Rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and Sjögren's syndrome have been consistently associated with an increased risk of non-Hodgkin's lymphoma (NHL). This study was initiated to evaluate the risks of NHL associated with a personal or family history of a wide range of autoimmune diseases.
A population-based case-control study was conducted that included 24,728 NHL patients in Denmark (years 1977-1997) and Sweden (years 1964-1998) and 55,632 controls. Using univariate logistic and hierarchical regression models, we determined odds ratios (ORs) of NHL associated with a personal history of hospital-diagnosed autoimmune conditions. Risks of NHL associated with a family history of the same autoimmune conditions were assessed by similar regression analyses that included 25,941 NHL patients and 58,551 controls.
A personal history of systemic autoimmune diseases (RA, SLE, Sjögren's syndrome, systemic sclerosis) was clearly linked with NHL risk, both for individual conditions (hierarchical odds ratios [OR(h)] ranged from 1.6 to 5.4) and as a group (OR(h) 2.64 [95% confidence interval (95% CI) 1.72-4.07]). In contrast, a family history of systemic autoimmune diseases was modestly and nonsignificantly associated with NHL (OR(h) 1.31 [95% CI 0.85-2.03]). An increased risk of NHL was found for a personal history of 5 nonsystemic autoimmune conditions (autoimmune hemolytic anemia, Hashimoto thyroiditis, Crohn's disease, psoriasis, and sarcoidosis) (OR(h) ranged from 1.5 to 2.6) of 27 conditions examined.
Overall, our results demonstrate a strong relationship of personal history of systemic autoimmune diseases with NHL risk and suggest that shared susceptibility may explain a very small fraction of this increase, at best. Positive associations were found for a personal history of some, though far from all, nonsystemic autoimmune conditions.