Diabetes during pregnancy does not alter whole body bone mineral content in infants

Bone Mass Accrual in First Six Months of Life: Impact of Maternal Diabetes, Infant Adiposity, and Cord Blood Adipokines

The perinatal period is a time of substantial bone mass accrual with many factors affecting long-term bone mineralization. Currently it is unclear what effect maternal gestational/type 2 diabetes has on infant bone mass accrual. This is a prospective study of offspring of Native American and Hispanic mothers with normoglycemia (n = 94) and gestational diabetes or type 2 diabetes (n = 64). Infant anthropometrics were measured at birth, 1, and 6 months of age. Cord blood leptin, high-molecular weight adiponectin (HMWA), pigment epithelium-derived factor (PEDF), vascular epithelium growth factor (VEGF), endoglin, and C-peptide were measured by ELISA. Infants had bone mineral density measurement at 1 month or/and 6 months of age using dual-energy x-ray absorptiometry scan. Mothers with diabetes were older (31 ± 6 years vs 25 ± 4 years) and had higher pre-pregnancy BMI (32.6 ± 5.8 vs 27.2 ± 6.4 kg/m²) than control mothers. Mean HbA1C of mothers with diabetes was 5.9 ± 1.0% compared to 5.1 ± 0.3% in controls early in pregnancy. Infants born to mothers with diabetes (DM-O) were born at a slightly lower gestational age compared to infants born to control mothers (Con-O). There was no difference in total body less head bone mineral content (BMC) or bone mineral density (BMD) between DM-O and Con-O. For both groups together, bone area, BMD, and BMC tracked over the first 6 months of life (r: 0.56, 0.38, and 0.48, respectively). Percent fat was strongly and positively correlated with BMC at 1 month of age (r = 0.44; p < 0.001) and BMC at both 1 and 6 months of age correlated strongly with birth weight. There were no associations between infant bone mass and cord blood leptin, PEDF, or VEGF, while C-peptide had a significant correlation with BMC at 1 and 6 months only in DM-O (p = 0.01 and 0.03, respectively). Infants born to mothers with well-controlled gestational/type 2 diabetes have normal bone mass accrual. Bone mineral content during this time is highly correlated with indices of infant growth and the association of bone mineral indices with percent body fat suggests that bone-fat crosstalk is operative early in life.

Boys but Not Girls Exposed to Maternal Gestational Diabetes Mellitus Have Unfavorable Fat Distribution

BACKGROUND

Maternal gestational diabetes mellitus (GDM) and overweight are associated with an increased risk of obesity and the metabolic syndrome in the adult offspring. We studied the influence of maternal GDM on prepubertal children's body composition and bone mineral biochemistry.

METHODS

A total of 134 prepubertal Caucasian children (age range 4.4-9.7 years) were studied in a controlled cross-sectional study. Seventy-six children had been exposed to maternal GDM and 58 children born after a normal pregnancy served as controls. The outcome variables were body fat %, android fat %, gynoid fat %, android/gynoid fat ratio, bone mineral density (BMD), bone mineral content (BMC), muscle mass, lean mass (LM) and serum 25-hydroxyvitamin D, ionized calcium, phosphate, and alkaline phosphatase concentrations.

RESULTS

There were no differences in body fat %, android fat %, BMD, BMC, muscle mass, or LM between the study groups. Gynoid fat % was higher in the GDM than control children (p = 0.03). Android fat %, gynoid fat %, and android/gynoid fat ratio were higher in the GDM boys than control boys (p = 0.046, 0.037, and 0.038) respectively, but no differences were found between the GDM and control girls.

CONCLUSIONS

Boys exposed to maternal GDM presented with more unfavorable fat distribution than their controls, whereas no difference was found between the girls. Otherwise, the differences in body composition were minimal between prepubertal GDM and control children.

