Lifestyle, anthropometric, and obesity-related physiologic determinants of insulin-like growth factor-1 in the Third National Health and Nutrition Examination Survey (1988-1994)

Pregnancy associated plasma protein-A2 (PAPP-A2) and stanniocalcin-2 (STC2) but not PAPP-A are associated with circulating total IGF-1 in a human adult population

The pappalysins pregnancy associated plasma protein-A (PAPP-A) and -A2 (PAPP-A2) act as proteinases of insulin-like growth factor-1 (IGF-1) binding proteins, while stanniocalcin-2 (STC2) was identified as a pappalysin inhibitor. While there is some evidence from studies in children and adolescents, it is unclear whether these molecules are related to concentrations of IGF-1 and its binding proteins in adults. We investigated cross-sectionally the association of circulating PAPP-A, PAPP-A2 and STC2 with IGF-1 and its binding proteins (IGFBPs) in 394 adult pretest participants (20-69 years) of the German National Cohort Berlin North study center. Plasma PAPP-A, PAPP-A2, total and free IGF-1, IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-5 and STC2 were measured by ELISAs. The associations of PAPP-A, PAPP-A2 and STC2 with IGF-1 or IGFBPs were investigated using multivariable linear regression analyses adjusting for age, sex, body mass index and pretest phase. We observed significant inverse associations of PAPP-A2 (difference in concentrations per 0.5 ng/mL higher PAPP-A2 levels) with total IGF-1 (- 4.3 ng/mL; 95% CI - 7.0; - 1.6), the IGF-1:IGFBP-3 molar ratio (- 0.34%; 95%-CI - 0.59; - 0.09), but not free IGF-1 and a positive association with IGFBP-2 (11.9 ng/mL; 95% CI 5.0; 18.8). PAPP-A was not related to total or free IGF-1, but positively associated with IGFBP-5. STC2 was inversely related to total IGF-1, IGFBP-2 and IGFBP-3 and positively to IGFBP-1. This first investigation of these associations in a general adult population supports the hypothesis that PAPP-A2 as well as STC2 play a role for IGF-1 and its binding proteins, especially for total IGF-1. The role of PAPP-A2 and STC2 for health and disease in adults warrants further investigation.

Obesity-induced thymic involution and cancer risk

Declining thymic functions associated either with old age (i.e., age-related thymic involution), or with acute involution as a result of stress, infectious disease, or cytoreductive therapies (e.g., chemotherapy/radiotherapy), have been associated with cancer development. A key mechanism underlying such increased cancer risk is the thymus-dependent debilitation of adaptive immunity, which is responsible for orchestrating immunoediting mechanisms and tumor immune surveillance. In the past few years, a blooming set of evidence has intriguingly linked obesity with cancer development and progression. The majority of such studies has focused on obesity-driven chronic inflammation, steroid/sex hormone and adipokine production, and hyperinsulinemia, as principal factors affecting the tumor microenvironment and driving the development of primary malignancy. However, experimental observations about the negative impact of obesity on T cell development and maturation have existed for more than half a century. Here, we critically discuss the molecular and cellular mechanisms of obesity-driven thymic involution as a previously underrepresented intermediary pathology leading to cancer development and progression. This knowledge could be especially relevant in the context of childhood obesity, because impaired thymic function in young individuals leads to immune system abnormalities, and predisposes to various pediatric cancers. A thorough understanding behind the molecular and cellular circuitries governing obesity-induced thymic involution could therefore help towards the rationalized development of targeted thymic regeneration strategies for obese individuals at high risk of cancer development.

Association between metabolic syndrome, insulin resistance, and IGF-1 in breast cancer survivors of DIANA-5 study

PURPOSE

Circulating insulin-like growth factor-1 (IGF-1) is positively associated with the risk of BC recurrence, and is more frequently dysregulated in older people, especially in those with metabolic syndrome (MetS) and obesity. This study aimed to analyze the association between IGF-1 levels and indices of MetS and insulin resistance in BC survivors.

METHODS

Baseline data of 563 BC survivors enrolled in the DIet and ANdrogen-5 (DIANA-5; NCT05019989) study were analyzed.

RESULTS

Lower circulating IGF-1 levels in subjects with MetS than in those without MetS were found. After stratification of the patients according to the diagnosis of MetS, we highlighted that the insulin was the main predictor of elevated IGF-1 levels only in subjects without MetS. Moreover, we found an interaction between high-density lipoprotein cholesterol (HDL-C), glycemia, and IGF-1 levels, showing a positive correlation between HDL-C and IGF-1, especially in subjects with higher values of glycemia and without a diagnosis of MetS.

CONCLUSIONS

While IGF-1 levels appear to be much more impaired in subjects diagnosed with MetS, in non-MetS subjects, IGF-1 levels may respond better to metabolic parameters and lifestyle changes. Further studies are needed to analyze the role of physical activity and/or dietary intervention in modulating IGF-1 concentrations in BC survivors.

IMPLICATIONS FOR CANCER SURVIVORS

These results could have important clinical implications for planning customized strategies aimed at modulating IGF-1 levels in BC survivors. In fact, while the IGF-1 system seems to be much more compromised in subjects with a diagnosis of MetS, in noMetS subjects, IGF-1 levels could better respond to lifestyle changes.

Physical activity in relation to circulating hormone concentrations in 117,100 men in UK Biobank

PURPOSE

Physical activity may reduce the risk of some types of cancer in men. Biological mechanisms may involve changes in hormone concentrations; however, this relationship is not well established. Therefore, we aimed to investigate the associations of physical activity with circulating insulin-like growth factor-I (IGF-I), sex hormone-binding globulin (SHBG, which modifies sex hormone activity), and total and free testosterone concentrations, and the extent these associations might be mediated by body mass index (BMI).

METHODS

Circulating concentrations of these hormones and anthropometric measurements and self-reported physical activity data were available for 117,100 healthy male UK Biobank participants at recruitment. Objectively measured accelerometer physical activity levels were also collected on average 5.7 years after recruitment in 28,000 men. Geometric means of hormone concentrations were estimated using multivariable-adjusted analysis of variance, with and without adjustment for BMI.

RESULTS

The associations between physical activity and hormones were modest and similar for objectively measured (accelerometer) and self-reported physical activity. Compared to men with the lowest objectively measured physical activity, men with high physical activity levels had 14% and 8% higher concentrations of SHBG and total testosterone, respectively, and these differences were attenuated to 6% and 3% following adjustment for BMI.

CONCLUSION

Our results suggest that the associations of physical activity with the hormones investigated are, at most, modest; and following adjustment for BMI, the small associations with SHBG and total testosterone were largely attenuated. Therefore, it is unlikely that changes in these circulating hormones explain the associations of physical activity with risk of cancer either independently or via BMI.

