Atopic dermatitis is associated with increased use of social benefits: a register‐based cohort study

Association of atopic dermatitis with autoimmune diseases: A bidirectional and multivariable two-sample mendelian randomization study

Background

Observational studies have suggested the association between atopic dermatitis (AD) and the risks of autoimmune diseases. It is still unclear, however, whether or in which direction causal relationships exist, because these associations could be confounded.

Objectives

Our study seeks to assess the possibility of AD as a cause of autoimmune diseases, and to estimate the magnitude of the causal effect.

Methods

Two-sample mendelian randomization (MR) analyses were performed using genome-wide association study (GWAS) summary-level statistics. Specifically, bidirectional MR analyses were conducted to examine the direction of association of AD with autoimmune diseases; multivariable MR analyses (MVMR1) were used to test the independence of causal association of AD with autoimmune diseases after controlling other atopic disorders (asthma and allergic rhinitis), while MVMR2 analyses were conducted to account for potential confounding factors such as smoking, drinking, and obesity. Genetic instruments for AD (Ncases=22 474) were from the latest GWAS meta-analysis. The GWAS summary data for asthma and allergic rhinitis were obtained from UK Biobank. The GWAS summary data for smoking, alcohol consumption, obesity and autoimmune diseases (alopecia areata, vitiligo, systemic lupus erythematosus, ankylosing spondylitis, rheumatoid arthritis, and type 1 diabetes) were selected from the largest GWASs available. Causal estimates were derived by the inverse-variance weighted method and verified through a series of sensitivity analyses.

Results

Genetically predicted AD linked to higher risks of rheumatoid arthritis (OR, 1.28; P=0.0068) (ORMVMR1, 1.65; P=0.0020) (ORMVMR2, 1.36; P<0.001), type 1 diabetes (OR, 1.37; P=0.0084) (ORMVMR1, 1.42; P=0.0155) (ORMVMR2, 1.45; P=0.002), and alopecia areata (OR, 1.98; P=0.0059) (ORMVMR1, 2.55; P<0.001) (ORMVMR2, 1.99; P=0.003) in both univariable and multivariable MR. These causal relationships were supported by sensitivity analyses. No causal effect of AD was identified in relation to systemic lupus erythematosus, vitiligo, and ankylosing spondylitis. Concerning the reverse directions, no significant association was noted.

Conclusion

The results of this MR study provide evidence to support the idea that AD causes a greater risk of rheumatoid arthritis, type 1 diabetes and alopecia areata. Further replication in larger samples is needed to validate our findings, and experimental studies are needed to explore the underlying mechanisms of these causal effects.

Childhood atopic dermatitis is associated with a decreased chance of completing education later in life: a register-based cohort study

BACKGROUND

Atopic dermatitis (AD) has far-reaching consequences in childhood and later in working life, but information on how it affects completion of education is sparse.

OBJECTIVES

To compare the educational achievement of individuals with AD in childhood/adolescence and individuals without a history of AD.

METHODS

The study population included patients diagnosed with AD prior to the age of 16 registered in the Danish National Patient Register (DNPR) born in the period 1977-1993 and a 23-fold matched control group from the background population. Cross-linkage of five different Danish registers from 1977 to 2015 allowed comparison of AD patients with controls regarding completion of education.

RESULTS

In total, 10 173 individuals were registered with AD in the DNPR, while 234 683 individuals served as control group. Mild/moderate AD was associated with a decreased chance of completing basic compulsory education [hazard ratios (HR): 0.92, 95% CI: 0.90-0.95] and further academic education (HR: 0.96, 95% CI: 0.93-0.98). Severe AD was associated with a decreased chance of completing further academic education (HR: 0.86, 95% CI: 0.80-0.92), further vocational education (HR: 0.90, 95% CI: 0.84-0.97) and higher education: master's level (HR: 0.66, 95% CI: 0.53-0.81).

CONCLUSION

Atopic dermatitis in childhood/adolescence is associated with a decreased chance of completing an education.