Developmental Programming of Body Composition: Update on Evidence and Mechanisms

PURPOSE OF REVIEW

A growing body of epidemiological and experimental data indicate that nutritional or environmental stressors during early development can induce long-term adaptations that increase risk of obesity, diabetes, cardiovascular disease, and other chronic conditions-a phenomenon termed "developmental programming." A common phenotype in humans and animal models is altered body composition, with reduced muscle and bone mass, and increased fat mass. In this review, we summarize the recent literature linking prenatal factors to future body composition and explore contributing mechanisms.

RECENT FINDINGS

Many prenatal exposures, including intrauterine growth restriction, extremes of birth weight, maternal obesity, and maternal diabetes, are associated with increased fat mass, reduced muscle mass, and decreased bone density, with effects reported throughout infancy and childhood, and persisting into middle age. Mechanisms and mediators include maternal diet, breastmilk composition, metabolites, appetite regulation, genetic and epigenetic influences, stem cell commitment and function, and mitochondrial metabolism. Differences in body composition are a common phenotype following disruptions to the prenatal environment, and may contribute to developmental programming of obesity and diabetes risk.

Sex- and bone-specific responses in bone structure to exogenous leptin and leptin receptor antagonism in the ovine fetus

Widespread expression of leptin and its receptor in developing cartilage and bone suggests that leptin may regulate bone growth and development in the fetus. Using microcomputed tomography, this study investigated the effects of exogenous leptin and leptin receptor antagonism on aspects of bone structure in the sheep fetus during late gestation. From 125 to 130 days of gestation (term ~145 days), chronically catheterized singleton sheep fetuses were infused intravenously for 5 days with either saline (0.9% saline, n = 13), recombinant ovine leptin at two doses (0.6 mg·kg^-1·day^-1 LEP1, n = 10 or 1.4 mg·kg^-1·day^-1 LEP2, n = 7), or recombinant superactive ovine leptin receptor antagonist (4.6 mg·kg^-1·day^-1 SOLA, n = 6). No significant differences in plasma insulin-like growth factor-I, osteocalcin, calcium, inorganic phosphate, or alkaline phosphatase were observed between treatment groups. Total femur midshaft diameter and metatarsal lumen diameter were narrower in male fetuses treated with exogenous leptin. In a fixed length of femur midshaft, total and bone volumes were reduced by the higher dose of leptin; nonbone space volume was lower in both groups of leptin-treated fetuses. Leptin infusion caused increments in femur porosity and connectivity density, and vertebral trabecular thickness. Leptin receptor antagonism decreased trabecular spacing and increased trabecular number, degree of anisotrophy, and connectivity density in the lumbar vertebrae. The increase in vertebral porosity observed following leptin receptor antagonism was greater in the malecompared with female, fetuses. Therefore, leptin may have a role in the growth and development of the fetal skeleton, dependent on the concentration of leptin, sex of the fetus, and bone type examined.

[Determinants of neonatal serum calcium in a peripheral maternity in Abidjan]

Introduction

Le transfert du calcium de la mère au nouveau-né est nécessaire pour la constitution de la charpente osseuse. L'hypocalcémie néonatale reste peu documentée en Afrique. En 1993, il a été observé au service de néonatologie du Centre hospitalo-universitaire de Yopougon à Abidjan une proportion d'hypocalcémie asymptomatique de 26.9%. L'objectif de ce travail était de préciser la prévalence de l'hypocalcémie néonatale dans une maternité périphérique de Yopougon et en déterminer les facteurs de risque.

Méthodes

Une étude transversale a été menée à la formation sanitaire de de Yopougon de février à mai 2012 auprès de 145 parturientes et leurs nouveau-nés. Les caractéristiques des mères et des nouveau-nés ont été recueillies. Les prélèvements de sang maternel et du cordon ont permis le dosage des paramètres du métabolisme phosphocalcique. Une régression linéaire multiple a été faite pour apprécier les éléments de prédilection de la calcémie néonatale.