Relationship between Levels of Pre-Stroke Physical Activity and Post-Stroke Serum Insulin-Like Growth Factor I

Physical activity (PA) and insulin-like growth factor I (IGF-I) have beneficial effects for patients who have suffered an ischemic stroke (stroke). However, the relationship between the levels of PA and IGF-I after stroke has not been explored in detail. We investigated the pre-stroke PA level in relation to the post-stroke serum IGF-I (s-IGF-I) level, at baseline and at 3 months after the index stroke, and calculated the change that occurred between these two time-points (ΔIGF-I). Patients (N = 380; 63.4% males; mean age, 54.7 years) with data on 1-year leisure-time pre-stroke PA and post-stroke s-IGF-I levels were included from the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS). Pre-stroke, leisure-time PA was self-reported as PA1–4, with PA1 representing sedentary and PA2–4 indicating progressively higher PA levels. Associations between s-IGF-I and PA were evaluated by multiple linear regressions with PA1 as the reference and adjustments being made for sex, age, history of previous stroke or myocardial infarctions, cardiovascular risk factors, and stroke severity. PA correlated with baseline s-IGF-I and ΔIGF-I, but not with the 3-month s-IGF-I. In the linear regressions, there were corresponding associations that remained as a tendency (baseline s-IGF-I, p = 0.06) or as a significant effect (ΔIGF-I, p = 0.03) after all the adjustments. Specifically, for each unit of PA, ΔIGF-I increased by 9.7 (95% CI 1,1−18.4) ng/mL after full adjustment. This supports the notion that pre-stroke PA is independently related to ΔIGF-I.

Relationship of circulating insulin-like growth factor-I and binding proteins 1-7 with mammographic density among women undergoing image-guided diagnostic breast biopsy

Background

Mammographic density (MD) is a strong breast cancer risk factor that reflects fibroglandular and adipose tissue composition, but its biologic underpinnings are poorly understood. Insulin-like growth factor binding proteins (IGFBPs) are markers that may be associated with MD given their hypothesized role in breast carcinogenesis. IGFBPs sequester IGF-I, limiting its bioavailability. Prior studies have found positive associations between circulating IGF-I and the IGF-I:IGFBP-3 ratio and breast cancer risk. We evaluated the associations of IGF-I, IGFBP-3, and six other IGFBPs with MD.

Methods

Serum IGF measures were quantified in 296 women, ages 40–65, undergoing diagnostic image-guided breast biopsy. Volumetric density measures (MD-V) were assessed in pre-biopsy digital mammograms using single X-ray absorptiometry. Area density measures (MD-A) were estimated by computer-assisted thresholding software. Age, body mass index (BMI), and BMI²-adjusted linear regression models were used to examine associations of serum IGF measures with MD. Effect modification by BMI was also assessed.

Results

IGF-I and IGFBP-3 were not strongly associated with MD after BMI adjustment. In multivariable analyses among premenopausal women, IGFBP-2 was positively associated with both percent MD-V (β = 1.49, p value = 0.02) and MD-A (β = 1.55, p value = 0.05). Among postmenopausal women, positive relationships between IGFBP-2 and percent MD-V (β = 2.04, p = 0.003) were observed; the positive associations between IGFBP-2 and percent MD-V were stronger among lean women (BMI < 25 kg/m²) (β = 5.32, p = 0.0002; p interaction = 0.0003).

Conclusions

In this comprehensive study of IGFBPs and MD, we observed a novel positive association between IGFBP-2 and MD, particularly among women with lower BMI. In concert with in vitro studies suggesting a dual role of IGFBP-2 on breast tissue, promoting cell proliferation as well as inhibiting tumorigenesis, our findings suggest that further studies assessing the role of IGFBP-2 in breast tissue composition, in addition to IGF-1 and IGFBP-3, are warranted.

Electronic supplementary material

The online version of this article (10.1186/s13058-019-1162-8) contains supplementary material, which is available to authorized users.

Low serum IGF1 is associated with hypertension and predicts early cardiovascular events in women with rheumatoid arthritis

OBJECTIVES

Since low insulin-like growth factor (IGF) 1 is often linked to inflammation, we analyze whether serum levels of IGF1 are associated with cardiovascular disease (CVD) in rheumatoid arthritis (RA) in a longitudinal observational study.

METHODS

A CVD risk was estimated (eCVR) in 184 female RA patients (mean age 52 years) and in 132 female patients after ischemic stroke (mean age 56 years) with no rheumatic disease, using the Framingham algorithm. The median level of IGF1 divided the cohorts in IGF1^high and IGF1^low groups. A 5-year prospective follow-up for new CVD events was completed in all RA patients. The Mantel-Cox analysis and event-free survival curves were prepared. Unsupervised clustering of proteins within the IGF1 signaling pathway was employed to identify their association with eCVR.

RESULTS

Low IGF1 resulted in a higher eCVR in RA patients (7.2% and 3.3%, p = 0.0063) and in stroke (9.3% and 7.1%, p = 0.033). RA had higher rate for new CVD events at prospective follow-up (OR 4.96, p = 0.028). Hypertension was the major risk factor associated with low IGF1 in RA and stroke. In hypertension, IGF1 was no longer responsible for intracellular activation and lost its correlation to IRS1/2 adaptor proteins. The clustering analysis confirmed that combination of low IGF1 and IRS1/2 with high IL6, insulin, and glucose predisposed to high eCVR and emphasized the functional role of serum IGF1.

CONCLUSIONS

Low serum IGF1 precedes and predicts development of early CVD events in female RA patients. Hypertension and aberrant IGF1 receptor signaling are highlighted as the important contributors to IGF1-related CVD events.

Effects of central obesity on maternal complications in Korean women of reproductive age

BACKGROUND

Considering the obesity-related complications in pregnancy and during delivery, prepregnancy central obesity may also affect pregnancy-related complications. This study aimed to assess the relationship between prepregnancy central obesity and adverse maternal outcomes in Korean women, by using the Korean National Health Insurance Service (NHIS) cohort.

METHODS

In this population-based retrospective cohort study, we used data from the NHIS database, which contains information of health-care utilisation, diagnosis and prescription, and mortality for almost the whole Korean population, together with data from the NHIS health checkup database from 2005 to 2015. The NHIS health checkup data (645-280 days before childbirth) of mothers who had deliveries (total, 783,406 deliveries) from 2006 to 2015 were collected. For maternal adverse outcome data, we searched for diagnoses of maternal complications made during the period of 280 days before each delivery. The odds for maternal complications according to 8 body mass index (BMI) and 10 waist circumference (WC) categories were analysed using logistic regression.

RESULTS

The incidence rates of eclampsia/preeclampsia, caesarean section, multiple gestation, and polycystic ovary syndrome (PCOS) increased according to the increase of BMI and WC. In contrast, the incidence rate of premature rupture of membrane (PROM) was inversely correlated with BMI and WC. In the low BMI (<17.5 and 17.5-19.9 kg/m²) and low WC (<60 and 60.0-64.0 cm) groups, the odds of threatened abortion were elevated.

CONCLUSION

Prepregnancy WC was closely linked to some maternal complications, including eclampsia/preeclampsia, cesarean section, PCOS, and PROM, in a manner similar to prepregnancy BMI.

The relationship between serum-free insulin- like growth factor-1 and metabolic syndrome in school adolescents of northeast China

PURPOSE

Free insulin-like growth factor-1 (IGF-1) ratio (the ratio of IGF-1/insulin-like growth factor binding protein-3 [IGFBP-3]) was shown to be negatively correlated with metabolic syndrome (MetS) in adults, but it was unknown in Chinese adolescents.

PATIENTS AND METHODS

The cross-sectional study enrolled 701 healthy school students (aged 12-16 years, 46.1% females) and 93 of them (18-22 years old, 46.2% females) were followed after 5 years.

