Lipid profile, glucose tolerance and insulin sensitivity after more than four years of growth hormone therapy in non-growth hormone deficient adolescents

Prevalence of diabetes among children treated with growth hormone in Israel

AIMS

To determine the long-term risk of diabetes in a cohort of children treated with recombinant human growth hormone in Israel, using data from the Israeli National Diabetes Register.

METHODS

Between 1988 and 2009, 2513 children were approved for growth hormone treatment. They were assigned to one of two groups. The first group included children treated for isolated growth hormone deficiency and who were small for gestational age and the second included those treated for multiple pituitary hormone deficiency, chronic renal failure, Turner syndrome or Prader-Willi syndrome. The cohort was cross-linked with the Israeli National Diabetes Register for 2014 (mean follow-up duration 12.1±5.3 years), and prevalent cases of diabetes were identified. Standardized prevalence ratios for diabetes were calculated for people aged 10-29 years.

RESULTS

In 2014, a total of 23 individuals were identified with diabetes (four with pre-existing diabetes, seven developed diabetes before age 17 years and 12 developed it at a later age). In the isolated growth hormone deficiency and small-for-gestational-age group there was no difference in the prevalence of diabetes compared with the general population (standardized prevalence ratio 2.05, 95% CI 0.94-3.89). In the group that included people with multiple pituitary hormone deficiency, chronic renal failure, Turner syndrome and Prader-Willi syndrome there was a significantly higher diabetes prevalence (standardized prevalence ratio 11.94, 95% CI 6.53-20.00) compared with the general population.

CONCLUSIONS

No difference in diabetes prevalence was found in the isolated growth hormone deficiency and small-for-gestational-age group, compared with the general population. Children treated with growth hormone with pre-existing risk factors had an increased prevalence of diabetes. It is advisable to monitor blood glucose levels closely during and after growth hormone treatment, especially in such children.

A preliminary trial of the effect of recombinant human growth hormone on short-term linear growth and glucose homeostasis in children with Crohn's disease

BACKGROUND

It is unclear whether recombinant human growth hormone (rhGH) improves linear growth in children with Crohn's disease (CD).

AIMS

To investigate the effects of rhGH on height velocity (HV) and glucose homeostasis over a 6-month period.

DESIGN AND SETTING

Randomized controlled trial in two tertiary children's hospitals in 22 children with inflammatory bowel disease amongst whom 21 had CD. Duration of disease from diagnosis and number of acute relapses requiring either exclusive enteral nutrition or therapeutic dose of oral prednisolone were similar in the treatment and control groups.

INTERVENTION

Either rhGH (0·067 mg/kg per day) as daily subcutaneous injections (rhGH group; n, 11) or no rhGH, (Ctrl; n, 11) for 6 months.

MAIN OUTCOME MEASURE

Percentage change in HV after 6 months in the two groups. Auxology, puberty, skeletal age, disease factors, treatment and glucose homeostasis were also assessed.

RESULTS

Median HV increased from 4·5 (range, 0·6, 8·9) at baseline to 10·8 (6·1, 15·0) cm/year at 6 month (P = 0·003) in the rhGH group, whereas in the Ctrl group, it was 3·8 (1·4, 6·7) and 3·5 cm/year (2·0, 9·6), respectively (P = 0·58). Median percentage increase in HV after 6 months in the rhGH group was 140% (16·7, 916·7) compared with 17·4% (-42·1%, 97·7%) in the Ctrl group (P < 0·001). There were no significant differences in disease activity and proinflammatory cytokines at baseline and 6 months in both groups and change in bone age for chronological age was also similar in the two groups. In the rhGH group, fasting insulin increased from 4·0 (2·0, 11·0) to 7·0 mU/l (2·0, 16·0) (P = 0·02), whereas in the Ctrl group, it was 3·0 (1·2, 12·7) and 3·8 mU/l (2·1, 7·0) (P = 0·72), respectively.

CONCLUSIONS

Although this pilot trial shows that rhGH can improve short-term linear growth in children with CD, the clinical efficacy of this therapy needs to be further studied in longer-term studies of growth, glucose homeostasis and disease status.

Risk factors for diabetes mellitus type 2 and metabolic syndrome are comparable for previously growth hormone-treated young adults born small for gestational age (sga) and untreated short SGA controls

CONTEXT

Low birth weight might increase risk of diabetes mellitus type 2 and metabolic syndrome (MS). GH has insulin-antagonistic properties. Therefore, long-term follow-up of GH-treated children born small for gestational age (SGA) is important.

OBJECTIVE AND PATIENTS

The objective of the study was to evaluate insulin sensitivity (Si) and disposition index (DI), all components of the MS and IGF-I and IGF binding protein (IGFBP)-3 levels in 37 previously GH-treated young SGA adults in comparison with 25 untreated short SGA controls.

