To examine monocyte chemotactic protein-1 (MCP-1) concentration and future rheumatoid arthritis (RA) risk, and investigate effect modification by human leukocyte antigen-shared epitope (HLA-SE) and several lifestyle factors.
We conducted a nested case-control study using stored plasma samples from the Nurses' Health Studies. Each pre-RA case was matched to three controls (N case = 220, N control = 675). Odds ratios (OR) for RA associated with MCP-1 concentration and interactions with HLA-SE, smoking, BMI and alcohol intake were estimated.
MCP-1 concentration was associated with both seropositive and seronegative RA, in particular <5 years of blood draw (OR: 2.42), and among HLA-SE positive (OR: 2.05). No interactions with smoking, BMI or alcohol were detected.
MCP-1 was associated with risk of RA, especially among HLA-SE positive, but did not differ by smoking status, BMI or alcohol intake.