Autoimmune conditions and pancreatic cancer risk in older American adults

Pancreatic cancer (PC) is highly fatal, and its incidence is increasing in the United States. Population‐based registry studies suggest associations between a few autoimmune conditions and PC risk, albeit based on a relatively small number of cases. We conducted a population‐based, nested case‐control study to examine the associations between autoimmune conditions and PC risk within the Surveillance, Epidemiology, and End Results Program (SEER)‐Medicare population. Incident primary malignant PC cases (n = 80 074) were adults ≥66 years and diagnosed between 1992 and 2015. Controls (n = 320 296) were alive at the time cases were diagnosed and frequency‐matched to cases (4:1 ratio) by age, sex, and year of diagnosis. We used multivariable‐adjusted, unconditional logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for 45 autoimmune conditions identified from Medicare claims. Eight autoimmune conditions including ankylosing spondylitis (OR = 1.45; 95% CI: 1.14‐1.84), Graves' disease (OR = 1.18; 95% CI: 1.03‐1.34), localized scleroderma (OR = 1.27; 95% CI: 1.06‐1.52), pernicious anemia (OR = 1.08; 95% CI: 1.02‐1.14), primary sclerosing cholangitis (OR = 1.37; 95% CI: 1.18‐1.59), pure red cell aplasia (OR = 1.31; 95% CI: 1.16‐1.47), type 1 diabetes (OR = 1.11; 95% CI: 1.07‐1.15), and ulcerative colitis (OR = 1.18; 95% CI: 1.07‐1.31) were associated with increased PC risk (false discovery rate‐adjusted P values