Background
Certain autoimmune and infectious conditions are associated with increased risks of subtypes of non-Hodgkin’s lymphomas (NHL). A few prior studies suggest that chronic inflammation may particularly elevate risk for the distinct NHL subtype Waldenström’s macroglobulinemia (WM). We assessed WM risk in relation to a wide range of chronic immune stimulatory conditions among 4 million U.S. veterans.
Methods
We identified 361 WM cases with up to 27 years of follow-up. Using time-dependent Poisson regression we estimated rate ratios (RR) and 95% confidence intervals (CI) for WM risk in relation to history of autoimmune diseases that typically have autoantibodies (with systematic or organ involvement) or do not have autoantibodies, infections, and allergies. All models were adjusted for attained age, calendar-year, race, number of hospital visits, and latency between study entry and exit.
Results
The age-standardized incidence of WM was 0.34/100,000 person-years. WM risk was elevated among individuals with any prior autoimmune condition (RR, 2.2; 95% CI, 1.7–3.0), autoantibodies with systemic involvement (RR, 2.50; 95% CI, 1.55–4.02), autoantibodies with organ involvement (RR, 2.30; 95% CI, 1.57–3.37). Risks for WM were also increased with hepatitis (RR, 3.39; 95% CI, 1.38–8.30), human immunodeficiency virus (HIV) (RR, 12.05; 95% CI, 2.83–51.46), and rickettsiosis (RR, 3.35; 95% CI, 1.38–8.14)
Conclusions
In the largest investigation of WM risk factors to date, we found 2- to 3-fold elevated risk of WM among persons with a personal history of autoimmune diseases with autoantibodies and notably elevated risks for hepatitis, HIV, and rickettsiosis. Our findings provide novel insights into the as yet unknown etiology of WM.