IGF-I in a normal population: relation to psychosocial factors

Studies of IGF-I and Klotho Protein in Relation to Anabolic-Androgenic Steroid and Growth Hormone Administrations

It has been suggested to longitudinally monitor Insulin-like growth factor I (IGF-I) as a biomarker for the detection of recombinant growth hormone (GH). Subsequently, it is of interest to understand any confounders of endogenous IGF-I. Herein we have studied if serum IGF-I concentration is affected by the intake of anabolic androgenic steroids (AAS) and the potential connection between IGF-I and klotho protein. Moreover, the usefulness of klotho as a biomarker for recombinant GH intake was assessed in healthy male volunteers. An ongoing administration of AAS did not affect the levels of IGF-I. Klotho protein was ~30% higher in men with an ongoing AAS use compared to those with previous (>2 months ago) AAS use, and the serum klotho protein correlated negatively with luteinizing hormone (LH) (r_s = −0.38, p = 0.04) and follicle stimulating hormone (FSH) (r_s = −0.35, p = 0.05) levels. Serum IGF-I and klotho concentrations showed no correlation in the AAS using population but showed a strong negative correlation in healthy volunteers (r_s = −0.86, p = 0.006). The intake of recombinant GH did not affect the serum concentrations of the klotho levels. In conclusion, IGF-I was not affected by supra-physiological AAS doses in men. Interestingly, an association between AAS intake and serum klotho was seen. The usefulness of klotho as an androgen biomarker warrants further studies, whereas klotho can be discarded as a promising biomarker for GH doping.

Aggression in Children Exposed to Intimate Partner Violence: A Comparison of Maternal, Sibling, and Observer Perspectives

The negative effects of exposure to intimate partner violence (IPV) on children have been well documented, including externalizing difficulties such as aggression. Although aggressive behavior is a common concern for these children, sibling aggression in children exposed to IPV has rarely been studied. Our purpose was to investigate similarities and differences in multiple informant reports of aggression by siblings exposed to IPV, and to examine how exposure to IPV was linked to these differing perspectives. Forty-seven sibling dyads and their mothers were recruited from the community. Aggression was assessed by observers, by mothers, and by the siblings themselves, whereas IPV was assessed by both maternal and child report. Informants had very differing views on aggression. Regression results indicated that children's reports of their own exposure to IPV accounted for significant variance in observed aggression between siblings, as well as in the maternal reports of aggression by both siblings. Aggression did not vary by sibling age, sex, or age spacing. Results were discussed within a risk and resilience framework.

IGF-I and IGFBP-1 in Relation to Body Composition and Physical Performance in Female Olympic Athletes

INTRODUCTION

Insulin- like growth factor-I (IGF-I) is an anabolic hormone that may affect athletic performance in female athletes, and insulin-like growth factor binding protein-1 (IGFBP-1) is an important regulator of bioactive IGF-I. There is limited knowledge of the role of endogenous IGF-I and IGFBP-1 for body composition and physical performance in female elite athletes.

PURPOSE

To examine IGF-I, age adjusted IGF-I (IGFSD), IGFBP-1 and insulin in female Olympic athletes compared with controls and different sport categories, and in relation to body composition and physical performance in the athletes.

METHODS

Female athletes (n=103) and untrained controls (n=113) were included in this cross-sectional study. Body composition was established by dual-energy X-ray absorptiometry. Serum IGF-I and IGFBP-1 were analyzed by radioimmunoassay and IGFSD was calculated. Insulin was analyzed by electrochemiluminescence immunoassay. Athletes were offered to participate in standardized physical fitness tests.

RESULTS

The athletes demonstrated significantly higher IGF-I, IGFSD and IGFBP-1 and lower insulin levels than controls (p<0.05, p<0.05, p<0.01, p<0.001 respectively). Power athletes had significantly higher IGFSD compared to both endurance and technical athletes (p<0.05, p<0.01, respectively). In athletes and controls combined, significant positive correlations were found between IGF variables and higher bone mineral density (BMD) and lean mass and lower fat percent. IGF-I was positively correlated with squat jump (r_s = 0.28, p<0.05) and IGFBP-1 correlated positively with squats (r_s =0.35, p<0.05).

CONCLUSION

We found higher IGF-I, IGFSD and IGFBP-1 in female athletes than controls, and the highest IGFSD in power athletes. IGF-I and IGFBP-1 were related to increased BMD and lean mass and lower fat percent, as well as were positively associated with physical fitness tests. Future studies are needed to elucidate if these results reflect adaptive responses to physical activity or genetic predisposition.

