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 [ORh] ranged from 1.6 to 5.4) and as a group (ORh 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 (ORh 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) (ORh 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.