RESULTS

In the cross-sectional study, the IGF-1/IGFBP-3 ratios were found correlated with low-density lipoprotein cholesterol (LDL-C; r= -0.071, P<0.05) and diastolic blood pressure (r= -0.077, P=0.034). A lower IGF-1/IGFBP-3 ratio was an independent risk factor for MetS (OR =2.348, 95% CI: 1.040-5.303), hypertension (OR=1.729, 95% CI: 1.040-5.303), and increased LDL-C (OR=1.841, 95% CI: 1.230-2.755). In the follow-up study, all the participants were >18 years old. We found a lower baseline ratio of IGF-1/IGFBP-3 in adolescence was an independent risk factor for MetS in adulthood (OR=10.724, 95% CI: 1.032-11.403) and also indicated a higher body mass index (β=-1.361, 95% CI: -2.513 to -0.208) after 5 years.

CONCLUSION

The lower IGF-1/IGFBP-3 ratio was an independent risk factor for MetS, hypertension, and high LDL-C in adolescents of northeast China and was also a predictive marker for MetS and increased body mass index in the adulthood.

Diagnosis of obesity and use of obesity biomarkers in science and clinical medicine

The global epidemic of obesity is a major public health problem today. Obesity increases the risk of many chronic diseases, such as type 2 diabetes, coronary heart disease, and certain types of cancer, and is associated with lower life expectancy. The body mass index (BMI), which is currently used to classify obesity, is only an imperfect measure of abnormal or excessive body fat accumulation. Studies have shown that waist circumference as a measure of fat distribution may improve disease prediction. More elaborate techniques such as magnetic resonance imaging are increasingly available to assess body fat distribution, but these measures are not readily available in routine clinical practice, and health-relevant cut-offs not yet been established. The measurement of biomarkers that reflect the underlying biological mechanisms for the increased disease risk may be an alternative approach to characterize the relevant obesity phenotype. The insulin/insulin-like growth factor (IGF) axis and chronic low-grade inflammation have been identified as major pathways. In addition, specific adipokines such as leptin, adiponectin and resistin have been related to obesity-associated health outcomes. This biomarker research, which is currently further developed with the application of high throughput methods, gives important insights in obesity-related disease etiology and pathophysiological pathways and may be used to better characterize obese persons at high risk of disease development and target disease-causing biomarkers in personalized prevention strategies.

Altered levels of circulating insulin-like growth factor I (IGF-I) following ischemic stroke are associated with outcome - a prospective observational study

Background

Insulin-like growth factor I (IGF-I) has neuroprotective effects in experimental ischemic stroke (IS). However, in patients who have suffered IS, various associations between the levels of serum IGF-I (s-IGF-I) and clinical outcome have been reported, probably reflecting differences in sampling time-points and follow-up periods. Since changes in the levels of post-stroke s-IGF-I have not been extensively explored, we investigated whether decreases in the levels of s-IGF-I between the acute time-point (median, 4 days) and 3 months (ΔIGF-I, further transformed into ΔIGF-I-quintiles, ΔIGF-I-q) are associated with IS severity and outcome.

Methods

In the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS) conducted in Gothenburg, Sweden, patients with IS who had s-IGF-I measurements available were included (N = 354; 65% males; mean age, 55 years). Baseline stroke severity was evaluated using the National Institutes of Health Stroke Scale (NIHSS) and converted into NIHSS-quintiles (NIHSS-q). Outcomes were assessed using the modified Rankin Scale (mRS) at 3 months and 2 years.

Results

In general, the levels of s-IGF-I decreased (positive ΔIGF-I), except for those patients with the most severe NIHSS-q. After correction for sex and age, the 3rd ΔIGF-I-q showed the strongest association to mRS 0–2 [Odds Ratio (OR) 5.11, 95% confidence interval (CI) 2.18–11.9], and after 2 years, the 5th ΔIGF-I-q (OR 3.63, 95% CI 1.40–9.38) showed the strongest association to mRS 0–2. The associations remained significant after multivariate correction for diabetes, smoking, hypertension, and hyperlipidemia after 3 months, but were not significant (p = 0.057) after 2 years. The 3-month associations withstood additional correction for baseline stroke severity (p = 0.035), whereas the 2-year associations were further attenuated (p = 0.31).

Conclusions

Changes in the levels of s-IGF-I are associated primarily with temporally near 3-month outcomes, while associations with long-term 2-year outcomes are weakened and attenuated by other factors. The significance of the change in post-stroke s-IGF-I is compatible with a positive role for IGF-I in IS recovery. However, the exact mechanisms are unknown and probably reflects combinations of multiple peripheral and central actions.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1107-3) contains supplementary material, which is available to authorized users.

Serum insulin-like growth factor (IGF)-I and IGF binding protein-3 in relation to terminal duct lobular unit involution of the normal breast in Caucasian and African American women: The Susan G. Komen Tissue Bank

Lesser degrees of terminal duct lobular unit (TDLU) involution, as reflected by higher numbers of TDLUs and acini/TDLU, are associated with elevated breast cancer risk. In rodent models, the insulin-like growth factor (IGF) system regulates involution of the mammary gland. We examined associations of circulating IGF measures with TDLU involution in normal breast tissues among women without precancerous lesions. Among 715 Caucasian and 283 African American (AA) women who donated normal breast tissue samples to the Komen Tissue Bank between 2009 and 2012 (75% premenopausal), serum concentrations of IGF-I and binding protein (IGFBP)-3 were quantified using enzyme-linked immunosorbent assay. Hematoxilyn and eosin-stained tissue sections were assessed for numbers of TDLUs ("TDLU count"). Zero-inflated Poisson regression models with a robust variance estimator were used to estimate relative risks (RRs) for association of IGF measures (tertiles) with TDLU count by race and menopausal status, adjusting for potential confounders. AA (vs. Caucasian) women had higher age-adjusted mean levels of serum IGF-I (137 vs. 131 ng/mL, p = 0.07) and lower levels of IGFBP-3 (4165 vs. 4684 ng/mL, p < 0.0001). Postmenopausal IGFBP-3 was inversely associated with TDLU count among AA (RR_T3vs.T1  = 0.49, 95% CI = 0.28-0.84, p-trend = 0.04) and Caucasian (RR_T3vs.T1 =0.64, 95% CI = 0.42-0.98, p-trend = 0.04) women. In premenopausal women, higher IGF-I:IGFBP-3 ratios were associated with higher TDLU count in Caucasian (RR_T3vs.T1 =1.33, 95% CI = 1.02-1.75, p-trend = 0.04), but not in AA (RR_T3vs.T1 =0.65, 95% CI = 0.42-1.00, p-trend = 0.05), women. Our data suggest a role of the IGF system, particularly IGFBP-3, in TDLU involution of the normal breast, a breast cancer risk factor, among Caucasian and AA women.

Impact of prolonged neuromuscular electrical stimulation on metabolic profile and cognition-related blood parameters in type 2 diabetes: A randomized controlled cross-over trial

AIMS

This study aimed to examine the effect of prolonged neuromuscular electrical stimulation (NMES) on the metabolic profile and cognition-related blood parameters in patients with type 2 diabetes mellitus (T2DM).

METHODS

Fourteen patients with T2DM (63.2 ± 3.0 years, 76.1 ± 3.5 kg) participated in a randomized controlled cross-over study, in which 8-week-long NMES interventions were performed on both legs. The NMES training protocol consisted of 40-min sessions, 5 days per week, for 8 weeks. The relative changes in glucose and lipid profiles, and cognition-related blood parameters were evaluated.

RESULTS

NMES training induced significant changes in the fasting glucose concentration (p < 0.05) and percent body fat (p < 0.05), although there were no significant changes in HbA1c and blood lipid levels (p ≥ 0.05). The change in plasma brain-derived neurotrophic factor (BDNF) levels was significantly higher in the NMES period than in the control period (p < 0.05).

