Autoimmune Diseases, Especially Hypothyroidism, Associated With MDS Risk

A new report shows that patients with a history of autoimmune diseases—and hypothyroidism in particular—appear to be at a higher risk of developing myelodysplastic syndromes (MDS).

Writing in the journal Cancer Epidemiology, the investigators explained that MDS is a category of neoplastic conditions that lead to dysplastic and ineffective hematopoiesis. They tend to become more common the older a patient gets. It is not clear how the syndromes form, but the investigators said there appears to be a correlation between these disorders and a history of chemotherapy or radiation therapy. Some cases of MDS will develop into acute myeloid lymphoma (AML).

The authors noted emerging evidence suggesting that certain diseases could in themselves be risk factors for MDS. A Swedish population-based study and several other studies have shown an apparent link between a history of autoimmune diseases and the development of MDS.

In the new study, the investigative team used a Minnesota database of patients with cancer to search for links between self-reported medical conditions and a diagnosis of MDS. They suspected that autoimmune diseases, which were among the conditions evaluated, would increase a patient’s risk of MDS.

The authors identified 395 patients with an MDS diagnosis and 694 healthy controls. After adjusting for age, sex, and several other potentially confounding factors, the investigators found that patients with any reported autoimmune disease were at a significantly higher risk of MDS (adjusted odds ratio, 1.41; 95% CI, 1.05-1.89) compared with those without autoimmune disease. Women with a history of autoimmune disease were at a particularly high risk. About 30% of patients with MDS and 23% of healthy controls had a history of autoimmune diseases, the authors reported.

They found that the majority of the association was based on patients with a history of hypothyroidism, although patients with other diseases like inflammatory bowel disease (IBD) and systemic lupus erythematosus (SLE) also appeared to be at elevated risk. Yet, when the investigators assessed risk on an individual-disease basis, only hypothyroidism, and not IBD or SLE, had a statistically significant association.

Although a history of autoimmune diseases appeared to affect a person’s risk of MDS, it did not appear to affect survival once the patient was diagnosed, the authors said.

They noted that there are a number of theories that have been posited for the apparent link. They include shared genetic or environmental risk factors, prior treatment for autoimmune diseases potentially damaging bone marrow and leading to malignancy, and inflammatory mechanisms of the malignancy leading to autoimmune disease.

The investigators noted that both MDS and autoimmune diseases have long latency periods, which makes it difficult to know which condition comes first. They added that the association between autoimmune disease and MDS held true even when they removed cases of the former that were diagnosed within 5 years of the latter diagnosis.

The authors also noted that patients with a history of cardiovascular disease had an increased risk of MDS. They said such a link is biologically plausible, but the association requires further investigation in order to be validated.

Reference:

Linabery AM, Roesler MA, Richardson M, et al. Personal history of autoimmune disease and other medical conditions and risk of myelodysplastic syndromes. Cancer Epidemiol. 2022;76:102090. doi:10.1016/j.canep.2021.102090