Insulin resistance and the metabolic syndrome in obese children referred to an obesity center

OBJECTIVE

The aim of this study was to describe insulin resistance and the metabolic syndrome in obese children and adolescents.

SUBJECTS

The cohort consisted of 518 patients, 250 boys, 268 girls, age +/- sd: 11.8 +/- 3.2 years, BMIsds +/- sd: 2.94 +/- 0.5. A standard OGTT was performed.

RESULTS

Impaired glucose tolerance was found in 9.4% of the boys and 5.5% of the girls. Impaired fasting glucose was found in 12.4% of the boys and 11.6% of the girls. The metabolic syndrome was present in 13.9% of children of 10 years or older. The proportion in which the metabolic syndrome was diagnosed was essentially not altered when pubertal groups were used instead of age groups.

CONCLUSION

Both impaired fasting glucose and impaired glucose tolerance as well as the metabolic syndrome are highly prevalent among obese children and adolescents.

Abnormal lipid profile and hyperinsulinaemia after a mixed meal: additional cardiovascular risk factors in young adults born preterm

AIMS/HYPOTHESIS

Low birthweight in infants born at term is related to the presence of the metabolic syndrome as an adult. Individuals born preterm invariably have low birthweights and may develop the metabolic syndrome as well. Although high BP, glucose intolerance and insulin resistance have been documented, dyslipidaemia has never been reported in individuals born preterm.

METHODS

In three groups of young adults [29 participants from the POPS (Project On Premature and Small for Gestational Age Infants) cohort born preterm appropriate for gestational age (POPS-AGA), 28 participants from the POPS cohort born preterm small for gestational age (POPS-SGA) and 30 individuals born at term with normal birthweight (CON)] we investigated fasting lipids as well as postprandial responses during a mixed meal test. The relationship between fasting and postprandial measurements and insulin sensitivity, measured by the hyperinsulinaemic clamp, was investigated.

RESULTS

Preterm participants had higher BP than CON individuals. Postprandial triacylglycerol levels were increased in POPS-SGA men. POPS-SGA individuals were hyperinsulinaemic during the mixed meal test.

CONCLUSIONS/INTERPRETATION

The mixed meal test provides additional information on cardiovascular risk factors. Postprandial triacylglycerol levels are increased in POPS-SGA men. Postprandial hyperinsulinaemia is found in POPS-SGA individuals.

Decreased insulin sensitivity in small for gestational age males treated with GH and preterm untreated males: a study in young adults

BACKGROUND

Low birth weight and preterm birth are associated with growth delay as well as the development of insulin resistance. Insulin resistance is especially seen in subjects with catch-up growth. GH therapy induces growth in short subjects with low birth weight at term, but little is known about the long-term effects on insulin sensitivity. GH therapy is now also proposed for preterms that remain short.

METHODS

We investigated insulin sensitivity using the gold standard hyperinsulinemic-euglycemic clamp technique in 10 young adult males born small for gestational age (SGA) who had been treated with GH during childhood (GH) in comparison with 15 males born preterm AGA (premAGA), 13 males born preterm SGA (premSGA), and 15 males born at term with normal birth weight (CON). Furthermore, we investigated the presence of the metabolic syndrome.

RESULTS

Insulin sensitivity was decreased in premAGA, premSGA, and GH subjects compared with CON males. The metabolic syndrome was not present in any of the groups.

CONCLUSION

Insulin sensitivity is decreased in GH-treated SGA born males as well as in preterm born males. With respect to the SGA subjects, whether the difference results from perinatal-, postnatal-, or GH therapy-related factors are not known. With respect to the preterm born subjects, close surveillance is needed when commencing GH therapy.

Growth during early childhood in asthmatic children: relation to inhalation steroid dose and clinical severity score

BACKGROUND/AIM

While short-term studies reported a growth retardation in children with asthma treated with inhaled steroids, long-term studies described attainment of adult heights within the target height range. In the present work, we describe the growth pattern of children with asthma.

METHODS

In 58 children with asthma, we compared the height at age 3 years with the height at a mean age of 7.5 years during a 12-month study period.

