Our immune system plays a key role in defending against infection, but if its functions are disrupted it can mistakenly attack healthy cells in the body, causing what is known as autoimmune diseasessome as frequent and well-known as rheumatoid arthritis, type 1 diabetes or multiple sclerosis, which are part of the more than 80 types of autoimmune diseases that are known.
New research analyzing medical data from more than 22 million people in the UK to investigate 19 of the most common autoimmune diseases has revealed that, taken together, affect about 10% of the population: 13% of women and 7% of men; that is, one in 10 people could develop one of these pathologies throughout their lives. These figures exceed estimates from previous studies that ranged from 3% to 9%, although they were generally based on smaller population samples and included fewer conditions.
The study was carried out by a team of experts in epidemiology, biostatistics, rheumatology, endocrinology and immunology from KU Leuven, University College London, University of Glasgow, Imperial College London, Cardiff University, University of Leicester and University of Oxford, who examined whether cases of autoimmune diseases are increasing and who is affected the most, whether this could be related to environmental factors or lifestyle changesand how different autoimmune diseases can coexist.
Risk factors for autoimmune diseases that are modifiable
Among the 22,009,375 individuals included in the study, 978,872 (mean age 54 years) had a new diagnosis of at least one autoimmune disease between January 1, 2000 and June 30, 2019 (63.9% were women and 36.1% were men). During the study period, the incidence rates of any autoimmune disease increased, with the largest increases seen in celiac disease, Sjogren’s syndrome, and Graves’ disease, while the incidence of pernicious anemia and Hashimoto’s thyroiditis decreased. significantly.
“Some autoimmune diseases may share common risk factors, such as genetic predispositions or environmental triggers”
The results have been published in The Lancet and show that, together, the 19 autoimmune disorders studied affected 10.2% of the population during the study period, specifically, 1,912,200 (13.1%) women and 668,264 (7.4%) men. The researchers observed that seasonal variations influenced the childhood-onset type 1 diabetes -which was diagnosed more frequently in winter- and vitiligo -whose diagnosis was more common in summer)-, and they also found regional variations for various conditions.
Autoimmune disorders were commonly associated with each other, particularly Sjögren’s syndrome, systemic lupus erythematosus, and systemic sclerosis. People with childhood-onset type 1 diabetes also had significantly higher rates of Addison’s disease, celiac disease, and thyroid disease, and multiple sclerosis had an especially low rate of co-occurrence with other autoimmune diseases.
The researchers also found evidence of socioeconomic inequalities, seasonal, and regional among various autoimmune diseases and suggest that these variations are unlikely to be attributable to genetic differences alone and that they could indicate the involvement of potentially modifiable risk factors, such as smoking, obesity, or stress, that contribute to autoimmune disease. development of certain autoimmune disorders. In addition, they found that, in some cases, a person with an autoimmune disease is more likely to develop a second one compared to someone without an autoimmune disease, a finding that will help in the investigation of possible common causes of these pathologies.
“We observed that some autoimmune diseases tended to coexist with each other more frequently than expected by chance alone or by increased surveillance. This could mean that some autoimmune diseases share common risk factors, such as genetic predispositions or environmental triggers. This was particularly visible among the rheumatic diseases and between endocrine diseases. But this phenomenon was not generalized in all autoimmune diseases: multiple sclerosis, for example, was notable for having low rates of coexistence with other autoimmune diseases, suggesting a different pathophysiology”, has stated the first author of the article, the Dra. Nathalie Conrad(Deep Medicine, Nuffield Department of Women’s & Reproductive Health, University of Oxford).
“Our study highlights the considerable burden that autoimmune diseases impose on individuals and the general population. Teasing out the commonalities and differences within this broad 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.” main article, the professor Geraldine Cambridgedel University College London.