Effect of Vitamin D Serum Levels and Supplementation on Atopic Dermatitis: A Systematic Review and Meta-analysis

Role of antioxidants supplementation in the treatment of atopic dermatitis: a critical narrative review

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by itching, epidermal barrier dysfunction, and an unbalanced inflammatory reaction. AD pathophysiology involves a dysregulated immune response driven by T helper-2 cells. Many factors, including reactive oxygen species (ROS), are involved in AD pathogenesis by causing cellular damage and inflammation resulting in skin barrier dysfunction. This narrative review aims to provide a comprehensive overview of the role of natural molecules and antioxidant compounds, highlighting their potential therapeutic value in AD prevention and management. They include vitamin D, vitamin E, pyridoxine, Vitamin C, carotenoids, and melatonin. Some studies report a statistically significant association between antioxidant levels and improvement in AD, however, there are conflicting results in which antioxidant supplementation, especially Vitamin D, did not result in improvement in AD. Therefore, the clinical efficacy of these dietary nutritional factors in the treatment of AD needs to be further evaluated in clinical trials. Meanwhile, antioxidants can be incorporated into the management of AD patients in a personalized manner, tailored to the severity of the disease, comorbidities, and individual needs.

Association Between Atopic Dermatitis and Aging: Clinical Observations and Underlying Mechanisms

As one of the most prevalent chronic inflammatory skin diseases, atopic dermatitis (AD) increasingly affects the aging population. Amid the ongoing global aging trend, it's essential to recognize the intricate relationship between AD and aging. This paper reviews existing knowledge, summarizing clinical observations of associations between AD and aging-related diseases in various systems, including endocrine, cardiovascular, and neurological. Additionally, it discusses major theories explaining the correlation, encompassing skin-mucosal barriers, systemic inflammation and stress, genes, signal transduction, and environmental and behavioral factors. The association between AD and aging holds significant importance, both in population and basic perspectives. While further research is warranted, this paper aims to inspire deeper exploration of inflammation/allergy-aging dynamics and the timely management of elderly patients with AD.

Sex and obesity status modify the association between vitamin D and eczema among adolescents

BACKGROUND

Epidemiologic studies have reported inconsistent associations between vitamin D and eczema. This study sought to assess whether sex and obesity status could modify the association between vitamin D and eczema.

METHODS

A cross-sectional study enrolled 763 adolescents in Kuwait. 25-hydroxyvitamin D (25(OH)D) was measured in venous blood. Current eczema was defined according to clinical history and characteristic morphology and distribution.

RESULTS

In sex-stratified analysis, decreased 25(OH)D levels were associated with increased current eczema prevalence among males (adjusted odds ratio (aOR)tertile 1 vs. tertile 3: 2.14, 95% confidence intervals (CI): 1.07-4.56), but not among females (aORtertile 1 vs. tertile 3: 1.08, 95% CI: 0.71-1.66). Further stratification by obesity status showed that lower 25(OH)D levels were associated with increased current eczema prevalence among overweight/obese males (per 10-unit decrease in 25(OH)D levels: aOR: 1.70, 95% CI: 1.17-2.46). Such an association was weaker and statistically non-significant among overweight/obese females (per 10-unit decrease in 25(OH)D levels: aOR: 1.26, 95% CI: 0.93-1.70).

CONCLUSIONS

Sex and obesity status modified the association between vitamin D levels and eczema, with an inverse association observed among overweight/obese males, but not among overweight/obese females. These results suggest that preventive and clinical management strategies could vary by sex and obesity status.

IMPACT

The current study showed that sex and obesity modify the association between vitamin D and eczema among adolescents. An inverse association between vitamin D and eczema was observed among overweight/obese males, but this association was not as pronounced among overweight/obese females. Vitamin D was not associated with eczema among underweight/normal weight males and females. The identification of effect modification by sex and obesity status add to the current scientific knowledge and further highlight the complexity of the association between vitamin D and eczema. These results may promote a more individualized approach to the future prevention and clinical management of eczema.

Serum vitamin D levels can be predictive of psoriasis flares up after COVID-19 vaccination: a retrospective case control study

Introduction

Many patients with chronic inflammatory dermatosis such as psoriasis usually ask about the safety of COVID-19 vaccination and if it would affect the course of their disease. Indeed, many case reports, case series and clinical studies, reporting psoriasis exacerbation following vaccination against COVID-19, were published during the pandemic. Also, many questions arise regarding the existence of exacerbating factors of these flare ups, including environmental triggers such as the insufficiency of vitamin D levels.

