Prevalence and risk factors of the metabolic syndrome in young adults with childhood-onset hypopituitary growth hormone deficiency

Dyslipidaemia and growth hormone deficiency - A comprehensive review

Growth hormone deficiency (GHD) is a common complication of several pituitary and hypothalamic disorders and dependent on the onset of disease. It may have severe clinical implications ranging from growth retardation in childhood-onset, to impaired lipid metabolism and increased cardiovascular risk and mortality in adults. GH effectively modulates lipid metabolism at multiple levels and GHD has been associated with an atherogenic lipid profile, that can be reversed by GH replacement therapy. Despite increasing knowledge on the effects of GH on several key enzymes regulating lipid metabolism and recent breakthroughs in the development and wider availability of recombinant GH preparations, several questions remain regarding the replacement therapy in adults with GHD. This review aims to comprehensively summarize the current knowledge on (i) lipid profile abnormalities in individuals with GHD, (ii) proposed mechanisms of action of GH on lipid and lipoprotein metabolism, and (iii) clinical implications of GH replacement therapy in individuals diagnosed with GHD.

Metabolic Impacts of Discontinuation and Resumption of Recombinant Human Growth Hormone Treatment during the Transition Period in Patients with Childhood-Onset Growth Hormone Deficiency

BACKGROUND

Discontinuing growth hormone (GH) treatment during the transition to adulthood has been associated with adverse health outcomes in patients with childhood-onset growth hormone deficiency (CO-GHD). This study investigated the metabolic changes associated with interrupting GH treatment in adolescents with CO-GHD during the transition period.

METHODS

This study included 187 patients with CO-GHD who were confirmed to have adult GHD and were treated at six academic centers in Korea. Data on clinical parameters, including anthropometric measurements, metabolic profiles, and bone mineral density (BMD) at the end of childhood GH treatment, were collected at the time of re-evaluation for GHD and 1 year after treatment resumption.

RESULTS

Most patients (n=182, 97.3%) had organic GHD. The median age at treatment discontinuation and re-evaluation was 15.6 and 18.7 years, respectively. The median duration of treatment interruption was 2.8 years. During treatment discontinuation, body mass index Z-scores and total cholesterol, low-density lipoprotein, and non-high-density lipoprotein (HDL) cholesterol levels increased, whereas fasting glucose levels decreased. One year after GH treatment resumption, fasting glucose levels, HDL cholesterol levels, and femoral neck BMD increased significantly. Longer GH interruption (>2 years, 60.4%) resulted in worse lipid profiles at re-evaluation. The duration of interruption was positively correlated with fasting glucose and non-HDL cholesterol levels after adjusting for covariates.

CONCLUSION

GH treatment interruption during the transition period resulted in worse metabolic parameters, and a longer interruption period was correlated with poorer outcomes. GH treatment should be resumed early in patients with CO-GHD during the transition period.

Safety of current recombinant human growth hormone treatments for adults with growth hormone deficiency and unmet needs

INTRODUCTION

Growth hormone (GH) deficiency (GHD) in adults is characterized by abnormal body composition, unfavorable cardiovascular risk factors, and poor quality of life. The diagnosis is made within appropriate clinical settings and according to established guidelines. Numerous studies have shown that GH treatment improves body composition, cardiovascular risk factors, physical capacity, and quality of life while issues on safety, in particular long-term safety, remain.

AREAS COVERED

Short- and long-term safety of GH replacement in adults with GHD.

EXPERT OPINION

Adults with GHD are an inhomogeneous group of patients and GH replacement requires individual considerations. Most adverse effects are mild and transient and related to fluid retention and GH dose. In patients without comorbidities long-term GH treatment is safe and development of diabetes, cardiovascular disease, or tumors are not increased. Furthermore, mortality is not increased. Patients with risk factors should be identified before GH treatment is initiated and an optimal balance between benefit and risk established. Studies with sufficient duration and power to identify the development of cardiovascular diseases and cancers are still awaited. Effective management of comorbidities can be expected to decrease morbidity and mortality and improve quality of life. Studies with long-acting GH formulations are ongoing and available data indicate similar effects and short-time safety.

Metabolic syndrome induced by anticancer treatment in childhood cancer survivors

The number of childhood cancer survivors is increasing as survival rates improve. However, complications after treatment have not received much attention, particularly metabolic syndrome. Metabolic syndrome comprises central obesity, dyslipidemia, hypertension, and insulin resistance, and cancer survivors have higher risks of cardiovascular events compared with the general population. The mechanism by which cancer treatment induces metabolic syndrome is unclear. However, its pathophysiology can be categorized based on the cancer treatment type administered. Brain surgery or radiotherapy may induce metabolic syndrome by damaging the hypothalamic-pituitary axis, which may induce pituitary hormone deficiencies. Local therapy administered to particular endocrine organs directly damages the organs and causes hormone deficiencies, which induce obesity and dyslipidemia leading to metabolic syndrome. Chemotherapeutic agents interfere with cell generation and growth, damage the vascular endothelial cells, and increase the cardiovascular risk. Moreover, chemotherapeutic agents induce oxidative stress, which also induces metabolic syndrome. Physical inactivity caused by cancer treatment or the cancer itself, dietary restrictions, and the frequent use of antibiotics may also be risk factors for metabolic syndrome. Since childhood cancer survivors with metabolic syndrome have higher risks of cardiovascular events at an earlier age, early interventions should be considered. The optimal timing of interventions and drug use has not been established, but lifestyle modifications and exercise interventions that begin during cancer treatment might be beneficial and tailored education and interventions that account for individual patients' circumstances are needed. This review evaluates the recent literature that describes metabolic syndrome in cancer survivors, with a focus on its pathophysiology.