Early Life Vitamin D Status and Lung Development

There is evidence of an association between early life vitamin D insufficiency and future risk of developing asthma. Given the high prevalence of vitamin D insufficiency in women during pregnancy when developmental programming is occurring, this may be of critical public health importance. There are plausible biological mechanisms for an association. Vitamin D is the pro-hormone of calcitriol, a secosteroid hormone with widespread pleiotropic actions. It is a powerful immune modulator and has been shown in animal and in vitro work to have a role in early lung development. Calcitriol may influence lung development through expression of the vitamin D receptor on lung and immune cells, and through epigenetic mechanisms. If the association between early life vitamin D status and childhood respiratory disease is shown to be causal, then this could have significant implications for public health policy. This hypothesis is currently being tested in a number of prospective intervention trials. The aim of this article is to review the evidence that vitamin D status influences early lung development, with a focus on early life mechanisms.