Within the MS community, I know several people who live with more than one autoimmune disease. For example, I have multiple sclerosis and rheumatoid arthritis. When someone has more than one disease, it is called a comorbidity. Comorbidities can increase other disease risk as is seen in RA patients with thyroid disorders who have an increased risk of cardiovascular disease.
The MS Comorbidities Project
An international team of researchers have conducted a systematic review of the medical literature regarding the incidence and prevalence of specific comorbidities in MS. Results of the review have recently been published in an open-access special issue of the Multiple Sclerosis Journal (no subscription necessary) in preparation for an upcoming scientific meeting.
Out of more than 7,000 studies identified, 249 studies conducted between 1905 and 2012 were included in the systematic review. Most of the studies were conducted in North America or Western Europe, highlighting the fact that little is known about comorbidity in Central or South America, Asia, or Africa. Findings were inconsistent among the studies which makes comparisons difficult.
Many of the MS researchers and authors were also part of the consortium that suggested redefining the phenotypes of MS last summer.
Highlights of MS comorbidity review
The five most prevalent disorders occurring with MS were depression, anxiety, high blood pressure, high cholesterol, and chronic lung disease.
Autoimmune disease: Based on population-based studies, the most prevalent autoimmune comorbidities were psoriasis (7.74%) and thyroid disease (6.44%). Researchers failed to detect an overall, non-specific increase in the risk of comorbid autoimmune disease with MS; however, they did find an increased risk of inflammatory bowel disease, uveitis and possibly pemphigoid. Findings were inconsistent for other conditions such as type I diabetes, systemic lupus erythematosus, and rheumatoid arthritis.
Cancer: Cervical, breast, and digestive cancers had the highest incidence in population-based studies of MS. The risk of meningiomas and urinary system cancers appeared higher than expected, while the risks of pancreatic, ovarian, prostate and testicular cancer were lower than expected, when comparing the MS population to the general population.
Cardiovascular disease: The prevalence of hypertension (high blood pressure) and hyperlipidemia (high cholesterol) exceeded 10% in the MS population and increased with age. Although the rates of ischemic heart disease, congestive heart failure, and stroke were less than 5% overall, these conditions occurred more frequently than expected. Cardiac valvular disease, however, affected the MS population less often than expected.
Gastrointestinal, musculoskeletal, ocular, pulmonary, and renal disorders: Irritable bowel syndrome and chronic lung disease occur in more than 10% of the MS population. Each of these conditions along with arthritis, fibromyalgia, cataracts and glaucoma were more common than expected.
Mental health: This review confirms that psychiatric comorbidity is common in people living with MS, particularly depression and anxiety, each of which affect more than 22% of the MS population. Depression, anxiety, and bipolar disorder occur more often in the MS population than the general population.
Sleep and seizure disorders: Researchers found that seizures disorders occur more often in the MS population with incidence and prevalence rates of 2.28% and 3.09%, respectively. The most studied sleep disorder, restless legs syndrome, occurs in up to 57.5% of the MS population, while obstructive sleep apnea affects 7-58%. Narcolepsy was much less prevalent occurring in 0-1.6% of the MS population based on one study.
Marrie RA, Cohen J, StÃ¼ve O, et al. A systematic review of the incidence and prevalence of comorbidity in multiple sclerosis: Overview. Mult Scler. 2015 Jan 26. pii: 1352458514564491. [Epub ahead of print]
Marrie RA, Reider N, Cohen J, et al. A systematic review of the incidence and prevalence of autoimmune disease in multiple sclerosis. Mult Scler. 2014 Dec 22. pii: 1352458514564490. [Epub ahead of print]
Marrie RA, Reider N, Cohen J, et al. A systematic review of the incidence and prevalence of cancer in multiple sclerosis. Mult Scler. 2014 Dec 22. pii: 1352458514564489. [Epub ahead of print]
Marrie RA, Reider N, Cohen J, et al. A systematic review of the incidence and prevalence of cardiac, cerebrovascular, and peripheral vascular disease in multiple sclerosis. Mult Scler. 2014 Dec 22. pii: 1352458514564485. [Epub ahead of print]
Marrie RA, Reider N, Cohen J, et al. A systematic review of the incidence and prevalence of sleep disorders and seizure disorders in multiple sclerosis. Mult Scler. 2014 Dec 22. pii: 1352458514564486. [Epub ahead of print]
Marrie RA, Reider N, StÃ¼ve O, et al. The incidence and prevalence of comorbid gastrointestinal, musculoskeletal, ocular, pulmonary, and renal disorders in multiple sclerosis: A systematic review. Mult Scler. 2014 Dec 23. pii: 1352458514564488. [Epub ahead of print]
Marrie RA, Reingold S, Cohen J, et al. The incidence and prevalence of psychiatric disorders in multiple sclerosis: A systematic review. Mult Scler. 2015 Jan 12. pii: 1352458514564487. [Epub ahead of print]
Lisa Emrich is a patient advocate, accomplished speaker, author of the award-winning blog Brass and Ivory: Life with MS and RA, and founder of the Carnival of MS Bloggers. Lisa uses her experience to educate patients, raise disease awareness, encourage self-advocacy, and support patient-centered research. Lisa frequently works with non-profit organizations and has brought the patient voice to health care conferences and meetings worldwide. Follow Lisa on Facebook, Twitter, and Pinterest.