Methods

This is a retrospective study that measures alterations in psoriasis activity and severity index (PASI) not exceeding 2 weeks after the first and second dose of COVID-19 vaccinations in the reported cases and assesses whether such changes have any association with patients' vitamin D levels. We retrospectively reviewed the case records of all patients with a documented flare up after COVID-19 vaccination in our department as well as those who did not, during a year.

Results

Among them, we found 40 psoriasis patients that had reported vitamin D levels in the form of 25-hydroxy-vitamin D within 3 weeks after vaccination, including 23 with exacerbation and 17 without exacerbation. Performing χ² and t-test controls for psoriasis patients with and without flare-ups, a statistically significant dependence emerged in the seasons of summer [χ²(1) = 5.507, p = 0.019], spring [χ²(1) = 11.429, p = 0.001] and in the categories of vitamin D [χ²(2) = 7.932, p = 0.019], while the mean value of vitamin D for psoriasis patients who did not have exacerbation (31.14 ± 6.67 ng/mL) is statistically higher [t(38) = 3.655, p = 0.001] than the corresponding value of psoriasis patients who had an exacerbation (23.43 ± 6.49 ng/mL).

Discussion

This study indicates that psoriasis patients with insufficient (21-29 ng/mL) or inadequate (<20 ng/mL) levels of vitamin D are more prone to postvaccination aggravation of the disease while vaccination in summer, a period with the most extent photo-exposition, can be a protective factor.

Are There Ethnic Differences in Hand Eczema? A Review

Hand eczema is a common disease with economic and social ramifications. This study undertakes a review of certain existing literature to provide insight into contributory factors which may result in the varying prevalence and severity of hand eczema among different ethnic groups, particularly to identify modifiable risk factors, as well as to ascertain knowledge gaps for future research direction. The existing literature suggests that factors including (a) genes, (b) differing skin physiology, (c) cultural practices, (d) dietary habits and associated food preparation, (e) climate, (f) predominant occupations, (g) socioeconomic factors, and (h) dissimilar laws and regulations may account for the disparity in the risk of hand eczema among different ethnicities. Given that endogenous factors cannot be avoided, but certain exogenous aspects can be modified, especially as the environment plays an important role in hand eczema flares, it is helpful from a practical perspective to focus on addressing the modifiable risk factors. These factors pertain to unique cultural practices, customs, and food preparation methods. Healthcare professionals should be well-acquainted with such factors to tailor the treatment approach for patients of different ethnicities accordingly because, with globalization, physicians face increasingly diverse patient populations such that cultural customs no longer remain limited to particular geographic regions.

Effect of Vitamin D on the Treatment of Atopic Dermatitis With Consideration of Heterogeneities: Meta-Analysis of Randomized Controlled Trials

Various therapeutic approaches, including supplemental nutritional support, have been tried for the treatment of atopic dermatitis (AD). Previous studies have reported the role of vitamin D in the treatment of AD with inconsistent results. The aim of this study was to evaluate the effectiveness of vitamin D in the treatment of AD, with considerations on the heterogeneities of AD. Randomized controlled trials (RCTs) on the efficacy of vitamin D supplementation for AD treatment, published before June 30, 2021 were identified in the PubMed, EMBASE, MEDLINE, and Cochrane Library databases. The quality of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluation system. This meta-analysis included 5 RCTs with 304 cases of AD. We found that vitamin D supplementation did not decrease AD severity, even when AD was classified as severe vs non-severe. However, vitamin D supplementation was found to be effective in the treatment of AD in RCTs that included both children and adults, but not in those that included only children. Geographic location was associated with a significant difference in the therapeutic effect of vitamin D supplementation. Moreover, vitamin D supplementation of > 2,000 IU/day decreased AD severity, but supplementation ≤ 2,000 IU/day did not. Vitamin D supplementation, in general, was not effective for the treatment of AD. However, vitamin D supplementation might provide a therapeutic effect depending on the geographic location and dose of supplementation. The results of the present meta-analysis suggest that vitamin D supplementation might be targeted for patients with AD who may benefit from vitamin D supplementation.