Résultats

Les valeurs moyennes étaient de 2,271 mmol/l pour la calcémie, 1,169 mmol/l pour le phosphore, 0,735 mmol/l pour le magnésium et 69 g/l pour les protides totaux chez les mères. La durée moyenne du travail était de 499 minutes. L’âge gestationnel moyen était de 39 semaines. Les constantes anthropométriques et cliniques des nouveau-nés étaient normales. Les paramètres phosphocalciques étaient en moyenne normaux (calcémie = 2,52 mmol/l, phosphorémie = 1,668 mmol/l, magnesémie = 0,777 mmol/l, protidémie = 63 g/l). Six gestantes (4,1%) étaient hypocalcémiques contre 12 nouveau-nés (8,1%). La durée du travail influençait la calcémie néonatale (p = 0,02). En analyse multivariée, 34% de la variabilité de la calcémie néonatale était expliqué par la calcémie maternelle et la durée du travail.

Conclusion

L'hypocalcémie néonatale est rare en zone tropicale. Dans cette étude, la proportion était de 8,1%. La durée du travail influençait la calcémie néonatale. Aussi, nous recommandons de poursuivre les investigations en dosant, en plus, la vitamine D et le Parathormone de la naissance à J7 de vie et préciser les étiologies de ces hypocalcémies.

Bone density among infants of gestational diabetic mothers and macrosomic neonates

Decreased bone density has been found among infants of diabetic mothers and among large-for-gestational-age newborns. To evaluate which etiologies (physical or metabolic effect) have the greatest impact on neonatal bone density. A case-control study was conducted that included two study groups: one comprising 20 appropriate-for-gestational-age (AGA) infants of gestational diabetic mothers (IGDM) and matched controls, and the other comprising 20 macrosomic infants (birth weight > 4 kg) and matched controls. Bone density was examined along the tibia bone using quantitative ultrasound that measured speed of sound. Bone density among the group of macrosomic infants was significantly lower than among the control group (2,976 vs. 3,120 m/s respectively, p < 0.005). No differences in bone density were found between infants of diabetic mothers and their controls (3,005 vs. 3,043 m/s respectively, p = 0.286). Low bone density was predicted only by birth weight (for every increase of 100 g) (OR 1.148 [CI 1.014-1.299], p = 0.003). Bone density was found to be low among macrosomic newborn infants, whereas among AGA-IGDM infants bone density was similar to that of the control group. These findings strengthen the hypothesis that reduced fetal movements secondary to fetal macrosomia constitute the mechanism for reduced bone density.

Association of cord plasma leptin with birth size in term newborns

BACKGROUND

Leptin is secreted from adipose tissue and plays an important role in obesity. Recent studies have shown that the relationship between Leptin and body fat mass may have ethnic differences. The purpose of our study was to investigate the relationship between venous umbilical cord plasma Leptin and anthropometric markers in term healthy Taiwanese newborns.

METHODS

Umbilical venous plasma samples were obtained from 98 term neonates (48 males and 50 females) and leptin Levels were analyzed by enzyme-linked immunosorbent assay.

RESULTS

Umbilical cord plasma Levels of leptin were significantly higher in the female neonates than in males (p<0.001). The large-for-gestationaL age and appropriate-for-gestational age newborns had significantly higher Leptin cord plasma levels than the small-for-gestational age newborns (p<0.01 and p<0.05, respectively). In both male and female neonates, umbilical Leptin Levels showed significant positive correlations with birth weight and birth Length. Multiple Linear regression analysis revealed that birth weight was the only significant predictor of umbilical cord plasma Leptin levels in both male and female neonates. However, the slopes of the regressions between Leptin and birth weight in male and female neonates were not different.

CONCLUSION

In Taiwanese healthy term neonates, leptin umbilical cord plasma Levels are associated with sex and birth weight of the neonate. The relationship between Leptin and birth weight may differ among different ethnic groups. These findings imply that the relationship between leptin and body fat mass may develop early in life.