Associations between inflammatory and neurological markers with quality of life and well-being in older adults

OBJECTIVES

Stressful experiences, poor self-rated health, and negative emotional states have been implicated with higher levels of inflammatory markers and lower levels of neurotrophic factors in some healthy adults and clinical populations, but these relationships are unclear in the elderly. This study aimed to identify the associations between systemic inflammatory and neurological markers with well-being and health-related quality of life (HR-QoL) in independently living elderly people.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

A total of 268 men and women aged ≥65 years living independently in retirement communities in Melbourne, Australia.

MEASURES

Questionnaires were used to assess HR-QoL [Short Form (SF)-36 version 2] and well-being (Personal Wellbeing Index). Serum inflammatory cytokines [interleukin (IL)-4, IL-6, IL-1β, IL-8, IL-10, tumor necrosis factor (TNF)-α, and high sensitive C-reactive protein (hs-CRP)] were standardised to Z-scores and used to calculate pro- and anti-inflammatory composite score and an overall composite inflammatory index. Plasma levels of the neurological markers amyloid β (1-40) and amyloid β (1-42), brain derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF), were also assessed.

RESULTS

No significant associations were found between any inflammatory or neurological marker with HR-OoL or well-being, with the exception that lower perceptions of the HR-QoL vitality subscale were associated with higher levels of hs-CRP [unstandardized beta-coefficient (β): -1.50; 95% CI: -2.53, -0.46; P = 0.004] and Z-scores in the pro-inflammatory composite score (β = -2.06; 95% CI: -3.49, -0.62; P = 0.005).

CONCLUSIONS/IMPLICATIONS

In elderly people residing in independent living retirement communities, there was no consistent evidence indicating that circulating inflammatory or neurological markers were associated with the key physical or mental HR-QoL domains or overall well-being. This suggests that these biomarkers may not be effective predictors in relatively healthy communities, and may be more beneficial in frail or clinical populations. Clinical Trials registry: Australian New Zealand Clinical Trials Registry (ACTRN12613001161718). http://www.anzctr.org.au/.

Growth hormone and insulin-like growth factor 1 secretions in eating disorders: Correlations with psychopathological aspects of the disorders

Hormonal alterations in Eating Disorders (ED) may result from the biochemical stress of malnutrition/starvation. The correlations between some hormonal impairments, particularly of the somatotropic axis, and the psychopathological aspects of ED are still undefined. We measured the plasma concentrations of the somatotropic hormone (GH) and the insulin-like growth factor-1 (IGF-1) in 136 patients with various forms of ED, 65 with restricted Anorexia Nervosa (ANR), 19 with bingeing-purging Anorexia Nervosa (ANBP), 12 with purging-non binging Anorexia Nervosa (ANP), 26 with Bulimia Nervosa (BN), 8 with ED not otherwise specified-anorexic type (EDNOS-AN), 7 with ED not otherwise specified-bulimic type (EDNOS-BN) and in 30 healthy controls. Psychological assessment of patients and controls was performed using two outpatient rating scales, the Eating Disorder Inventory-2 (EDI-2) and the Symptom Checklist-90 (SCL-90). Significant negative or positive correlations were observed between GH-IGF-1 concentrations and impairments on several EDI-2 subscales (drive for thinness, body dissatisfaction, interoceptive awareness, sense of ineffectiveness, interpersonal distrust, maturity fear) and on SCL-90 subitems (depression, hostility, obsessivity compulsivity, anxiety), suggesting a possible hormonal modulatory effect on specific aspects of ED psychopathology.

Increase in insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 1 after supplementation with selenium and coenzyme Q10. A prospective randomized double-blind placebo-controlled trial among elderly Swedish citizens

Background

Insulin-like growth factor-1(IGF-1) has a multitude of effects besides cell growth and metabolism. Reports also indicate anti-inflammatory and antioxidative effects. The concentrations of IGF-1 decrease with age and during inflammation. As selenium and coenzyme Q10 are involved in both the antioxidative defense and the inflammatory response, the present study aimed to examine the effects of supplementation with selenium and coenzyme Q10 on concentrations of IGF-1 and its binding protein IGFBP-1 in a population showing reduced cardiovascular mortality following such supplementation.

Methods

215 elderly individuals were included and given the intervention for four years. A clinical examination was performed and blood samples were taken at the start and after 48 months. Evaluations of IGF-1, the age adjusted IGF-1 SD score and IGFBP-1 were performed using group mean values, and repeated measures of variance.

Findings

After supplementation with selenium and coenzyme Q10, applying group mean evaluations, significantly higher IGF-1 and IGF-1 SD scores could be seen in the active treatment group, whereas a decrease in concentration could be seen of the same biomarkers in the placebo group.

