Genetic variation at the IGF1 locus shows association with post-stroke outcome and to circulating IGF1

OBJECTIVE

In humans, serum IGF1 (s-IGF1) is associated with outcome after ischemic stroke (IS). Therefore variation at the IGF1 locus could also associate with both IS and s-IGF1. We investigated whether genetic variation at the IGF1 locus is associated with i) s-IGF1, ii) IS occurrence, iii) IS severity, and iv) post-stroke outcome.

DESIGN/METHODS

Patients (n=844; 66% males, mean age 56 years) and community controls (n=668) were included from the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). Post-stroke outcome was evaluated with the modified Rankin Scale at 3 and 24 months after index stroke, and baseline stroke severity with the Scandinavian Stroke Scale. s-IGF1 was determined in patients and after random selection in 40 of the controls.

RESULTS

Eleven single nucleotide polymorphisms (SNPs) were selected in the IGF1 gene. In healthy controls the major allele of rs7136446 was associated with higher s-IGF1, whereas in patients no such association was found. No SNP was associated with IS, nor with stroke severity. After multivariate correction for presence of diabetes, smoking, and hypertension, the major allele of rs7136446 was associated with favorable functional outcome 24-months post-stroke (odds ratio 1.46; 95% CI 1.09-1.96).

CONCLUSION

Variation in rs7136446 of the IGF1 gene associates with post-stroke outcome in relatively young IS patients. Also, rs7136446 associates with s-IGF1 in controls but not in IS, which indicates that IS perturbs a normal genetic impact on s-IGF1 levels.

Cerebrospinal fluid (CSF) 25-hydroxyvitamin D concentration and CSF acetylcholinesterase activity are reduced in patients with Alzheimer's disease

BACKGROUND

Little is known of vitamin D concentration in cerebrospinal fluid (CSF) in Alzheimer's disease (AD) and its relation with CSF acetylcholinesterase (AChE) activity, a marker of cholinergic function.

METHODS

A cross-sectional study of 52 consecutive patients under primary evaluation of cognitive impairment and 17 healthy controls. The patients had AD dementia or mild cognitive impairment (MCI) diagnosed with AD dementia upon follow-up (n = 28), other dementias (n = 12), and stable MCI (SMCI, n = 12). We determined serum and CSF concentrations of calcium, parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), and CSF activities of AChE and butyrylcholinesterase (BuChE).

FINDINGS

CSF 25OHD level was reduced in AD patients (P < 0.05), and CSF AChE activity was decreased both in patients with AD (P < 0.05) and other dementias (P < 0.01) compared to healthy controls. None of the measured variables differed between BuChE K-variant genotypes whereas the participants that were homozygous in terms of the apolipoprotein E (APOE) ε4 allele had decreased CSF AChE activity compared to subjects lacking the APOE ε4 allele (P = 0.01). In AD patients (n=28), CSF AChE activity correlated positively with CSF levels of total tau (T-tau) (r = 0.44, P < 0.05) and phosphorylated tau protein (P-tau) (r = 0.50, P < 0.01), but CSF activities of AChE or BuChE did not correlate with serum or CSF levels of 25OHD.

CONCLUSIONS

In this pilot study, both CSF 25OHD level and CSF AChE activity were reduced in AD patients. However, the lack of correlations between 25OHD levels and CSF activities of AChE or BuChE might suggest different mechanisms of action, which could have implications for treatment trials.

The ELISA-measured increase in cerebrospinal fluid tau that discriminates Alzheimer's disease from other neurodegenerative disorders is not attributable to differential recognition of tau assembly forms

Elevated cerebrospinal fluid concentrations of tau discriminate Alzheimer's disease from other neurodegenerative conditions. The reasons for this are unclear. While commercial assay kits are widely used to determine total-tau concentrations, little is known about their ability to detect different aggregation states of tau. We demonstrate that the leading commercial enzyme-linked immunosorbent assay reliably detects aggregated and monomeric tau and evinces good recovery of both species when added into cerebrospinal fluid. Hence, the disparity between total-tau levels encountered in Alzheimer's disease and other neurodegenerative conditions is not due to differential recognition of tau assembly forms or the extent of degeneration.

Serum but not cerebrospinal fluid levels of insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 (IGFBP-3) are increased in Alzheimer's disease

BACKGROUND

Although insulin-like growth factor-I (IGF-I) is of importance for the adult function of the central nervous system (CNS), little is known of the significance of IGF-I in cerebrospinal fluid (CSF) in relation to Alzheimer's disease (AD).