Diabetes in rat pregnancy alters renal calcium and magnesium reabsorption and bone formation in adult offspring

AIMS/HYPOTHESIS

We tested the hypothesis that diabetes in pregnancy can result in the in-utero reprogramming of renal calcium and magnesium handling and of bone formation in the offspring, which persists into adulthood.

METHODS

Male offspring of streptozotocin-treated diabetic rats (OD rats) and of control non-diabetic animals (OC rats) were investigated as neonates and at 8, 12 and 16 weeks of age.

RESULTS

Compared with OC rats, urinary calcium and magnesium output was significantly reduced in OD rats at every age studied; Na+ and K+ outputs were unaffected. The renal expression of proteins involved in the tubular reabsorption of calcium (calcium ATPase, calbindin-D28k and epithelial calcium channel) was increased in OD animals compared with that in OC animals. Additionally, we observed that adult OD rats had lower trabecular and higher cortical femoral bone volumes, explained by deposition of bone on the endosteal surface.

CONCLUSIONS/INTERPRETATION

These data show that diabetes in pregnancy has profound effects on male offspring in terms of renal tubular calcium and magnesium reabsorption and the normal pattern of bone formation. These effects persist into adulthood. Such long-lasting effects of diabetes on kidney and the skeleton were not suspected and could have important implications for the health of children born to diabetic women.

Intrauterine programming of urinary calcium and magnesium excretion in children born to mothers with insulin dependent diabetes mellitus

BACKGROUND

Offspring of diabetic rats have reduced urinary calcium and magnesium excretion compared with offspring of controls; these differences persist up to 16 weeks after birth, a time equivalent to young adulthood in humans.

OBJECTIVES

To test the hypothesis that urinary calcium and magnesium excretion would be lower in children born to mothers with insulin dependent diabetes mellitus (ChMIDDM) than those born to non-diabetic mothers.

METHODS

Concentrations of calcium, magnesium, sodium, and creatinine were measured in first void spot urine samples collected from 45 (28 male; median age 9.6 years) ChMIDDM and 127 (58 male; median age 11.3 years) controls. Analysis of covariance was used to test for differences in urinary calcium to creatinine ratios (UCa/Cr), magnesium to creatinine ratios (UMg/Cr), and log sodium to creatinine ratios (logUNa/Cr) between controls and ChMIDDM after allowing for the effects of sex and age.

RESULTS

UCa/Cr (difference -0.10, 95% confidence interval (CI) -0.19 to -0.01; p = 0.03) and UMg/Cr (difference -0.15, 95% CI -0.22 to -0.08; p<0.0001) were lower in ChMIDDM than controls. However, logUNa/Cr did not differ between ChMIDDM and controls (difference -0.14, 95% CI -0.33 to 0.05; p = 0.1). The daily estimated intake of magnesium, sodium, and protein were significantly higher and that of calcium non-significantly higher in ChMIDDM than controls. In ChMIDDM, UCa/Cr and UMg/Cr were not related to diabetic control of mothers.

CONCLUSIONS

Results of this study provide the first evidence that in humans, as in rats, there is modification of renal Ca and Mg handling in ChMIDDM, which persists well into childhood.

Bone mineralization and growth are enhanced in preterm infants fed an isocaloric, nutrient-enriched preterm formula through term

BACKGROUND

Because recent data on the effects of mineral concentrations in preterm infant formula on bone mineralization are lacking, recommendations for the mineral content of preterm infant formula differ greatly between committees.

OBJECTIVE

The goal of the study was to assess the effects of an isocaloric, nutrient-enriched preterm formula, which was fed from the age when full enteral feedings were tolerated through expected term, on bone mineralization in preterm infants.

DESIGN

We conducted a prospective, randomized, double-blind study in healthy, preterm infants (gestational age of 28-32 wk) who were fed either a control preterm formula (n=20) or an isocaloric, nutrient-enriched preterm formula (n=21) until 3 mo of age (ie, approximate expected term). Serum calcium indexes were taken throughout the study, and bone mass was determined by using dual-energy X-ray absorptiometry at hospital discharge and expected term.