Applying the repeated measures of variance evaluations, the same significant increase in concentrations of IGF-1 (F = 68; P>0.0001), IGF-1 SD score (F = 29; P<0.0001) and of IGFBP-1 (F = 6.88; P = 0.009) could be seen, indicating the effect of selenium and coenzyme Q10 also on the expression of IGF-1 as one of the mechanistic effects of the intervention.

Conclusion

Supplementation with selenium and coenzyme Q10 over four years resulted in increased levels of IGF-1 and the postprandial IGFBP-1, and an increase in the age-corrected IGF-1 SD score, compared with placebo. The effects could be part of the mechanistic explanation behind the surprisingly positive clinical effects on cardiovascular morbidity and mortality reported earlier. However, as the effects of IGF-1 are complex, more research on the result of intervention with selenium and coenzyme Q10 is needed.

Effects of protein-rich nutritional supplementation and bisphosphonates on body composition, handgrip strength and health-related quality of life after hip fracture: a 12-month randomized controlled study

BACKGROUND

The catabolic state that follows hip fracture contributes to loss of muscle mass and strength, that is sarcopenia, which impacts functional ability and health-related quality of life. Measures to prevent such long-term postoperative consequences are of important concern. The aim of this study was to evaluate the combined effects of protein-rich nutritional supplementation and bisphosphonate on body composition, handgrip strength and health-related quality of life following hip fracture.

METHODS

The study included 79 men and women with hip fracture, mean age 79 years (SD 9), without severe cognitive impairment, who were ambulatory and living independently before fracture. Patients were randomized postoperatively to receive liquid supplementation that provided 40 g of protein and 600 kcal daily for six months after the fracture, in addition to bisphosphonates once weekly for 12 months (group N, n = 26), or bisphosphonates alone once weekly for 12 months (group B, n = 28). All patients, including the controls (group C, n = 25) received calcium 1 g and vitamin D3 800 IU daily. Body composition as measured by dual-energy X-ray absorptiometry (DXA), handgrip strength (HGS) and health-related quality of life (HRQoL) were registered at baseline, six and 12 months postoperatively.

RESULTS

There were no differences among the groups regarding change in fat-free mass index (FFMI), HGS, or HRQoL during the study year. Intra-group analyses showed improvement of HGS between baseline and six months in the N group (P = 0.04). HRQoL decreased during the first year in the C and B groups (P = 0.03 and P = 0.01, respectively) but not in the nutritional supplementation N group (P = 0.22).

CONCLUSIONS

Protein-rich nutritional supplementation was unable to preserve FFMI more effectively than vitamin D and calcium alone, or combined with bisphosphonate, in this relatively healthy group of hip fracture patients. However, trends toward positive effects on both HGS and HRQoL were observed following nutritional supplementation.

TRIAL REGISTRATION

Clinicaltrials.gov NCT01950169 (Date of registration 23 Sept 2013).

Maladaptive and adaptive emotion regulation through music: a behavioral and neuroimaging study of males and females

Music therapists use guided affect regulation in the treatment of mood disorders. However, self-directed uses of music in affect regulation are not fully understood. Some uses of music may have negative effects on mental health, as can non-music regulation strategies, such as rumination. Psychological testing and functional magnetic resonance imaging (fMRI) were used explore music listening strategies in relation to mental health. Participants (n = 123) were assessed for depression, anxiety and Neuroticism, and uses of Music in Mood Regulation (MMR). Neural responses to music were measured in the medial prefrontal cortex (mPFC) in a subset of participants (n = 56). Discharge, using music to express negative emotions, related to increased anxiety and Neuroticism in all participants and particularly in males. Males high in Discharge showed decreased activity of mPFC during music listening compared with those using less Discharge. Females high in Diversion, using music to distract from negative emotions, showed more mPFC activity than females using less Diversion. These results suggest that the use of Discharge strategy can be associated with maladaptive patterns of emotional regulation, and may even have long-term negative effects on mental health. This finding has real-world applications in psychotherapy and particularly in clinical music therapy.

Sex differences in type 2 diabetes: focus on disease course and outcomes

BACKGROUND

Women with type 2 diabetes (T2D) are less likely to reach the goals for hemoglobin A1c compared with men, and have higher all-cause mortality. The risk of cardiovascular disease is elevated among both men and women with T2D, however, the risk has declined among men over recent years while it remains stationary in women. Reasons for these sex differences remain unclear, and guidelines for diabetes treatment do not differentiate between sexes. Possible causes for varying outcome include differences in physiology, treatment response, and psychological factors. This review briefly outlines sex differences in hormonal pathophysiology, and thereafter summarizes the literature to date on sex differences in disease course and outcome.

