Prevention of bone demineralization by calcium supplementation in precocious puberty during gonadotropin-releasing hormone agonist treatment

Long-term effects and significant Adverse Drug Reactions (ADRs) associated with the use of Gonadotropin-Releasing Hormone analogs (GnRHa) for central precocious puberty: a brief review of literature

Central precocious puberty (CPP) is defined as an early pubertal development that occurs before the age of 9 years in boys and 8 years in girls. It results from premature activation of the hypothalamic-pituitary-gonadal axis. Gonadotropin-releasing hormone agonists (GnRHa) have been the gold standard therapy for CPP for more than 30 years. These compounds have a high affinity for the pituitary LHRH receptor and are resistant to enzymatic degradation. Through continuous stimulation, GnRHa inhibit the pulsatile secretion of gonadotropin, resulting in hormonal suppression, cessation of pubertal development, and normalization of growth and skeletal maturation rates. The goal of therapy is to halt pubertal progression and delay epiphyseal maturation that leads to improvement of final adult height. There are no widely accepted guidelines for how long to continue treatment with a GnRHa for CPP, and individual practice varies widely. Furthermore, conflicting results have been published on the long-term effects of GnRHa therapy in patients with CPP. Therefore, we reviewed the current literature focusing our attention on the long-term effects and the significant adverse drug reactions (ADRs) observed during treatment with GnRHa in patients with CPP. Our review may provide the necessary data to enable clinicians to administer GnRHa in the safest and most appropriate way. Further studies are necessary to identify the mechanisms of development of potential adverse drug reactions related to GnRHa therapy in CPP.

Review: Gonadal functioning and preservation of reproductive fitness with juvenile systemic lupus erythematosus

Increased survival of children with juvenile systemic lupus erythematosus (jSLE) and improved prognosis have led to a change in the long-term health issues arising for jSLE patients. Preservation of gonadal functioning and fertility are of increasing importance for young adults with jSLE. Events during childhood, such as exposure to alkylating agents, may compromise the reproductive potential. Even in the absence of gonadotoxic therapies, fertility may be decreased through organs specific involvement with jSLE. Strategies to preserve the reproductive potential of girl and boys with jSLE are discussed. Lupus (2007) 16, 593—599.

An Examination of the Effects of Leuprolide Acetate Used in the Treatment of Central Precocious Puberty on Bone Mineral Density and 25-Hydroxy Vitamin D

AIM

Leuprolide acetate is a gonadotropin-releasing hormone (GnRH) analogue frequently used in the treatment of central precocious puberty. Research is currently taking place into its effects on endocrine systems. The aim of this study is to investigate the effect of leuprolide acetate on vitamin D and bone mineral density.

METHODS

Twenty-three children diagnosed with central precocious puberty and receiving leuprolide acetate therapy for at least 12 months, and a control group of 17 healthy children were enrolled. In the study group, calcium, phosphorus, alkaline phosphatase, parathormone and 25-hydroxy vitamin D levels and bone mineral density were measured. The results were compared with those of the control group.

RESULTS

25-Hydroxy vitamin D levels in the study and control groups were 15.17 ± 7 mg/dL and 22.2 ± 6.1 mg/dL, respectively (p < 0.05). In terms of bone mineral density, osteopenia was determined in 13 (56.5%) patients in the study group and osteoporosis in one (4.3%), while osteopenia was identified in seven patients in the control group, with no osteoporosis being identified (p > 0.05).

CONCLUSION

Gonadotropin-releasing hormone agonists may have an adverse effect on bone health. They may exhibit these effects by impacting on vitamin D levels. These levels should be periodically monitored in patients receiving treatment, and vitamin D support should be given in cases where the deficiency is identified.

Long-term effects of gonadotropin-releasing hormone analogs in girls with central precocious puberty

