• Leah Hess

What is Causing the U.S. Uptick in Autoimmunity?


Over the past 2-3 decades, there has been a significant increase in autoimmunity in the United States. Autoimmunity refers to the presence of proteins called antibodies that could potentially lead to autoimmune diseases. Testing for autoimmunity involves measuring the amount of anti-nuclear antibodies (ANA) in the blood, which has increased significantly since the 1980s, according to a study by the American College of Rheumatology. Autoimmune diseases are diseases in which the body’s immune system mistakenly attacks its own healthy cells. Some common examples of autoimmune diseases are type 1 diabetes, rheumatoid arthritis, lupus, Hashimoto's disease, multiple sclerosis, Crohn’s disease, celiac disease, and psoriasis. Most autoimmune disorders are chronic, meaning that they are long-lasting (often lifelong); treatment can often control symptoms.


The cause of these disorders is largely unknown, but current research points to autoimmune disorders being caused by a combination of genetic factors and environmental influences. The uptick in autoimmunity in the U.S. has led to increased consideration of environmental and lifestyle factors, as a few decades is not enough time for genetic changes to occur. “Environmental influences”, however, is a broad term that can mean many different things. Dietary changes, chemical exposure, infections and viruses, and medications are all examples of environmental influences since they do not depend on a person’s genetic makeup. This article will explore some of the possible environmental factors that have led to the recent rise in autoimmune diseases.


Microbiome


The microbiome is the aggregate of all of the bacteria, fungi, protozoa, and viruses (microbes) that reside in a person’s body- and there’s a lot (over 100 trillion of them!). Gut bacteria aid in digestion, extracting nutrients from food eaten to be used throughout the body. New research suggests that microbiota is involved in a wide range of biological processes, including those involved in innate immunity (the class of immune responses that serve as the first line of defense against foreign pathogens). Diabetes, Crohn’s Disease, autoimmune arthritis, and other conditions have been linked to problems in the gut microbiomes of mice. If applicable to humans, this theory would explain the rise in autoimmune conditions in the past decades. The western diet is becoming more processed and contains more high-fat, high-sugar, and low fiber foods than ever before. These foods adversely affect a person's microbiome and could explain the increased autoimmunity of those in the United States. Therefore, maintaining a healthy gut microbiota through diet is very important to a person’s long-term health. The good news is that gut bacteria respond rapidly to dietary changes; eating meals that include high-fiber fruits, vegetables, and legumes, as well as fermented foods with probiotic effects can increase the helpful gut bacterias bifidobacteria and lactobacilli in a matter of days. Feeding these “good” bacteria also helps to crowd out harmful bacteria that may interfere with the body’s processes, allowing the body to maintain a healthy equilibrium.



Stress


The stress of the modern lifestyle could also be at play. It’s no secret that life has become increasingly hectic as technology changes and societal expectations evolve. The pressure to stay connected, the constant access to information, the growing wage gap, and political turmoil are just some of the stressors of modern life. In fact, a Penn State study confirmed that life is significantly more stressful than it was in previous decades. This could be wreaking havoc on our immune systems. Another study published in the Journal of the American Medical Association found that individuals diagnosed with a stress-related disorder had a higher rate of autoimmune diseases than those without a stress-related disorder. Together, these conclusions make a case for stress being at the root of increased autoimmunity.


Pollution


Advances in technology and manufacturing and increased demand for energy have also led to more chemical pollutants in the air. Occupational studies have linked exposure to crystalline silica (used in industries such as foundry work and hydraulic fracturing) and asbestos (a common building material in houses built before 1970) to diseases such as rheumatoid arthritis, lupus, and systemic sclerosis. The groundwater contaminant trichloroethylene (TCE), used in paints and adhesives, has also been linked to autoimmune hepatitis, among other diseases. The most obvious correlation would be the uptick of autoimmunity with increased air pollution due to fossil fuel burning. Americans are consuming more fuel than ever before, which releases chemicals such as nitrogen oxides, ozone, sulfur dioxide, particulate matter, and other volatile compounds. These have all been linked to adverse health effects, including autoimmune dysfunction.


Hygiene hypothesis


A theory called the “hygiene hypothesis” questions if the increase in autoimmunity could be due to the decreased incidence of infections in high-income countries. Furthermore, it states that early childhood exposure to certain germs and infections contributes to the development of a healthy immune system. Public health measures, such as pasteurization of food, vaccination against common childhood infections, the widespread use of antibiotics, and regulation of the water supply have made the rates of common infections in industrialized countries far less than in non-industrialized countries. In these non-industrialized countries, where people are chronically affected by these pathogens, chronic disease is low. In other words, the strides we have made in lowering the spread of infectious disease could, in turn, result in autoimmune disease.

None of these hypotheses are currently substantiated enough to be named a cause of autoimmunity, but they are worth considering if you are concerned about your health or are curious about the rise in U.S. autoimmune cases. Regardless, more research is needed before these claims serve as medical advice, and a doctor should always be consulted before implementing major lifestyle changes. The good news is that autoimmunity makes up a robust area of scientific research, and vast strides are expected to be made in the coming years. As suggested in the discussion above, prevention may be the key to autoimmunity, and countless grants and funding efforts are being allocated to finding out for sure.

 

Speaking Plainly:

  • In recent decades, there has been an increase in anti-nuclear antibodies, which can lead to the development of autoimmune disorders, among those in the U.S.

  • These conditions are believed to be caused by both genetic and environmental factors, but the specifics are largely unknown.

  • Four environmental influences that could explain the recent rise in autoimmunity are changes in people’s microbiomes, increases in pollution, increasingly stressful lifestyles, and the hygiene hypothesis.

  • These theories are so far inconclusive, and more research is needed to solve the autoimmunity mystery.