RESULTS

A total of 37 infants (experimental formula, n=19; control formula, n=18) completed the study. Compared with control subjects, infants fed the experimental formula had 25% and 40% higher intakes of calcium and phosphorus, respectively. Serum calcium, phosphorus, osteocalcin, and alkaline phosphatase concentrations and urinary collagen type I cross-linked N-telopetide concentrations were not significantly different between the groups at any time point. The bone mineral content of infants fed the experimental formula was 23% (P=0.039) and 35% (P=0.002) higher at hospital discharge and expected term, respectively.

CONCLUSIONS

Bone mineralization at hospital discharge and expected term was significantly higher in preterm infants fed the isocaloric, nutrient-enriched formula than in those fed control formula. Continuation of the experimental formula beyond hospital discharge, through expected term, further improved bone mineralization.

Bone speed of sound in infants of mothers with gestational diabetes mellitus

OBJECTIVE

Bone strength in infants of mothers with gestational diabetes mellitus (IGDM) was reported to be either decreased or unaltered. However, no report using quantitative ultrasound measurement of speed of sound (QUS-SOS) for bone strength assessment has been published. The aim of the present study was to assess bone strength by QUS-SOS measurements in IGDM in comparison to healthy matched full-term infants.

DESIGN

Nineteen IGDM and 18 healthy controls participated in the study. Postnatal tibial bone SOS was measured by Sunlight Omnisense.

RESULTS

Mean birth weight (BW) of IGDM (3,587.6+/-148.6 g) was higher compared to the control infants (3,311.1+/-74.5 g), but this difference was not statistically significant. Mean bone SOS was significantly lower in IGDM (2,976.7+/-27.2 m/sec) compared to the control infants (3,093.3+/-23.6 m/sec; p <0.003). There was a significant negative correlation between bone SOS and BW in all the study participants (r = -0.32, p <0.025). No significant difference in BW and bone SOS was noted between infants with postnatal hypoglycemia and normoglycemia. There was no correlation between maternal HbA1c during pregnancy and neonatal bone SOS.

CONCLUSIONS

Bone strength was significantly decreased in IGDM compared to healthy controls. Neonates with higher BW had lower bone SOS. Since mechanical strain is a potent stimulation for bone formation and strength, it is suggested that the reduced bone strength in IGDM may also be the result of reduced intrauterine fetal mobility due to maternal gestational diabetes mellitus.

Decreased bone ultrasound velocity in large-for-gestational-age infants

BACKGROUND

Bone speed of sound is a measure of bone breakability. There are few reports on bone mineral content in large for gestational age infants; most of them in infants of diabetic mothers. There are no data on bone speed of sound in large for gestational age infants of nondiabetic mothers.

OBJECTIVE

To test the hypothesis that large for gestational age infants of nondiabetic mothers have lower bone speed of sound than appropriate for gestational age infants.

DESIGN/METHODS

Bone speed of sound was measured within the first 96 hours of life at the right tibial midshaft in 25 singleton large for gestational age infants of non diabetic mothers and compared to appropriate for gestational age controls.

RESULTS

Bone speed of sound measured in large for gestational age infants of nondiabetic mothers was lower than in controls.

CONCLUSIONS

Large for gestational age infants of nondiabetic mothers have lower bone speed of sound than controls.

ATP dependent Ca2+ transport across basal membrane of human syncytiotrophoblast in pregnancies complicated by intrauterine growth restriction or diabetes

