SEASONAL VARIATION IN GROWTH RATE OF CHILDREN TREATED WITH BIOSYNTHETIC GROWTH HORMONE

Abstract

Seasonal variation in growth rate is documented in normal children, however conflicting reports have been published regarding children treated with growth hormone (GH). We analyzed the growth rate of children who were treated with GH and enrolled in the NCGS for GH deficiency or idiopathic short stature. Only pre-pubertal children (males ≤11 y.o., females ≤10 y.o.) were included. Two-thirds of the data points were for male patients. A growth rate was assigned to a season based on the month in which the midpoint of the interval fell. Winter was defined as the 3 months of December, January, and February, and so on for the other 3 seasons. The table below shows seasonal growth rate by latitude [mean±SD, (n)]: An analysis of variance for year 2 showed no interaction between seasonal growth and either dosing schedule or sex, although each of these factors had a significant effect on the growth rate individually. ConCLUSIONS: As noted for normal children, those treated with growth hormone also show seasonal variation in growth rate, suggesting that factors other than circulating growth hormone concentrations are related to variations in growth rate.