Gonadotropin-releasing hormone analogs (GnRHa) are widely used to treat central precocious puberty (CPP). The efficacy and safety of GnRHa treatment are known, but concerns regarding long-term complications are increasing. Follow-up observation results after GnRHa treatment cessation in female CPP patients up to adulthood showed that treatment (especially <6 years) was beneficial for final adult height relative to that of pretreated or untreated patients. Puberty was recovered within 1 year after GnRHa treatment discontinuation, and there were no abnormalities in reproductive function. CPP patients had a relatively high body mass index (BMI) at the time of CPP diagnosis, but BMI standard deviation score maintenance during GnRHa treatment seemed to prevent the aggravation of obesity in many cases. Bone mineral density decreases during GnRHa treatment but recovers to normal afterwards, and peak bone mass formation through bone mineral accretion during puberty is not affected. Recent studies reported a high prevalence of polycystic ovarian syndrome in CPP patients after GnRHa treatment, but it remains unclear whether the cause is the reproductive mechanism of CPP or GnRHa treatment itself. Studies of the psychosocial effects on CPP patients after GnRHa treatment are very limited. Some studies have reported decreases in psychosocial problems after GnRHa treatment. Overall, GnRHa seems effective and safe for CPP patients, based on long-term follow-up studies. There have been only a few long-term studies on GnRHa treatment in CPP patients in Korea; therefore, additional long-term follow-up investigations are needed to establish the efficacy and safety of GnRHa in the Korean population.

Pros and cons of GnRHa treatment for early puberty in girls

The timing of puberty has considerable biological, psychosocial and long-term health implications. Secular trends in age at pubertal development, the effects of obesity and the potential effects of environmental endocrine disruptors challenge the standard definitions of precocious puberty and the indications for intervention with gonadotropin-releasing hormone agonists (GnRHa) in girls with precocious puberty. GnRHa therapy is effective in improving adult height in patients who present with classic central precocious puberty (at <8 years old), without causing adverse effects on body composition, BMD and reproductive function. However, its benefits in patients with atypical forms of early puberty not driven by luteinising hormone are not well defined. The role of GnRHa in these patients and the potential benefits in terms of later growth, psychosocial functioning and long-term risk of adult diseases that are associated with early menarche, such as breast cancer and the metabolic syndrome, have not been established.

The effect of gonadotropin releasing hormone analogue therapy in girls with idiopathic central precocious puberty

It has been proven for more than two decades that gonadotropin releasing hormone analogue therapy is the only choice of treatment in patients with central precocious puberty. Aims: The aim of the authors was to assess the effect of gonadotropin releasing hormone analogue treatment on final height, body mass index, bone mineral density and ovarian function in girls with idiopathic central precocious puberty. Methods: Predicted adult height, target height and achieved height due to therapy was assessed in 15 girls with idiopathic precocious puberty treated with gonadotropin releasing hormone analogue. At the beginning of the treatment, the age of the girls was 7.0±0.8 years (mean±SD) and at the end of the treatment 12±0.8 years. The duration of gonadotropin-releasing hormone analogue treatment was 4.48±0.8 years. At the time of achieving final height, the age of the patients was 18.2±2.0 years and the height was 160.4±7.1 cm. When final height was reached, the authors evaluated bone mineral density Z-score values, levels of bone markers and the function of the hypothalamic-pituitary-gonadal axis. 15 healthy prepubertal girls, 15 pubertal girls and 15 girls who reached final height matched for chronological age were selected as control groups. Results: The majority of the gonadotropin releasing hormone-treated girls reached or almost reached their expected height predicted on the basis of the heights of their parents, but the therapy resulted only in a modest beneficial effect on height gain. Despite the fact that the body weight of patients increased during the treatment, there was no significant difference in their body mass index when they reached their final height as compared to controls. As compared to controls, patients had a decreased bone mineral density at the time when they reached their final height (lumbar spine 2-4 Z score, –0.27±1.2 vs. 0.5±0.7 in controls; p = 0.0377), which could be explained by their overweight that already existed before treatment, lack of exercise and poor calcium uptake. Their menarche occurred 12±4.6 months after discontining the treatment. Conclusions: Gonadotropin releasing hormone analogue therapy exerts a modest beneficial effect on final height gain. There are no detrimental effects on body mass index, bone mineral density and ovarian function after treatment. Side-effects are of minor severity and they are tolerable. Orv. Hetil., 2012, 153, 418–424.

Bone mineral density and body composition in girls with idiopathic central precocious puberty before and after treatment with a gonadotropin-releasing hormone agonist

OBJECTIVES

Idiopathic central precocious puberty and its postponement with a (gonadotropin-releasing hormone) GnRH agonist are complex conditions, the final effects of which on bone mass are difficult to define. We evaluated bone mass, body composition, and bone remodeling in two groups of girls with idiopathic central precocious puberty, namely one group that was assessed at diagnosis and a second group that was assessed three years after GnRH agonist treatment.