RESULTS

GH-treated subjects were 22.3 (1.7) yr old. Mean duration of GH treatment had been 7.3 (1.3) yr. Mean period after discontinuation was 6.5 (1.4) yr. Si and DI were comparable for GH-treated and untreated SGA subjects. Fasting glucose and insulin levels increased during GH treatment but recovered after discontinuation. Body mass index, waist circumference, high-density lipoprotein cholesterol levels, and triglycerides were equivalent. Systolic and diastolic blood pressure and cholesterol were significantly lower in GH-treated subjects. Thirty-two percent of untreated controls vs. none of the GH-treated subjects had an increased blood pressure. GH-induced rises in IGF-I and IGFBP-3 levels had completely recovered after GH stop.

CONCLUSION

At 6.5 yr after discontinuation of long-term GH treatment, Si, DI, fasting levels of glucose and insulin, body mass index, waist circumference, and IGF-I and IGFBP-3 levels were equivalent for GH-treated and untreated young SGA adults. Systolic and diastolic blood pressure and serum cholesterol were even lower in GH-treated subjects. These data are reassuring because they suggest that long-term GH treatment does not increase the risk for diabetes mellitus type 2 and MS in young adults.

Growth Hormone Therapy in Short Children Born Small for Gestational Age

There is still a lack of data from randomized, controlled, long-term studies of growth hormone (GH) treatment in children born small for gestational age (SGA), but the available evidence indicates consistently that GH therapy is a valid growth-promoting treatment in these children, particularly if started early. Whilst side effects appear uncommon, ongoing surveillance is required and treated children should be monitored for changes in glucose homeostasis, lipid profiles and blood pressure, especially during puberty. We provide an update on the safety and efficacy of GH treatment in short children born SGA.

Growth hormone therapy in short children born small for gestational age

Being born small for gestational age (SGA) is one of the most common causes of childhood short stature, and recombinant GH therapy has been recently licensed to promote growth in short SGA children from the age of 4 years old. Studies are now reporting very encouraging effects on adult height gains, especially in those children who started GH therapy early, at least 2 years prior to the onset of puberty. Compared to the age at starting treatment, the GH dose has a less significant impact on final height, and more attention needs to be paid now to identify earlier those SGA children who fail to catch-up spontaneously. The benefits are not just in terms of height, but also in body composition and possibly blood pressure and lipid levels. However the risk of side effects and long-term complications, particularly related to the expected metabolic effects of GH in inducing insulin resistance and hyperinsulinaemia, need to be carefully monitored especially in SGA children with a family history of type 2 diabetes. Recently, GH therapy was found to amplify the adrenarche of short SGA children and to induce a pro-inflammatory shift, as judged by a rise of neutrophil count and circulating interleukin-6 (IL-6), and a fall in adiponectin levels. Further progress is anticipated to assess the addition of insulin-sensitizing therapy to attenuate the GH-induced hyperinsulinemia, in order to alter the pro-inflammatory course, to avoid excessive release of adrenal androgens, and to slow down the potential rapid tempo of pubertal progression in SGA children. In the meantime, post-SGA short stature is rapidly becoming one of the prime indications for GH therapy in childhood.

Effects of lamivudine therapy on the glucose metabolism in children with chronic hepatitis B: first year follow-up results

BACKGROUND AND AIM

Although the most common major toxicity of lamivudine has been pancreatitis, there is no report investigating possible impaired pancreatic functions, including glucose intolerance due to lamivudine therapy. The aim of this study was to evaluate the effects of lamivudine on the glucose metabolism in children.

METHOD

Twenty-three children were included: eight patients were treated with lamivudine, others with both lamivudine and interferon-alpha. An oral glucose tolerance test (OGTT) was performed before the treatment, and after 6 and 12 months.

RESULTS

After 6 and 12 months of the treatment four (18.4%) and eight (34.8%) patients had impaired OGTT, respectively. We did not find any relationship between impaired OGTT and age, gender, elevated amylase, abdominal pain and the mode of therapy (P>0.05). While mean glucose value after 2 h was higher than that of baseline, mean insulin concentrations and area under the curve values were not different (P<0.0001, P>0.05, and P>0.05, respectively).

CONCLUSION

This is the first report demonstrating that lamivudine may impair the OGTT. Since at least 8.7% of our patients had persistently impaired OGTTs during the first year of the therapy, it may be reasonable to screen children before lamivudine therapy is started.

Carbohydrate metabolism is not impaired after 3 years of growth hormone therapy in children with Prader-Willi syndrome

BACKGROUND/AIM

In children with Prader-Labhart-Willi syndrome (PWS), the insulin secretion is reduced, despite obesity, being ascribed to the growth hormone (GH) deficiency of hypothalamic origin. Besides, an increased prevalence of diabetes mellitus was described in this syndrome. Hence, we addressed the questions of how body composition and insulin secretion are interrelated and what impact GH therapy has on the carbohydrate metabolism in PWS.

