Researchers from the Konkuk University in Seoul, South Korea found that blood vitamin D levels of sufferers of atopic dermatitis – the most common form of eczema – was on average 2.03 nanograms (ng) per milliliter (mL) lower across all age groups compared to healthy controls.
Looking at children alone, this difference was more marked at 3.03 ng/mL lower for those with the skin condition.
They also found evidence of a significant decrease in symptoms of the condition after vitamin D supplementation.
Weighing up evidence
Vitamin D supplements were explored as a possible strategy against eczema in a Cochrane review back in 2012. Yet this review said available evidence was poor quality and results were unconvincing.
The results of this latest Korean review were based on meta-analysis of seven observational studies on serum D levels and atopic dermatitis, and four randomised controlled trials on vitamin D supplementation as a treatment for sufferers.
The Korean researchers said their meta-analysis pointed to vitamin D as a potential new treatment, but urged caution because the review included only a small adult sample.
They called for large-scale clinical trials to pinpoint specific mechanisms behind the link.
Need for novel treatments
Sufferers of the condition, which causes the skin to become itchy, red, dry and cracked, are often given steroid creams as a treatment.
“These classic treatments are focused on reducing skin inflammation, but their potential side effects and poor patient adherence indicate the importance of finding new therapeutic options,” the researchers wrote in the journal Nutrients.
Steroid creams, or corticosteroids, reduce skin inflammation and irritation. Yet long-term use of very potent creams can lead to thinning of the skin and changes in skin colour.
An international study in the 1990s reported that the condition affects 5–20% of children and 1%–3% adults worldwide, with this prevalence increasing in industrialised countries.
The figures were based on data for 256,410 children aged six to seven years in 90 different centres and 458,623 children aged 13 to 14 years in 153 centres.
Prevalence of symptoms of atopic eczema ranged from less than 2% in Iran to over 16% in Japan and Sweden in the six to seven year age range and less than 1% in Albania to over 17% in Nigeria for the 13 to 14 year age range.
Australasia and Northern Europe saw the higher prevalence while Eastern and Central Europe and Asia saw the lowest.
In most cases eczema develops before a child reaches the age of five, and it can improve significantly or clear completely as they get older.
However, the condition can continue into or develop in adulthood.
Published online ahead of print, doi:10.3390/nu8120789
“Vitamin D Status and Efficacy of Vitamin D Supplementation in Atopic Dermatitis: A Systematic Review and Meta-Analysis”
Authors: M. Jung Kim, S. N. Kim, Y. Won Lee, Y. Beom Choe and K. Joong Ahn