Global, regional and national epidemiology of allergic disorders in children from 1990 to 2019: findings from the Global Burden of Disease study 2019.

OBJECTIVE: This modelling study aimed to estimate the burden for allergic diseases in children during a period of 30 years. DESIGN: Population-based observational study. MAIN OUTCOMES AND MEASURES: The data on the incidence, mortality and disability-adjusted life years (DALYs) for childhood allergic diseases, such as atopic dermatitis (AD) and asthma, were retrieved from the Global Burden of Disease study 2019 online database. This data set spans various groups, including different regions, ages, genders and Socio-Demographic Indices (SDI), covering the period from 1990 to 2019. RESULTS: In 2019, there were approximately 81 million children with asthma and 5.6 million children with AD worldwide. The global incidence of asthma in children was 20 million. Age-standardised incidence rates showed a decrease of 4.17% for asthma, from 1075.14 (95% uncertainty intervals (UI), 724.63 to 1504.93) per 100 000 population in 1990 to 1030.33 (95% UI, 683.66 to 1449.53) in 2019. Similarly, the rates for AD decreased by 5.46%, from 594.05 (95% UI, 547.98 to 642.88) per 100 000 population in 1990 to 561.61 (95% UI, 519.03 to 608.29) in 2019. The incidence of both asthma and AD was highest in children under 5 years of age, gradually decreasing with age. Interestingly, an increase in SDI was associated with a rise in the incidence of both conditions. However, the mortality rate and DALYs for asthma showed a contrasting trend. CONCLUSIONS: Over the past three decades, there has been a worldwide increase in new asthma and AD cases, even though mortality rates have significantly declined. However, the prevalence of these allergic diseases among children varies considerably across regions, countries and age groups. This variation highlights the need for precise prevalence assessments. These assessments are vital in formulating effective strategies for prevention and treatment.

Assisted reproductive techniques and subsequent risk of asthma and allergic rhinitis in offspring: a nationwide birth cohort study in South Korea.

OBJECTIVE: The relationship between assisted reproductive techniques (ART) and the risk of asthma and allergic rhinitis (AR) is controversial. Thus, we aimed to investigate the relationship between ART and the risk of asthma and AR in a nationwide, large-scale birth cohort. PATIENTS AND METHODS: This study utilized the National Health Insurance Service data in South Korea to conduct a nationwide, large-scale, population-based birth cohort. We included all infants born between 2017 and 2018. AR, asthma, food allergies, and atopic dermatitis were defined using the International Classification of Diseases tenth edition codes. Asthma was classified as allergic or non-allergic based on accompanying allergic diseases (AR, food allergy, or atopic dermatitis). Using 1:10 propensity score matching, we compared infants conceived through ART with those conceived naturally (non-ART). After matching, logistic regression was used to compare the hazard ratio for asthma and AR between the two groups. RESULTS: We included 543,178 infants [male infants, 280,194 (51.38%)]. After matching, 8,925 and 74,229 infants were selected for the ART and non-ART groups, respectively. The ART group showed a decreased risk of asthma in the offspring [adjusted hazard ratio (aHR), 0.45; 95% confidence interval (CI), 0.41-0.48]. Similarly, for AR, being conceived by ART was associated with a decreased risk of AR (aHR, 0.25; 95% CI, 0.12-0.37). ART offspring showed a decreased risk of asthma and AR in offspring compared to that observed in non-ART offspring. CONCLUSIONS: Our study offers important insights for clinicians, researchers, and parents regarding the health outcomes of ART-conceived infants and enhances our understanding of ART's impact on respiratory health.

Population-based cohort study to investigate the changes in prevalence, severity profile, and treatment modalities used in Korean atopic dermatitis patients.

