Short stature in Scottish schoolchildren : a community study with special emphasis on the prevalence of severe growth hormone deficiency
Vimpani, Graham V.
The primary objective of this study has been to determine timr prevalence of growth hormone deficiency among Scottish school children. To achieve this it m first essential to identify a large number of very small children in a defined population and it was proposed to study thereafter all those comprising the smallest 1% in the population. Clearly, sany children had factors other than growth horsona deficiency contributing to their short stature, and therefore the literature relating both to this and the influences of genetic, environmental and other biological factors upon growth has been reviewed. The method originally proposed for identifying these children was based upon a central computer-baaed file of the heights of children at the school entrance medical inspection. Intractable difficulties inherent in this approach soon emerged and, as these would have prevented the identification of all short children within a defined population and made it impossible to accurately estimate the true prevalence of growth hormone deficiency, this method had to be discarded. The revised method entailed personally screening the heights of 48,221 children attending all education authority schools and & selection of independent schools in Edinburgh, Glasgow and Aberdeen, and identifying from them all children who were -2.5 standard deviations or more below the mm height for their chronological age (N = 449). Permission was sought from the parents of those found to be of small stature to undertake studies of the medical and social background and where appropriate to gather auxological data. Where no definite cause for short stature was apparent, these children were screened for growth horaone deficiency wherever possible. Children who failed to produce adequate growth hormone levels on the screening test and/or those whose twelve aonth height velocities were below average (less than the 25th centile for chronological age) were then further investigated for growth hormone deficiency with an insulin tolerance test. A group of control children from a similar social background but of average height for age was also selected in .Edinburgh and Glasgow. c.oae of the social and medical data from this group has been compared to the group of children with short stature in an attempt to identify any significant differences, the study has confirmed the strong association of previously recognised environmental and genetic factors with short stature. The results of the study also suggest that severe growth horaone deficiency is a acre comma cause of short stature than previously thought and that it frequently remains undiagnosed for longer than necessary.