METHODS

A cross-sectional study of 60 consecutive patients under primary evaluation of cognitive impairment and 20 healthy controls. The patients had AD dementia or mild cognitive impairment (MCI) diagnosed with AD dementia upon follow-up (n=32), stable MCI (SMCI, n=13), or other dementias (n=15). IGF-I, IGF-binding protein-3 (IGFBP-3), and insulin were measured in serum and CSF.

RESULTS

Serum IGF-I level was increased in AD patients and in patients with other dementias compared to healthy controls (P=0.01 and P<0.05, respectively). Serum IGFBP-3 concentration was increased in AD and SMCI patients compared to controls (P=0.001 and P<0.05, respectively). CSF levels of IGF-I and IGFBP-3 as well as serum and CSF levels of insulin were similar in all study groups. In the total study population (n=80), serum levels of IGF-I and IGFBP-3 correlated negatively with CSF β-amyloid₁₋₄₂ (Aβ₁₋₄₂) level (r=-0.29, P=0.01 and r=-0.27, P=0.02, respectively) and in the AD patients (n=32), the increased CSF/serum IGF-I ratio correlated positively with the CSF level of phosphorylated tau protein (P-tau; r=0.42, P=0.02).

CONCLUSION

Patients with AD as well as other dementias had high levels of IGF-I in serum but not in CSF. In AD patients, the IGF-I system was associated with biomarkers of AD disease status.

Bayesian soft X-ray tomography using non-stationary Gaussian Processes

In this study, a Bayesian based non-stationary Gaussian Process (GP) method for the inference of soft X-ray emissivity distribution along with its associated uncertainties has been developed. For the investigation of equilibrium condition and fast magnetohydrodynamic behaviors in nuclear fusion plasmas, it is of importance to infer, especially in the plasma center, spatially resolved soft X-ray profiles from a limited number of noisy line integral measurements. For this ill-posed inversion problem, Bayesian probability theory can provide a posterior probability distribution over all possible solutions under given model assumptions. Specifically, the use of a non-stationary GP to model the emission allows the model to adapt to the varying length scales of the underlying diffusion process. In contrast to other conventional methods, the prior regularization is realized in a probability form which enhances the capability of uncertainty analysis, in consequence, scientists who concern the reliability of their results will benefit from it. Under the assumption of normally distributed noise, the posterior distribution evaluated at a discrete number of points becomes a multivariate normal distribution whose mean and covariance are analytically available, making inversions and calculation of uncertainty fast. Additionally, the hyper-parameters embedded in the model assumption can be optimized through a Bayesian Occam's Razor formalism and thereby automatically adjust the model complexity. This method is shown to produce convincing reconstructions and good agreements with independently calculated results from the Maximum Entropy and Equilibrium-Based Iterative Tomography Algorithm methods.

Reduced cerebrospinal fluid level of thyroxine in patients with Alzheimer's disease

BACKGROUND

Little is known of the association between thyroid hormones in the central nervous system and Alzheimer's disease (AD). We determined thyroid hormone levels in serum and cerebrospinal fluid (CSF) in a well-defined homogeneous mono-center population.

METHODS

Fifty-nine consecutive patients under primary evaluation for cognitive impairment were recruited. The participants included patients with AD or mild cognitive impairment (MCI) diagnosed with AD upon follow-up (n=31), patients with stable MCI (SMCI, n=13), patients with other dementias (n=15), and healthy controls (n=19). Thyroid hormones in serum and CSF and AD biomarkers in CSF were analyzed using established immunochemical assays. Cognitive impairment was estimated using mini-mental state examination (MMSE).

RESULTS

Serum levels of free and total thyroxine (T4) and triiodothyronine (T3) were similar in all groups whereas a marginal increase in serum thyroid-stimulating hormone (TSH) level was observed in the AD patients. The CSF level of total T4 was decreased in patients with AD and other dementias compared to SMCI (both P=0.01) and healthy controls (both P=0.001), whereas CSF levels of TSH and total T3 were unchanged. In the total study population, CSF total T4 level correlated positively with MMSE score (r=0.26, P<0.05) and negatively with CSF total-tau (T-Tau) level (r=-0.23, P<0.05).

CONCLUSION

Patients with AD as well as other dementias had signs of mild brain hypothyroidism, which could only to a small extent be detected in serum values.