In this retrospective study spanning from 2002 to 2019, we analyzed data from 355,277 Korean patients diagnosed with atopic dermatitis (AD) through the National Health Insurance System. Our objective was to comprehensively analyze the trends in prevalence, severity profiles, and treatment approaches for AD in Korea over this 18-year period. Initially, AD prevalence stood at 3.88% in 2002 but notably rose to 5.03% by 2019. During the same period, while AD prevalence decreased in the 0-1-year-old group (from 34.52% to 24.83%), it remained relatively stable in the 1-11-year-old group. Conversely, the 12-19-year-old and 20 years or older age groups witnessed substantial increases in AD prevalence, climbing from 2.55 to 6.02% and 1.44% to 3.53%, respectively. Moreover, the proportion of patients classified as having moderate to severe AD grew from 30.96 to 39.78%. Surprisingly, the prescription pattern, predominantly based on corticosteroid administration, exhibited minimal change despite the rising prevalence of moderate and severe AD cases. These findings underline a persistent reliance on corticosteroid-based treatments for AD, even as the condition's severity escalates among Korean adolescents and adults. Consequently, there is a pressing need to develop novel treatment guidelines emphasizing biologics that offer enhanced safety and efficacy.

INDIVIDUAL ARTICLE: Atopic Dermatitis Skincare and Impact on Quality of Life for Patients with Skin of Color.

Atopic Dermatitis (AD) epidemiologic studies report a higher incidence and prevalence among populations with skin of color (SOC). Additionally, differences in AD underlying gene mutations and skin morphology are observed to lead to frequent and prominent xerosis, pruritus, and pigmentary sequelae in patients of color. However, populations with SOC are underrepresented in dermatology clinical trials, including AD. This article reviews the nuances in AD epidemiology, clinical presentation, and impact on quality-of-life among populations with SOC, plus highlight the role of skincare in AD management. J Drugs Dermatol. 2024;23:3(Suppl 2):s6-11.

Maternal dietary indexes are not linked to early childhood wheezing or atopic eczema.

BACKGROUND: Several recent studies have investigated the association between maternal diet during pregnancy and wheezing or asthma in children. However, whether a specific dietary pattern during pregnancy protects children from wheezing or atopic diseases remains unclear. This study investigated the association between The Alternative Healthy Eating Index for Pregnancy (AHEI-P), the Dietary Inflammatory Index (DII), and the risk for wheezing and atopic eczema in children during the first year of life. METHODS: This study included 1330 mother-child pairs who attended the Kuopio Birth Cohort (KuBiCo) study and had dietary information during the last trimester and information on children's health in the first year of life. AHEI-P and DII indicate a healthy diet and dietary inflammation potential during pregnancy. The AHEI-P and DII were compared with reported wheezing and doctor-diagnosed atopic eczema in children during the first year of life. RESULTS: Neither AHEI-P nor DII is associated with wheezing or atopic eczema in children when analyzed by continuous variables and by tertiles. The odds ratio (95% CI) for AHEI-P and wheezing was 0.99 (0.98-1.01), for AHEI-P and atopic eczema1.01 (0.99-1.02), for DII and wheezing 1.02 (0.95-1.09), and for DII and atopic eczema 0.97 (0.91-1.04). CONCLUSION: In this cohort study, AHEI-P and DII during pregnancy were not associated with wheezing or atopic eczema in the offspring during the first year of life.

Symptoms of Cognitive Impairment Among Children With Atopic Dermatitis.