CONCLUSIONS

This study showed that an 8-week NMES training program could induce greater changes in the blood glucose concentration, percent body fat, and plasma BDNF levels than the control intervention in patients with T2DM. NMES training might prove to be an alternative exercise method for patients who might have difficulties in performing adequate voluntary exercise.

Objective Measures of Physical Activity and Cardiometabolic and Endocrine Biomarkers

PURPOSE

Although physical activity is an established risk factor for chronic disease prevention, the specific mechanisms underlying these relationships are poorly understood. We examined the associations between total activity counts and moderate-vigorous physical activity (MVPA) measured by accelerometer, and physical activity energy expenditure measured by doubly labeled water, with plasma levels of proinsulin, insulin, c-peptide, insulin growth factor binding protein-3, insulin growth factor-1, adiponectin, leptin, and leptin-sR.

METHODS

We conducted a cross-sectional analysis of 526 healthy US women in the Women's Lifestyle Validation Study, 2010 to 2012. We performed multiple linear regression models adjusting for potential lifestyle and health-related confounders to assess the associations between physical activity, measured in quartiles (Q) and biomarkers.

RESULTS

Participants in Q4 versus Q1 of total activity counts had lower proinsulin (-20%), c-peptide (-7%), insulin (-31%), and leptin (-46%) levels, and higher adiponectin (55%), leptin-sR (25%), and insulin growth factor-1 (9.6%) levels (all P trend ≤ 0.05). Participants in Q4 versus Q1 of MVPA had lower proinsulin (-26%), c-peptide (-7%), insulin (-32%), and leptin (-40%) levels, and higher adiponectin (31%) and leptin-sR (22%) levels (all P trend ≤ 0.05). Further adjustment for body mass index (BMI) attenuated these associations, but the associations with adipokines remained significant. Those in Q4 versus Q1 of physical activity energy expenditure had lower leptin (-21%) and higher leptin-sR (10%) levels (all P trend ≤ 0.05), after additional adjustment for BMI. In the sensitivity analysis, the associations were similar but attenuated when physical activity was measured using the subjective physical activity questionnaire.

CONCLUSIONS

Our data suggest that greater physical activity is modestly associated with favorable levels of cardiometabolic and endocrine biomarkers, where the strongest associations were found with accelerometer-measured physical activity. These associations may be only partially mediated through BMI, further supporting the role of physical activity in the reduction of cardiometabolic and endocrine disease risk, independent of adiposity.

Associations of objective physical activity with insulin sensitivity and circulating adipokine profile: the Framingham Heart Study

The purpose of this study was to explore the relation of physical activity (PA) and sedentary time (SED) to insulin sensitivity and adipokines. We assessed PA and SED using Actical accelerometers and insulin resistance (HOMA-IR) in 2109 participants (free of type 1 and 2 diabetes mellitus) from Framingham Generation 3 and Omni 2 cohorts (mean age 46 years, 54% women). Systemic inflammation (C-reactive protein [CRP]) and circulating adipokines were measured 6 years earlier. Steps per day, moderate-to-vigorous PA (MVPA) and SED per wear time (%SED) were predictor variables in multivariable regression analyses, with HOMA-IR, CRP and circulating adipokines as outcome measures. We reported that higher MVPA and more steps per day were associated with lower HOMA-IR, adjusting for %SED (β = -0.036, P = 0.002; β = -0.041, P = 0.005). Steps were inversely associated with CRP, but were directly associated with insulin-like growth factor (IGF)-1 levels (β = -0.111, P = 0.002; β = 3.293, P = 0.007). %SED was positively associated with HOMA-IR (β = 0.033, P < 0.0001), but non-significant after adjusting for MVPA (P = 0.13). %SED was associated with higher ratio of leptin/leptin receptor (sOB-R) and higher adipocyte fatty acid-binding protein (FABP)4 (β = 0.096, P < 0.0001; β = 0.593, P = 0.002). Our findings suggest differential influences of PA vs. SED on metabolic pathways, with PA modulating insulin resistance and inflammation, whereas SED influences FABPs.

Low insulin-like growth factor 1 is associated with low high-density lipoprotein cholesterol and metabolic syndrome in Chinese nondiabetic obese children and adolescents: a cross-sectional study

Background

Low serum high-density lipoprotein cholesterol (HDL-C) is an independent risk factor for developing cardiovascular disease. Insulin-like growth factor 1(IGF-1) levels have been proven to be positively associated with HDL-C, but few studies were based on the dataset of children or adolescents. The aim of this study is to investigate the relationship among IGF-1, HDL-C and the metabolic syndrome in Chinese nondiabetic obese children and adolescents.

Methods

As a cross-sectional study, this study includes 120 obese Chinese children and adolescents and 120 healthy ones. The obese subjects were divided into two groups based on using 1.03 mmol/L as a threshold value for HDL-C. Clinical examination and laboratory examinations were assessed for all participants.

Results

Obese subjects had significantly lower IGF-1SDS and higher Height SDS than those in the control group. Among 120 obese children and adolescents, 22 (18.3 %) subjects had an HDL-C level <1.03 mmol/L. IGF-1SDS was significantly lower (P = 0.001) in obese subjects with low HDL-C. According to the results of multivariate logistic regression analysis, IGF-1 SDS is significantly associated with low HDL-C(OR 0.518, 95 % CI 0.292–0.916; P = 0.024), after being adjusted for age, gender, pubertal status, BMI SDS, SBP, DBP, HOMR-IR, total cholesterol, low density lipoprotein-cholesterol, triglycerides, ALT and uric acid. In addition, IGF-1 SDS is significantly correlated with the level of serum HDL-C in study population (r = 0.19, P = 0.003). Based on logistic regression analysis with adjustment for age, gender and pubertal status, the increased IGF-1 SDS was associated with a decreased probability of metabolic syndrome (OR 0.555, 95 % CI 0.385–0.801; P = 0.002) and hypertriglyceridemia (OR 0.582, 95 % CI 0.395–0.856; P = 0.006), but no significant correlation with hypertension.

Conclusion

Obese children had lower IGF-1SDS and taller stature compared with the control group. Low levels of IGF-1 SDS were associated with low levels of HDL-C in chinese nondiabetic obese children and adolescents, independent of insulin resistance, as well as other traditional cardiovascular disease risk markers.

Socioeconomic conditions across life related to multiple measures of the endocrine system in older adults: Longitudinal findings from a British birth cohort study

Background

Little is known about how socioeconomic position (SEP) across life impacts on different axes of the endocrine system which are thought to underlie the ageing process and its adverse consequences. We examined how indicators of SEP across life related to multiple markers of the endocrine system in late midlife, and hypothesized that lower SEP across life would be associated with an adverse hormone profile across multiple axes.

Methods

Data were from a British cohort study of 875 men and 905 women followed since their birth in March 1946 with circulating free testosterone and insulin-like growth factor-I (IGF-I) measured at both 53 and 60–64 years, and evening cortisol at 60–64 years. Indicators of SEP were ascertained prospectively across life—paternal occupational class at 4, highest educational attainment at 26, household occupational class at 53, and household income at 60–64 years. Associations between SEP and hormones were investigated using multiple regression and logistic regression models.

