Osteoarthritis Initiative

Alternate Titles(s): OAI
UID: 10162

The Osteoarthritis Initiative (OAI) was a longitudinal cohort study which investigated the natural history of knee osteoarthritis across the spectrum of the disease through the collection of imaging, biochemical, genetic, and risk markers of knee OA. Measures included knee symptoms and function (evaluated using the West Ontario and McMaster Universities Arthritis Index (WOMAC) and the Knee injury and Osteoarthritis Outcome Score (KOOS), hip and other joint symptoms, general quality of life, physical performance, knee examination, risk factors, health behaviors, psychosocial measures, and medication and supplements taken.

OAI enrolled a total of 4,796 participants aged 45 to 79 years old at time of recruitment. Biospecimens collected include blood, urine, DNA, and lymphocytes. Images collected throughout the study include baseline and annual bilateral knee x-ray and bilateral knee MRI and other joint imaging (e.g., hip, pelvis, and hand x-rays; MRI of the thigh; and full limb MRI for knee alignment). The schedule of completed assessments is available on the OAI website.

2004 - 2019
Geographic Coverage
Rhode Island
Local Expert
Subject of Study
Subject Domain
Population Age
Adult (19 years - 64 years)
Senior (65 years - 79 years)


Free to All
Application Required

Prospective users must log in to the NIMH Data Archive (NDA) through the Research Auth Service (RAS) with a eRA Commons account, Login.gov account, or PIV/CAC credentials. To request access to OAI data, users must also create a NDA account or link an existing NDA account, then agree to OAI data access terms.

Biospecimens must be requested separately through the OAI NIAMS website. Biospecimen applications will require 6-10 weeks for review and processing.

Access via OAI NDA

Accession #: 2343

Access via OAI NIAMS

Application for biospecimens

Associated Publications
Data Type
Study Type
Data Collection Instruments
West Ontario and McMaster Universities Arthritis Index (WOMAC)
Knee injury and Osteoarthritis Outcome Score (KOOS)
PubMed Search
View articles which use this dataset
Other Resources