RESULTS

No differences in growth could be detected within the study year. Children in the lowest tertile but not in other tertiles for asthma severity score and inhaled steroid dose showed a significant decrease in height standard deviation scores from age 3 to age 7.5 years.

CONCLUSION

The decrease in height standard deviation scores might be explained by undertreatment or an individual sensitivity to inhaled steroids.

High dose growth hormone treatment induces acceleration of skeletal maturation and an earlier onset of puberty in children with idiopathic short stature

BACKGROUND

Long term growth hormone (GH) treatment in children with idiopathic short stature (ISS) results in a relatively small mean gain in final height of 3-9 cm, which may not justify the cost of treatment. As it is unknown whether GH treatment during puberty adds to final height gain, we sought to improve the cost-benefit ratio, employing a study design with high dose GH treatment restricted to the prepubertal period.

AIMS

To assess the effect of short term, high dose GH treatment before puberty on growth, bone maturation, and pubertal onset.

METHODS

Five year results of a randomised controlled study are reported. Twenty six boys and nine girls were randomly assigned to a GH treatment group (n = 17) or a control group (n = 18). Inclusion criteria were: no signs of puberty, height less than -2 SDS, age 4-8 years for girls or 4-10 years for boys, GH concentration >10 micro g/l after provocation, and normal body proportions. To assess GH responsiveness, children assigned to the GH treatment group received GH treatment for two periods of three months (1.5 IU/m2/day and 3.0 IU/m2/day), separated by three month washout periods, during the first year of study. High dose GH treatment (6.0 IU/m2/day) was then started and continued for at least two full years. When puberty occurred, GH treatment was discontinued at the end of a complete year's treatment (for example, three or four years of GH treatment).

RESULTS

In response to at least two years on high dose GH treatment, mean (SD) height SDS for chronological age increased significantly in GH treated children from -2.6 (0.5) to -1.3 (0.5) after two years and -1.4 (0.5) SDS after five years of study. No changes in height SDS were observed in controls. A rapid rate of bone maturation of 3.6 years/2 years in treated children compared to 2 years/2 years in controls was observed in response to two years high dose GH treatment. Height SDS for bone age was not significantly different between groups during the study period. GH treated children entered into puberty at a significantly earlier age compared to controls.

CONCLUSIONS

High dose GH treatment before puberty accelerates bone age and induces an earlier onset of puberty. This may limit the potential therapeutic benefit of this regimen in ISS.

Decreased galanin mRNA levels in growth hormone-releasing hormone neurons after perinatally induced growth retardation

Intrauterine growth retardation (IUGR) is associated with persistent postnatal growth retardation accompanied by dysfunction of the hypothalamic components of the growth hormone (GH) axis. At the adult stage, this is reflected by increased somatostatin (SS) and decreased neuropeptide Y (NPY) mRNA levels, whereas the GH-releasing hormone (GHRH) mRNA levels are normal and the output of GH remains unchanged. To extend our insight into the hypothalamic control of GH secretion in growth retarded rats, we determined galanin (GAL) mRNA levels at the adult stage of perinatally malnourished (i.e. IUGR and early postnatally food restricted) rats. Analyses included comparison of GAL mRNA levels in GHRH neurons in perinatally malnourished adult rats using a semi-quantitative double labeling in situ hybridization technique. We report that IUGR is accompanied by a 60% decrease in GAL mRNA levels in all GHRH neurons in the male IUGR group whereas a tendency towards a decrease was observed in the male early postnatally food restricted (FR) group. These effects became more pronounced when the analysis was restricted to GHRH neurons coexpressing GAL mRNA i.e. decreased GAL mRNA levels were seen in both male and female IUGR rats and in FR males. These data show that GAL mRNA levels in GHRH neurons are persistently decreased after perinatal malnutrition. Taking these results together with our previous data on SS, NPY and GHRH mRNA levels, we can conclude that IUGR leads to a reprogramming of the hypothalamic regulation of GH secretion.