METHODS

Systematic searches were performed on PubMed using "sex", "gender", and various glucose-lowering therapies as keywords. Earlier reviews are summarized and results from individual studies are reported. Reference lists from studies were used to augment the search.

RESULTS

There is an increased risk of missing the diagnosis of T2D when screening women with only fasting plasma glucose instead of with an oral glucose tolerance test. The impact of various risk factors for complications may differ by sex. Efficacy and side effects of some glucose-lowering drugs differ between men and women. Men with T2D appear to suffer more microvascular complications, while women have higher morbidity and mortality in cardiovascular disease and also fare worse psychologically.

CONCLUSION

Few studies to date have focused on sex differences in T2D. Several questions demand further study, such as whether risk factors and treatment guidelines should be sex-specific. There is a need for clinical trials designed specifically to evaluate sex differences in efficacy and outcome of the available treatments.

Disruption of fetal hormonal programming (prenatal stress) implicates shared risk for sex differences in depression and cardiovascular disease

Comorbidity of major depressive disorder (MDD) and cardiovascular disease (CVD) represents the fourth leading cause of morbidity and mortality worldwide, and women have a two times greater risk than men. Thus understanding the pathophysiology has widespread implications for attenuation and prevention of disease burden. We suggest that sex-dependent MDD-CVD comorbidity may result from alterations in fetal programming consequent to the prenatal maternal environments that produce excess glucocorticoids, which then drive sex-dependent developmental alterations of the fetal hypothalamic-pituitary-adrenal (HPA) axis circuitry impacting mood, stress regulation, autonomic nervous system (ANS), and the vasculature in adulthood. Evidence is consistent with the hypothesis that disruptions of pathways associated with gamma aminobutyric acid (GABA) in neuronal and vascular development and growth factors have critical roles in key developmental periods and adult responses to injury in heart and brain. Understanding the potential fetal origins of these sex differences will contribute to development of novel sex-dependent therapeutics.

Body composition and endocrine profile of male Olympic athletes striving for leanness

OBJECTIVE

To investigate the endocrine profile, body composition, and state of mood in male Olympic athletes participating in sports that do or do not emphasize leanness.

DESIGN

Cross-sectional study.

SETTING

Research unit at a university hospital.

PARTICIPANTS

Forty-four Swedish male Olympic athletes participating in 26 different sport disciplines.

MAIN OUTCOME MEASURES

Body composition was determined by dual-energy x-ray absorptiometry, and blood levels of steroid hormones and biomarkers of nutritional status were analyzed. In addition, states of mood were assessed employing the profile of mood states (POMS) test. The athletes were divided into 2 groups on the basis of whether their sporting discipline emphasized leanness or not.

RESULTS

In all subjects, body composition, hormone levels, and POMS scores were within normal ranges. However, the leanness athletes (n = 18) displayed significantly lower proportion of body fat (P < 0.01), higher spinal bone mineral density (P < 0.05), lower serum levels of free testosterone and leptin (P < 0.05), and higher serum levels of insulin-like growth factor binding protein 1 (P < 0.05) than nonleanness athletes (n = 26). Leanness athletes also had higher POMS scores for depression and anger, and a higher global POMS score (P < 0.05), the latter being positively correlated to the frequency of illness (r = 0.42, P < 0.01) before the Olympic Games.

CONCLUSION

Although there were no indications of energy deficiency or endocrine disturbance in the leanness athletes, their higher POMS scores and frequency of illness may indicate the potential harmfulness of their pursuit of outstanding athletic performance.

Human conditions of insulin-like growth factor-I (IGF-I) deficiency

Insulin-like growth factor I (IGF-I) is a polypeptide hormone produced mainly by the liver in response to the endocrine GH stimulus, but it is also secreted by multiple tissues for autocrine/paracrine purposes. IGF-I is partly responsible for systemic GH activities although it possesses a wide number of own properties (anabolic, antioxidant, anti-inflammatory and cytoprotective actions). IGF-I is a closely regulated hormone. Consequently, its logical therapeutical applications seems to be limited to restore physiological circulating levels in order to recover the clinical consequences of IGF-I deficiency, conditions where, despite continuous discrepancies, IGF-I treatment has never been related to oncogenesis. Currently the best characterized conditions of IGF-I deficiency are Laron Syndrome, in children; liver cirrhosis, in adults; aging including age-related-cardiovascular and neurological diseases; and more recently, intrauterine growth restriction. The aim of this review is to summarize the increasing list of roles of IGF-I, both in physiological and pathological conditions, underlying that its potential therapeutical options seem to be limited to those proven states of local or systemic IGF-I deficiency as a replacement treatment, rather than increasing its level upper the normal range.

