A world-first study has found a clear association between vitamin D deficiency in young children and development of asthma
Researchers at the WA-based Telethon Kids Institute recruited 267 children at high risk for asthma and allergy and followed them from birth until the ages of five and 10.
At birth, the majority of participants had Vitamin D concentrations of less than 50 nmol/L, which is commonly classed as vitamin deficiency. Between the ages six months and four years, the majority also had concentrations indicative of insufficiency, with levels improving from the age of five onwards.
Analysis found that repeated bouts of vitamin D deficiency in early childhood were associated with increased risk for asthma, wheeze, eczema and sensitisation at 10 years.
Lead author Dr Elysia Hollams says the findings shed new light on the potential association.
“We know vitamin D plays an important role in regulating the immune system and promoting healthy lung development,” says Dr Hollams.
“But while it has been suggested that inadequate vitamin D may be a factor contributing to the surge in asthma rates over recent decades, previous studies investigating the relationship have yielded conflicting results.
“Our study is the first to track vitamin D levels from birth to asthma onset, and it has shown a clear link between prolonged vitamin D deficiency in early childhood and the development of asthma.”
Dr Hollams says earlier research has identified the first two years of childhood as a critical time during which allergies and chest infections could combine to drive asthma development in sensitive children.
“Our new findings identify vitamin D deficiency as a co-factor that may promote this process.”
However, she cautioned against pushing to sell vitamin D supplements just yet.
“We still don’t know what the optimal level of vitamin D is for good lung health and immune function, and we don’t if know if supplementation would address this issue, or if healthy sun exposure is what is required, given that vitamin D is an indirect measure of recent sun exposure, Dr Hollams added.
Co-author Professor Prue Hart, also from the Telethon institute, says the findings support the importance of getting enough vitamin D throughout childhood.
“UV radiation, from sunlight, is the best natural source of vitamin D. However, one should know their skin type and should not ignore sun-safe guidelines,” she added.