Importance: Previous studies suggest that atopic dermatitis (AD) is associated with cognitive impairment in children, but these studies have relied primarily on neurodevelopmental diagnoses (rather than symptoms) as proxy measures of cognitive function. It remains unknown if certain subpopulations of children with AD are at greater risk of cognitive impairment. Objective: To examine the association of AD with symptoms of cognitive impairment (difficulty in learning or memory) among US children and whether this association varies according to the presence or absence of neurodevelopmental comorbidities (attention-deficit/hyperactivity disorder [ADHD], developmental delay, or learning disability). Design, Setting, and Participants: This cross-sectional study used 2021 data from the US National Health Interview Survey collected on children aged 17 years or younger without intellectual disability or autism. The presence of AD was based on a parent or adult caregiver's report indicating either a current diagnosis of AD or a previous medical confirmation of AD by a health care professional. Main Outcomes and Measures: Difficulty with learning or memory as reported by the child's caregiver. Results: Among the weighted total of 69 732 807 participants, 9 223 013 (13.2%) had AD. Compared with children without AD, children with AD were more likely to experience difficulties with learning (10.8% [95% CI, 7.8%-15.8%] vs 5.9% [95% CI, 5.1%-6.9%]; P < .001) and difficulties with memory (11.1% [95% CI, 8.0%-15.9%] vs 5.8% [95% CI, 4.9%-6.9%]; P < .001). In multivariable logistic regression models adjusted for sociodemographic factors, asthma, food allergies, and seasonal allergies or hay fever, AD was associated with increased odds of difficulties in learning (adjusted odds ratio [AOR], 1.77; 95% CI, 1.28-2.45) and memory (AOR, 1.69; 95% CI, 1.19-2.41). In analyses stratified by neurodevelopmental comorbidities, AD was associated with 2- to 3-fold greater odds of memory difficulties among children with any neurodevelopmental disorder (AOR, 2.26; 95% CI, 1.43-3.57), including ADHD (AOR, 2.90; 95% CI, 1.60-5.24) or learning disabilities (AOR, 2.04; 95% CI, 1.04-4.00). However, AD was not associated with learning or memory difficulties among children without neurodevelopmental conditions. Conclusions and Relevance: Results of this cross-sectional study suggest that pediatric AD was generally associated with greater odds of reported difficulties in learning and memory. However, this association was primarily limited to children with neurodevelopmental comorbidities, such as ADHD or learning disabilities. These findings may improve the risk stratification of children with AD for cognitive impairments and suggest that evaluation for cognitive difficulties should be prioritized among children with AD and neurodevelopmental disorders.

Association between Outdoor and Indoor Air Pollution Sources and Atopic Eczema among Preschool Children in South Africa.

The objective of the study was to investigate the association between outdoor and indoor air pollution sources and atopic eczema among preschool children in South Africa. A cross-sectional design, following the International Study of Asthma and Allergies in Childhood (ISAAC) Phase III protocol, was applied. The study was conducted in Mabopane and Soshanguve Townships in the City of Tshwane Metropolitan Municipality in Gauteng, South Africa. A total population of 1844 preschool children aged 7 years and below participated in the study; 1840 were included in the final data analysis. Data were analyzed using multilevel logistic regression analysis. The prevalence of eczema ever (EE) and current eczema symptoms (ESs) was 11.9% and 13.3%, respectively. The use of open fires (paraffin, wood, or coal) for cooking and heating increased the likelihood of EE (OR = 1.63; 95% CI: 0.76-3.52) and current ESs (OR = 1.94; 95% CI: 1.00-3.74). Environmental tobacco smoke (ETS) exposure at home increased the likelihood of EE (OR = 1.66; 95% CI: 1.08-2.55) and current ESs (OR = 1.61; 95% CI: 1.07-2.43). Mothers or female guardians smoking cigarettes increased the likelihood of EE (OR = 1.50; 95% CI: 0.86-2.62) and current ESs (OR = 1.23; 95% CI: 0.71-2.13). The use of combined building materials in homes increased the likelihood of EE, and corrugated iron significantly increased the likelihood of current ESs. The frequency of trucks passing near the preschool children's residences on weekdays was found to be associated with EE and current ESs, with a significant association observed when trucks passed the children's residences almost all day on weekdays. Atopic eczema was positively associated with exposure to outdoor and indoor air pollution sources.

Cracking the code: unveiling the nexus between atopic dermatitis and addictive behavior: a cross-sectional exploration of risk factors.

