Sjögren’s syndrome is an autoimmune disorder that affects the moisture-producing glands in the body, most commonly the tear and saliva glands. This leads to the hallmark symptoms of Sjögren’s: dry eyes and dry mouth. Sjögren’s is estimated to impact up to 4 million people in the United States. While for many Sjögren’s is manageable with treatment, some patients experience more systemic complications from the disease. One complication that patients may be concerned about is whether Sjögren’s increases the risk for developing multiple sclerosis (MS).
MS is another autoimmune condition that affects the central nervous system. In MS, the immune system mistakenly attacks the protective covering around nerve fibers, leading to damage of the nerves. This disruption in nerve signaling produces an array of symptoms including numbness, fatigue, mobility problems, and more. There are approximately 1 million people living with MS in the US currently.
For patients diagnosed with Sjögren’s, the question may arise: does having Sjögren’s put someone at increased risk for later developing MS? Here we will explore the connection between these two autoimmune disorders and examine what the research says about the potential for Sjögren’s patients to develop MS.
The Autoimmune Connection
Sjögren’s and MS are both autoimmune disorders, meaning they are caused by the body’s immune system improperly attacking its own healthy cells and tissues. This raises the question of whether having an autoimmune condition like Sjögren’s predisposes someone to developing a second autoimmune disorder.
Research has uncovered connections between various autoimmune diseases. For example, patients with rheumatoid arthritis or lupus have higher rates of also developing autoimmune thyroid disorders compared to the general public. However, having one autoimmune disease does not necessarily mean someone will develop a second – this depends on the specific conditions involved.
So what do we know about the overlap between Sjögren’s syndrome and MS? Let’s examine what the research shows so far.
Prevalence of MS in Sjögren’s Patients
Several studies have tried to pin down if patients with Sjögren’s have an increased occurrence of also developing MS. The research on this question has yielded mixed results.
Some small studies have found higher rates of MS among Sjögren’s patients compared to the general population. For example, one study of 39 Sjögren’s patients found 5 patients (13%) also had MS – much higher than the 0.1% MS prevalence in the general public.[1]
However, larger studies have not found strong evidence for increased MS risk among Sjögren’s patients:
– A study of over 1,000 Sjögren’s patients found only 0.6% also had MS, similar to general population rates.[2]
– Another study of nearly 600 Sjögren’s patients found just 1 patient with both Sjögren’s and MS, reflecting no increased overlap.[3]
Based on these larger-scale studies, there does not appear to be a substantially higher rate of MS among Sjögren’s populations compared to the public.
Prevalence of Sjögren’s Syndrome in MS Patients
Coming at it from the opposite angle – are patients with MS more likely to have Sjögren’s compared to the general public? Again, study results are conflicting.
Some research has found a higher prevalence of Sjögren’s antibodies in MS patients, suggesting increased overlap between the conditions. One study found Sjögren’s antibodies in 13% of MS patients compared to 2-4% of the general population.[4]
However, other studies have not found evidence of increased Sjögren’s among MS patients. One study found just 1% of MS patients also had Sjögren’s – on par with the 0.1-0.4% rate in the general population.[5]
Overall, the body of evidence does not conclusively show either patient population is at substantially increased risk of having both Sjögren’s and MS. Larger-scale studies incorporating more patients are still needed.
Explanations for Autoimmune Overlap
While an increased overlap between Sjögren’s and MS has not been definitively proven, some patients may develop both conditions. Why might this autoimmune overlap occur in some cases? Research points to a few possible explanations:
Genetic Susceptibility
Certain genetic markers have been connected to increased risk of autoimmune disorders. For example, the genes HLA-DR2 and HLA-DR3 are linked to both MS and Sjögren’s risk.[6] Having a genetic predisposition for autoimmunity could increase the chance of developing more than one autoimmune disease.
Environmental Triggers
Factors like viruses, bacteria, and toxins are hypothesized triggers for autoimmune conditions. Exposure to one environmental trigger could potentially lead to the onset of multiple autoimmune diseases in genetically susceptible individuals.
Bystander Activation
This theory suggests that autoimmune tissue injury in one organ has the potential to activate autoimmunity in other tissue types as well. For example, Sjögren’s-related glandular damage could theoretically trigger autoimmune processes that lead to MS.[7] However, more research is needed to understand to what degree this bystander activation occurs between specific diseases.
Risk Factors
While a direct causative link between Sjögren’s and MS has not been established, certain risk factors are associated with increased likelihood of developing both diseases:
Sex
Female sex confers increased risk for several autoimmune conditions including Sjögren’s and MS. Up to 9 out of 10 Sjögren’s patients are female.[8] Similarly, MS occurs over twice as frequently in women compared to men.[9] The role of sex hormones and genetics are hypothesized contributors.
