Twenty years ago, seeing the acronym "GF" on a cafe menu might provoke head-scratching; nowadays, "GF" is the near-universally recognized shorthand for gluten-free. That well-known acronym is a testament to the incredible rise in the number of people with the chronic autoimmune condition known as celiac disease — now, as many as 2 million Americans, or 1% of people on Earth.
The reasons that celiac disease became so common are not entirely known. Some experts speculate that it has to do merely with awareness and an improvement in diagnoses; others believe it is a reaction to modern flours having more types of compounds that trigger immune reactions.
The largest increases in autoimmune disorders were seen in celiac disease, Sjogren's syndrome and Graves' disease.
Whatever the reason, new research suggests the prevalence of celiac may merely be a piece of a rising trend of autoimmune disorders. In a new study published in The Lancet. researchers estimate that one in ten people have an autoimmune disorder — with more women being affected than men. The huge study involved 22 million people.
Autoimmune diseases, which occur when the immune system mistakenly attacks healthy cells in the body, include type 1 diabetes, celiac disease, asthma, eczema and rheumatoid arthritis. Researchers looked at a large dataset of anonymized electronic health records in the United Kingdom of 22 million individuals to identify 19 of the most common autoimmune disorders. Their goal was to identify who is affected the most by these conditions, how some coexist with each other, and whether or not some are on the rise.
Using their dataset, they found that about 10 percent of the studied population had one of the identified 19 autoimmune disorders; 13 percent of women had them and 7 percent of men. The estimates are higher than previous ones which ranged from 3 to 9 percent, in studies that often had smaller sample sizes.
"Our data is based on the United Kingdom, we know that autoimmune disease prevalence will vary by geography, and hence it is difficult to speculate how these estimates apply to other countries," said Nathalie Conrad, author of the paper and an Honorary Research Fellow at the University of Glasgow. "Nevertheless, there are a number of findings that contribute to better understanding autoimmune disorders around the world."
Those findings, Conrad said, include evidence of socioeconomic, seasonal, and regional disparities for several autoimmune diseases.
"We believe that such variations are unlikely to be attributable to genetic differences alone and suggest that potentially modifiable risk factors may be implicated in the development of autoimmune diseases," Conrad said.
Conrad told Salon that she and her colleagues were expecting to see a greater increase of autoimmune disease incidence over time. But their study found that trends over the last two decades "do not support the idea of an epidemic of autoimmunity, at least not pre-COVID and in the UK."
Conrad explained that in the years between 2000 and 2019, new diagnoses of autoimmune diseases per person per year increased by 4% — "similarly for men and women."
"Considering the increased awareness and availability of diagnostic tests over the same period, this is relatively modest," Conrad added.
However, researchers found the largest increases in autoimmune disorders were seen in celiac disease, Sjogren's syndrome and Graves' disease. As Salon previously reported, the number of celiac disease cases keep going up — yet due to lack of funding, researchers still aren't sure why. Despite a common misconception, celiac disease isn't a gastrointestinal disease, but an autoimmune one. People who have celiac disease have developed an immune reaction to gluten, which is a protein found in wheat, rye, barley and triticale. Autoimmune disorders occur when the body's immune system mistakenly attacks its normal cells because it can't tell the difference between foreign ones and your own body's cells.
As to why these autoimmune disorders are on the rise, in addition to autoimmune diseases in general — even if it's a gradual rise — is unclear.
"We don't know this precisely," Conrad said. "One aspect certainly is increased awareness, earlier recognition, and availability of diagnostic tests."
Conrad added that there are other reasons regarding suspected risk factors and environmental triggers that could play a role, such as diet, obesity, viruses, and vitamin D.
"In our study, we did not have data to examine this question in detail," she said.
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However, the researchers did have the data to start examining and identifying patterns as to why some autoimmune disorders might coexist.
"In our study, clustering was particularly visible among rheumatic diseases and among endocrine diseases," Conrad said. "Interestingly, multiple sclerosis for example, stood out as having low rates of co-occurrence with other autoimmune diseases."
Conrad said she hopes the biggest takeaway from this study is that most of these diseases are incurable and require lifelong treatment, and they affect about 10 percent of the population.
"And as of today, we know very little about their causes and there are no prevention measures that might help alleviate the burden of these diseases on patients and the wider society," Conrad said. "In my view, there is a real need for more research into understanding underlying disease mechanisms and developing effective preventative measures."
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