Management of puberty in constitutional delay of growth and puberty

Constitutional delay of growth and puberty (CDGP) is the most common presenting form of short stature, but no single test can infallibly discriminate CDGP and isolated hypogonadotrophic hypogonadism. Management of puberty in CDGP aims to optimise not only growth maintaining body proportions and improving peak bone mass without impairing growth potential--but also well-being; for example, the distress boys often suffer because of their lack of growth and pubertal progression can affect their school performance and social relationships. Typical sex steroid treatments to induce puberty in boys with CDGP include testosterone (T) enanthate, T undecanoate, mixed T esters, T transdermal patches, and oxandrolone p.o. Compared with other regimens, short-course low-dose depot T i.m. is an effective, practical, safe, well tolerated, and inexpensive regimen. Some unresolved problems in management include optimal timing and dose of sex steroid treatment, the role of GH in CDGP, and the management of CDGP in girls.

Multiple pituitary hormone deficiency: management of puberty for optimal auxological results

The overview in this paper focuses on ways of achieving optimal auxological results in puberty, principally in idiopathic and congenital multiple pituitary hormone deficiency (MPHD), suggested by the co-authors. We agreed that diagnosing gonadotrophin insufficiency/deficiency is difficult in young children and should be repeated in late prepuberty, but a firm diagnosis of MPHD helps avoid endocrine re-testing at the end of growth. The hypothalamic-pituitary axis must be reassessed periodically in evolving endocrinopathies, though current practice varies widely. Optimum age to induce puberty is 11-12 years in girls and 13-14 boys, and sex steroids are the preferred agents. Short-course testosterone to increase micropenis size is advantageous, but inducing early testicular maturation is not known to improve later fertility. There is also little evidence for increasing the dose of GH during puberty, though therapy should continue to final height, and possibly until peak bone mass is achieved. Delaying puberty is an option in septo-optic dysplasia, and minimising the dose of hydrocortisone is crucial in treating ACTH/cortisol insufficiency. Many unresolved questions remain in this difficult area.

Pubertal maturation characteristics and the rate of bone mass development longitudinally toward menarche

To assess risks for osteoporosis and to compare bone mass in different groups of healthy children or children with diseases, it is important to have knowledge of their sexual maturation status during puberty. The aim of our study was to evaluate bone mass formation longitudinally in relation to pubertal maturation characteristics in healthy white girls. We investigated the bone mineral content (BMC) and the bone mineral density (BMD) at different skeletal sites in 151 girls with increasing pubertal stages in relation with their chronological age and with an early or late onset of puberty or menarche and with a slow or fast maturation. Bone mass was measured at the onset of puberty, during puberty, and at menarche. We conclude the following: (1) from midpuberty to menarche, the increase in bone mass formation is highest at all skeletal sites in white girls; (2) early mature girls at the onset of puberty have slightly but definitely lower bone masses at all skeletal sites and at all pubertal stages than late mature girls, whereas the average bone mass formation from the onset of puberty to menarche is similar in both groups; (3) girls with a slow rate of pubertal maturation have lower bone mass values 2 years after the onset of puberty, but at menarche bone mass is similar compared with fast maturers; and (4) it cannot be confirmed that there is an effect of menarcheal age on bone mass values at menarche.

Psychological responses to the needle-free Medi-Jector or the multidose Disetronic injection pen in human growth hormone therapy

