Vitamin D in infancy and childhood: factors determining vitamin D status.

Gestational age, age, race, sex, maternal influences, diet, and environmental factors affect vitamin D and calcium metabolism. These specific factors are only beginning to be understood in the infant and child, a period in which there are rapidly changing stresses related to growth and skeletal development. The adaptability of the infant and child to face these challenges and maintain calcium homeostasis is a remarkable testament to the inherent capabilities of the vitamin D- and calcium-regulating system.