Psychosocial health and levels of employment in 851 hypopituitary Swedish patients on long-term GH therapy

CONTEXT

The psychosocial health and working capacity in hypopituitary patients receiving long-term growth hormone (GH) therapy are unknown.

OBJECTIVE

Psychosocial health and levels of employment were compared between GH deficient (GHD) patients on long-term replacement and the general population.

DESIGN AND PARTICIPANTS

In a Swedish nationwide study, 851 GHD patients [101 childhood onset (CO) and 750 adult onset (AO)] and 2622 population controls answered a questionnaire regarding current living, employment and educational level, alcohol consumption and smoking habits. The median time on GH therapy for both men and women with CO GHD was 9 years and for AO GHD 6 years, respectively.

RESULTS

As compared to the controls, the GHD patients were less often working full time, more often on sick leave/disability pension, and to a larger extent alcohol abstainers and never smokers (all; P<0.05). Predominantly CO GHD women and men, but to some extent also AO GHD women and men, lived less frequently with a partner and more often with their parents. Particularly AO GHD craniopharyngioma women used more antidepressants, while AO GHD men with a craniopharyngioma used more analgesics.

CONCLUSIONS

A working capacity to the level of the general population was not achieved among hypopituitary patients, although receiving long-term GH therapy. Patients were less likely to use alcohol and tobacco. The CO GHD population lived a less independent life.

Liver-derived endocrine IGF-I is not critical for activation of skeletal muscle protein synthesis following oral feeding

BACKGROUND

Insulin-like growth factor-1 (IGF-1) is produced in various tissues to stimulate protein synthesis under different conditions. It is however, difficult to distinguish effects by locally produced IGF-1 compared to liver-derived IGF-1 appearing in the circulation. In the present study the role of liver-derived endocrine IGF-I for activation of skeletal muscle protein synthesis following feeding was evaluated.

RESULTS

Transgenic female mice with selective knockout of the IGF-I gene in hepatocytes were freely fed, starved overnight and subsequently refed for 3 hours and compared to wild types (wt). Liver IGF-I knockout mice had 70% reduced plasma IGF-I. Starvation decreased and refeeding increased muscle protein synthesis (p < 0.01), similarly in both IGF-I knockouts and wt mice. Phosphorylation of p70s6k and mTOR increased and 4EBP1 bound to eIF4E decreased in both IGF-I knockouts and wt mice after refeeding (p < 0.05). Muscle transcripts of IGF-I decreased and IGF-I receptor increased (p < 0.01) in wild types during starvation but similar alterations did not reach significance in knockouts (p>0.05). mTOR mRNA increased in knockouts only during starvation. Plasma glucose decreased during starvation in all groups in parallel to insulin, while plasma IGF-I and GH did not change significantly among the groups during starvation-refeeding. Plasma amino acids declined and increased during starvation-refeeding in wild type mice (p < 0.05), but less so in IGF-I (-/-) knockouts (p < 0.08).

CONCLUSION

This study demonstrates that re-synthesis of muscle proteins following starvation is not critically dependent on endocrine liver-derived IGF-I.

Diabetic ketoacidosis at the onset of type 1 diabetes is associated with future HbA1c levels

AIMS/HYPOTHESIS

We investigated the long-term impact of diabetic ketoacidosis (DKA) at onset on metabolic regulation and residual beta cell function in a Danish population with type 1 diabetes.

METHODS

The study is based on data from DanDiabKids, a Danish national diabetes register for children. The register provides clinical and biochemical data on patients with type 1 diabetes diagnosed in 1996-2009 and then followed-up until 1 January 2012. Repeated-measurement models were used as statistical methods.

RESULTS

The study population comprised 2,964 children <18 years. The prevalence of DKA at diagnosis was 17.9%. Of the total subjects, 8.3% had mild, 7.9% had moderate and 1.7% had severe DKA. DKA (moderate and severe) was associated with increased HbA1c (%) levels (0.24; 95% CI 0.11, 0.36; p = 0.0003) and increased insulin dose-adjusted HbA1c (IDAA1c, 0.51; 95% CI 0.31, 0.70; p < 0.0001) during follow-up, after adjustment for covariates. Children without a family history of diabetes were more likely to present with DKA (19.2% vs 8.8%, p < 0.0001); however, these children had a lower HbA1c (%) level over time (-0.35; 95% CI -0.46, -0.24; p < 0.0001). Continuous subcutaneous insulin infusion (CSII) was associated with a long-term reduction in HbA1c, changing the effect of DKA, after adjustment for covariates (p < 0.0001).