The aim of the study was to test the hypothesis that daily administration of growth hormone using the Medi-Jector results in fewer adverse psychological responses than needle injection with a multidose injection pen. The Medi-Jector is a needle-free injection device that can deliver growth hormone subcutaneously through jet injection. The group studied consisted of 18 children aged 10 y or over who were participating in a study of the bioequivalence and bioequipotence of the administration of growth hormone through jet injection or needle injection. Previously, all subjects had received growth hormone therapy with commercially available multidose injection pens. The study was designed as a prospective, randomized, two-period cross-over trial. A questionnaire was used to assess psychological responses such as non-compliance, opinion on ease of preparation, affective responses to administration and local side-effects, as well as overall preference. In addition, the subjects kept a diary during the study. The subjects found the Medi-Jector less offputting (p < 0.01), less painful with respect to both frequency (p < 0.04) and intensity (p < 0.01) and less unpleasant (p < 0.05) than a multidose injection pen with a 28G needle (p < 0.01). No difference in compliance was detected. Most subjects preferred the Medi-Jector for future use (p < 0.05). The mean score on a 1-10 point scale (10 is excellent) was 7.9 (SD 1.4) for the Medi-Jector and 6.8 (SD 2.3) for the multidose injection pen (p < 0.08). The prevalence of visible bruises each day was higher (p < 0.01) with the Medi-Jector (2.5, SD 2.1) than with the multidose injection pen (0.7, SD 1.1), but children showed indifferent affective responses to bruising. Thirteen out of 18 subjects decided to continue therapy with the Medi-Jector (p < 0.06). It is concluded that use of the Medi-Jector in growth hormone therapy tends to lead to fewer adverse psychological responses than a multidose injection pen with 28G needles.

Pharmacokinetics and pharmacodynamics of recombinant human growth hormone by subcutaneous jet- or needle-injection in patients with growth hormone deficiency

Eighteen growth hormone (GH) deficient children and adolescents (11 6/12-20 9/12 y) participated in a randomized open, two-period (4 weeks) cross-over study to evaluate the pharmacokinetics and pharmacodynamics of recombinant human growth hormone (rhGH) administered daily, either by subcutaneous jet-injection or conventional needle-injection. Plasma growth hormone (GH), insulin-like growth factor 1 (IGF-1), insulin-like growth factor binding protein 3 (IGFBP-3), glucose, insulin, HbAlc and serum-free fatty acids (FFA) levels were analysed repeatedly. GH absorption characteristics, expressed as AUC(0-infinity), Cmax and Tmax ratio (%) jet-injected over needle-injected were similar in both groups. IGF-I and IGFBP-3 plasma levels were identical in both groups. Serum FFA concentrations were comparable after GH administration with either injection device. Surprisingly nocturnal blood glucose decreased to asymptomatic hypoglycaemic levels in all patients. The results of this study showed equal responses concerning absorption and bioavailability of growth hormone administered daily for 4 weeks by either a jet- or a needle-injection device in GH-deficient children and adolescents.

Effects of recombinant human growth hormone treatment in intrauterine growth-retarded preterm newborn infant on growth, body composition and energy expenditure

The effects of recombinant human growth hormone treatment during the early postnatal period on growth, body composition and energy expenditure were studied in seven intrauterine growth-retarded newborns. Seven infants were studied as controls. No differences were seen in bodyweight or height gain (15.9 +/- 1.5 g/kg per day and 1.02 +/- 0.24 cm/week in the treated and 16.3 +/- 1.4 g/kg per day and 1.11 +/- 0.30 cm/week in the control group). Skinfold growth rate was 0.52 +/- 0.20 mm/week in the treated vs. 0.56 +/- 0.28 mm/week in the control group. Total body water (as a percentage of bodyweight, 80 +/- 3.0% vs. 80 +/- 4.0%) and energy expenditure (67.5 +/- 7.4 vs. 66.7 +/- 6.4kcal/kg per day) using 2H2 18O showed identical results in both groups. We conclude that the recombinant human growth hormone treatment directly after birth in intrauterine growth-retarded newborn infants results neither in an increase in growth rate nor a change in body composition or energy expenditure during the early postnatal period.

Long-term results of growth hormone therapy in children with short stature, subnormal growth rate and normal growth hormone response to secretagogues. Dutch Growth Hormone Working Group

BACKGROUND AND OBJECTIVE

Growth hormone treatment in children with idiopathic short stature (ISS) leads to growth acceleration in the first years, but the effect on final height is still poorly documented. We therefore studied the long-term effect of GH therapy in children with idiopathic short stature.

DESIGN

We have treated 27 prepubertal children with ISS with recombinant human GH (rhGH) in an initial dosage of 2 IU/m2 body surface/day subcutaneously, which was doubled either after the first year if the height velocity increment was less than 2 cm/year, or thereafter if height velocity fell below the P50 for bone age. Growth and bone maturation of the treatment group (ISS group, n = 21) were compared to those of an untreated control group with ISS (ISS controls, n = 27) and of a group of rhGH treated children with isolated GH deficiency (GHD group, n = 7).

