Genetic and environmental components of interindividual variation in circulating levels of IGF-I, IGF-II, IGFBP-1, and IGFBP-3.

We assessed the magnitude of the genetic component in the variation of circulating levels of insulin-like growth factors I and II (IGF-I and IGF-II), and their binding proteins IGFBP-1 and IGFBP-3 by measuring their serum concentrations in 32 monozygotic and 47 dizygotic adult twin pairs of the same sex. The intrapair correlation for the IGF-I levels was r = 0.41 (P < 0.009) for monozygotic twins and r = 0.12 (P < 0.22) for dizygotic twins. For the IGF-II concentration the intrapair correlations were r = 0.66 (P < 0.0001) for the monozygotic and r = 0.34 (P < 0.01) for the dizygotic twins. No significant intrapair correlation was found for IGFBP-1 levels in either group. The correlations for IGFBP-3 concentration were r = 0.65 (P < 0.0001) and r = 0.23 (P < 0.06) for monozygotic and dizygotic twins, respectively. Women had higher IGF-II levels than men (635+/-175 vs. 522+/-144 microg/liter; P < 0.0001) and IGFBP-3 levels were also higher in women compared with men (5441+/-1018 vs. 4496+/-1084 microg/liter; P < 0.001). The proportion of variance attributable to genetic effects was 38% for the IGF-I concentration, 66% for the IGF-II concentration, and 60% for the IGFBP-3 concentration. No significant heritability was found for the IGFBP-1 concentrations. Our results show that, in adults, there is a substantial genetic contribution responsible for interindividual variation of the circulating levels of IGF-I, IGF-II, and IGFBP-3, but not for the IGFBP-1 levels.

Significance of meconium staining of the amniotic fluid.

The study was conducted to determine the significance of meconium staining and more specifically its association with fetal heart rate patterns. Five hundred and one patients in labor were examined, 106 of whom had meconium stained amniotic fluid. A multivariate analysis of the data was performed by logistic regression analysis using meconium staining as the dependent variable. The determinants of meconium in the amniotic fluid were gestational age, base deficit, calcified placenta, late decelerations and placental weight. The following variables had no effect on the occurrence of meconium: maternal age, type of risk, parity, fetal sex, duration of labor, duration of the second stage of labor, entanglement of the umbilical cord, FHR variability, variable decelerations, oxytocin usage, type of anesthesia, maternal smoking and alcohol consumption habits. In conclusion, meconium in the amniotic fluid seems to be associated with placental rather than with umbilical insufficiency.

Low serum insulin-like growth factor-binding protein-1 is associated with an unfavourable cardiovascular risk profile in elderly men.

Serum insulin-like growth factor-binding protein-1 (IGFBP-1) is regulated by insulin and has been suggested to be a marker of the insulin resistance syndrome. The aim of this study was to investigate whether serum IGFBP-1 is associated with cardiovascular risk factors. Serum insulin-like growth factor-I and IGFBP-3 were also determined. 331 men aged 70-89 years were examined from the Finnish cohort of the Seven Countries Study. Serum IGFBP-1 concentrations were measured by immunofluorometric assay, and the results were analysed with respect to markers of cardiovascular risk, insulin resistance, and insulin secretion that were determined by using the homeostasis model assessment. Fasting serum IGFBP-1 correlated inversely with fasting serum insulin, serum insulin 2 h after oral glucose challenge test, body mass index, and serum triglycerides, and it correlated positively with age and serum high-density lipoprotein (HDL) cholesterol. After adjustment for age, fasting serum IGFBP-1 correlated positively with HDL cholesterol and inversely with fasting serum insulin and triglycerides. Serum IGFBP-1 correlated positively with insulin sensitivity and negatively with beta-cell function. In conclusion, low serum IGFBP-1 levels in elderly men are associated with a number of cardiovascular risk factors.

High serum insulin-like growth factor binding protein-1 is associated with increased cardiovascular mortality in elderly men.

Insulin-like growth factor binding protein-1 (IGFBP-1) has been implicated in the development of cardiovascular disease, but it is not known whether IGFBP-1 is related to cardiovascular mortality. We examined the relation of circulating IGFBP-1 to death from coronary heart disease, cardiovascular disease, and all causes in a cohort study consisting of 622 men aged 65 - 84 years, at baseline in 1984. Fasting serum IGFBP-1 and other risk factors were measured in 1984 and 1989. Cardiovascular events for those who died between 1984 and 1995 were analyzed, and cardiovascular diagnoses were coded centrally according to standardized procedures. Of the 622 men, 358 died between 1984 and 1995; 160 deaths were due to cardiovascular causes, 113 of which were coronary deaths. High fasting serum IGFBP-1 concentration (> 75 percentile) in 1984 was associated with increased five-year total mortality (OR 2.05, 95 % CI 1.41 - 2.99; p < 0.0002), cardiovascular mortality (OR 2.20, 95 % CI 1.37 - 3.50; p < 0.0009) and coronary heart disease mortality (OR 2.29, 95 % CI 1.35 - 3.88; p < 0.002). After adjustment for age, high serum IGFBP-1 concentrations still carried an increased risk of total mortality due to (OR 1.73, 95 % CI 1.16 - 2.59; p < 0.007), cardiovascular (OR 1.91 95 % CI 1.18 - 3.09; p < 0.008) and coronary heart disease (OR 2.02. 95 % CI 1.18 - 3.47; p < 0.01). In conclusion, high fasting serum IGFBP-1 is related to increased five-year total and cardiovascular mortality in elderly men.