Results

Lower SEP was associated with lower free testosterone among men, higher free testosterone among women, and lower IGF-I and higher evening cortisol in both sexes. For example, the mean standardised difference in IGF-I comparing the lowest with the highest educational attainment at 26 years (slope index of inequality) was −0.4 in men (95% CI -0.7 to −0.2) and −0.4 in women (−0.6 to −0.2). Associations with each hormone differed by SEP indicator used and sex, and were particularly pronounced when using a composite adverse hormone score. For example, the odds of having 1 additional adverse hormone concentration in the lowest compared with highest education level were 3.7 (95% CI: 2.1, 6.3) among men, and 1.6 (1.0, 2.7) among women (P (sex interaction) = 0.02). We found no evidence that SEP was related to apparent age-related declines in free testosterone or IGF-I.

Conclusions

Lower SEP was associated with an adverse hormone profile across multiple endocrine axes. SEP differences in endocrine function may partly underlie inequalities in health and function in later life, and may reflect variations in biological rates of ageing. Further studies are required to assess the likely functional relevance of these associations.

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Socioeconomic position (SEP) across life was related to multiple hormone measures.

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Lower SEP was related to lower testosterone in men, higher testosterone in women.

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Lower SEP was related to lower IGF-I and higher evening cortisol in both sexes.

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SEP differences in multiple hormone axes may underlie later life health inequality.

Superoxide anion radicals induce IGF-1 resistance through concomitant activation of PTP1B and PTEN

The evolutionarily conserved IGF-1 signalling pathway is associated with longevity, metabolism, tissue homeostasis, and cancer progression. Its regulation relies on the delicate balance between activating kinases and suppressing phosphatases and is still not very well understood. We report here that IGF-1 signalling in vitro and in a murine ageing model in vivo is suppressed in response to accumulation of superoxide anions () in mitochondria, either by chemical inhibition of complex I or by genetic silencing of -dismutating mitochondrial Sod2. The -dependent suppression of IGF-1 signalling resulted in decreased proliferation of murine dermal fibroblasts, affected translation initiation factors and suppressed the expression of α1(I), α1(III), and α2(I) collagen, the hallmarks of skin ageing. Enhanced led to activation of the phosphatases PTP1B and PTEN, which via dephosphorylation of the IGF-1 receptor and phosphatidylinositol 3,4,5-triphosphate dampened IGF-1 signalling. Genetic and pharmacologic inhibition of PTP1B and PTEN abrogated -induced IGF-1 resistance and rescued the ageing skin phenotype. We thus identify previously unreported signature events with , PTP1B, and PTEN as promising targets for drug development to prevent IGF-1 resistance-related pathologies.

Endogenous hormones, inflammation, and body size in premenopausal Mexican women: results from the Mexican Teachers' Cohort (MTC, ESMaestras)

PURPOSE

Obesity is a major risk factor for several cancers, including female cancers. Endogenous hormones and inflammatory factors may mediate the association between anthropometric measures and cancer risk, although these associations have been studied mainly in Caucasians. The aim of the current study was to explore the association of circulating hormones, adipokines, and inflammatory factors with obesity and overweight in premenopausal Mexican women.

METHODS

We conducted a cross-sectional analysis of 504 premenopausal women from the large Mexican Teachers' Cohort (MTC, ESMaestras) study to determine the association of insulin-like growth factor I (IGF-I), its major circulating binding protein (IGFBP-3), leptin, adiponectin, C-peptide, and C-reactive protein with comprehensive measures of body size. Biomarkers were measured by immunoassays. Multivariate regression analyses were performed to compare geometric mean biomarker concentrations with measured markers of body size and adiposity.

RESULTS

Mean IGF-I and IGFBP-3 concentrations significantly increased with increasing height and leg length. Concentrations of IGF-I, adiponectin, and the IGF-I/IGFBP-3 ratio strongly decreased with increasing BMI, weight, waist and hip circumferences, waist-to-hip ratio (WHpR), and waist-to-height ratio (WHtR), while CRP, leptin, C-peptide concentrations, and the leptin/adiponectin ratio strongly increased. Adiponectin and the leptin/adiponectin ratio remained significantly related to measures of central adiposity (waist circumference, WHpR, and WHtR) after adjustment by body mass index.

CONCLUSIONS

The results of our study suggest a strong relation between biomarkers and body size in this study population and suggest that different fat depots may have different metabolic properties.

Changes in insulin-like growth factor-I and -II associated with fat but not lean mass in early old age

OBJECTIVE

To test the hypothesis that insulin-like growth factors-I and II (IGF-I and II) decline during late midlife and that greater declines are related to higher fat mass and lower lean mass.

METHODS

A total of 1,542 men and women in a British birth cohort study had IGF-I and II measured by immunoassay of blood samples at age 53 and/or 60-64 years. Fat mass, android:gynoid fat ratio, and appendicular lean mass were measured at 60-64 years using dual-energy X-ray absorptiometry (DXA). Associations between changes in IGF-I or II and body composition outcomes were examined using conditional change linear regression models.

RESULTS

Mean IGF-I and IGF-II concentrations were lower at 60-64 than at 53 years, by 12.8% for IGF-I and by 12.5% for IGF-II. Larger declines in either IGF-I or II were associated with higher fat mass at 60-64 years. Although higher IGF-I at 53 years was associated with higher lean mass, there was little evidence linking changes in IGF-I or II to lean mass.

CONCLUSIONS

The findings suggest that IGF-I and II concentrations decline with age, and greater declines are associated with higher fat mass levels. These results provide some evidence for the suggested roles of IGF-I and II in regulating fat mass but not lean mass in older age.

Mind over hormones: sex differences in associations of well-being with IGF-I, IGFBP-3 and physical activity in the KORA-Age study

OBJECTIVES

A ssociations between well-being, serum levels of insulin-like growth factor 1 (IGF-I), and its primary binding protein IGFBP-3, were examined in an epidemiologic study. The influence of physical activity on the effect of hormones on well-being was considered.

METHODS

Cross-sectional data from participants of the KORA-Age study (n=985, age 64-93) was analyzed in sex-specific multivariable regressions of well-being (World Health Organization (WHO) -5) or ill-being (geriatric depression scale (GDS) -15). Models were adjusted for age, physical activity, sleep, BMI, smoking, and cognition. Adjusted WHO-5 means demonstrated the interaction between hormone quintiles with physical activity.

RESULTS

Full models indicated that increased IGFBP-3 positively associated with well-being in women (β estimate=0.14, standard error (SE)=0.06) and less so in men (β=0.11, SE=0.07). IGF-I associated positively with depression (β=0.11, SE=0.06) and negatively with well-being (β=-0.11, SE=0.06) in women. Similar but not statistically discernable effects were observed in men. Adjusted mean WHO-5 scores illustrated the positive effect of physical activity and IGFBP-3 on well-being in women only.

CONCLUSIONS

Opposite and independent associations of IGF-I and IGFBP-3 on well-being observed in women suggests neuroprotective effects of IGFBP-3 in age.

Circulating IGF-axis protein levels and their relation with levels of plasma adipocytokines and macronutrient consumption in women

OBJECTIVE

Circulating free insulin-like growth factor (IGF)-I and its binding proteins, most notably, IGFBP-1 and IGFBP-2, have been prospectively associated with incident type 2 diabetes in women. However, little is known regarding the factors that may influence these IGF-axis protein levels. The aim is to study the relation of IGF-axis protein levels with adipcytokines, macronutrient consumption, and other factors related to diabetes.

