Incidence, prevalence, and co-occurrence of autoimmune disorders over time and by age, sex, and socioeconomic status: a population-based cohort study

Incidence, prevalence, and co-occurrence of autoimmune disorders over time and by age, sex, and socioeconomic status: a population-based cohort study of 22 million individuals in the UK

Summary
Background
A rise in the incidence of some autoimmune disorders has been described. However, contemporary estimates of the overall incidence of autoimmune diseases and trends over time are scarce and inconsistent. We aimed to investigate the incidence and prevalence of 19 of the most common autoimmune diseases in the UK, assess trends over time, and by sex, age, socioeconomic status, season, and region, and we examine rates of co-occurrence among autoimmune diseases.
Methods
In this UK population-based study, we used linked primary and secondary electronic health records from the Clinical Practice Research Datalink (CPRD), a cohort that is representative of the UK population in terms of age and sex and ethnicity. Eligible participants were men and women (no age restriction) with acceptable records, approved for Hospital Episodes Statistics and Office of National Statistics linkage, and registered with their general practice for at least 12 months during the study period. We calculated age and sex standardised incidence and prevalence of 19 autoimmune disorders from 2000 to 2019 and used negative binomial regression models to investigate temporal trends and variation by age, sex, socioeconomic status, season of onset, and geographical region in England. To characterise co-occurrence of autoimmune diseases, we calculated incidence rate ratios (IRRs), comparing incidence rates of comorbid autoimmune disease among individuals with a first (index) autoimmune disease with incidence rates in the general population, using negative binomial regression models, adjusted for age and sex.
Findings
Among the 22 009 375 individuals included in the study, 978 872 had a new diagnosis of at least one autoimmune disease between Jan 1, 2000, and June 30, 2019 (mean age 54·0 years [SD 21·4]). 625 879 (63·9%) of these diagnosed individuals were female and 352 993 (36·1%) were male. Over the study period, age and sex standardised incidence rates of any autoimmune diseases increased (IRR 2017–19 vs 2000–02 1·04 [95% CI 1·00–1·09]). The largest increases were seen in coeliac disease (2·19 [2·05–2·35]), Sjogren's syndrome (2·09 [1·84–2·37]), and Graves' disease (2·07 [1·92–2·22]); pernicious anaemia (0·79 [0·72–0·86]) and Hashimoto's thyroiditis (0·81 [0·75–0·86]) significantly decreased in incidence. Together, the 19 autoimmune disorders examined affected 10·2% of the population over the study period (1 912 200 [13·1%] women and 668 264 [7·4%] men). A socioeconomic gradient was evident across several diseases, including pernicious anaemia (most vs least deprived area IRR 1·72 [1·64–1·81]), rheumatoid arthritis (1·52 [1·45–1·59]), Graves' disease (1·36 [1·30–1·43]), and systemic lupus erythematosus (1·35 [1·25–1·46]). Seasonal variations were observed for childhood-onset type 1 diabetes (more commonly diagnosed in winter) and vitiligo (more commonly diagnosed in summer), and regional variations were observed for a range of conditions. Autoimmune disorders were commonly associated with each other, particularly Sjögren's syndrome, systemic lupus erythematosus, and systemic sclerosis. Individuals with childhood-onset type 1 diabetes also had significantly higher rates of Addison's disease (IRR 26·5 [95% CI 17·3–40·7]), coeliac disease (28·4 [25·2–32·0]), and thyroid disease (Hashimoto's thyroiditis 13·3 [11·8–14·9] and Graves' disease 6·7 [5·1–8·5]), and multiple sclerosis had a particularly low rate of co-occurrence with other autoimmune diseases.
Interpretation
Autoimmune diseases affect approximately one in ten individuals, and their burden continues to increase over time at varying rates across individual diseases. The socioeconomic, seasonal, and regional disparities observed among several autoimmune disorders in our study suggest environmental factors in disease pathogenesis. The inter-relations between autoimmune diseases are commensurate with shared pathogenetic mechanisms or predisposing factors, particularly among connective tissue diseases and among endocrine diseases.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(23)00457-9/fulltext

 

So those are just confirmed diagnoses found in health records from a short list. Which are always an undercount. And in a context where healthcare keeps getting more expensive while delivering less for it, about an issue that they famously struggle with.

For sure the response to this will be full psychosocial, so I guess the numbers will keep increasing until... something? The Zapp Brannigan strategy. It doesn't work, but I guess it must feel really damn good, or something. I'm sure whatever is causing those diseases also have a set kill count and will stop once they reach it. Failproof strategy. Since if it doesn't work it'll just be covered up anyway.

 

Come to think of it, if enough people develop autoimmune disease to remove the possibility of a control population, the current methods of medicine will essentially make it impossible to see any of it anymore because there wouldn't be significant differences.

That won't happen but wow does it emphasize how poor those tools are, because this is essentially what happened with LC and it is used to explicitly dismiss all of it. A statistical approach to medicine is just catastrophically bad when you look at the big picture, how it depends on conditions that simply don't make sense.

 

There's no mention of ME. I'm pretty sure that my ME is autoimmune.

But I'm intrigued that 1 in 10 people have autoimmune disease.