Atopic dermatitis (AD) stands as a prevalent chronic inflammatory skin disorder with a global reach. Beyond its cutaneous manifestations, AD is accompanied by comorbidities and psychological issues, significantly compromising the overall quality of life for individuals who suffer from AD. Previous research has evidenced a heightened prevalence of addictive disorders among dermatological patients when compared to the general population. Considering these findings, this study endeavors to examine the prevalence of addictive disorders among AD patients and, furthermore, to discern potential risk factors associated with this comorbidity. Therefore, a cross-sectional study was conducted involving patients with AD diagnosed by dermatologists within a large university hospital in Munich, South Germany, between January 2016 and December 2019. Patients received an anonymous paper-based questionnaire comprising standardized and reliable assessment tools concerning disease severity, quality of life, sexual dysfunction, well-being, and anxiety disorder as well as screening tools for various addictive disorders (compulsive internet use, drug abuse, pathological alcohol consumption, and smoking). Data were analyzed descriptively, and a multivariate logistic regression model was conducted. A total of 208 patients participated in the study, comprising 38% males and 62% females with a mean age of 44.8 ± standard deviation:17.9 years. Females showed a higher mean POEM (Patient-Oriented Eczema Measure) score compared to males (female 14.6 ± 7.8; male 12.5 ± 7.7), as well as a higher DLQI (Dermatology Life Quality Index) (female 8.5 ± 6; male 6.5 ± 6.5). Positive addictions were found in 14.9% for daily smoking, 15.4% for critical alcohol consumption, 16.8% for compulsive internet use, and 5.8% for drug abuse. Younger patients were more likely to be affected by one or multiple addictions than older patients. Patients with at least one addiction showed significantly impaired well-being and increased severe anxiety symptoms. Given the notable prevalence of addictive disorders among individuals with AD, it could be useful to implement systematic screening for such conditions as part of patient-centered care, especially focusing on young AD patients or those displaying concurrent indications of depression or anxiety.

Factors influencing the quality of life in children with atopic dermatitis in Korea: A multicenter cross-sectional study.

Background: There is a lack of studies about which factors affect the quality of life (QoL) in children with atopic dermatitis (AD), although it is well known that AD has considerably negative effects on their QoL. Objective: This study aimed to measure the QoL in children with AD and identify the factors that affect their QoL. Methods: A questionnaire derived from the Children's Dermatology Life Quality Index (CDLQI) was used to measure QoL. Family history, allergic comorbidities, exacerbation-related factors, time of exacerbation, and previous and current treatment were also evaluated. The total immunoglobulin E (IgE) level and specific IgE sensitization were determined by the multiple allergen simultaneous test, allergy test, or skin-prick test. AD severity was categorized into mild, moderate, and severe based on treatments. Results: In total, 254 children (46.4 months, 53% boys) from seven hospitals completed the survey. The mean CDLQI score was 7.2 ± 5.5 (total score range of 0-30). The respondents were divided into three groups according to their QoL score distribution, with 0 - 4 points (n = 84), 5 - 9 points (n = 90), and ≥10 points (n = 80) representing good, fair, and poor QoL, respectively. The more severe AD showed the higher CDLQI score significantly (p = 0.001). Compared with other groups, children with poor QoL were more sensitized to inhalant allergens (odds ratio [OR] 1.29 [95% confidence interval {CI}], 1.03 - 1.62) and had more exacerbating factors (OR 1.26 [95% CI, 1.04 - 1.54]), which included inhalation allergen-related exacerbating factors (OR 2.54 [95% CI, 1.23 - 5.23), even after adjusting for age, total IgE, body mass index, severity, and use of moisturizer. The concordance between animal sensitization and an exacerbating factor, including dog and cat, was fair, with 0.39 κ and 0.85 accuracy. Conclusion: This study showed that impaired QoL in children with AD is associated with inhalant allergen sensitization and inhalant allergen-related exacerbation factors. Especially, dog and cat sensitization was a significant exacerbating factor. The inhalation-related exacerbation factors, including animal allergens, might be addressed to improve AD management in children.

Causal association between atopic dermatitis and Parkinson's disease: A bidirectional Mendelian randomization study.

BACKGROUND: Atopic dermatitis is one of the most common skin disorders. Evidence has suggested an association between skin disorders, such as atopic dermatitis, and Parkinson's disease (PD). However, whether atopic dermatitis has a causal effect on PD remains unknown. METHODS: The study aimed to determine whether their association between atopic dermatitis and PD is causal, using a bidirectional two-sample Mendelian randomization method. Genetic variants from the public genome-wide association studies for atopic dermatitis (n = 10788 cases and 30047 controls) were selected to evaluate their causal effects on the risk of PD (33,674 cases and 449,056 controls). The inverse variance weighted (IVW) method was used as the primary analysis. RESULTS: The IVW results indicated that atopic dermatitis was associated with decreased risk of PD {fixed effects: odds ratio [OR] [95% confidence interval (CI)]: .905 [.832-.986], p = .022; OR [95% CI]: .905 [.827-.991], p = .032}. However, we failed to detect the causal effects of PD on risk of atopic dermatitis in the reverse causation analysis. CONCLUSION: This study indicated causal association of genetically proxied atopic dermatitis with the risk of PD. Future studies are warranted to explore the underlying mechanism and investigate the targeting effect of atopic dermatitis on PD.