Age
Most autoimmune disorders develop between ages 20-50. This is true for both Sjögren’s and MS, which have average onset ages of 40 and 30 years old respectively.[8,9]
Family History
Having a first-degree relative with an autoimmune disease increases a person’s risk of developing an autoimmune condition. Those with a family history of Sjögren’s or MS could have higher risk of both.[6]
Vitamin D Deficiency
Low blood levels of vitamin D have been associated with increased autoimmune disease risk and severity. Vitamin D deficiency occurs more frequently in both Sjögren’s and MS patients.[10]
| Risk Factor | Sjögren’s | MS |
|---|---|---|
| Female Sex | Yes | Yes |
| Age of Onset | 40 years old | 30 years old |
| Family History | Increased risk | Increased risk |
| Vitamin D Deficiency | Associated | Associated |
Symptom Overlap
Sjögren’s and MS also share some symptomatic similarities that could make distinguishing between them difficult. Key overlapping symptoms include:
Fatigue
Fatigue significant enough to reduce quality of life is experienced by up to 70% of Sjögren’s patients.[11] Similarly, debilitating fatigue affects over 80% of MS patients.[12]
Numbness/Tingling
About 20% of Sjögren’s patients experience numbness or tingling.[13] Numbness and paresthesia are also common early MS symptoms, experienced by up to 85% of patients.[14]
Cognitive Difficulties
Neurological manifestations of Sjögren’s can include memory loss, confusion, and concentration problems. MS also frequently impairs cognition, reported by over 60% of patients.[15]
Bladder Problems
Bladder and urinary dysfunction are seen in about 30% of Sjögren’s cases.[16] MS also commonly causes bladder control issues, affecting up to 80% of patients.[17]
While not definitive for diagnosis, recognizing these overlapping symptoms is important, as either Sjögren’s or MS could potentially explain their presence.
When to Seek Evaluation
For Sjögren’s patients, new neurologic symptoms should prompt consultation with a doctor to determine if MS could be developing. Recommended reasons to seek medical evaluation include:
– Numbness or tingling spreading to new parts of the body
– Worsening fatigue impacting daily activities
– Bladder or bowel control problems
– Vision changes, eye pain or redness
– Cognitive changes like forgetfulness or confusion
– Weakness, impaired coordination, or balance problems
Diagnosing MS requires excluding other potential causes of symptoms. Sjögren’s can cause neurologic manifestations than may mimic MS. To distinguish between Sjögren’s and MS, physicians will likely conduct tests including:
Blood Tests
Blood tests help identify antibodies and proteins associated with Sjögren’s and MS. Presence of these markers provides clues to what condition may be causing symptoms.
Imaging
MRI scans of the brain and spinal cord are key for MS diagnosis. These images allow doctors to detect lesions and nerve damage consistent with MS.
Nerve Studies
Nerve conduction studies and EMG measure how well nerves transmit signals. Abnormal results can demonstrate the nerve dysfunction seen in MS.
Lumbar Puncture
Spinal fluid is extracted through lumbar puncture (spinal tap) and analyzed for signs of MS. Inflammatory proteins and IgG bands in the CSF can help confirm MS.
Accurate testing is important for distinguishing MS from Sjögren’s-related neurologic manifestations. Diagnosing the cause of symptoms guides treatment to best manage the condition.
Treatment Implications
If Sjögren’s symptoms do progress to MS, disease-modifying therapy for MS would be warranted. Commonly used MS medications include:
Interferon Beta
Interferons reduce inflammation and may slow disease progression in relapsing-remitting MS. Delivery methods include intramuscular injection (Avonex, Rebif) or subcutaneous injection (Betaseron, Extavia).
Glatiramer Acetate
Sold under the brand name Copaxone, this medication may block myelin damage in MS patients. It is administered daily or three times weekly via subcutaneous injection.
Ocrelizumab
This intravenous anti-CD20 therapy suppresses inflammatory B cells that drive MS progression. Ocrevus is given every six months after initial dosing.
Fingolimod
Taken orally once daily, this drug prevents inflammatory immune cell migration into the central nervous system in MS. Gilenya is the brand name.
These MS drugs can reduce relapse rates and slow disability progression. However, they also have potential side effects that require consistent monitoring.
Treatment for both Sjögren’s and comorbid MS aims to alleviate symptoms and improve quality of life. Lifestyle adjustments like diet, exercise, and stress reduction techniques may also help manage the burden of both conditions.
Prognosis
For the majority Sjögren’s patients who do not develop MS, prognosis related to Sjögren’s itself may be of greater concern. Wide variance exists in Sjögren’s outcomes:
Mild Sjögren’s
Many patients experience mild, stable disease controlled with conservative symptom management. Life expectancy is unaffected.
Systemic Complications
Up to 20% of Sjögren’s patients develop systemic manifestations affecting organs like lungs, kidneys, and liver.[8] This can negatively impact prognosis.
Lymphoma Risk
There is a nearly 50-fold increased risk of developing B cell lymphomas among Sjögren’s patients compared to the public.[8] Lymphoma is a serious complication that worsens prognosis.
For Sjögren’s patients who do develop MS, having both conditions concurrently could theoretically worsen prognosis compared to MS alone. However, research on this question is limited. More study is needed on the impacts on prognosis when Sjögren’s and MS co-occur.
Conclusion
In summary, while Sjögren’s and MS both fall under the umbrella of autoimmune disease, strong evidence linking the two conditions is lacking. Large-scale studies show neither patient population has dramatically higher rates of having both diseases concurrently compared to the general public. However, for the minority of patients who do develop both Sjögren’s and MS, likely contributing factors include genetic predisposition, environmental exposures, and bystander activation of autoimmunity.
There are significant symptomatic overlaps between Sjögren’s and MS which can make differentiating between them challenging. New neurologic symptoms in Sjögren’s patients should prompt medical evaluation to determine if MS could be emerging. Accurate testing and diagnosis are important to direct appropriate treatment. More research is still needed to better understand the relationship and impacts of concurrent Sjögren’s and MS. Patients with autoimmune conditions should stay vigilant for new symptoms and not hesitate to follow up with their provider if anything concerning develops.