METHODS

We measured weight, lean and fat mass (by dual-energy X-ray absorptiometry), triglycerides, HbA(1c), and fasting insulin and glucose levels in 17 children (age range 1.5-14.6 years) with PWS to examine whether the carbohydrate metabolism is altered during 36 months of therapy with 8 mg GH/m(2) body surface/week. In a subgroup of 8 children, the insulin secretion was longitudinally assayed during oral glucose tolerance at 0 and 12 months of therapy.

RESULTS

Before therapy, the insulin secretion was lower and markedly delayed as compared with reference data and did not rise during therapy. The glucose tolerance was impaired in 2 of 12 children examined by oral glucose tolerance test before therapy and normalized during therapy. Fasting insulin and insulin resistance being normal at the beginning, significantly increased at 12 months and returned to initial levels at 36 months of GH therapy. Fasting glucose as well as HbA(1c) and triglyceride levels were always normal. The fat mass before GH therapy was increased (39.5%) and dropped into the upper normal range (28.3%) during 3 years of therapy, being correlated with fasting insulin concentration and indices of insulin sensitivity before and after 1 year of therapy.

CONCLUSIONS

Children with PWS are characterized by an intact insulin sensitivity with a decrease and a delay of insulin secretion, regardless of moderate obesity or GH treatment. In the present setting, the carbohydrate metabolism is not impaired by GH therapy, but by the excessively increased fat mass.

Pubertal alterations in growth and body composition. VI. Pubertal insulin resistance: relation to adiposity, body fat distribution and hormone release

OBJECTIVE

To investigate the independent influence of alterations in fat mass, body fat distribution and hormone release on pubertal increases in fasting serum insulin concentrations and on insulin resistance assessed by the homeostasis model (HOMA).

DESIGN AND SUBJECTS

Cross-sectional investigation of pre- (n=11, n=8), mid- (n=10, n=11), and late-pubertal (n=10, n=11) boys and girls with normal body weight and growth velocity.

MEASUREMENTS

Body composition (by a four-compartment model), abdominal fat distribution and mid-thigh interfascicular plus intermuscle (extramyocellular) fat (by magnetic resonance imaging), total body subcutaneous fat (by skinfolds), mean nocturnal growth hormone (GH) release and 06:00 h samples of serum insulin, sex steroids, leptin and insulin-like growth factor-I (IGF-I).

RESULTS

Pubertal insulin resistance was suggested by greater (P<0.001) fasting serum insulin concentrations in the late-pubertal than pre- and mid-pubertal groups while serum glucose concentrations were unchanged and greater (P<0.001) HOMA values in late-pubertal than pre- and mid-pubertal youth. From univariate correlation fat mass was most related to HOMA (r=0.59, P<0.001). Two hierarchical regression models were developed to predict HOMA. In one approach, subject differences in sex, pubertal maturation, height and weight were held constant by adding these variables as a block in the first step of the model (r(2)=0.36). Sequential addition of fat mass (FM) increased r(2) (r(2)((inc)remental)=0.08, r(2)=0.44, P<0.05) as did the subsequent addition of a block of fat distribution variables (extramyocellular fat, abdominal visceral fat, and sum of skinfolds; r(2)(inc)=0.11, r(2)=0.55, P<0.05). Sequential addition of a block of hormone variables (serum IGF-I and log((10)) leptin concentrations; r(2)(inc)=0.04, P>0.05) did not reliably improve r(2) beyond the physical characteristic and adiposity variables. In a second model, differences in sex and pubertal maturation were again held constant (r(2)=0.25), but body size differences were accounted for using percentage fat data. Sequential addition of percentage body fat (r(2)((inc)remental)=0.11, r(2)=0.36, P<0.05), then a block of fat distribution variables (percentage extramyocellular fat, percentage abdominal visceral fat, and percentage abdominal subcutaneous fat; r(2)(inc)=0.08, r(2)=0.44, P=0.058), and then a block of serum IGF-I and log((10)) leptin concentrations (r(2)(inc)=0.07, r(2)=0.51, P<0.05) increased r(2). Mean nocturnal GH release was not related to HOMA (r=-0.04, P=0.75) and therefore was not included in the hierarchical regression models.

CONCLUSION

Increases in insulin resistance at puberty were most related to FM. Accumulation of fat in the abdominal visceral, subcutaneous and muscular compartments may increase insulin resistance at puberty beyond that due to total body fat. Serum concentrations of leptin and IGF-I may further modulate HOMA beyond the effects of adiposity and fat distribution. However, the results are limited by the cross-sectional design and the use of HOMA rather than a criterion measure of insulin resistance.