Increased Urine IgM and IgG(2) Levels, Indicating Decreased Glomerular Size Selectivity, Are Not Affected by Dalteparin Therapy in Patients with Type 2 Diabetes

Fifty-four type 2 diabetic patients with neuroischemic foot ulcers were randomised to treatment with 5000 IU of dalteparin, (n = 28), or physiological saline, (n = 26), once daily until ulcer healing or for a maximum of 6 months. Thirty-three patients had normo-, 15 micro-, and 6 macroalbuminuria. The urinary levels of IgM and IgG₂ were elevated in 47 and 50 patients, respectively. Elevated urinary levels of IgM and IgG₂ indicate decreased glomerular size selectivity. Urine IgM levels were associated with IGF-1/IGFBP-1 and IGFBP-1 levels. Dalteparin treatment increased urinary levels of glycosaminoglycans (P < 0.001) and serum IGFBP-1 (P < 0.05) while no significant effects were seen in any of the other studied parameters. In conclusion, dalteparin therapy in patients with type 2 diabetes had no effects on urinary levels of albumin, IgM, or IgG₂ despite significantly increased glycosaminoglycans in urine. Elevated urinary levels of IgM and IgG₂ might be more sensitive markers of renal disease than albuminuria in patients with type 2 diabetes and antihypertensive therapy.

The insulin-like growth factor system, metabolic syndrome, and cardiovascular disease risk

The metabolic syndrome is a combination of metabolic and clinical features that aggregate in individuals and increase cardiovascular disease (CVD) risk considerably. It is believed, although sometimes controversially, that the underlying basis for this syndrome is insulin resistance (IR) and accompanying compensatory hyperinsulinemia. Insulin and insulin-like growth factors (IGFs) have significant homology and interact with differing affinity with the same receptors. Therefore, their actions can be complementary, and this becomes particularly significant clinico-pathologically when their circulating levels are altered. This review of currently available information attempts to answer the following questions: (1) Is there any evidence for changes in the components of the IGF system in individuals with established CVD or with increased CVD risk as with the metabolic syndrome? (2) What are the underlying mechanisms for interactions, if any, between insulin and the IGF system, in the genesis of CVD? (3) Can knowledge of the pathophysiological changes in the IGF system observed in macrosomic newborn infants and growth hormone (GH)-treated children and adults explain some of the observations in relation to the IGF system and the metabolic syndrome? (4) Can the experimental and clinical evidence adduced from the foregoing be useful in designing novel therapies for the prevention, treatment, and assignment of prognosis in metabolic syndrome-associated disease, particularly ischemic heart disease? To answer these questions, we have performed a literature review using bibliographies from PubMed, Medline, and Google Scholar published within the last 10 years. We suggest that IGF-1 levels are reduced consistently in individuals with the metabolic syndrome and its components and in those with ischemic CVD. Such changes are also seen with GH deficiency in which these changes are partially reversible with GH treatment. Furthermore, changes are seen in levels and interactions of IGF-binding proteins in these disorders, and some of these changes appear to be independent of IGF-binding capability and could potentially impact on risk for the metabolic syndrome and CVD. The promising therapeutic implications of these observations are also discussed.

Interrelations and associations of serum levels of steroids and pituitary hormones with markers of insulin resistance, inflammatory activity, and renal function in men and women aged >70 years in an 8-year longitudinal study of opposite-sex twins

BACKGROUND

The physiological serum levels of steroids and pituitary hormones in older men and women have been sparsely reported in the literature.

OBJECTIVES

The aims of this study were to investigate the normal variation and sex differences in steroids and pituitary hormones in those aged >70 years, and to study the interrelation between these hormones and indicators of the metabolic syndrome, inflammatory activity, and renal function.

METHODS

The investigation comprised a population-based sample of pairs of white opposite-sex twins from the Swedish Twin Registry. At baseline in 1996 and at the 8-year follow-uup in 2004, serum levels of progesterone, cortisol, testosterone, estradiol, follicle-stimulating hormone, luteinizing hormone, prolactin, creatinine, C-reactive protein (CRP), and urea were analyzed. Serum levels of insulin and cystatin were analyzed only at the follow-up.

