Rheumatoid factor positivity increases all-cause and cancer mortality: a cohort study

Area of Science:

• Immunology
• Epidemiology
• Public Health

Background:

• Rheumatoid factor (RF) is an antibody often associated with autoimmune diseases like rheumatoid arthritis (RA).
• The prognostic value of RF in healthy individuals without diagnosed RA is not well-established.
• Understanding RF's role in mortality risk can inform preventative health strategies.

Purpose of the Study:

• To investigate the association between rheumatoid factor (RF) and mortality from all-cause, cardiovascular disease (CVD), and cancer in healthy South Korean adults.
• To determine if RF titer levels correlate with increased mortality risks.
• To clarify the independent prognostic significance of RF in a general population free from RA.

Main Methods:

• A large-scale cohort study involving 295,837 South Korean adults who underwent health screening between 2002 and 2012.
• Participants were presumed to be free of rheumatoid arthritis (RA) and osteoarthritis at baseline.
• Mortality data (all-cause, CVD, cancer) were collected via National Death Index records over a median follow-up period.
• Statistical analysis included multivariable adjustments to assess hazard ratios (HR) for RF-positive versus RF-negative individuals and by RF titer levels.

Main Results:

• The prevalence of RF positivity (≥20 IU/mL) was 4.4% in the study cohort.
• RF positivity was significantly associated with a 1.50-fold increased risk of all-cause mortality and a 1.56-fold increased risk of cancer mortality.
• Individuals with RF titers >100 IU/mL showed substantially higher risks for all-cause (HR=2.68) and cancer mortality (HR=2.89).
• No significant association was found between RF positivity and cardiovascular disease (CVD) mortality (HR=0.98).

Conclusions:

• In healthy South Korean adults without RA, the presence of rheumatoid factor (RF) is an independent risk factor for increased all-cause and cancer mortality.
• Higher RF titers are associated with a significantly greater risk of premature death from all causes and cancer.
• These findings suggest RF may serve as a potential biomarker for long-term health risks in seemingly healthy individuals.