DESIGN

Fasting plasma from 558 controls enrolled in a nested case-control study within the Nurses' Health Study of incident type 2 diabetes in women was tested for: IGF-axis proteins (free and total IGF-I, IGFBP-1, IGFBP-2, IGFBP-3), adipocytokines (leptin, adiponectin, resistin), soluble leptin receptor (sOB-R), inflammatory factors (IL-18 and C-reactive protein (CRP)), insulin, and glycated hemoglobin (HbA1C).

RESULTS

In multivariate models, each 1% increase in sOB-R (mean 34.9ng/mL, standard deviation (SD) ±11.3) was associated with -0.20% total IGF-I (P=0.0003) and -0.42% free IGF-I (P=0.002), as well as 0.73% higher IGFBP-1 (P<0.0001) and 0.27% IGFBP-2 (P=0.003). For example, a one SD change from the mean sOB-R level was associated with 11% lower free IGF-I. Insulin levels (mean 6.8μU/mL±5.3) were inversely and adiponectin (mean 18.3μg/mL±7.4) positively associated with IGFBP-1 and IGFBP-2 (all P<0.01). Consumption of dairy protein, monounsaturated fats, and saturated fats, was also correlated with IGF-axis protein levels (all P<0.05).

CONCLUSIONS

Several molecular factors and macronutrients were independently associated with plasma IGF-axis protein levels. Which of these, if any, reflect biologic relationships that can be intervened upon to influence IGF-axis protein concentrations warrants further investigation.

Obesity and cancer--mechanisms underlying tumour progression and recurrence

Over the past several years, the field of cancer research has directed increased interest towards subsets of obesity-associated tumours, which include mammary, renal, oesophageal, gastrointestinal and reproductive cancers in both men and women. The increased risk of breast cancer that is associated with obesity has been widely reported; this has drawn much attention and as such, warrants investigation of the key mechanisms that link the obese state with cancer aetiology. For instance, the obese setting provides a unique adipose tissue microenvironment with concomitant systemic endocrine alterations that favour both tumour initiation and progression. Major metabolic differences exist within tumours that distinguish them from non-transformed healthy tissues. Importantly, considerable metabolic differences are induced by tumour cells in the stromal vascular fraction that surrounds them. The precise mechanisms that underlie the association of obesity with cancer and the accompanying metabolic changes that occur in the surrounding microenvironment remain elusive. Nonetheless, specific therapeutic agents designed for patients with obesity who develop tumours are clearly needed. This Review discusses recent advances in understanding the contributions of obesity to cancer and their implications for tumour treatment.

Low circulating levels of IGF-1 in healthy adults are associated with reduced β-cell function, increased intramyocellular lipid, and enhanced fat utilization during fasting

CONTEXT

Low serum IGF-1 levels have been linked to increased risk for development of type 2 diabetes. However, the physiological role of IGF-1 in glucose metabolism is not well characterized.

OBJECTIVE

Our objective was to explore glucose and lipid metabolism associated with variations in serum IGF-1 levels.

DESIGN, SETTING AND PARTICIPANTS

IGF-1 levels were measured in healthy, nonobese male volunteers aged 18 to 50 years from a biobank (n = 275) to select 24 subjects (age 34.8 ± 8.9 years), 12 each in the lowest (low-IGF) and highest (high-IGF) quartiles of age-specific IGF-1 SD scores. Evaluations were undertaken after a 24-hour fast and included glucose and glycerol turnover rates using tracers, iv glucose tolerance test to estimate peripheral insulin sensitivity (IS) and acute insulin and C-peptide responses (indices of insulin secretion), magnetic resonance spectroscopy to measure intramyocellular lipids (IMCLs), calorimetry, and gene expression studies in a muscle biopsy.

MAIN OUTCOME MEASURES

Acute insulin and C-peptide responses, IS, and glucose and glycerol rate of appearance (Ra) were evaluated.

RESULTS

Fasting insulin and C-peptide levels and glucose Ra were reduced (all P < .05) in low-IGF compared with high-IGF subjects, indicating increased hepatic IS. Acute insulin and C-peptide responses were lower (both P < .05), but similar peripheral IS resulted in reduced insulin secretion adjusted for IS in low-IGF subjects (P = 0.044). Low-IGF subjects had higher overnight levels of free fatty acids (P = .028) and β-hydroxybutyrate (P = .014), increased accumulation of IMCLs in tibialis anterior muscle (P = .008), and a tendency for elevated fat oxidation rates (P = .058); however, glycerol Ra values were similar. Gene expression of the fatty acid metabolism pathway (P = .0014) was upregulated, whereas the GLUT1 gene was downregulated (P = .005) in the skeletal muscle in low-IGF subjects.

CONCLUSIONS

These data suggest that serum IGF-1 levels could be an important marker of β-cell function and glucose as well as lipid metabolic responses during fasting.

Relationship between serum circulating insulin-like growth factor-1 and liver fat in the United States

BACKGROUND AND AIM

Nonalcoholic fatty liver disease (NAFLD), circulating insulin-like growth factor-1 (IGF-1), and IGF-1/IGF-binding protein-3 (IGFBP-3) concentrations are associated with adiposity and insulin resistance. We aimed to determine whether serum IGF-1, IGFBP-3, and IGF-1/IGFBP-3 are associated with presence or severity of NAFLD independent of potential confounding.

METHODS

We performed a cross-sectional analysis of data from the Third National Health and Nutrition Examination Survey, 1988–1994, a representative sample of the United States adult population. Among participants who had a fasting blood draw and ultrasound examination, we excluded those with missing data, viral hepatitis, iron overload, excessive alcohol intake, pregnancy, or taking glucose-lowering therapy, yielding 4172 adults for this analysis.

RESULTS

In logistic regression analyses adjusted for age, gender, and race/ethnicity, higher IGF-1 and IGF-1/IGFBP-3 quartiles were associated with lower likelihood of NAFLD and lower grade steatosis. These associations became non-significant when further adjusted for adiposity (body mass index, waist circumference) with the exception of the association between IGF-1/IGFBP-3 and severity of NAFLD which remained significant after adjustment for homeostasis model assessment for insulin resistance (HOMA-IR) (odds ratio [95% CI]: Q3: 0.71 [0.53–0.96], Q4: 0.62 [0.43–0.89]) and adiposity (Q4: 0.67 [0.47–0.96]). Full adjustment (age, gender, race/ethnicity, adiposity, HOMA-IR, A1C%) further attenuated associations between IGF-1 or IGF-1/IGFBP-3 and liver fat such that they were no longer significant.

CONCLUSIONS

Adiposity explains much of the observed association between IGF-1 or IGF-1/IGFBP-3 and liver fat. These findings do not support a direct role for the growth hormone-IGF-1/IGFBP-3 axis in the pathophysiology of NAFLD.

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.

A study of caloric restriction versus standard diet in overweight men with newly diagnosed prostate cancer: a randomized controlled trial

INTRODUCTION

Obese men have an increased risk of prostate cancer (PCa)-specific mortality. Potential mechanisms include insulin and related proteins. We investigate whether a short-term caloric restriction diet in overweight/obese men with newly diagnosed PCa can lead to measurable changes in patient anthropometrics and insulin-related proteins.

METHODS

Overweight and obese PCa patients choosing active surveillance or radical prostatectomy were randomized to a 6-week, caloric-restricted diet or to continue their current diet. Changes from baseline to end of study in anthropometrics, dietary constituents and serum proteins (insulin, c-peptide, IGF-1, adiponectin, IGF-BP3) were compared between the intervention and control groups using a Generalized Estimating Equation model.