CONCLUSIONS/INTERPRETATION

DKA at diagnosis was associated with poor long-term metabolic regulation and residual beta cell function as assessed by HbA1c and IDAA1c, respectively; however, CSII treatment was associated with improvement in glycaemic regulation and residual beta cell function, changing the effect of DKA at onset in our population.

Fifteen years of GH replacement improves body composition and cardiovascular risk factors

OBJECTIVE

Few studies have determined the effects of more than 5-10 years of GH replacement in adults on body composition and cardiovascular risk factors.

DESIGN/PATIENTS

In this prospective, single-center, open-label study, the effects of 15 years of GH replacement on body composition and cardiovascular risk factors were determined in 156 hypopituitary adults (93 men) with adult-onset GH deficiency (GHD). Mean age was 50.5 (range 22-74) years at study start. Body composition was measured using dual-energy X-ray absorptiometry.

RESULTS

The mean initial GH dose of 0.55 (S.E.M. 0.03) mg/day was gradually lowered to 0.40 (0.01) mg/day after 15 years. The mean serum IGF1 SDS increased from -1.53 (0.10) at baseline to 0.74 (0.13) at study end (P<0.001 vs baseline). Lean soft tissue (LST) increased to 3% above the baseline level at study end (P<0.001). After a 9% decrease during the first year of treatment (P<0.001 vs baseline), body fat (BF) started to increase and had returned to the baseline level after 15 years. Serum levels of total cholesterol and LDL-cholesterol decreased and serum HDL-cholesterol level increased. Fasting plasma glucose increased from 4.4 (0.1) at baseline to 4.8 (0.1) mmol/l at study end (P<0.001). However, blood HbA1c decreased from 5.0 (0.1) to 4.6 (0.1) % (P<0.001).

CONCLUSIONS

Fifteen-year GH replacement in GHD adults induced a transient decrease in BF and sustained improvements of LST and serum lipid profile. Fasting plasma glucose increased whereas blood HbA1c was reduced.

Deaths among adult patients with hypopituitarism: hypocortisolism during acute stress, and de novo malignant brain tumors contribute to an increased mortality

CONTEXT

Patients with hypopituitarism have an increased standardized mortality rate. The basis for this has not been fully clarified.

OBJECTIVE

To investigate in detail the cause of death in a large cohort of patients with hypopituitarism subjected to long-term follow-up.

DESIGN AND METHODS

All-cause and cause-specific mortality in 1286 Swedish patients with hypopituitarism prospectively monitored in KIMS (Pfizer International Metabolic Database) 1995-2009 were compared to general population data in the Swedish National Cause of Death Registry. In addition, events reported in KIMS, medical records, and postmortem reports were reviewed.

MAIN OUTCOME MEASURES

Standardized mortality ratios (SMR) were calculated, with stratification for gender, attained age, and calendar year during follow-up.

RESULTS

An excess mortality was found, 120 deaths vs 84.3 expected, SMR 1.42 (95% confidence interval: 1.18-1.70). Infections, brain cancer, and sudden death were associated with significantly increased SMRs (6.32, 9.40, and 4.10, respectively). Fifteen patients, all ACTH-deficient, died from infections. Eight of these patients were considered to be in a state of adrenal crisis in connection with death (medical reports and post-mortem examinations). Another 8 patients died from de novo malignant brain tumors, 6 of which had had a benign pituitary lesion at baseline. Six of these 8 subjects had received prior radiation therapy.

CONCLUSION

Two important causes of excess mortality were identified: first, adrenal crisis in response to acute stress and intercurrent illness; second, increased risk of a late appearance of de novo malignant brain tumors in patients who previously received radiotherapy. Both of these causes may be in part preventable by changes in the management of pituitary disease.

The synthetic progestin levonorgestrel is a potent androgen in the three-spined stickleback (Gasterosteus aculeatus)

The use of progestins has resulted in contamination of aquatic environments and some progestins have in experimental studies been shown to impair reproduction in fish and amphibians at low ng L(-1) concentrations. The mechanisms underlying their reproductive toxicity are largely unknown. Some progestins, such as levonorgestrel (LNG), exert androgenic effects in mammals by activating the androgen receptor (AR). Male three-spined stickleback (Gasterosteus aculeatus) kidneys produce spiggin, a gluelike glycoprotein used in nest building, and its production is directly governed by androgens. Spiggin is normally absent in females but its production in female kidneys can be induced by AR agonists. Spiggin serves as the best known biomarker for androgens in fish. We exposed adult female sticklebacks to LNG at 5.5, 40, and 358 ng L(-1) for 21 days. Androgenic effects were found at LNG concentrations ≥40 ng L(-1) including induction of spiggin transcription, kidney hypertrophy, and suppressed liver vitellogenin transcription. These are the first in vivo quantitative data showing that LNG is a potent androgen in fish supporting the contention that androgenic effects of certain progestins contribute to their reproductive toxicity.

