Serum insulin-like growth factor I and its binding protein 3 in their relation to intima-media thickness: results of the study of health in Pomerania (SHIP).

OBJECTIVE: Previous studies detected associations between lower insulin-like growth factor I (IGF-I) levels and increased risk of congestive heart failure or ischaemic heart disease. The aim of the present study was to assess the association of IGF-I and its binding protein 3 (IGFBP-3) with the carotid intima-media thickness (IMT) as marker of asymptomatic cardiovascular disease. DESIGN AND POPULATION: From the population-based Study of Health in Pomerania (SHIP), a total of 2286 participants aged 45 years or older with readable ultrasound of the carotid arteries were available for the present analyses. METHODS AND MEASUREMENTS: Serum IGF-I and IGFBP-3 levels were categorized into three groups (low, moderate, high) according to the sex-specific 10th and 90th percentile. Analyses of variance (anova) and logistic regression analyses adjusted for age, waist circumference, diabetes, hypertension and creatinine clearance were performed. RESULTS: After adjusting for confounding factors, IGF-I and the IGF-I/IGFBP-3 ratio were positively related to IMT in anova. Logistic regression analyses confirmed these findings and showed that high IGF-I levels, a high IGF-I/IGFBP-3 ratio and low IGFBP-3 levels were associated to higher odds of increased IMT. CONCLUSION: In conclusion, high IGF-I or high IGF-I/IGFBP-3 ratio values and low IGFBP-3 levels are associated with increased IMT. Therefore, systemic levels of the IGF axis or alterations in the balance of its components are associated with subclinical atherosclerotic disease.

Mortality and serum insulin-like growth factor (IGF)-I and IGF binding protein 3 concentrations.

BACKGROUND: Previous studies provided conflicting results regarding the association of serum IGF-I or IGF-binding protein-3 (IGFBP-3) and mortality. The aim of this study was to assess the relation of IGF-I and IGFBP-3 levels with mortality from all causes, cardiovascular disease (CVD), and cancer in a prospective population-based study. METHODS: From the Study of Health in Pomerania (SHIP) 1988 men and 2069 women aged 20-79 yr were followed up on average 8.5 yr. Causes of deaths were coded according to the International Classification of Diseases, 10th revision. Serum IGF-I and IGFBP-3 levels were determined by chemiluminescence immunoassays and categorized into three groups (low, normal, high) according to the sex- and age-specific 10th and 90th percentiles. RESULTS: Adjusted analyses revealed that men with low but not high IGF-I levels had an almost 2-fold higher risk of all-cause mortality [hazard ratio (HR) 1.92 (95% confidence interval [CI] 1.35; 2.73)], CVD mortality [HR 1.92 (95% CI 1.00; 3.71)], and cancer mortality [HR 1.85 (95% CI 1.00; 3.45)] compared with men with normal IGF-I levels. In women, no association between IGF-I and mortality was found. Moreover, low IGFBP-3 levels were associated with higher all-cause mortality in men [HR 1.87 (95% CI 1.31; 2.64)] and women [HR 1.63 (95% CI 0.96; 2.76)]. CONCLUSIONS: The present study found inverse associations between IGF-I or IGFBP-3 levels and mortality from all causes, CVD, or cancer in men and between IGFBP-3 and all-cause mortality in women.

Five commercially available insulin-like growth factor I (IGF-I) assays in comparison to the former Nichols Advantage IGF-I in a growth hormone treated population.

BACKGROUND: The serum insulin-like growth factor I (IGF-I) level is accepted to diagnose the growth hormone (GH) status. Here, we evaluated the DRG IGF-I 600 ELISA, DSL IGF-I ELISA, IDS OCTEIA IGF-I, Mediagnost IGF-I-ELISA, and the Siemens Immulite 2500 IGF-I in comparison to the former Nichols Advantage IGF-I assay. METHODS: Imprecision was determined by use of a serum pool and commercial control materials. Accuracy was evaluated by means of a method comparison to Nichols in 173 serum samples of GH deficient patients. RESULTS: The Siemens and the IDS IGF-I assays showed the lowest imprecision with coefficients of variation up to 3.6% and 6.9%, respectively. Both correlated best to Nichols (Siemens: y=0.667X+8.8 microg/L, r=0.950; IDS: y=0.527 X+4.6 microg/L, r=0.927) with the lowest dispersion of residuals from a linear equation. The DSL assay had the highest comparability to Nichols (y=1.000 X+35.5 microg/L, r=0.864), but with a considerable scattering. CONCLUSIONS: To yield IGF-I determination comparable to the former Nichols IGF-I, either the Siemens or the IDS assay should be applied, and the results should be converted by a linear method transformation. Where a conversion factor is not desired, the DSL assay should be selected.

Reference ranges of serum IGF-1 and IGFBP-3 levels in a general adult population: results of the Study of Health in Pomerania (SHIP).

OBJECTIVE: Insulin-like growth factor I (IGF-1), which is mostly carried by IGF binding protein 3 (IGFBP-3), mediates endocrine actions of growth hormone and represents an important prognostic factor for systemic diseases. The main objectives of the present study were (1) to calculate age- and sex-specific reference values for serum IGF-1 and IGFBP-3 levels using the Gaussian mean+/-1.96 *standard deviation method and the quantile regression method and (2) to perform a comparison of the results from both statistical methods. DESIGN: Cross-sectional study (Study of Health in Pomerania). The study population included 2499 men and women aged 20-79 years. METHODS: Serum IGF-1 and IGFBP-3 levels were determined by chemiluminescence immunoassays. Linear and quantile regressions were performed to calculate age- and sex-related reference ranges. RESULTS: Both statistical methods generated different results: The reference ranges based on linear regression identified 43 (1.7%) subjects with serum IGF-1 levels and 99 (4.0%) subjects with serum IGFBP-3 levels outside the reference range. Using quantile regression, 117 (4.7%) or 118 subjects (4.7%) with serum IGF-1 or IGFBP-3 levels outside the range were detected, respectively. CONCLUSION: The present study established age- and sex-specific reference ranges for serum IGF-1 and IGFBP-3 levels. Quantile regression should be preferred to calculate reference ranges because a better concordance to original data is possible due to no distribution assumption are required and the robustness against outliers is given.

Endocrine tumors of the pancreas.

Neuroendocrine tumors of the pancreas are rare neoplasms of the heterogeneous group of neuroendocrine gastroenteropancreatic tumors that originate from totipotential stem cells or preexisting endocrine cells within the pancreas. Most neuroendocrine tumors of the pancreas are benign or show an indolent course of disease.A subset of them shows a very aggressive behavior, becomes highly malignant, and metastasizes early with life-limiting consequences. An effective disease-management includes the diagnostic approach with hormonal testing and localization and surgical treatment with histologic classification in combination with biotherapy, chemotherapy, or therapy with radionucleotides, de-pending on the individual behavior of the tumor. The primary goal is the improvement of symptoms leading to an acceptable quality of life in the individual patient.