RESULTS

In 9 patients of the ISS group still on treatment, height standard deviation score (HSDS) for chronological age increased from -3.8 +/- 0.7 to -2.3 +/- 0.9 (mean +/- standard deviation) over 6 years, while in matched ISS controls HSDS for age did not change. HSDS for age in the GHD group increased from -3.9 +/- 0.6 to -1.8 +/- 0.7 after 4 years, significantly more than the ISS group. Bone maturation was accelerated in the ISS and GHD groups. HSDS for bone age and predicted adult height did not change in either group. Final height in 12 children of the ISS group was -2.6 +/- 1.0 SDS. In the untreated controls final height was similar. A low integrated GH concentration over 24 hours, a low GH peak to provocative stimuli, and minimal initial BA delay predicted a favourable outcome.

CONCLUSION

rhGH treatment in this group of children with idiopathic short stature did not increase average final height. Part of the heterogeneity of the response can be attributed to the variation in endogenous GH secretion and initial bone age delay.

Pulsatile GnRH treatment in boys and girls with idiopathic hypogonadotrophic hypogonadism

In order to induce pubertal development, low-dose, pulsatile gonadotrophin-releasing hormone (GnRH) was administered i.v. in adolescent boys and girls with an isolated hypogonadotrophic hypogonadism. The first study included GnRH treatment in 21 male patients with the goal of initiating testicular growth and spermatogenesis; in the second study, GnRH was administered in three adolescent boys and two girls in an increasing pulse frequency as well as pulse dose in order to imitate the 'physiological' pubertal changes. In the first study gonadotrophin and testosterone levels increased in all patients, and testicular growth also occurred. When GnRH treatment was discontinued spermatogenesis was present in 14 out of the 17 patients examined, and was observed in another patient during subsequent human chorionic gonadotrophin (HCG) treatment. Ultimately, 15 out of the 19 patients developed spermatozoa. In the second study, small increases in luteinizing hormone (LH) and follicle stimulating hormone (FSH) were observed during a low-frequency GnRH schedule, followed by a further rise during the 'physiological' schedule with a 90-min pulse interval; testosterone and oestradiol also increased. An increased secretion of growth hormone occurred only in boys during GnRH treatment, after their testosterone levels had increased. In girls, none of the GnRH treatment schedules was associated with an increase in growth hormone. Pulsatile GnRH treatment is thus feasible as a method of inducing testicular growth and spermatogenesis. A GnRH treatment schedule with an increasing pulse frequency and pulse dose can imitate the 'physiological' pubertal changing pattern of gonadotrophins just as well as the use of sex steroid. However, with respect to growth hormone secretion, GnRH will induce an increase in boys only.

Induction of testicular growth and spermatogenesis by pulsatile, intravenous administration of gonadotrophin-releasing hormone in patients with hypogonadotrophic hypogonadism

OBJECTIVE

To induce testicular growth including spermatogenesis, 38 patients with hypogonadotrophic hypogonadism were treated with long-term pulsatile GnRH administration.

PATIENTS

The group of patients comprised 17 individuals with idiopathic hypogonadotrophic hypogonadism, 11 with Kallmann's syndrome, four with multiple pituitary hormone deficiencies and six with a secondary hypogonadotrophic hypogonadism due to surgical removal of a brain tumour. Thirteen patients (seven with idiopathic hypogonadotrophic hypogonadism and six with Kallmann's syndrome) had undescended testes, of whom six had undergone surgery on both testes and four on one testis. Sixteen of the 17 had previously received androgen therapy and six others had received gonadotrophin treatment, of whom three had long-term treatment to induce testicular development, without success.

TREATMENT

GnRH was administered intravenously in a dose of 2-20 micrograms per pulse every 90 minutes. After GnRH discontinuation, hCG treatment was instituted, 1500-3000 IU (i.m.) twice weekly.

