Early lifecycle UV-exposure calibrates adult vitamin D metabolism: Evidence for a developmentally originated vitamin D homeostat that may alter related adult phenotypes.

Increased solar irradiance/UV exposure during the first trimester of pregnancy calibrates adult vitamin D metabolism, which is an important hormone in maintaining calcium balance. This may explain how very early lifecycle UV exposure can influence skeletal development (adult height) and modify risk for the skeletal degenerative disorder osteoporosis. The data demonstrate humans are tuned to the world (exposome) in ways we have not yet fully considered, and which are entrained at the earliest phase of the lifecycle.