Importance of circulating IGF-1 for normal cardiac morphology, function and post infarction remodeling

IGF-1 plays an important role in cardiovascular homeostasis, and plasma levels of IGF-1 correlate inversely with systolic function in heart failure. It is not known to what extent circulating IGF-1 secreted by the liver and local autocrine/paracrine IGF-1 expressed in the myocardium contribute to these beneficial effects on cardiac function and morphology. In the present study, we used a mouse model of liver-specific inducible deletion of the IGF-1 gene (LI-IGF-1 -/- mouse) in an attempt to evaluate the importance of circulating IGF-I on cardiac morphology and function under normal and pathological conditions, with an emphasis on its regulatory role in myocardial phosphocreatine metabolism. Echocardiography was performed in LI-IGF-1 -/- and control mice at rest and during dobutamine stress, both at baseline and post myocardial infarction (MI). High-energy phosphate metabolites were compared between LI-IGF-1 -/- and control mice at 4 weeks post MI. We found that LI-IGF-1 -/- mice had significantly greater left ventricular dimensions at baseline and showed a greater relative increase in cardiac dimensions, as well as deterioration of cardiac function, post MI. Myocardial creatine content was 17.9% lower in LI-IGF-1 -/- mice, whereas there was no detectable difference in high-energy nucleotides. These findings indicate an important role of circulating IGF-1 in preserving cardiac structure and function both in physiological settings and post MI.

Both low and high serum IGF-I levels associate with cancer mortality in older men

BACKGROUND

Although recent population-based studies suggest a U-shaped relationship between serum IGF-I concentration and all-cause mortality, the distribution of death causes underlying this association remains unclear. We hypothesized that high IGF-I levels associate with increased cancer mortality, whereas low IGF-I levels associate with increased cardiovascular disease (CVD) mortality.

METHODS

Serum IGF-I levels were measured in 2901 elderly men (mean age 75.4, range 69-81 yr) included in the prospective population-based Osteoporotic Fractures in Men Study (Sweden) study. Mortality data were obtained from central registers with no loss of follow-up. The statistical analyses included Cox proportional hazards regressions with or without a spline approach.

RESULTS

During the follow-up (mean 6.0 yr), 586 of the participants died (cancer deaths, n = 211; CVD deaths, n = 214). As expected, our data revealed a U-shaped association between serum IGF-I levels and all-cause mortality. Low as well as high serum IGF-I (quintile 1 or 5 vs. quintiles 2-4) associated with increased cancer mortality [hazard ratio (HR) = 1.86, 95% confidence interval (CI) = 1.34-2.58; and HR = 1.90, 95% CI = 1.37-2.65, respectively]. Only low serum IGF-I associated with increased CVD mortality (quintile 1 vs. quintiles 2-4, HR = 1.48, 95% CI = 1.08-2.04). These associations remained after adjustment for multiple covariates and exclusion of men who died during the first 2 yr of follow-up.

CONCLUSIONS

Our findings demonstrate that both low and high serum IGF-I levels are risk markers for increased cancer mortality in older men. Moreover, low IGF-I levels associate with increased CVD mortality.

Trends in childhood type 1 diabetes incidence in Europe during 1989-2008: evidence of non-uniformity over time in rates of increase

AIMS/HYPOTHESIS

The aim of the study was to describe 20-year incidence trends for childhood type 1 diabetes in 23 EURODIAB centres and compare rates of increase in the first (1989-1998) and second (1999-2008) halves of the period.

METHODS

All registers operate in geographically defined regions and are based on a clinical diagnosis. Completeness of registration is assessed by capture-recapture methodology. Twenty-three centres in 19 countries registered 49,969 new cases of type 1 diabetes in individuals diagnosed before their 15th birthday during the period studied.