METHODS

The precocious puberty diagnosis and precocious puberty treatment groups consisted of 12 girls matched for age and weight to corresponding control groups of 12 (CD) and 14 (CT) girls, respectively. Bone mineral density and body composition were assessed by dual X-ray absorptiometry. Lumbar spine bone mineral density was estimated after correction for bone age and the mathematical calculation of volumetric bone mineral density. CONEP: CAAE-0311.0.004.000-06.

RESULTS

Lumbar spine bone mineral density was slightly increased in individuals diagnosed with precocious puberty compared with controls; however, after correction for bone age, this tendency disappeared (CD = -0.74 + 0.9 vs. precocious puberty diagnosis = -1.73 + 1.2). The bone mineral density values of girls in the precocious puberty treatment group did not differ from those observed in the CT group.

CONCLUSION

There is an increase in bone mineral density in girls diagnosed with idiopathic central precocious puberty. Our data indicate that the increase in bone mineral density in girls with idiopathic central precocious puberty is insufficient to compensate for the marked advancement in bone age observed at diagnosis. GnRH agonist treatment seems to have no detrimental effect on bone mineral density.

Long-term observation of 87 girls with idiopathic central precocious puberty treated with gonadotropin-releasing hormone analogs: impact on adult height, body mass index, bone mineral content, and reproductive function

OBJECTIVE

We assessed in a retrospective unicenter study the impact of treatment with GnRH analogs (GnRHa) on adult height (AH), body mass index (BMI), bone mineral density (BMD), and reproductive function in girls with idiopathic central precocious puberty (ICPP).

PATIENTS

Eighty-seven ICPP patients were treated with GnRHa for 4.2 +/- 1.6 yr (range 3-7.9) and observed for 9.9 +/- 2.0 yr (range 4-10.6 yr) after discontinuation of treatment; to estimate the efficacy better, 32 comparable ICPP untreated girls were analyzed.

RESULTS

AH was 159.8 +/- 5.3 cm, significantly higher than pretreatment predicted AH (PAH) either for accelerated or for average tables of Bayley and Pinneau. The gain in centimeters between pretreatment PAH and AH was 5.1 +/- 4.5 and 9.5 +/- 4.6 cm, respectively. Hormonal values and ovarian and uterine dimensions, reduced during treatment, increased to normal after 1 yr without therapy. Age of menarche was 13.6 +/- 1.1 yr with an interval of 0.9 +/- 0.4 yr after therapy. Menstrual pattern was normal. Six girls became pregnant and delivered normal offspring. BMI sd score for chronological age increased, but not significantly, before, during, and after therapy. BMD at discontinuation of treatment was significantly lower and increased to control values after gonadal activity resumption.

CONCLUSIONS

GnRHa treatment in ICPP is safe for the reproductive system, BMD, and BMI and helpful in reaching AH close to target height; however, the variability of individual responses suggests that one choose more parameters than increment in height, especially in girls with pubertal onset over 8 yr of age.

Calcium supplementation for improving bone mineral density in children

BACKGROUND

Clinical trials have shown that calcium supplementation in children can increase bone mineral density (BMD) although this effect may not be maintained. There has been no quantitative systematic review of this intervention.

OBJECTIVES

. To determine the effectiveness of calcium supplementation for improving BMD in children. . To determine if any effect varies by sex, pubertal stage, ethnicity or level of physical activity, and if any effect persists after supplementation is ceased.

SEARCH STRATEGY

We searched CENTRAL, (Cochrane Central Register of Controlled Trials) (Issue 3, 2005), MEDLINE (1966 to 1 April 2005), EMBASE (1980 to 1 April 2005), CINAHL (1982 to 1 April 2005), AMED (1985 to 1 April 2005), MANTIS (1880 to 1 April 2005) ISI Web of Science (1945 to 1 April 2005), Food Science and Technology Abstracts (1969 to 1 April 2005) and Human Nutrition (1982 to 1 April 2005). Conference abstract books (Osteoporosis International, Journal of Bone and Mineral Research) were hand-searched.

SELECTION CRITERIA

Randomised controlled trials of calcium supplementation (including by food sources) compared with placebo, with a treatment period of at least 3 months in children without co-existent medical conditions affecting bone metabolism. Outcomes had to include areal or volumetric BMD, bone mineral content (BMC), or in the case of studies using quantitative ultrasound, broadband ultrasound attenuation and ultrasonic speed of sound, measured after at least 6 months of follow-up.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data including adverse events. We contacted study authors for additional information.

