the prevalence of growth hormone deficiency ( ghd ) is estimated on 1  :  4  000 to 1  :  20  000 of children which places this pathology in the group of rare diseases . however , the number of children referred to pediatric endocrinology clinics for short stature evaluation is much higher . moreover , in many of them ghd based on the results of gh stimulation tests is diagnosed and they are treated for several years with daily injections of recombinant gh ( rgh ) . although in children with mid - line defects or in severe idiopathic ghd deficiency the diagnosis is clear and substitution of the missing hormone is essential for linear growth , glucose homeostasis , and development of normal body composition [ 24 ] , in many short stature patients with mild gh deficiency the diagnosis remains equivocal . in this group the results of the prolonged , expensive , and invasive treatment with rgh are often not satisfactory and the individual response varies widely [ 57 ] . the diagnosis of ghd is based on auxological parameters and on the results of two stimulation tests which are supposed to examine the pituitary gh reserve . various substances are being used for laboratory testing ( e.g. , insulin , arginine , glucagon , and clonidine ) as well as overnight gh secretion , none of them being the ideal one . the tests are poorly reproducible and children with ghd quite often have a normal response in later life [ 811 ] . cut - off value of peak gh secretion is also more or less arbitrary . in most pediatric endocrinology centers the diagnosis of ghd is made on the basis of peak gh concentration 10  ng / ml , as published in the gh research society guidelines in 2000 . this cut - off value is being questioned by several authors who suggest that this concentration is too high and should be lowered to 7 or 8  ng / ml [ 9 , 13 , 14 ] . however traditionally a peak gh between 7 and 10  ng / ml is considered indicative of moderate ghd ( mghd ) and children with this diagnosis are treated in the same manner as these with severe ghd ( sghd ) [ 6 , 7 ] . moreover , in many mghd patients low insulin - like growth factor ( igf-1 ) concentration is found , which strengthens the hypothesis that such children have clinical characteristics intermediate between sghd and no growth hormone deficient ( noghd ) short children . severe ghd induces abnormalities in body composition such as increased fat mass and reduced lean body mass [ 1517 ] . demonstrated that one year of rgh therapy not only significantly reduced the fat mass ( by 15% ) but also had a beneficial effect on the cardiovascular risk reducing carotid intima media thickness ( cimt ) in children with ghd . ciresi et al .   showed a beneficial effect of rgh administration on metabolic parameters such as leptin level and insulin resistance ( homa - ir ) in gh deficient children . the link between rgh therapy and body composition improvement was particularly observed in children with prader - willi syndrome . rgh administration in these patients resulted in fat mass reduction and gain in lean body mass and was maintained over the years . body composition parameters have not been extensively studied in children with impaired gd secretion who do not fulfil the stringent criteria of sghd and in whom mghd is diagnosed . the aim of our study was to compare body composition parameters in short children with sghd , mghd , and noghd . study group ( sg ) comprised 61 prepubertal short children ( 40 boys and 21 girls ) at the mean age of 10.7  2.6 years . they were consecutively recruited for the study from the patients referred to our department between september 2013 and march 2014 . exclusion criteria comprised chromosomal aberrations , dysmorphic syndromes , bone dysplasia , children born small for gestational age or with intrauterine growth retardation , and patients with chronic diseases , acquired ghd , including posttraumatic or postneoplastic deficiencies . short stature was defined as the height below 2 standard deviation scores ( sds ) from the population mean , referred to the national growth charts . peak gh concentration below 10  ng / ml in the night profile and two stimulation tests ( after clonidine and insulin administration ) were considered diagnostic for ghd . stimulation test methodology was as follows : oral administration of clonidine at the dose of 0.15  mg / m body surface ( iporel , polfa ) and intravenous administration of insulin in the dose of 0.1  u / kg ( actrapid , novonordisk ) resulting in hypoglycaemic state ( serum glucose concentration below 40  mg / dl ) . blood samples for gh estimation were collected every 30 minutes ( from 0 to 120  min ) for both tests , clonidine or insulin . gh concentrations were measured by a two - site chemiluminescent enzyme immunometric assay ( hgh immulite , dpc ) . children with ghd were then categorized according to the maximal gh level into moderate and severe ghd ( max gh  7.0  ng / ml and < 7.0  ng / ml , resp . ) . additionally , the concentration of igf-1 was measured by solid - phase enzyme - labelled chemiluminescent immunometric assays ( immulite , dpc ) in all children and was analyzed as a number of standard deviation score ( sds ) from the mean . based on the normal picture of the magnetic resonance imagining ( mri ) idiopathic form of ghd was diagnosed in both mghd and sghd subgroups . patient rights were also respected according to the declaration of helsinki with its subsequent modifications . standing height was measured by a wall - mounted harpenden stadiometer to the nearest 0.1  cm and weight ( in patients in their underwear ) by electronic scale with readings accurate to 0.1  kg . height standard deviation score ( hsds ) was calculated for all studied children referred to the national growth charts . midparental height ( mph ) sds and  height sds ( hsds  mph sds ) were also assessed . body mass index ( bmi ) was calculated , using the standard formula ( kilograms per meter squared ) . bmi z - scores were derived using who anthroplus , version 1.0.4 ( based on world health organization growth references ) . waist circumference was measured midway between the lower rib margin and the iliac crest in the standing position and waist / height ratio ( w / htr ) was calculated . body composition parameters : fat mass ( fat ) , fat - free mass ( ffm ) , predicted muscle mass ( pmm ) , and total body water ( tbw ) were assessed ( as percentage of body weight [ % ] ) based on bioelectrical impedance analysis ( bia ) using segmental body composition analyzer ( mc-980 ma tanita europe bv , hoofddorp , the netherlands ) . comparative analysis of the groups for variables of normal distribution was carried out using one - way anova and results were reported as least squares mean  95% confidence interval ( ci ) . further post hoc analysis all statistical analysis was made by the statistica 10 pl software and p < 0.05 was considered significant . in 34 ( 66% ) of children ghd was excluded ( noghd group ) . based on the peak gh concentration 27 children with ghd were subdivided into two groups , moderate ( mghd , n = 16 ) and severe growth hormone deficient ( sghd , n = 11 ) . none of the three subgroups differed significantly by means of chronological age , ba and gender distribution ( table 1 ) . post hoc analysis revealed that patient with sghd differed significantly from both mghd and noghd , having higher bmi z - score , w / htr , and fat tissue ( fat% ) ( p < 0.05 ; p < 0.01 ; p < 0.01 , resp . ) , while other body composition parameters such as ffm% , pmm% , and tbw% were significantly lower ( p < 0.01 ) in the sghd group . all measured anthropometrical parameters in children with mghd were not significantly different from children with normal gh . no statistically significant differences in height sds ,  height sds , and igf-1 sds were found between all three evaluated subgroups ( table 1 ) . moreover , children with igf-1 sds < 2 ( n = 20 ) did not differ significantly in anthropometrical and body composition parameters from those with igf-1 sds  2 ( n = 41 ) . however , peak gh level in the night profile correlated significantly with body composition parameters in the whole studied population ( r = 0.311 for fat% , r = 0.314 for ffm% , r = 0.313 for pmm% , and r = 0.313 for tbw% , p < 0.05 ) ( table 2 ) . in our study we evaluated the usefulness of baseline body composition characteristics as the potential tool for confirming the diagnosis of severe or moderate ghd in short statured children . similarly to other authors , we found an impairment of body composition in sghd children who experienced increased fat mass and reduced lean body mass [ 1517 ] . children with sghd also had significantly higher bmi z - score and w / htr . moreover , children with sghd have similar ba delay and no statistically different igf-1 sds level from those with mghd and noghd . therefore in our study body composition parameters were the only ones differentiating children with sghd from noghdt and mghd patients . on the other hand we did not find any statistically significant differences neither in body composition parameters nor in bmi z - score and w / htr between mghd and noghd children . therefore the study results did not show that children with mghd had body composition impairment and did not support the hypothesis that children with gh level between 7 and 10  ng / ml have body composition characteristics intermediate between sghd and noghd patients . many of them believe that cut - off level of gh secretion in stimulation tests should be decreased to 7  ng / ml [ 9 , 10 , 13 , 14 , 24 ] . wagner et al .   established recently a new cut - off limit of 7.09  ng / ml which was based on clinical evidence . these new cut - off limits are recommended by murray et al .   