RESULTS

The study sample included 219 men and 183 women aged 71 to 80 years (mean [SD], 74.5 [2.5] years) at baseline in 1996, and 127 men and 135 women at follow-uup in 2004. At baseline, in both men and women, the variation of progesterone in serum was positively correlated with that of estradiol (men: r = 0.226, P < 0.01; women: r = 0.115, P = NS), testosterone (men: r = 0.178, P < 0.01; women: r = 0.315, P < 0.001), and cortisol (men: r = 0.314, P < 0.001; women: r = 0.296, P < 0.001). The values of progesterone and other steroid hormones were associated with markers of insulin resistance (iie, insulin, waist circumference), inflammatory activity (ie, CRP) for progesterone (men: r = 0.267, P < 0.001; women: r = 0.150, P < 0.05), and renal function (ie, creatinine) for progesterone (men: r = 0.424, P < 0.001; women: r = 0.212, P < 0.01). Estradiol and prolactin were associated with insulin resistance, inflammation, and renal function. Furthermore, progesterone was associated with prolactin (men: r = 0.275, P < 0.001; women: r = 0.172, P < 0.05).. Among both men and women, there was a strong correlation between testosterone and estradiol (men: r = 0.753, P < 0.001; women: r = 0.526, P < 0.001); in women, there was also a link between testosterone and cortisol at follow-up (r = 0.340, P < 0.01). For progesterone, there was a significant correlation between the values of the co-twins (in 1996: r = 0.16, P < 0.05; in 2004: r = 0.45, P < 0.001). Higher serum levels of progesterone (2.0 [0.7] nmol/L in men and 1.7 [0.8] nmol/L in women) and prolactin (6 [5] microg/L in men and 8 [10] microg/L in women) were found among those who were deceased at follow-up compared with survivors (progesterone: 1.8 [0.5] nmol/L in men and 1.4 [0.6] nmol/L in women, P < 0.01; prolactin: 4 [3] microg/L in men and 5 [2] microg/L in women, P < 0.001).

CONCLUSIONS

In this study of opposite-sex Swedish twins aged >70 years, there was a sex difference in the serum levels of steroids and pituitary hormones between men and women. Progesterone and other steroid hormones were associated with markers of insulin resistance, inflammatory activity, and renal function. Progesterone and prolactin levels were associated with increased risk of mortality in this sample.

Effect of environment on growth: auxological and hormonal parameters in African and Italian children

OBJECTIVE

Genetic factors are the most important determinant of final height in developed countries, while in underprivileged countries food intake is crucial. Nutrients, in turn, may importantly affect IGF-IGFBP system which is a critical regulator of growth. The aim of this study was to evaluate the influence of nutrition on IGF system components, as well as on growth by comparing these variables in two selected populations of children living either in poor or in privileged environmental conditions.

DESIGN

Height and weight were recorded in 38 normal African children, living in a Catholique Mission in Ivory Coast, and in 93 normal Italian children. IGF-I, IGF-II, IGFBP-3 and ALS were evaluated in all subjects.

RESULTS

A normal height in spite of markedly reduced IGF-I, IGFBP-3, ALS and BMI was observed in African children, while the ratio IGF-I/IGFBP-3 was comparable in the two populations. IGF-II was slightly but significantly higher in Africans than in Italians.

CONCLUSIONS

In Africans a suboptimal nutritional condition may produce a dramatic reduction of IGF-I, ALS and IGFBP-3, although the final height results minimally affected. This suggests that only a small fraction of the circulating IGF-I is sufficient for growth and confirms what has been reported on liver IGF-I-deficient and ALS knock-out mice. The secular statural trend observed in developed countries is probably due to the increase of IGF-I consequent to the improved nutritional conditions.

Normal age-dependent values of serum insulin growth factor-I: results from a healthy Italian population

Serum IGF-I levels were measured in 547 non-hypopituitaric, non-acromegalic healthy subjects of both sexes in Italy to develop reference values in relation to age and sex. Participant subjects were stratified in three age classes (25- 39, 40-59 and >or=60 yr) and IGF-I assay was carried out by double-antibody radio immunoassay. Pearson's correlation coefficient between age and IGF-I values was calculated by sex and predefined age ranges. IGF-I levels significantly decreased with age (p<0.001, Kruskal-Wallis test) while sex was not a significant factor. The median IGF-I levels were 206 ng/ml in the 25-39 yr range, 147 ng/ml in the 40-59 yr range and 103 ng/ml in the >or=60 yr range. Pearson's correlation coefficient confirmed the negative correlation between age and IGF-I levels in the total sample of subjects (r=-0.529). The r coefficient between age and IGF-I levels did not differ between sexes (r=-0.570 in males and r=-0.529 in females), thus reflecting no sex-effect on IGF-I levels decline over years. No correlations were found in the 25-39 yr range (r=-0.036) or in the 40-59 yr range (r=-0.080) either, while in subjects aged >60 yr, IGF-I levels tended to further decrease with increased age (r=0.389). Ranges of normal values set at the 2.5th-97.5th percentile in the three age ranges were 95.6-366.7 ng/ml between 25 and 39 yr, 60.8-297.7 ng/ml between 40 and 59 yr and 34.5-219.8 ng/ml in subjects aged >or=60 yr. This study may contribute to the development of age-specific reference ranges for IGF-I determination in serum of normal subjects of both sexes in Italy.

