Family History of Autoimmune Diseases Associated With Increased Risk for RA

Family history of several autoimmune and nonautoimmune conditions is associated with increased risk of developing rheumatoid arthritis (RA), according to study results published in Arthritis Care & Research.

In this case-control study, researchers used the Mayo Clinic Biobank to identify cases of RA (n=821) and matched 3 healthy controls to each case (n=2455) based on age, sex, recruitment year, and recruitment location. Study participants completed the Biobank’s baseline questionnaires to report general health, personal and family medical histories, health behaviors, and environmental exposures. Family history for 79 comorbidities was self-reported; these included RA; autoimmune disorders such as Crohn disease or ulcerative colitis, celiac disease, and hyperthyroidism/hypothyroidism; 22 types of cancer including but not limited to thyroid, lung, breast, esophageal, pancreatic, and stomach; and non-autoimmune diseases such as osteoarthritis and obstructive sleep apnea.

Family history of several diseases other than RA was associated with RA risk, including other rheumatologic autoimmune diseases (adjusted odds ratio [aOR], 1.89; 95% CI, 1.41-2.52), pulmonary fibrosis (aOR, 2.12; 95%, 1.16-3.80), inflammatory bowel disease (aOR, 1.45; 95% CI, 1.05-1.98), hyperthyroidism/hypothyroidism (aOR, 1.34; 95% CI, 1.10-1.63), and obstructive sleep apnea (aOR, 1.28; 95% CI, 1.05-1.55). Parkinson disease and type 2 diabetes were associated with a statistically decreased risk of developing RA, which did not meet the prespecified threshold of P <.01 (aOR, 0.70 [95% CI, 0.49-0.98] and aOR, 0.81 [95% CI, 0.67-0.97].

Study limitations included the use of a convenience sample for selection, which potentially created selection bias and limited generalizability. Using a self-report rather than verified RA and family history may have increased the likelihood of misclassification; recall bias could have been possible when asking patients about RA and family history. The questionnaire did not include specific diseases, including lupus or scleroderma, which may preclude any interpretation about family history. The percentage of participants who did not respond for each family history item was somewhat high (7%-13%), perhaps from an assumption that not providing a response meant absence of family history. The sample size was too limited for the sensitivity analysis of incident RA to permit adjustment.

These findings were consistent with findings from previous studies that family history of RA was most strongly associated with developing RA.

“The present study thus fills an important knowledge gap by finding an association between family history of other autoimmune diseases and RA even after controlling for several important confounders,” the researchers concluded. “Family history of several [nonrheumatologic] autoimmune diseases were also associated with later developing RA. These findings can help refine tools to predict RA risk. These findings highlight opportunities for better predicting risk [for] RA as well as understanding disease pathogenesis.

Reference

Kronzer VL, Crowson CS, Sparks JA, Myasoedova E, Davis J. Family history of rheumatologic, autoimmune, and non-autoimmune diseases and risk of rheumatoid arthritis [published online November 30, 2019]. Arthritis Care Res. doi:10.1002/acr.24115