in their very recent critical review on diagnosis and management of ghd in children . the need for lowering of peak gh level was also recently confirmed by guzzetti et al . . they found that the optimal gh cut - off level varies from 5.1  ng / ml ( for insulin tolerance test ) to 6.8  ng / ml ( for clonidine ) . some studies recommend sex - steroid priming before performing gh stimulation tests in prepubertal short children to confirm the diagnosis of gh deficiency . hypothesis of mghd was not supported event in group of children receiving ethinyl estradiol or testosterone enanthate priming for 510 days before testing . in one of our studies final height of children with mghd treated with rgh was not significantly different from untreated peers with idiopathic short stature matched for basal age , height , and ba delay . all of them had normal gh secretion in stimulation tests repeated after cessation of therapy . results of several studies showed that majority of adolescents having received rgh treatment during childhood for ghd have normal gh secretion at retesting after growth completion [ 811 ] . about 15% of them continue to have mghd and exhibit changes in body composition after therapy cessation similar to those seen in children with sghd , although less marked . discontinuation of lean body mass accrual was described by carroll et al .   in patients who did not continue rgh therapy after attainment of final height , but all the subjects studied had organic ghd or sghd . beneficial effects of rgh therapy on body fat decrease in children born small for gestational age were reported by willemsen et al . but no such effects were found by hgler et al .   in children with idiopathic short stature . in the available literature we did not find data comparing body composition differences in children with moderate and severe ghd treated with rgh . in our study , significant correlations between body composition parameters and peak gh in the night profile were found . .   demonstrated that peak gh in the stimulation test ( ghrh - arginine ) was strongly influenced by body composition . significant correlation between baseline body composition assessed by bia method and growth response to rgh therapy was found by esen et al .   in children with ghd . . increased bmi z - score and higher whtr were predictors of more pronounced growth response in prepubertal subjects . the authors concluded that baseline body composition data can be used for prediction of growth response to rgh treatment . it is not considered a gold stand technique as it may be influenced by many factors . moreover , use of the dual - energy x - ray absorptiometry ( dxa ) , which is a gold standard for the body composition analysis , is limited in children by radiation exposure , costs , and low availability . the process of bia validation resulted in the development of standards and centile charts for healthy children . good correlation was found between bia and dual - energy x - ray absorptiometry in the study of de lorenzo et al . moreover , our recent study confirmed its utility in children and adolescents with idiopathic scoliosis . the results of our study confirm previous findings that severe growth hormone deficiency is associated with an increase in fat tissue , decrease in fat - free mass , predicted muscle mass , and total body water . in contrast our results indicate that mghd has no significant influence on body composition in the short statured children . therefore , body composition assessment based on bia seems to be a useful tool in diagnosing gh deficiency in children as well as in distinguishing its severe and moderate form . however the data need to be confirmed in a prospective study based on more accurate body composition assessment methods ( e.g. , dxa ) and on a larger group of patients .
objective . to compare body composition parameters in short children with severe versus moderate and no growth hormone deficiency ( ghd ) . design and method . 
 61 children ( 40 boys ) were studied . 
 height sds , bmi z - score , waist / height ratio ( w / htr ) , and body composition parameters ( bia ) as fat tissue ( fat% ) , fat - free mass ( ffm% ) , predicted muscle mass ( pmm% ) , and total body water ( tbw% ) were evaluated . 
 gh secretion in the overnight profile and two stimulation tests and insulin - like growth factor 1 ( igf-1 ) level were measured . 
 results . 
 overall , in 16 ( 26% ) moderate ( 7.0 > peak gh < 10  ng / ml ) and in 11 ( 18% ) severe ( gh  7.0  ng / ml ) ghd was diagnosed . in children with sghd 
 bmi z - score , w / htr and fat% were significantly higher , while ffm% , pmm% , and tbw% were significantly lower versus mghd and versus noghd subgroups . 
 no significant differences between mghd and noghd were found . there were no differences in height sds and igf-1 sds between evaluated subgroups . 
 night gh peak level correlated significantly with fat% , ffm% , pmm% , and tbw% , ( p < 0.05 ) in the entire group . 
 conclusions . 
 only sghd is associated with significant impairment of body composition . 
 body composition analysis may be a useful tool in distinguishing between its severe and moderate form of ghd .