Why are autoimmune diseases more common in developed countries

Common, life-threatening, difficult to diagnose and incurable — autoimmune diseases are as mysterious as they are dangerous.

More than 80 different autoimmune diseases have been identified, and the National Institutes of Health (NIH) report that 23.5 million Americans are affected. The American Autoimmune Related Diseases Association (AARDA) estimates that number is closer to 50 million Americans, citing incomplete data contributing to the NIH estimate.

Regardless of the discrepancy, both agencies report that the prevalence of autoimmune disease is rising. “There are so many triggers for autoimmune disease, including stress, diet, lack of exercise, insufficient sleep and smoking. Anything that causes chronic inflammation in the body can eventually lead to the development of an autoimmune disease, which could be one reason they’re are becoming increasingly common,” said Ryon Parker, MD, Chief Medical Officer at Parker Medical and internal medicine physician at Southern Hills Hospital and Medical Center.

While there is still much to be discovered about autoimmune diseases, managing inflammation and understanding the warning signs can help.

What is an autoimmune disease?

An autoimmune disease describes a condition wherein the patient’s immune system attacks part of their own body.

Usually, a healthy immune system is able to discern the difference between the self and the non-self—attacking only foreign invaders, such as germs. In the case of autoimmune disease, the immune system attacks the body’s own tissues as it would with a harmful virus or bacteria. This causes inflammation in the area targeted and different associated symptoms.

Common autoimmune diseases

• Rheumatoid arthritis: Immune system attacks the joints, causing inflammation, swelling and pain.
• Alopecia areata: Immune system attacks hair follicles, causing hair loss and baldness.
• Type 1 diabetes: Immune system attacks the pancreas and cells that produce insulin.
• Lupus: Immune system attacks various tissues within the body, commonly affecting the joints, lungs, blood cells, nerves and kidneys.
• Multiple sclerosis: Immune system attacks the nerve cells.
• Inflammatory bowel disease (including ulcerative colitis and Crohn’s disease): Immune system attacks the lining of the intestines.
• Psoriasis: Immune system over-produces blood cells that collect in the skin, causing plaque buildup.
• Hashimoto’s disease: Immune system attacks the thyroid gland.

Causes and risk factors

It’s currently unknown what causes autoimmune diseases, but it’s thought to be a combination of genetic factors and environmental influences. “The immune system is so complex, we haven’t even begun to fully understand it,” Parker said.

While many people develop autoimmune disease without any identifiable cause, risk factors include being a woman of childbearing age, having a family history of autoimmune disease, being exposed to certain environmental irritants and being of certain races/ethnic backgrounds.

Symptoms

Because there are so many different autoimmune diseases — all affecting different parts of the body with varying symptomatic consequences — each specific disease comes with its own unique symptoms. However, most autoimmune diseases have a few common traits.

Inflammation: Swelling, pain, redness and heat are all common symptoms of autoimmune disease which tend to be concentrated on the body part(s) affected.

Flare-ups: Many autoimmune diseases get better or worse depending on specific triggers, including stress and diet, causing “flare-ups” in symptoms.

Early/mid-life onset: Most autoimmune diseases appear in a person’s teens through early 30s. Most people aren’t born with an autoimmune disease; the disease develops and adapts over time.

Fatigue: Extreme or chronic fatigue are common symptoms, likely because of the energy exerted by the immune system fighting against the body.

Autoimmune disease and women

The AARDA reports that women account for 75 percent of all patients with autoimmune diseases. While there are no definitive answers to why this may be, it’s speculated that women may have more sophisticated immune responses which contributes to overactivity and/or female sex hormones that may influence inflammation.

Diagnosing autoimmune disease

Autoimmune diseases are notoriously difficult to identify and many patients suffer for years without a medical diagnosis.

“With so many autoimmune conditions out there, it can take a skilled clinician to properly diagnose them. Most can be diagnosed with a blood test looking for the presence of specific antibodies but the doctor has to know which tests to order,” Parker said.

For patients who think they have an undiagnosed autoimmune disease, Parker recommends they ask their doctor about an ANA (antinuclear antibody) test, which can strongly indicate whether it’s an autoimmune disease or something else entirely.

He also suggests patients ask about CRP (c-reactive protein) and/or a ESR (erythrocyte sedimentation rate) test, both of which can detect inflammation within the body.

Take care of your immune system by managing stress

The immune system is very sensitive to stress, which can cause all types of disease. “Stress is a fight or flight response. Overstimulating stress hormones will weaken the immune system over time and leave people vulnerable,” Parker said.

Managing stress is one of the best things anyone can do to boost their immune system and protect themselves against the development of disease.

A rise in healthcare in the last century has significantly decreased morbidity rates and increased the average lifespan of humans. We have fought and won over previously life-threatening infections like influenza and SARS. However, this modernisation has brought with itself a new problem of autoimmune diseases - rheumatoid arthritis, type 1 diabetes, and celiac disease to name a few. 

Unlike infectious diseases, autoimmune diseases don’t occur due to a microbe. Instead, these diseases occur when our immune system starts making antibodies against and destroying healthy cells. Autoimmune diseases can lead to inflammation and in some cases debility.

Representational image. Getty Images

There are a lot of possible factors that can increase your risk of developing an autoimmune disease. While scientists have been busy trying to pinpoint the reasons behind it, there has been a gradual increase in the number of cases of these diseases over the last decade.

Here are some of the theories behind this steep rise:

Evolution

Evolution is a brutal process, letting only the fittest survive. Thanks to being exposed to so many infectious diseases, we have developed genetic changes to evade harmful pathogens over time. Now researchers at the Radboud University Nijmegen Medical Centre, Netherlands say that the same genes that protect us from infectious diseases also make us prone to autoimmune diseases. And this diversity varies with the change in geographical location, for example, Eurasian people are more resistant to certain diseases like staph infections but they are also more prone to allergies and asthma.

It is believed that as evolution continues, there would be more of these genetic changes and possibly more autoimmune diseases. This is because our immune system can build defences but it can’t prevent infections.

Being a woman

If you are a woman, you are much more likely to get an autoimmune disease. Dr Maunil K Desai, a researcher at the University of South California, explained why in his 2019 research published in Frontiers in Endocrinology, a peer-reviewed journal published by the Frontiers Media. He wrote that a woman’s body goes through several hormonal changes in life. These hormonal changes directly affect both the innate (the one you are born with) and the adaptive (the one you develop over time) immunity along with the immune tolerance in women. It has been found that androgens (produced more in the male body) like testosterone reduce inflammation, a most common symptom of autoimmune disease while estrogens (produced more in the female body) have pro-inflammatory effects.

Additionally, experts say that faulty expression of the X chromosome in women may make them prone to autoimmune diseases. 

Then there is the fact that women live longer than men. The longer you live, the more infections your immune system fights and the higher your chances to get an autoimmune disease.

Environmental factors

It’s not just about excessive exposure to microbes. Less exposure can increase your risk of autoimmune diseases as well. With rising awareness, humans have created more sterile environments around themselves, especially in developed countries. The immune system of growing children in such countries do not get exposed to enough bacteria (both, good and bad) and is thus more likely to act up. It is called the ‘hygiene hypothesis’ of autoimmune diseases.

Other factors like stress, smoking, diet and exposure to toxic chemicals are also considered to be risk factors for autoimmune diseases.

For more on this topic, please read our article on Celiac Disease.

Health articles in Firstpost are written by myUpchar.com, India’s first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.

Updated Date: January 13, 2020 12:58:39 IST