RESULTS

During treatment plasma levels of LH, FSH and testosterone increased. In 35 out of the 38 patients plasma testosterone levels increased into the normal adult range. In all patients testicular volume increased. Mean pretreatment testicular volume per patient group ranged from 2.4 to 4.8 ml and increased to 11.5-18.1 ml by the end of treatment. There was a significant difference in the achieved testicular volumes between the patients with Kallmann's syndrome and the brain tumour patients. GnRH treatment mean lasted between 46 and 75 weeks in the different groups. On hCG therapy, testicular development was either maintained or improved. Semen analysis revealed the presence of spermatogenesis in 31 out of the 38 patients (26 patients already on GnRH, and in another five patients on hCG therapy). All three patients pretreated with gonadotrophins as well as three patients with bilateral testicular surgery developed a detectable sperm count. In 19 adolescent patients with growth potential, an adequate height velocity was observed during GnRH treatment.

CONCLUSIONS

GnRH is a feasible way to induce testicular growth as well as spermatogenesis in hypogonadotrophic male patients, even in patients in whom gonadotrophin treatment has failed. After GnRH treatment, hCG alone can maintain or even improve testicular development, including spermatogenesis. GnRH treatment may also induce a physiological growth spurt in hypogonadotrophic adolescents.

Effects of two years of methionyl growth hormone therapy in two dosage regimens in prepubertal children with short stature, subnormal growth rate, and normal growth hormone response to secretagogues. (Dutch Growth Hormone Working Group)

Thirty short, slowly growing children with normal plasma growth hormone response to standard provocation tests were randomly assigned to a group (n = 20) undergoing therapy with methionyl growth hormone, 2 IU/m2 subcutaneously once daily, (group 1) or a control group (n = 10, group 2). The mean (+/- SD) height velocity increment in group 1 was 3.0 +/- 1.9 cm/yr in the first year, compared with -0.2 +/- 0.7 cm/yr in group 2. Of the 18 children who completed the first year of treatment, 12 had a height velocity increment of more than 2 cm/yr and 11 of them continued treatment for a second year (group 1A). The remaining six children also reached height velocities greater than the mean for bone age, but because of a low height velocity increment they were termed nonresponders and their growth hormone dosage was increased to 4 IU/m2/day (group 1B). Of the 10 children in the control group, seven received authentic biosynthetic growth hormone in the second year of the study (group 2); the remaining three received no therapy (group 3). The mean height velocities (measured in centimeters per year) before and during the first and second years of therapy were 3.6, 7.6, and 6.1 in group 1A; 5.7, 6.9, and 7.3 in group 1B; 4.2, 4.0, and 6.7 in group 2; and 5.0, 4.9, and 5.2 in group 3. The effect of doubling the dosage was a further increase of 1.9 cm/yr. Bone age advance paralleled growth acceleration, resulting in an unchanged height standard deviation score for bone age and ambiguous results on final height prediction. Growth hormone therapy in such short children appears to be safe and efficacious in increasing growth velocity for 2 years, but its efficacy in terms of increasing final height is uncertain.

Effect of LHRH treatment on testicular descent and hormonal response in cryptorchidism

In a double-blind placebo-controlled study in 49 boys with cryptorchidism the effect of intranasal synthetic LHRH was studied. After 8 weeks improvement in testicular location was found in 13 testes (37%), but this improvement was considered sufficient of only six testes. Placebo resulted in an improved location in 18% of the testes. The mean change in testicular position (expressed in cm) after LHRH therapy was slightly greater than after placebo but only in the squatting position did this difference reach significance. Aggressive behaviour was reported in 23% of the children treated with LHRH. A second LHRH course did not result in significant improvement in any of the patients. At follow-up reascent was frequently seen. The final results in unilateral cryptorchidism are poorer than those in bilateral cryptorchidism. LHRH therapy leads to higher plasma LH levels and a lower FSH in response to an intravenous LHRH test. In 15 boys plasma testosterone levels rose above 0.4 nmol/l. We conclude that intranasal LHRH application has a limited value for the treatment of cryptorchidism but may be suitable as a diagnostic test.