Having One Autoimmune Condition Can Increase Your Chance of Developing Others—Here’s Why

Genes are a big factor in these diseases, but they don’t necessarily seal your fate.

Reviewed by Dietitian Emily Lachtrupp, M.S., RD

An autoimmune disease is life-altering for the 50 million Americans—that’s 1 in 5—who have one, according to the Autoimmune Association. And there’s data to suggest that the rates of autoimmunity have increased over the past two decades, per 2023 research in The Lancet. As if having one autoimmune condition wasn’t enough, the unfortunate reality is that one-quarter of people who have autoimmune disease have more than one, according to the Autoimmune Association. With over 100 autoimmune diseases—including rheumatoid arthritis, lupus, celiac disease and inflammatory bowel disease—there are many ways for your immune system to go sideways.

So, what’s going on? Why does having one autoimmune condition increase your chance of developing others? Here, we will dive into the factors that increase the risk of autoimmune conditions, as well as a few daily habits that may delay or lessen risk.

Related: Rheumatoid Arthritis Diet Plan 

The Immune System: A Great Thing…Until It Malfunctions

The immune system is the body’s natural defense system, constantly on surveillance for threats, such as harmful bacteria, viruses and other pathogens, per InformedHealth.org. When the immune system detects a threat, it jumps into action to fight off the invader. Most of the time, the response is so effective that you don’t even realize you encountered something that could have made you sick. Other times, the immune system’s initial response isn’t enough, and you get an infection or illness.

Everyone gets sick sometimes. Overall, your body’s natural defense system does a pretty amazing job at keeping your body healthy. But even the most well-designed systems can malfunction, and this is what happens when autoimmune conditions develop.

Whereas the immune system is normally laser-focused on outside hazards, autoimmunity is when this system mistakenly says the threat is coming from inside the house. In other words, your body mounts an attack against itself, destroying healthy tissue, according to the National Library of Medicine.

What Triggers the Onset of Autoimmune Diseases

Genetics are a primary risk factor, and most everyone carries genes associated with certain autoimmune conditions. Yet, according to the National Institutes of Health, most people won’t develop an autoimmune condition unless something in their environment or lifestyle triggers those specific genes to malfunction.

Identified triggers include bacterial or viral infections such as Epstein-Barr; certain drugs and exposure to toxins like smoke, mercury, chemicals or excessive sunlight; changes to gut health caused by a poor diet; and stress.

So back to the original question: why does having one autoimmune condition increase your chance of developing others? Here are some of the theories surrounding why this occurs.

Genes

Among some of the more studied autoimmune conditions, researchers have identified certain genes associated with a greater risk for developing these diseases, and there is some overlap. For example, lupus, rheumatoid arthritis, systemic sclerosis and Sjögren’s syndrome all share several common genetic factors, according to a 2022 study in Clinical Reviews in Allergy and Immunology. This is why some of these diseases may occur together.

Genetic factors like family history, sex, race and ethnicity appear to also influence susceptibility to autoimmune disease. A family history increases risk by 20%, and 3 out of 4 individuals diagnosed with an autoimmune disease are female, according to statistics from the Autoimmune Association.

Similarly, race can also affect your risk. Twice as many Black Americans are diagnosed with polymyositis and lupus, while twice as many Native Americans are diagnosed with scleroderma, alopecia and rheumatoid arthritis, compared to White Americans, according to a 2020 study in Autoimmune Reviews. Underlying factors like these can all increase one’s genetic predisposition to developing autoimmune conditions.

Shared Risk Factors

Many autoimmune conditions share some of the same risk factors. For example, the Epstein-Barr virus, which is a common virus that affects most people, says the Centers for Disease Control and Prevention, is associated with rheumatoid arthritis, Sjögren’s syndrome, celiac disease, multiple sclerosis and others, according to a 2022 study in Pathophysiology.

Similarly, smoking is associated with the development of rheumatoid arthritis, thyroid autoimmunity, lupus and multiple sclerosis, points out a 2021 study in Pathophysiology.

Exposure Accumulation

Another factor centers on something that’s been termed the exposome. While we often think of exposures to smoking, stress or an infection as momentary or temporary, research suggests that the body keeps an ongoing tally of disruptors like these over the span of one’s life. This record is termed the exposome and is the cumulative environmental exposure one has over their lifespan, beginning during prenatal development, according to the aforementioned 2021 Pathophysiology research. The exposome theory may explain why some people are more susceptible to autoimmunity, if their exposures reach a tipping point.

3 Daily Habits That May Lower Autoimmune Risk

While genetics can’t be modified, you may be able to make certain changes to your diet and lifestyle that reduce your risk of developing autoimmunity.

1. Take a Vitamin D Supplement

Vitamin D helps keep immune responses in check. Low blood levels of the nutrient may be associated with the development of rheumatoid arthritis, lupus and other autoimmune conditions, notes 2021 research in the journal Biology of Sex Differences. While it’s been unclear if supplementation of the nutrient lowers risk, a 2022 study published in BMJ found that daily supplementation of vitamin D (2000 IUs) for five years reduced the incidence of autoimmune diseases by 22%.

2. Reduce Intake of Highly Processed Foods

A healthy gut microbiota is important for a healthy immune system. An imbalance of gut bacteria makes it easier for harmful substances like toxins to pass into the bloodstream, something that can trigger an autoimmune response, according to a 2021 summary in the journal Nutrients. To foster a healthier gut, limit highly processed foods that are sources of trans fats, added sugars and food additives like dyes when possible.

3. Adopt a Whole-Food Approach

The same Nutrients article also highlighted another diet aspect impacting gut health: low intake of fruits, vegetables and whole grains. Beneficial bacteria in the gut rely on the fiber and other compounds in these foods for survival. While it’s important to limit the foods with components that hurt gut health, it’s equally important to take care of existing beneficial bacteria in the gut by feeding them what they need. Choosing more whole or minimally processed foods rich in fiber, like fruits, vegetables, whole grains, legumes, nuts and seeds, is the best way to do this.

4. Get Enough Sleep

Sleep disorders, such as insomnia, can wreak havoc on our health—including our immune system. Research published in Nature notes that long-term lack of quality sleep can increase the risk of developing an autoimmune disease, such as rheumatoid arthritis, lupus and systemic sclerosis. In a go-go-go society, getting a restful night’s sleep can feel elusive. Wondering how to get started? Check out our 4 Ways to Get a Better Night's Sleep, According to an Expert.

5. Stop Smoking

The negative health impacts of smoking are well-documented, particularly when it comes to conditions like cancer and chronic obstructive pulmonary disease (COPD). But smoking can also play a role in increasing the risk of developing autoimmune diseases, like rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis and other autoimmune diseases, notes the Global Autoimmune Institute. If you’re looking for support to stop smoking, consider reaching out to your health care provider or checking out the CDC for more resources.

Related: What Is the Autoimmune Protocol Diet? Here's What a Dietitian Has to Say

Bottom Line

Autoimmunity comprises a large group of diseases where one’s own immune system has turned on itself by destroying healthy tissue. One-quarter of people with autoimmunity have more than one of these conditions. Genetics as well as lifestyle and environmental factors all factor into the development of these conditions. Reducing your intake of processed foods, eating more whole foods and taking a vitamin D supplement are a few dietary strategies that may help keep your immune system healthy and lessen your risk of autoimmune disease.

Read the original article on Eating Well.