MAIN RESULTS

The 19 trials included 2859 participants, of which 1367 were randomised to supplementation and 1426 to placebo. There was no heterogeneity in the results of the main effects analyses to suggest that the studies were not comparable. There was no effect of calcium supplementation on femoral neck or lumbar spine BMD. There was a small effect on total body BMC (standardised mean difference (SMD) +0.14, 95% CI+0.01, +0.27) and upper limb BMD (SMD +0.14, 95%CI +0.04, +0.24). Only the effect in the upper limb persisted after supplementation ceased (SMD+0.14, 95%CI+0.01, +0.28). This effect is approximately equivalent to a 1.7% greater increase in supplemented groups, which at best would reduce absolute fracture risk in children by 0.1-0.2%per annum. There was no evidence of effect modification by baseline calcium intake, sex, ethnicity, physical activity or pubertal stage. Adverse events were reported infrequently and were minor.

AUTHORS' CONCLUSIONS

While there is a small effect of calcium supplementation in the upper limb, the increase in BMD which results is unlikely to result in a clinically significant decrease in fracture risk. The results do not support the use of calcium supplementation in healthy children as a public health intervention. These results cannot be extrapolated to children with medical conditions affecting bone metabolism.

Central precocious puberty: current treatment options

Central precocious puberty (CPP) is characterized by early pubertal changes, acceleration of growth velocity, and rapid bone maturation that often result in reduced adult height. An onset of pubertal signs before the age of 8 years in girls and 9 years in boys should always be evaluated. A combination of clinical signs, bone age, pelvic echography in girls, and hormonal data are required to diagnose CPP and make a judgment concerning progression and prognosis. Not all children with apparently true CPP require medical intervention. The main reasons for treatment are to prevent compromised adult height and to avoid psychosocial or behavioral problems. The need for treatment for auxologic reasons is based on estimation of predicted adult height, with the finding of a reduced height potential, which may require a follow-up. Indication for treatment on the basis of psychologic and behavioral anomalies has to be determined on an individual basis. The main short-term aims of therapy are to stop the progression of secondary sex characteristics and menses (in girls) and to treat the underlying cause, when known. Long-term goals are to increase final adult height and to promote psychosocial well-being. Once it has been decided that treatment is appropriate, it should be initiated immediately with depot gonadotropin-releasing hormone (GnRH) agonists. The effective suppression of pituitary gonadal function is achieved with these compounds in practically all CPP patients. Long-term data are now available from 2 decades of GnRH agonist treatment for patients with CPP. Treatment preserves height potential in the majority of patients (especially in younger patients) and improves the final adult height of children with rapidly progressing CPP, with a complete recovery of the hypothalamic-pituitary-gonadal axis after treatment. GnRH agonist treatment using depot preparations is useful and has a good safety profile, with minimal adverse effects and no severe long-term consequences. Although further data are need, there may be a role in the future for combining somatropin (growth hormone) and GnRH agonist treatment for some patients with significantly impaired growth velocity. The introduction of GnRH antagonists is likely to improve the treatment options for CPP.

Altered bone metabolism in children infected with human immunodeficiency virus

AIM

Data on bone homoeostasis of children infected with human immunodeficiency virus (HIV), at the time of the gain in bone mass, are very rare. To determine possible alterations in bone metabolism, 13 prepubertal vertically HIV-infected children were studied.

METHODS

Viral load, CD4 count, interleukin-6 (IL-6), growth hormone, insulin-like growth factor-I (IGF-I), IGF binding protein-3 (IGFBP-3), acid-labile subunit (ALS), IGFBP-3 proteolysis, osteocalcin in blood and N-terminal telopeptide of type I collagen in urine were determined. Lumbar spine bone mineral density was examined by dual-energy X-ray absorptiometry.

RESULTS

Low osteocalcin levels were found in all patients. Low IGF-I was found in only six children, who had low CD4 count and high IL-6 levels, with normal levels of IGFBP-3 and ALS, absent IGFBP-3 proteolysis and decreased bone mineral density, irrespective of viral load or growth.

CONCLUSION

Low serum osteocalcin levels appear to be an initial warning sign of possible altered bone metabolism in HIV-infected children. However, only when the immune system becomes more seriously compromised is bone loss measurable by bone densitometry.