Assessing severity of COVID-19 and the development of multi system inflammatory syndrome in children (MIS-C) in pediatric patients with atopic disease.

Background: Research surrounding the coronavirus disease 2019 (COVID-19) pandemic and its impact on patients who are atopic has mainly focused on adults. After the delta variant showed increased rates of COVID-19 in children, the pediatric population needs to be assessed as well. Objective: The objective was to assess and report outcomes in patients with COVID-19 and with and without certain atopic diseases in our patient cohort at the University of Mississippi Medical Center. Methods: We conducted a retrospective review of patients by using a de-identified data base that allows querying via medical claims codes from the University of Mississippi Medical Center's Research Data Warehouse. We searched for patients who were COVID-19 positive and ages 0-21 years from January 1, 2020, to December 31, 2021. We then divided this population into two cohorts: an atopic population and a non-atopic population. The incidence of hospitalizations, intensive care unit (ICU) admissions, death, length of stay, inhaled corticosteroid prescription history, and the incidence of multi-system inflammatory syndrome in children (MIS-C) outcomes in the two populations were collected. Results: There were 5261 patients ages 0-21 years and with confirmed COVID-19. After exclusion criteria were applied, there were 1420 patients in the atopic cohort and 2525 patients in the non-atopic cohort. There were more hospitalizations and a longer length of stay in the atopic population. Mortality was equivalent in the atopic and non-atopic populations. There were more ICU admissions in the atopic population. There were 101 patients total with the diagnosis of MIS-C, and the incidence of MIS-C was similar in the atopic and non-atopic populations. There were more patients who were atopic on inhaled corticosteroid than were the patients who were non-atopic. Conclusion: This study sought to further elucidate whether asthma, atopic dermatitis, and allergic rhinitis in pediatric patients was associated with severe COVID-19. Our study showed increased hospitalizations, length of stay, and intensive care in the atopic population but similar outcomes in mortality and the development of MIS-C. Future longitudinal prospective studies are needed to assess the long-term effects on patient's atopic disease after COVID-19 infection.

Antibiotic exposure during pregnancy increases risk for childhood atopic diseases: a nationwide cohort study.

PURPOSE: The prevalence of atopic diseases has increased in recent decades. A possible link between antibiotic use during pregnancy and childhood atopic disease has been proposed. The aim of this study is to explore the association of antibiotic exposure during pregnancy with childhood atopic diseases from a nationwide, population-based perspective. METHODS: This was a nationwide population-based cohort study. Taiwan's National Health Insurance Research Database was the main source of data. The pairing of mothers and children was achieved by linking the NHIRD with the Taiwan Maternal and Child Health Database. This study enrolled the first-time pregnancies from 2004 to 2010. Infants of multiple delivery, preterm delivery, and death before 5 years old were excluded. All participants were followed up at least for 5 years. Antenatal antibiotics prescribed to mothers during the pregnancy period were reviewed. Children with more than two outpatient visits, or one admission, with a main diagnosis of asthma, allergic rhinitis, or atopic dermatitis were regarded as having an atopic disease. RESULTS: A total of 900,584 children were enrolled in this study. The adjusted hazard ratios of antibiotic exposure during pregnancy to childhood atopic diseases were 1.12 for atopic dermatitis, 1.06 for asthma, and 1.08 for allergic rhinitis, all of which reached statistical significance. The trimester effect was not significant. There was a trend showing the higher the number of times a child was prenatally exposed to antibiotics, the higher the hazard ratio was for childhood atopic diseases. CONCLUSIONS: Prenatal antibiotic exposure might increase the risk of childhood atopic diseases in a dose-dependent manner.