RESULTS

Nineteen patients were randomized to the intervention (N = 10) or control (N = 9) group. Men in the intervention group had a 1.7% (3.7 lbs) mean decline in weight versus 1.0% (2.0 lbs) in controls (P < 0.05), and a reduced intake of calories, total and saturated fat, protein and starch (all P < 0.1 compared to controls). There was a significant difference (P = 0.002) in mean serum IGFBP-3 between the intervention (+2.8%) and control group (-6.9%). Other biomarkers changed with the diet intervention to a degree similar to previous weight loss studies but were not statistically significant compared with controls.

CONCLUSION

In this small pilot study, a 6-week caloric restricted diet in men with newly diagnosed PCa produced changes in weight, diet and serum proteins possibly related to prognosis. These results support larger-scale trials testing longer-term weight loss effects on potential PCa progression biomarkers.

Influence of pretreatment ideal body weight percentile and albumin on prognosis of nasopharyngeal carcinoma: Long-term outcomes of 512 patients from a single institution

BACKGROUND

The purpose of this study was to investigate the relationship between pretreatment nutritional status and prognosis of nasopharyngeal carcinoma (NPC).

METHODS

Pretreatment nutritional status was evaluated by ideal body weight percentile (IBW%) and serum albumin for 512 patients with NPC who underwent radical radiotherapy. Kaplan-Meier methods, log-rank test, and a Cox model were applied for survival analysis.

RESULTS

Before radiotherapy, IBW% <90% was related to poorer overall survival (OS) and distant metastasis-free survival (DMFS; p = .031 and p = .012, respectively); albumin ≤43.0 g/L was related to poorer OS and DMFS (p < .001 and p = .042, respectively); both IBW% and albumin were independent prognostic factors for OS; those patients with IBW% <90% and albumin ≤43.0 g/L simultaneously had the worst OS and DMFS.

CONCLUSION

Decrease of pretreatment IBW% and albumin was related to poorer survival of NPC.

Serum IGF1, metabolic syndrome, and incident cardiovascular disease in older people: a population-based study

OBJECTIVE

High as well as low levels of IGF1 have been associated with cardiovascular diseases (CVD). The relationship of IGF1 with (components of) the metabolic syndrome could help to clarify this controversy. The aims of this study were: i) to investigate the association of IGF1 concentration with prevalent (components of) the metabolic syndrome; and ii) to examine the role of (components of) the metabolic syndrome in the relationship between IGF1 and incident CVD during 11 years of follow-up.

METHODS

Data were used from the Longitudinal Aging Study Amsterdam, a cohort study in a representative sample of the Dutch older population (≥65 years). Data were available in 1258 subjects. Metabolic syndrome was determined using the definition of the US National Cholesterol Education Program Adult Treatment Panel III. CVD were ascertained by self-reports and mortality data.

RESULTS

Levels of IGF1 in the fourth quintile were associated with prevalent metabolic syndrome compared with the lowest quintile (odds ratio: 1.59, 95% confidence interval (CI) 1.09-2.33). The middle up to the highest quintile of IGF1 was positively associated with high triglycerides in women. Metabolic syndrome was not a mediator in the U-shaped relationship of IGF1 with CVD. Both subjects without the metabolic syndrome and low IGF1 levels (hazard ratio (HR) 1.75, 95% CI 1.12-2.71) and subjects with the metabolic syndrome and high IGF1 levels (HR 2.28, 95% CI 1.21-4.28) demonstrated increased risks of CVD.

CONCLUSIONS

In older people, high-normal IGF1 levels are associated with prevalent metabolic syndrome and high triglycerides. Furthermore, this study suggests the presence of different pathomechanisms for both low and high IGF1 levels and incident CVD.

Association of serum C-peptide concentrations with cancer mortality risk in pre-diabetes or undiagnosed diabetes

Background

Known associations between diabetes and cancer could logically be attributed to hyperglycemia, hypersecretion of insulin, and/or insulin resistance. This study examined the relationship between initial glycemic biomarkers among men and women with impaired fasting glucose or undiagnosed diabetes and cancer mortality during follow up.

Methods

The cohort included subjects aged 40 years and above from the Third National Health and Nutrition Examination Survey (NHANES III) with fasted serum glucose >100 mg/dl without the aid of pharmaceutical intervention (insulin or oral hypoglycemics). Cancer mortality was obtained from the NHANES III-linked follow-up database (up to December 31, 2006). A Cox regression model was applied to test for the associations between cancer mortality and fasting serum glucose, insulin, glycosylated hemoglobin (HbA1c), C-peptide, insulin like growth factor (IGF-1), IGF binding protein 3 (IGFBP3) and estimated insulin resistance.

Results

A total of 158 and 100 cancer deaths were recorded respectively from 1,348 men and 1,161 women during the mean 134-month follow-up. After adjusting for the effect of age and smoking in women, all-cause cancer deaths (HR: 1.96 per pmol/ml, 95% CI: 1.02–3.77) and lung cancer deaths (HR: 2.65 per pmol/ml, 95% CI: 1.31–5.36) were specifically associated with serum C-peptide concentrations. Similar associations in men were not statistically significant. Serum glucose, HbA1c, IGF-1, IGFBP3 and HOMA were not independently related to long-term cancer mortality.

Conclusion

C-peptide analyses suggest a modest association with both all-cause and lung cancer mortality in women but not in men. Further studies will be required to explore the mechanisms.

Beyond waist circumference in an adult male population of Southern Italy: Is there any role for subscapular skinfold thickness in the relationship between insulin-like growth factor-I system and metabolic parameters?

BACKGROUND

Apart from waist circumference, other adiposity measures, such as subscapular skin fold (SST), arouse growing interest due to their relationship to metabolic complications and cardiovascular risk. The IGF-I system is deregulated in obese subjects in proportion to their degree of visceral adiposity.

AIM

To examine the association among IGF-I, IGF-binding protein (BP)-1 and -3 levels and different measures of adiposity in a sample of adult male population in Southern Italy.

MATERIALS AND METHODS

A complete database for this analysis was available for 229 (age range 50-82 yr) participating at 2002-2004 Olivetti Heart Study follow-up.

RESULTS

After adjustment for age, IGF-I was inversely associated with body mass index (BMI) and waist circumference (p<0.05). IGFBP-1 was inversely associated with BMI, waist circumference, SST, homeostasis model assessment (HOMA) index, fat mass. HOMA index, age, and SST significantly predicted the IGFBP-1 plasma levels, with 24% of IGFBP-1 variability explained at a linear regression analysis.

CONCLUSIONS

IGFBP-1 inversely correlated to adiposity and HOMA index. Among adiposity indexes, SST was the best predictor of IGFBP-1 levels. The evaluation of some components of the IGF system, and simple measures of body adiposity, such as SST, may represent a further tool to better evidence phenotype profiles associated to the pathogenetic mechanism of cardiovascular risk factor clustering in male adults.

Early origins of the metabolic syndrome: role of small size at birth, early postnatal weight gain, and adult IGF-I

BACKGROUND

The relationship between low birth weight and increased risk for metabolic syndrome (MetS) in later life has been frequently described, but mechanisms underlying this association remain unknown.