The role of IGF-I and its binding proteins in the development of type 2 diabetes and cardiovascular disease

Patients with insulin resistance and type 2 diabetes have an excessive risk of cardiovascular disease (CVD); this increased risk is not fully explained by traditional risk factors such as hypertension and dyslipidaemias. There is now compelling evidence to suggest that abnormalities of insulin-like growth factor-I (IGF-I) and one of its binding proteins, insulin-like growth factor-binding protein-1 (IGFBP-1), occur in insulin-resistant states and may be significant factors in the pathophysiology of CVD. We reviewed articles and relevant bibliographies following a systematic search of MEDLINE for English language articles between 1966 and the present, using an initial search strategy combining the MeSH terms: IGF, diabetes and CVD. Our aim was first to review the role of IGF-I in vascular homeostasis and to explore the mechanisms by which it may exert its effects. We also present an overview of the physiology of the IGF-binding proteins, and finally, we sought to summarize the evidence to date describing the changes in the insulin/IGF-I/IGFBP-1 axis that occur in type 2 diabetes and CVD; in particular, we have focused on the potential vasculoprotective effects of both IGF-I and IGFBP-1. We conclude that this system represents an interesting and novel therapeutic target in the prevention of CVD in type 2 diabetes.

The role of IGF-I and IGFBP-1 status and secondary hyperparathyroidism in relation to osteoporosis in elderly Swedish women

IGFBP-1 showed a strong inverse relation to the BMD values. The IGF-I values had a significant positive relation to the BMD values at all sites with the exception of the lumbar spine. The use of loop diuretics was a more important cause of secondary hyperparathyroidism than vitamin D status.

INTRODUCTION

Our aim was to investigate among elderly women the relationship to osteoporosis of calcium-regulating hormones and insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-1 (IGFBP-1).

METHODS

A population-based cross-sectional study of 350 elderly women (mean age 73 years). Measurements of bone mineral density (BMD) of the left hip, lumbar spine and heel and risk markers for osteoporosis were studied.

RESULTS

The BMD values showed significant inverse relationship with the values of IGFBP-1 at all sites of measurement and significant positive relationship with the values of IGF-I at all sites with the exception of the lumbar spine. There was no significant association between the values of BMD and the values of 25-hydroxy vitamin D (25(OH)D). The use of loop diuretics was strongly and significantly associated with elevated levels of PTH >65 pg/ml (OR 4.4, P < 0.001).

CONCLUSIONS

The anabolic growth factor IGF-I and its modulating binding protein IGFBP-1 showed a stronger association with the BMD values than the calcium regulating hormones 25(OH)D and PTH. In this study the use of loop diuretics was a more important cause of secondary hyperparathyroidism than vitamin D status.

Insulin resistance is inversely related to prostate cancer: a prospective study in Northern Sweden

Factors related to insulin resistance have been implicated in prostate cancer development, however, few analytical studies support such an association. We performed a case control study on 392 prostate cancer cases and 392 matched controls nested in a prospective cohort in Northern Sweden. Plasma concentrations of C-peptide, leptin, glycated haemoglobin (HbA1c) and fasting and post-load glucose were analysed and homeostatic model assessment of insulin resistance (HOMA-IR) was calculated. Conditional logistic regression analyses were used to calculate odds ratios (OR) of prostate cancer. High levels of C-peptide, HOMA-IR, leptin and HbA1c were associated with significant decreases in risk of prostate cancer, with ORs for top vs. bottom quartile for C-peptide of 0.59 (95% Confidence Interval [CI], 0.40-0.89; p(trend) = 0.008), HOMA-IR 0.60 (95% CI, 0.38-0.94; p(trend) = 0.03), leptin 0.55 (95% CI, 0.36-0.84; p(trend) = 0.006) and HbA1c 0.56 (95% CI, 0.35-0.91; p(trend) = 0.02). All studied factors were strongly inversely related to risk among men less than 59 years of age at blood sampling, but not among older men, with a significant heterogeneity between the groups for leptin (p(heterogeneity) = 0.006) and fasting glucose (p(heterogeneity) = 0.03). C-peptide and HOMA-IR were strongly inversely related to non-aggressive cancer but were non-significantly positively related to risk of aggressive disease (p(heterogeneity) = 0.007 and 0.01, respectively). Our data suggest that androgens, which are inversely associated with insulin resistance, are important in the early prostate cancer development, whereas insulin resistance related factors may be important for tumour progression.