Comorbidities associated with adult asthma: a population-based matched cohort study in Finland.

BACKGROUND: Asthma is a common chronic disease characterised by variable respiratory symptoms and airflow limitation, affecting roughly 4%-10% of the adult population. Adult asthma is associated with higher all-cause mortality compared to individuals without asthma. In this study, we investigate the comorbidities that may affect the management of asthma. METHODS: Total of 1648 adults with asthma and 3310 individuals without asthma aged 30-93 were matched with age, gender and area of residency, and followed from 1 January 1997 to 31 December 2013. Baseline information was collected with questionnaires 1997 and follow-up register data from the national discharge registry Finnish Institute for Health and Welfare. Data included diagnoses from outpatient care and day surgery of specialised health care, and data from inpatient care of specialised and primary health care. We included all main diagnoses that had at minimum 200 events and number of diagnoses based on their common appearance with adult asthma. RESULTS: The mean follow-up time varied between 14.2 and 15.1 years, and age at the time of enrolment was 53.9 years for subjects without asthma and 54.4 years for patients with asthma. Chronic obstructive pulmonary disease was 10 times more common among asthmatics. Risk of acute rhinosinusitis, chronic rhinosinusitis with nasal polyps, atopic dermatitis and vocal cord dysfunction was fourfold and risk of pneumonia, and chronic rhinosinusitis was 2.5 times more common among asthmatics. Sleep apnoea, gastro-oesophageal reflux disease, diabetes, allergic rhinitis and dysfunctional breathing were twofold and cataract nearly twofold higher in the asthmatic group. Adult asthma was also significantly associated with musculoskeletal diseases, incontinence and bronchiectasis. CONCLUSIONS: The most common and most severe comorbidity of adult asthma in this study was chronic obstructive pulmonary disease. Other common comorbidities of adult asthma include acute rhinosinusitis, chronic rhinosinusitis with nasal polyps, atopic dermatitis, allergic rhinitis, dysfunctional breathing, diabetes, pneumonia, sleep apnoea and gastro-oesophageal reflux disease.

The relationship between childhood atopic dermatitis and asthma in an under resourced community.

Background: Atopic dermatitis (AD) is an inflammatory skin disease caused by allergen exposures and estimated to affect ∼20% of children. Children in urban areas have a higher prevalence of AD compared with those living outside of urban areas. AD is believed to lead to asthma development as part of the "atopic march." Objective: Our objective was to determine the sequential and chronological relationships between AD and asthma for children in an under-resourced community. Methods: The progression from AD to asthma in the under-resourced, urban community of Sun Valley, Colorado, was examined by assessing Medicaid data for the years 2016 to 2019 for a diagnosis of AD or asthma in children 6 and 7 years old. Results: Pearson correlations between AD and asthma diagnoses were significant only with respect to AD at age 6 years compared with asthma 1 year later, at age 7 years. Conclusion: By studying a susceptible community with a consistent but mixed genetic background, we found sequential and chronological links between AD and asthma.

Comparison of metabolic and neurological comorbidities in Asian patients with psoriasis and atopic dermatitis.

Although various comorbidities have been noted to be associated with atopic dermatitis (AD) and psoriasis, few studies have compared comorbidities between the two diseases, and little is known about whether these comorbidities vary by the subtypes of psoriasis. In this study of 1:1 age- and sex-matched pair analysis between patients diagnosed with either psoriasis or AD at Asan Medical Center between 1991 and 2020, comorbidities, as determined by the International Classification of Diseases-10 codes, and likelihood ratios of metabolic and neurologic comorbidities in psoriasis compared with AD were studied using a logistic regression model. Among a total of 14,128 patients, the psoriasis group had higher odds of obesity (odds ratio [95% confidence interval]: 1.49 [1.34-1.66]), hypertension (1.14 [1.03-1.26]), diabetes mellitus (1.46 [1.29-1.66]), chronic kidney disease (1.59 [1.22-2.08]), and Parkinson's disease (2.1 [1.15-3.83]) than the AD group. Subgroup analysis revealed that patients with plaque psoriasis had higher odds of obesity (1.18 [1.05-1.33]), hypertension (1.18 [1.06-1.32]), diabetes mellitus (1.53 [1.34-1.75]), chronic kidney disease (1.66 [1.26-2.17]), and Parkinson's disease (2.12 [1.16-3.88]) compared with AD. Meanwhile, guttate psoriasis was associated with higher odds of dementia (3.63 [1.06-12.40]) and patients with generalized pustular psoriasis showed higher odds of diabetes mellitus (5.42 [1.56-18.83]) compared with AD. In conclusion, Asian patients with all types of psoriasis should be closely monitored for the development of metabolic and neurologic diseases, especially men and those aged ≥ 40 years.

