Circulating plasma metabolites and risk of rheumatoid arthritis in the Nurses' Health Study.

Objectives: RA develops slowly over years. We tested for metabolic changes prior to RA onset using a large non-targeted metabolomics platform to identify novel pathways and advance understanding of RA development.

Methods: Two hundred and fifty-four incident RA cases with plasma samples drawn pre-RA onset in the Nurses' Health Study (NHS) cohorts were matched 1:2 to 501 controls on age, race, menopause/post-menopausal hormone use and blood collection features.

Timing of Elevations of Autoantibody Isotypes Prior to Diagnosis of Rheumatoid Arthritis.

Objective: To evaluate patterns of elevations of isotypes of rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPAs) pre-rheumatoid arthritis (RA) diagnosis and post-RA diagnosis.

Methods: Using the Department of Defense Serum Repository we identified 214 RA cases and 210 matched controls. Up to 3 pre-RA diagnosis and 1 post-RA diagnosis serum samples per subject were tested for RF and for IgA, IgG, and IgM ACPAs.