Is Vitamin D3 a Worthy Supplement Protecting against Secondary Infections in Dogs with Atopic Dermatitis?

Canine atopic dermatitis (CAD) is a common, chronic, inflammatory skin disease in dogs worldwide. This disease often predisposes for secondary organisms overgrowth and skin infections with pathogens, such as Staphylococcus pseudintermedius and Malassezia pachydermatis. Unfortunately, the causes of this disease in both humans and animals are not fully understood; therefore, the only possible option is a lifelong, symptomatic treatment. The management of CAD is mainly based on limiting contact with allergens and antipruritic therapy, most often with glucocorticoids and antihistamines. A serious problem in this situation is the fact, that long-term administration of glucocorticoids leads to side effects like polyuria, alopecia, increased susceptibility to infection, muscle atrophy, and many others. For this reason, great emphasis is placed on the development of replacement and supportive therapies. It is a well-documented fact that reduced concentrations of serum vitamin D3 contribute to the severity of atopic dermatitis symptoms in humans. Moreover, unlike the most commonly used therapeutic methods, of which the main goal is to ameliorate inflammation and pruritus, namely the symptoms of AD, vitamin D3 supplementation affects some underlying factors of this disease. Therefore, in this review, we summarize the current state of knowledge regarding the role of vitamin D3 in CAD, its protective effect against secondary bacterial and fungal infections, and the potential of its supplementation in dogs.

Causal Associations between Vitamin D Levels and Psoriasis, Atopic Dermatitis, and Vitiligo: A Bidirectional Two-Sample Mendelian Randomization Analysis

BACKGROUND

Vitamin D level has been reported to be associated with psoriasis, atopic dermatitis, and vitiligo. However, its causal relationship with the risk of these three diseases remains unclear.

METHODS

We obtained genome-wide association statistics for three measures of circulating vitamin D levels (25(OH)D in 120,618 individuals, and 25(OH)D3 and epimeric form C3-epi-25(OH)D3 in 40,562 individuals) and for the diseases psoriasis (3871 cases and 333,288 controls), atopic dermatitis (21,399 cases and 95,464 controls), and vitiligo (4680 cases and 39,586 controls). We performed Mendelian randomization using inverse-variance weighted, weighted median, MR-Egger, and MR-pleiotropy residual sum and outlier methods. We carried out sensitivity analyses to evaluate the robustness of the results.

RESULTS

We showed that elevated vitamin D levels protected individuals from developing psoriasis (OR = 0.995, p = 8.84 × 10^-4 for 25(OH)D; OR = 0.997, p = 1.81 × 10^-3 for 25(OH)D₃; and OR = 0.998, p = 0.044 for C3-epi-25(OH)D₃). Genetically predicted risk of atopic dermatitis increased the levels of 25(OH)D (OR = 1.040, p = 7.14 × 10^-4) and 25(OH)D₃ (OR = 1.208, p = 0.048). A sensitivity analysis suggested the robustness of these causal associations.

CONCLUSIONS

This study reported causal relationships between circulating vitamin D levels and the risk of psoriasis, atopic dermatitis, and vitiligo. These findings provide potential disease intervention and monitoring targets.

Oral vitamin D modulates the epidermal expression of the vitamin D receptor and cathelicidin in children with atopic dermatitis

Although vitamin D (VD) is known to have multiple effects on the skin and immunity, its effects on atopic dermatitis (AD) severity remain unclear. We investigated whether oral cholecalciferol (VD3) supplementation changes stratum corneum expression of the vitamin D receptor (vdr), and the epidermal alarmins Cathelicidin Antimicrobial Peptide (camp/LL-37) and Thymic Stromal Lymphopoietin (tslp) in children with AD. We conducted an open-label supplementation study with weekly oral VD3 for six weeks in children with AD. Serum 25-hydroxyvitamin D (25OHD), lesional Staphylococcus aureus colonization, and AD severity evaluated by SCORAD index were evaluated before and after supplementation. Tape stripping (TS) was performed on non-lesional and lesional skin to measure mRNA expression of vdr, camp, and tslp through RT-qPCR and LL-37 peptide by ELISA. Twenty-two children with moderate-severe AD received weekly oral VD3 for six weeks. Total serum 25OHD increased from 45.1 ± 23 to 93.5 ± 24.3 nmoL/L (p < 0.0001), while SCORAD decreased from 41.4 ± 13.5 to 31.5 ± 15.8 (p < 0.0001). After treatment, epidermal gene expression of camp increased significantly in non-lesional (p = 0.014) and lesional (p = 0.0007) tape stripping samples, while vdr only increased in lesional skin samples (p < 0.0001). LL-37 peptide increased significantly only in lesional skin samples (p = 0.008). Gene expression of tslp did not change after oral VD3 treatment. In children with AD, oral VD3 supplementation was associated with improved VD status and AD severity, as well as increased VDR and Cathelicidin expression in lesional skin, which provide mechanistic clues on its effects.