Treatment of adult atopic dermatitis patients according to disease characteristics and demographics

Little is currently known about possible associations between disease specific characteristics of atopic dermatitis (AD) and use of medical treatments. We explored the use of AD treatments within the past 12 months in Danish adults according to distinct patient characteristics. Patients who had received a diagnosis of AD in a hospital in- or outpatient setting as adults were surveyed and data cross-linked to a national prescription registry. AD severity was measured by the Patient-Oriented SCORing Atopic Dermatitis (PO-SCORAD). A total of 3834 patients participated. Use of topical medication in the past 12 months increased with increasing AD severity, whereas no difference was observed for systemic medication use. Positive associations between AD in the face and neck, and use of mild and moderately potent topical corticosteroids were observed, while involvement of palms and chest was associated with use of more potent topical corticosteroids. The mean DLQI, skin pain, and itch severity scores were lower in patients managed only with topical corticosteroids (5.5, 3.2, and 4.3, respectively) compared to patients treated with both oral and topical medication (7.1, 3.8, and 5.0, respectively). Patients with frequent topical corticosteroid use tended to be older (50.7 vs 48.6 years), males (50.0% vs 33.6%), current daily smokers (17.3% vs 13.7%), and having asthma (59.1% vs 43.8%) compared with infrequent users of topical corticosteroids. We found a disconnect between the severity of AD signs and symptoms, and use of AD therapies. In particular, a very modest use of systemic immunosuppressants was seen even among patients with severe AD symptoms. However, the underlying clinical decisions and reasons behind this disconnect is not clear based on the current data.

Association between atopic dermatitis and autoimmune diseases: a population-based case-control study

Background

Atopic dermatitis (AD) is a common chronic skin disorder and is well known to be associated with other atopic conditions. There is increasing evidence for an association also with nonatopic conditions, including autoimmune diseases, but data are limited about several autoimmune diagnoses.

Objectives

To investigate the association between AD and autoimmune diseases.

Methods

This case–control study used Swedish national healthcare registers. The source population comprised the entire Swedish population aged ≥ 15 years from 1968 to 2016. Cases, including all those with an inpatient diagnosis of AD (from 1968) and/or a specialist outpatient diagnosis of AD (from 2001), were matched by sex and age to healthy controls (104 832 cases of AD, 1 022 435 controls).

Results

AD was significantly associated with one or more autoimmune diseases compared with controls – adjusted odds ratio (aOR) 1·97, 95% confidence interval (CI) 1·93–2·01 – and this association was significantly stronger in the presence of multiple autoimmune diseases compared with only one. The association was strongest for autoimmune disorders involving the skin (aOR 3·10, 95% CI 3·02–3·18), the gastrointestinal tract (aOR 1·75, 95% CI 1·69–1·82) or connective tissue (aOR 1·50, 95% CI 1·42–1·58). In the overall analysis, men with AD had a stronger association with rheumatoid arthritis and coeliac disease than did women with AD. In subanalyses, the findings remained stable in multivariable analyses after adjustment for smoking and parental autoimmune disease.

Conclusions

This large population‐based study indicates significant autoimmune comorbidity of adults with AD, especially between AD and autoimmune dermatological, gastrointestinal and rheumatological diseases. Having multiple autoimmune diseases resulted in a stronger association with AD than having only one autoimmune disease.

What is already known about this topic?

Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases.

Some studies have shown that AD is associated with some autoimmune diseases, such as Crohn disease, ulcerative colitis, coeliac disease, alopecia areata and vitiligo, but data are limited for several major autoimmune diagnoses.

What does this study add?

In this study, AD was associated with several autoimmune diseases, especially those involving the skin, the gastrointestinal tract or connective tissue.

The association was stronger for individuals with multiple autoimmune comorbidities.

Linked Comment: J.I. Silverberg. Br J Dermatol 2021; 185:243–244.

Plain language summary available online