Background: The cumulative risk of non-Hodgkin lymphoma (NHL) in Sweden by age 80 years has increased to 1.1 in women and 1.6% in men in 2011. Increased risk of NHL associated with personal histories of some autoimmune diseases (ADs) is known. It is unclear whether there are other NHL-related ADs and whether this association holds across different sex, age and year of diagnosis, or NHL histological subtypes.
Patients and methods: Over an average of 9.4-year (maximum 47 years) follow-up of 878 161 patients diagnosed in 1964-2010 with 33 different ADs, 3096 subsequent NHL were diagnosed (data: Swedish Cancer Registry).
Results: Of 33 studied ADs, 21 showed significantly increased risk of NHL; 6 of them tended to increase the risk and none significantly decreased it. The overall standardized incidence ratio (SIR) for NHL after ADs was 1.6 [novel findings: immune thrombocytopenic purpura (ITP) = 7.5, polymyositis/dermatomyositis = 4.1, primary biliary cirrhosis = 3.9, myasthenia gravis = 2.2, Behcet = 1.7, rheumatoid fever = 1.7, ulcerative colitis = 1.5, polymyalgia rheumatica = 1.4, and chronic rheumatic heart disease = 1.4; confirmatory findings: autoimmune hemolytic anemia = 27.2, Sjögren = 4.9, Celiac = 4.8, systemic lupus erythematosus = 4.4, polyarteritis nodosa = 2.9, discoid lupus erythematosus = 2.7, sarcoidosis = 2.6, Crohn = 2.1, systemic sclerosis = 2.1, rheumatoid arthritis = 2.0, and Hashimoto/hypothyroidism and psoriasis = 1.4]. SIR for NHL diagnosis before age 60 (2.2) was significantly higher than that in older ages (age ≥60: 1.5). The SIRs in women or men and in period 1993-2010 or 1964-1992 were similar. Risk of all common NHL histology subtypes significantly increased after ADs (cutaneous/peripheral T cell and anaplastic large T and null cell = 2.2; small B-cell lymphocytic = 1.7; diffuse large B cell = 1.6; follicular and mantel cell = 1.3).
Conclusion: Many of 33 studied ADs (except for ankylosing spondylitis, diabetes type I graves/hyperthyroidism, multiple sclerosis, chorea minor, and pernicious anemia), especially when diagnosed at younger ages, were associated with higher risk of NHL. However, the absolute risk of NHL in many ADs is still small.
Keywords: Sweden; autoimmune diseases; autoimmunity; hematology; non-Hodgkin lymphoma; standardized incidence ratio.
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