Es. Feliciano et al., SEASONAL AND GEOGRAPHICAL VARIATIONS IN THE GROWTH-RATE OF INFANTS INCHINA RECEIVING INCREASING DOSAGES OF VITAMIN-D SUPPLEMENTS, Journal of tropical pediatrics, 40(3), 1994, pp. 162-165
In theory, sunshine exposure is sufficient to maintain normal vitamin
D concentrations for the optimal growth of newborn infants. To determi
ne whether season of birth, latitude (north v. south) and increasing d
osages of vitamin D supplements would influence the growth rate for th
e first 6 months of life, 255 healthy fall-and spring-born infants fro
m two northern and two southern cities in China were randomly assigned
to receive either 100, 200, or 400 IU of vitamin D a day. The study s
howed that season of birth and dose of vitamin D did not affect the gr
owth rate of infants born in the same latitude, but a significant diff
erence was found in the gain in length over the 6-month period between
infants from the north and infants from the south (P=0.0001). Regiona
l differences among the Chinese people, other than sunshine exposure,
may have influenced the difference in length gain.