

317 (99%)

1012

1011 (100%)

187

184 (98%)

30 months

1492

1485 (100%)

316

313 (99%)

1002

997 (100%)

183

174 (95%)

60 months

1445

1410 (98%)

302

280 (93%)

960

928 (97%)

175

150 (86%)

72 months

1401

1379 (98%)

293

277 (95%)

915

906 (99%)

169

153 (91%)

84 months

1380

1346 (98%)

287

270 (94%)

890

872 (98%)

164

150 (91%)

         1 "Enrolled" means enrolled at baseline and continuing participation (not deceased and not withdrawn).
         2 "Data collected" means all or some data collected (measurements and exams completed or partially completed).


Biological specimen samples (blood and urine) were collected at baseline, 30 months, and 60 months. Access to biospecimens is by submission of a MOST ancillary study proposal to the MOST Executive Committee. For more information, see Biospecimen Request.

Longitudinal readings of baseline, 15-month, 30-month, 60-month, and 84-month knee x-rays have been completed. Semiquantitative readings of selected baseline, 15-month, 30-month, 60-month, and 84-month knee MRIs have been completed.

MOST is funded through grants from the National Institutes of Health / National Institute on Aging (NIA). This rich database will provide valuable information to help identify and define modifiable biomechanical, bone and structural, nutritional, and other risk factors for new disease and progression of existing disease.