No causal association between atopic dermatitis and COVID-19 outcomes: A Mendelian randomization study.

BACKGROUND: Frequent hand washing and disinfection during the corona virus disease (COVID-19) pandemic may lead to skin-related disability. The causal relationship between atopic dermatitis (AD), the most common chronic, noninfectious, inflammatory skin disease, and COVID-19 remains unclear. We used Mendelian randomization (MR) to explore the causal inference of atopic dermatitis with COVID-19 outcomes. METHODS: Genome-wide association study (GWAS) data for AD, consisting of 8383 cases and 236,162 controls of European ethnicity, were provided by the FinnGen database. The GWAS outcome data were derived from the COVID-19 Host Genetics Initiative and consisted of COVID-19 susceptibility (122,616 cases and 2,475,240 controls), hospitalization (32,519 cases and 2,062,805 controls), and very severe respiratory disease (13,769 cases and 1,072,442 controls). The inverse variance weighted with a fixed effects model (IVW (fe)) was used as the main statistical approach to assess the causality between AD and COVID-19 in this study. Several other analytical methods have also been used to complement or identify pleiotropy and heterogeneity. RESULTS: MR analysis showed no causality between AD and COVID-19 outcomes. The odds ratios (OR) were 1.00 (95% confidence interval (CI), 0.99-1.02) for susceptibility, 1.00 (95% CI, 0.96-1.04) for hospitalization, 0.97 (95% CI, 0.92-1.03) for very severe respiratory disease by the method of IVW (fe). CONCLUSION: In conclusion, we found no causal relationship between AD and COVID-19 outcomes. This study provides additional ideas for the exploration of the risk factors for COVID-19.

Systemic lupus erythematosus and Atopic dermatitis: A two sample Mendelian randomization study.

BACKGROUND: Systemic lupus erythematosus (SLE) and atopic dermatitis (AD) are common diseases in human populations. Previous studies have suggested a potential association between SLE and AD. However, the causal relationship and direction between the two conditions remain unclear. OBJECTIVE: The aim of this study is to evaluate the causal relationship between SLE and AD. METHODS: In this study, we employed Mendelian randomization (MR) analysis to investigate the causal relationship between SLE and AD. MR analysis has the advantage of reducing confounding factors, determining the direction of causality, and providing quantitative effect estimates. We obtained summary data from genome-wide association studies (GWAS) on SLE and AD from publicly available databases. Five MR methods, namely MR Egger, weighted median, inverse variance weighted, simple mode, and weighted mode, were used to assess the causal relationship between SLE and AD. Several techniques, including MR-Egger intercept, MR-PRESSO, and Cochran's Q test, were utilized to evaluate heterogeneity and pleiotropy. RESULTS: Our study demonstrated a causal relationship between the prevalence of SLE and an increased risk of AD (MR Egger OR: 1.567, 95% CI: [1.041, 1.285], P = 0.009; IVW OR: 1.085, 95% CI: [1.005, 1.143], P = 0.035). Furthermore, sensitivity analyses did not detect heterogeneity or pleiotropy. CONCLUSION: Our research finds that SLE is a contributing factor to the development of AD, providing valuable insights into the pathogenesis and prevention of both diseases. Key Points • Currently, there is no research that clearly indicates a causal relationship between SLE and AD. This study, for the first time, identified a positive causal relationship between SLE and AD. • The results of this study contribute to our understanding of the pathogenesis and treatment strategies for SLE and AD, providing some guidance for future clinical practice.