METHODS

In 280 young adults of the PROGRAM study, aged 18-24 yr, we investigated associations of birth weight, gain in weight for length during early life, and adult IGF-I sd score (SDS), with number of MetS components (ordinal regression analyses), prevalence of MetS components and MetS (logistic regression analyses), and other metabolic parameters (linear regression analyses). Revised criteria of the National Cholesterol Educational Program (Adult Treatment Panel III) were used to determine components of MetS. The other metabolic parameters were C-reactive protein, insulin sensitivity, trunk fat mass, total cholesterol, and low-density lipoprotein cholesterol.

RESULTS

More gain in weight for length SDS in the first 3 months of life was significantly associated with an increased number of MetS components [odds ratio (OR) = 1.34], prevalence of low high-density lipoprotein cholesterol (OR = 1.49), prevalence of MetS (OR = 2.51), increased C-reactive protein levels, and lower insulin sensitivity (P = 0.007) at the age of 21 yr. Low birth weight SDS was associated with lower insulin sensitivity (P = 0.036), but low birth weight SDS and adult IGF-I SDS were not significantly associated with any of the MetS components or MetS prevalence at 21 yr.

CONCLUSION

Our study demonstrates that higher gain in weight for length in the first 3 months of life is associated with a higher prevalence of MetS at 21 yr, whereas low birth weight and low adult IGF-I are not.

Basal growth hormone concentration increased following a weight loss focused dietary intervention in older overweight and obese women

OBJECTIVES

Growth and sex steroid hormones decrease with aging and obesity. The effect of dietary weight loss and exercise training lifestyle interventions was examined on hormones as well as determining their relationships with physical function in older obese and overweight adults.

DESIGN

Individuals were randomized into one of four 18 month interventions: Healthy Lifestyle (HL), Exercise, Diet, and Exercise-Diet.

SETTING

Clinical research setting with facility based exercise and nutrition education and behavior classrooms.

PARTICIPANTS

Older (≥60 yrs) overweight and obese (BMI≥28 kg/m(2)) adults with knee osteoarthritis (n=309) were recruited for the study.

INTERVENTION

Weight loss goal for Diet groups was ≥5%. Exercise groups trained (mostly walking and resistance training) 3 days/week for 60 min/session.

MEASUREMENTS

Body weight, growth hormone (GH), corticosterone, sex-hormone binding globulin (SHBG), testosterone, and dehydroepiandrosterone (DHEA) were measured at baseline, 6, and 18 months. Physical function was determined through performance task (6-min walking distance) and self-reported questionnaires (Western Ontario McMaster University Osteoarthritis Index-WOMAC) at similar time points.

RESULTS

Diet, Exercise, and Exercise-Diet groups lost 4.9%, 3.5%, and 6.2% of their weight at 18 months, respectively. There was a significant diet treatment effect on GH levels in women as higher concentrations of this hormone were apparent following dietary weight loss intervention (p=0.01). No other hormones were affected by either diet or exercise treatments in men or women. A significant inverse correlation between baseline 6-minute walking distance and SHBG (r=-0.33) was found in men.

CONCLUSION

The increase in basal GH levels from the diet treatment in women suggests that this lifestyle behavior intervention may mitigate the age- and obesity-related decreases in growth hormone levels, to help preserve muscle mass, strength, and physical function in older adults.

Serum insulin-like growth factor-I and insulin-like growth factor binding protein-3 levels with risk of malignant melanoma

We examined the relationship of insulin-like growth factor-I (IGF-I) and its primary growth factor, IGF binding protein-3 (IGFBP-3) with malignant melanoma using interview data and sera from cases (n = 286) and controls (n = 289) in a population-based case-control study conducted in 1986-1992 on Oahu, Hawaii. Serum IGF-I and IGFBP-3 concentrations were measured by ELISA. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by unconditional logistic regression and adjusting for age, sex, education, number of blistering sunburns, ability to tan, hair color, energy intake, BMI, height, smoking status, and drinking status. An inverse relationship was found between IGF-I concentration and melanoma (OR for upper vs. lower tertile: 0.44, 95% CI: 0.25-0.79), but clear associations were not observed between malignant melanoma and upper tertiles of IGFBP-3 and the IGF-1/IGFBP-3 molar ratio. The inverse association with IGF-I was strongest among subjects who did not report a history of non-melanoma skin cancer (NMSC) (OR for ≥ vs. < median: 0.39, 95% CI: 0.24-0.65), and a positive association was found among those with such a history (OR: 3.6, 95% CI: 1.0-13; p (interaction) = 0.0035). Our findings observed here between serum IGF-I and malignant melanoma warrants replication in studies with a larger sample size and a prospective design.

IGF-1 and atherothrombosis: relevance to pathophysiology and therapy

IGF-1 (insulin-like growth factor-1) plays a unique role in the cell protection of multiple systems, where its fine-tuned signal transduction helps to preserve tissues from hypoxia, ischaemia and oxidative stress, thus mediating functional homoeostatic adjustments. In contrast, its deprivation results in apoptosis and dysfunction. Many prospective epidemiological surveys have associated low IGF-1 levels with late mortality, MI (myocardial infarction), HF (heart failure) and diabetes. Interventional studies suggest that IGF-1 has anti-atherogenic actions, owing to its multifaceted impact on cardiovascular risk factors and diseases. The metabolic ability of IGF-1 in coupling vasodilation with improved function plays a key role in these actions. The endothelial-protective, anti-platelet and anti-thrombotic activities of IGF-1 exert critical effects in preventing both vascular damage and mechanisms that lead to unstable coronary plaques and syndromes. The pro-survival and anti-inflammatory short-term properties of IGF-1 appear to reduce infarct size and improve LV (left ventricular) remodelling after MI. An immune-modulatory ability, which is able to suppress 'friendly fire' and autoreactivity, is a proposed important additional mechanism explaining the anti-thrombotic and anti-remodelling activities of IGF-1. The concern of cancer risk raised by long-term therapy with IGF-1, however, deserves further study. In the present review, we discuss the large body of published evidence and review data on rhIGF-1 (recombinant human IGF-1) administration in cardiovascular disease and diabetes, with a focus on dosage and safety issues. Perhaps the time has come for the regenerative properties of IGF-1 to be assessed as a new pharmacological tool in cardiovascular medicine.

Is growth hormone resistance/IGF-1 reduction good for you?

GH, IGF-1, and insulin are emerging as important and independent mediators of tumor development and aging. Two recent studies report that humans with GH-receptor deficiency are protected from developing cancer through alterations in GH, IGF-1, and insulin signaling, decreasing the susceptibility of cells to DNA damage and abnormal proliferation.

Effect of low-intensity aerobic exercise on insulin-like growth factor-I and insulin-like growth factor-binding proteins in healthy men

Increased concentrations of circulating insulin-like growth factor-I (IGF-I) or IGF-I relative to IGF-binding proteins (IGFBPs) are associated with increased risk of developing several forms of cancer. Conversely, exercise is linked with reduced risk. This study aims to investigate the effect of a low-intensity exercise program on circulating levels of IGF-I, IGFBP-1, and IGFBP-3, in previously sedentary males. Fourteen healthy men participated in cycle ergometer training at lactate threshold intensity for 60 min/day, 5 days/week for 6 weeks. After aerobic training, insulin sensitivity improved by 20%, while fasting insulin levels decreased by 13%. Simultaneously, low-intensity aerobic training decreased the circulating levels of IGF-I by 9%, while IGFBP-1 levels increased by 16%. An interesting finding was that higher pretraining level of IGF-I was associated with greater decline in IGF-I with training. Insulin-sensitizing low-intensity aerobic exercise is thus considered to be an effective method for downregulating IGF-I and upregulating IGFBP-1 levels.