Gender differences in the relation of insulin-like growth factor binding protein-1 to cardiovascular risk factors: a population-based study

OBJECTIVE

A possible involvement of insulin-like growth factor-I (IGF-I) and its binding protein IGFBP-1 in the pathogenesis of cardiovascular disorder has been suggested. However, few publications have addressed the gender differences in cardiovascular risk factors in relation to the IGF/IGFBP system. The aim of the present study was to study gender differences in the relationship between fasting serum levels of IGFBP-1 and cardiovascular risk factors in a normal population of men and women.

DESIGN

Cross-sectional study. Patients A normal population of 273 men and women aged 20-74 years.

MEASUREMENTS

A medical examination was performed and blood drawn in the morning after subjects had been fasting overnight. Before the examination, they were asked to fill out a questionnaire concerning lifestyle and psychosocial factors.

RESULTS

Fasting IGFBP-1 was lower in men than in women and was positively correlated to age in men but not in women. The men had in general a more disadvantageous cardiovascular risk profile than women, with several indicators of the metabolic syndrome: higher blood pressure and higher serum levels of total cholesterol, triglycerides, low density lipoprotein cholesterol (LDL-C), plasma-glucose and insulin, as well as lower IGFBP-1. Women had lower physical activity, lower consumption of alcohol, and lower values on indicators of psychosocial and mental health but had a healthier diet. Our findings indicate that low circulating levels of IGFBP-1 are associated with the well-known risk factors of cardiovascular disease; however, the association showed a different pattern for men and women. In men we found a negative association with body mass index (BMI), insulin resistance and diastolic blood pressure, and a positive association with SHBG, cortisol and testosterone. For women low IGFBP-1 appears in negative associations with BMI, waist-hip ratio (WHR), insulin resistance and testosterone, and in positive associations with SHBG and cortisol. Significant gender differences in the correlation with IGFBP-1 are seen for testosterone, cortisol, SHBG, WHR and oestradiol. For HDL-C and diastolic blood pressure the gender difference in correlation was at the limit of significance (P < 0.10).

CONCLUSION

Low circulating levels of IGFBP-1 are associated with the well-known risk factors of cardiovascular disease; however, the association showed a different pattern for men and women. The most marked gender differences in the correlation with IGFBP-1 are seen for testosterone, cortisol, SHBG, WHR, oestradiol, HDL-C and diastolic blood pressure. Our study emphasizes the importance of separate analyses for men and women. The results presented are a step towards gaining a better understanding of the gender differences in cardiovascular disease and in the regulation of IGFBP-1, though further prospective studies are needed.

Associations between Plasma Insulin-Like Growth Factor Proteins and C-Peptide and Quality of Life in Patients with Metastatic Colorectal Cancer

OBJECTIVE

Predictors of quality of life (QOL) in patients with metastatic colorectal cancer are lacking. The insulin-like growth factor (IGF) family of proteins is associated with QOL in noncancer populations. We sought to study whether these proteins are associated with QOL in patients with colorectal cancer.

METHOD

We used a cohort of 526 patients with metastatic colorectal cancer treated with combination chemotherapy. Plasma samples of IGF-I, IGF-II, IGF binding protein-3, and C-peptide were collected before initiation of chemotherapy. QOL was measured by the uniscale instrument and the Symptom Distress Scale at baseline and throughout treatment.

RESULTS

Baseline plasma levels of IGF-I and IGF-II before initiation of chemotherapy were significantly associated with several important baseline QOL measures in patients with metastatic colorectal cancer. Patients with lower levels of IGF-I reported increased distress with regard to appearance, appetite, cough, and nausea intensity after adjustment for potential confounders. Similarly, decreased levels of IGF-II were predictive of worse quality related to appearance, appetite, fatigue, nausea frequency and intensity, pain frequency, and composite Symptom Distress Scale score. IGF binding protein-3 and C-peptide were not predictive of baseline QOL. Baseline biomarkers were not associated with subsequent changes in QOL during treatment. Higher body mass index was significantly associated with superior baseline QOL in several areas; nonetheless, the association of IGF-I and IGF-II with baseline QOL measures remained significant even after controlling for baseline body mass index.

CONCLUSION

Baseline plasma IGF-I and IGF-II are significantly associated with symptom distress. Whether this association is simply reflective of patient nutritional status and/or disease burden or represents an independent biological effect of IGFs on QOL remains uncertain. Nonetheless, these data suggest that molecular biomarkers may be useful predictors of QOL in cancer patients.