The number of people developing autoimmune disorders in the United Kingdom is growing, including diseases like type 1 diabetes and rheumatoid arthritis. But why?
The exact causes of autoimmune disorders and diseases are still predominantly a mystery and still require much further research.
Our current understanding of autoimmune disorders explains that they occur when the normal role of the immune system in defence against infections is disturbed, resulting in it mistakenly attacking normal healthy cells in the body.
There are more than 80 types of autoimmune diseases known, but certain autoimmune disorders, such as type 1 diabetes, seem to be increasing in cases over the past several decades.
Common autoimmune disorders include:
- Rheumatoid arthritis
- Crohn’s disease
- Ulcerative colitis
- Addison disease
- Celiac disease
- Graves disease
- Hashimoto thyroiditis
- Multiple sclerosis
- Myasthenia gravis
- Pernicious anemia
Investigating why certain autoimmune disorders are on the rise, researchers look to explore common environmental factors or behavioural changes.
Studying 22 million individuals to understand autoimmune disorders
For this study, a multidisciplinary research team anonymised electronic health records from 22 million individuals in the UK.
Investigating 19 of the most common autoimmune diseases, researchers sought to understand who is most affected by these conditions and how different autoimmune diseases may co-exist with each other.
Their research revealed that these 19 autoimmune diseases studied affect about 10% of the UK population – 13% of women and 7% of men.
This is higher than previous estimates, which ranged from 3-9% and often relied on smaller sample sizes and included fewer autoimmune conditions.
Because individual autoimmune diseases are rare, and because there are so many different types of autoimmune diseases, it has been very difficult to undertake sufficiently large studies and establish reliable estimates to answer these questions previously.
What factors affected the prevalence of these diseases?
Socioeconomic, seasonal, and regional disparities were prevalent among numerous autoimmune disorders in the UK.
These variations indicated that they are unlikely to be attributable to genetic differences alone and may instead show the involvement of more modifiable risk factors such as smoking, obesity or stress that contribute to the development of some autoimmune diseases.
Smoking, obesity or stress can contribute to the development of some autoimmune diseases
Additionally, in some cases, a person with one autoimmune disease is more likely to develop a second compared to someone without an autoimmune disease.
Some autoimmune diseases share common risk factors
First author of the paper, Dr Nathalie Conrad at the University of Oxford, commented: ‘We observed that some autoimmune diseases tended to co-occur with one another more commonly than would be expected by chance or increased surveillance alone.
“This could mean that some autoimmune diseases share common risk factors, such as genetic predispositions or environmental triggers. This was particularly visible among rheumatic diseases and among endocrine diseases.
“But this phenomenon was not generalised across all autoimmune diseases – multiple sclerosis for example, stood out as having low rates of co-occurrence with other autoimmune diseases, suggesting a distinct pathophysiology.’
Senior author of the paper, Professor Geraldine Cambridge (University College London), said: ‘Our study highlights the considerable burden that autoimmune diseases place upon individuals and the wider population.
“Disentangling the commonalities and differences within this large and varied set of conditions is a complex task.
“There is a crucial need, therefore, to increase research efforts aimed at understanding the underlying causes of these conditions, which will support the development of targeted interventions to reduce the contribution of environmental and social risk factors.’
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