RESULTS

Ascertainment exceeded 90% in most registers. During the 20-year period, all but one register showed statistically significant changes in incidence, with rates universally increasing. When estimated separately for the first and second halves of the period, the median rates of increase were similar: 3.4% per annum and 3.3% per annum, respectively. However, rates of increase differed significantly between the first half and the second half for nine of the 21 registers with adequate coverage of both periods; five registers showed significantly higher rates of increase in the first half, and four significantly higher rates in the second half.

CONCLUSIONS/INTERPRETATION

The incidence rate of childhood type 1 diabetes continues to rise across Europe by an average of approximately 3-4% per annum, but the increase is not necessarily uniform, showing periods of less rapid and more rapid increase in incidence in some registers. This pattern of change suggests that important risk exposures differ over time in different European countries. Further time trend analysis and comparison of the patterns in defined regions is warranted.

Facial clefts involving the midline in combination with intracranial anomalies: case studies illustrating surgical treatment and medical substitution

Malmö and Uppsala have been regional centres for the treatment of cleft lip and palate since the beginning of the 1950s. We have about 80 new cases every year and most patients have conventional oronasal clefts, either cleft lip and palate or isolated cleft palate. During a 10-year period we have come across four patients who have had varying degrees of midface dysplasia combined with intracranial anomalies. One child died at an early age, but the other three children were given medical substitution of hypopituitarism and have had their clefts reconstructed.

Superior beta cell proliferation, function and gene expression in a subpopulation of rat islets identified by high blood perfusion

AIMS/HYPOTHESIS

The blood perfusion of individual pancreatic islets is highly variable, with a subgroup of islets having high perfusion and blood vessels responsive to further blood flow increase induced by glucose. This study tested the hypothesis that there is heterogeneity between islets with regard to beta cell proliferation, function and gene expression based on differences in their blood perfusion.

METHODS

Fluorescent microspheres were injected into the ascending aorta, and then microsphere-containing and non-microsphere-containing pancreatic islets were isolated for investigation. By this procedure, the 5% of islets with the greatest blood perfusion were identified for study. Islet endothelial cells were isolated separately to investigate the role of improved vascular support in the observed differences.

RESULTS

The vascular network was found to be more dense and tortuous in microsphere-containing than other islets. The most highly blood-perfused islets also had a higher rate of beta cell proliferation, superior beta cell function and a markedly different gene expression from other islets. Cultured islets exposed to islet endothelial cell products had a similarly increased beta cell proliferation rate, yet significantly fewer changes in gene expression than observed in the most highly blood-perfused islets.

CONCLUSIONS/INTERPRETATION

A novel heterogeneity between islets was observed, with superior beta cell proliferation, function and gene expression in a subpopulation of islets identified by high blood perfusion. In contrast with a previously described population of low-oxygenated, sleeping islets, which are recruited into functionality when needed, the presently described heterogeneity is shown to remain in vitro after islet isolation.

Fifteen years of GH replacement increases bone mineral density in hypopituitary patients with adult-onset GH deficiency

OBJECTIVE

Few studies have determined the effects of more than 5-10 years of GH replacement in adults on bone mineral content (BMC) and bone mineral density (BMD).

DESIGN/PATIENTS

In this prospective, single-centre, open-label study, the effects of 15 years of GH replacement on BMC and BMD, measured using dual-energy X-ray absorptiometry, were determined in 126 hypopituitary adults (72 men) with adult-onset GH deficiency (GHD). Mean age was 49.4 (range 22-74) years at the initiation of the study.

RESULTS

The mean initial GH dose of 0.63 (s.e.m. 0.03) mg/day was gradually lowered to 0.41 (0.01) mg/day after 15 years. The mean serum IGF1 SDS increased from -1.69 (0.11) at baseline to 0.63 (0.16) at the study end (P<0.001 vs baseline). The 15 years of GH replacement induced a sustained increase in total body BMC (+5%, P<0.001) and BMD (+2%, P<0.001). Lumbar (L2-L4) spine BMC increased by 9% (P<0.001) and BMD by 5% (P<0.001). In femur neck, a peak increase in BMC and BMD of 7 and 3%, respectively, was observed after 7 years (both P<0.001). After 15 years, femur neck BMC was 5% above the baseline value (P<0.01), whereas femur neck BMD had returned to the baseline level. In most variables, men had a more marked response to GH replacement than women.

CONCLUSIONS

Fifteen-year GH replacement in GHD adults induced a sustained increase in total body and lumbar (L2-L4) spine BMC and BMD. In femur neck, BMC and BMD peaked at 7 years and then decreased towards baseline values.