Risk factors for food sensitization in children with atopic dermatitis: a single-center cross-sectional study

OBJECTIVES

To study the risk factors for food sensitization and the influence of food sensitization on quality of life and clinical signs in children with atopic dermatitis (AD).

METHODS

A retrospective analysis was performed on the medical data of 241 children with AD, including demographic features, age of onset, severity of AD, quality of life, physical examination results, skin prick test (SPT) results, serum total IgE levels, and eosinophil count. According to the results of SPT, the children were divided into a food sensitization group (n=127) and a non-food sensitization group (n=114). The multivariate logistic regression analysis was used to identify the risk factors for food sensitization in children with AD.

RESULTS

The prevalence rate of food sensitization was 52.7% (127/241) in the children with AD. The multivariate logistic regression analysis showed that birth in autumn or winter, age of onset of AD<12 months, severe AD, and total IgE>150 IU/mL were risk factors for food sensitization (P<0.05). Compared with the non-food sensitization group, the food sensitization group had a significantly poorer quality of life (P=0.008) and significantly higher prevalence rates of non-specific hand/foot dermatitis and palmar hyperlinearity (P<0.05). Compared with the single food sensitization group, the multiple food sensitization group had more severe AD and a significantly higher proportion of children with exclusive breastfeeding or total IgE>150 IU/mL (P<0.05).

CONCLUSIONS

The AD children born in autumn or winter, or those with early onset (<12 months), severe AD or total IgE>150 IU/mL have a higher risk of food sensitization. The AD children with food sensitization have a poorer quality of life and are more likely to develop non-specific hand/foot dermatitis and palmar hyperlinearity.

Serum Vitamin D Level and Efficacy of Vitamin D Supplementation in Children with Atopic Dermatitis: A Systematic Review and Meta-analysis

Background

The relationship between vitamin D and atopic dermatitis (AD) is controversial. This meta-analysis is aimed at exploring vitamin D level and its deficiency in pediatric AD and at evaluating the efficacy of vitamin D supplementation.

Methods

PubMed, Medline, Embase, Ovid, Cochrane Library, ISI Web of Science, and ClinicalTrials were searched. Binary variables and continuous variables were measured by odds ratio (OR) and mean difference (MD) with 95% confidence intervals, respectively. The modified Jadad scale, Newcastle-Ottawa Scale (NOS), and Cochrane's bias risk tools were used to evaluate study quality and the risk of bias of eligible studies, respectively.

Results

A total of 22 literature were included in the analysis. Serum 25 (OH) D level in pediatric AD patients was significantly lower than that of the control group with a combined MD value of -8.18 (95% CI: -13.15, -3.22). Patients with AD were more prone to develop vitamin D deficiency with a combined OR value of 2.17 (95% CI: 1.15, 4.11). According to the score of SCORAD, the level of serum 25 (OH) D level in patients with severe AD was significantly lower than that in patients with mild AD (combined MD = 9.23, 95% CI: 6.92, 11.55). Both self-control studies and randomized controlled trials showed improved SCORAD score and EASI score after vitamin D supplementation.

Conclusion

This meta-analysis showed lower serum 25 (OH) D level and increased risk of vitamin D deficiency in pediatric AD patients as compared with healthy controls. The serum 25 (OH) D level in severe AD patients was significantly lower than that in the mild AD patients. The SCORAD and EASI score improved after vitamin D supplementation, suggesting its beneficial effect to AD patients. At the same time, more homogeneous studies are needed to reduce confounding factors and further evaluate the impact of vitamin D treatment on the outcome of AD patients.