Neonates born after pregnancies complicated by diabetes or intrauterine growth restriction (IUGR) have increased incidence of hypocalcaemia. Furthermore, IUGR is associated with reduced bone mineralization in infancy and osteoporosis in adult life. We tested the hypothesis that placental calcium transport is altered in these pregnancy complications. Transport of calcium into syncytiotrophoblast basal plasma membrane (BM) vesicles was studied by rapid filtration and protein expression of Ca(2+) ATPase by Western blot. In IUGR Ca(2+) ATPase activity was increased by 48 per cent (n=13; P< 0.05) whereas protein expression was 15 per cent lower (n=13; P< 0.05) than in controls (n=16). Basal membrane ATP dependent calcium transport was unaltered in gestational diabetes (GDM) but increased by 54 per cent in insulin dependent diabetes (IDDM) compared to controls (P< 0.05; n =14). Diabetes did not affect Ca(2+) ATPase expression in BM. We have previously shown that the mid-molecular fragment of parathyroid hormone related peptide (PTHrP midmolecule) stimulates BM Ca(2+) ATPase in vitro. PTHrP midmolecule concentrations in umbilical cord plasma were measured using radioimmunoassay. The concentrations in umbilical cord plasma were increased in IUGR, but unaltered in diabetes. In conclusion, placental calcium pump is activated in IUGR and IDDM, which may be secondary to increased foetal calcium demand. We speculate that PTHrP midmolecule may be one mechanism for activating BM Ca(2+) ATPase in IUGR.

Effects of prematurity, intrauterine growth status, and early dexamethasone treatment on postnatal bone mineralisation

AIM

To examine the hypothesis that, apart from prematurity, intrauterine growth status (expressed as gestational age specific birth weight standard deviation scores), neonatal factors, and duration of dexamethasone treatment influence bone mineralisation in early infancy.

METHODS

In this prospective study, groups consisted of 15 preterm small for gestational age infants (SGA group) and 43 preterm appropriate for gestational age infants (AGA group). A reference group contained 17 term infants. Body size is known to affect bone mineral content (BMC), therefore postnatal bone mineralisation was measured when the study infants and controls had attained a similar body size. Bone mineral density (BMD) and BMC were determined by dual energy x ray absorptiometer of the lumbar spine (L2-L4).

RESULTS

Both preterm groups had significantly lower BMC and BMD than the weight matched term reference group, but no difference was found in BMC and BMD between preterm SGA and AGA infants. In stepwise regression analysis, bone area, duration of dexamethasone treatment, weight at examination, and weight gain per week were the most significant factors, explaining 54% of the variance of the BMC values.

CONCLUSION

In particular, weight at examination, prematurity, and possibly dexamethasone treatment, but not intrauterine growth status, affect postnatal bone mineralisation.

Perinatal metabolism of vitamin D

During pregnancy, maternal serum concentrations of 25-hydroxyvitamin D, the circulating form of vitamin D, correlate with dietary vitamin D intake. Maternal serum concentrations of 1,25-dihydroxyvitamin D, the hormonal circulating and active form of vitamin D, are elevated during pregnancy; 1,25-dihydroxyvitamin D is synthesized mainly by the decidual cells of the placenta and allows for increased calcium absorption. The fetus is entirely dependent on the mother for its supply of 25-hydroxyvitamin D, which is believed to cross the placenta. Hypocalcemia and increased parathyroid hormone secretion induce synthesis of 1,25-dihydroxyvitamin D after birth in both full-term and preterm neonates. Nevertheless, serum concentrations of 25-hydroxyvitamin D are a rate-limiting factor in the synthesis of 1,25-dihydroxyvitamin D. In vitamin D-replete infants, circulating 1,25-dihydroxyvitamin D concentrations are higher than those observed in older infants. In countries where dairy products are not routinely supplemented with vitamin D, maternal vitamin D supplementation during pregnancy is necessary. However, there is no indication for the use of pharmacologic doses of vitamin D or its metabolites in the perinatal period.

Factors affecting newborn bone mineral content: in utero effects on newborn bone mineralization

Several factors have been found recently to have a significant impact on newborn bone mineral content (BMC) and developing fetal bone. Recently we showed that maternal vitamin D deficiency may affect fetal bone mineralization. Korean winter-born newborn infants had extremely low serum 25-hydroxyvitamin D (25-OHD), high serum cross-linked carboxy-terminal telopeptide of type I collagen (ICTP; a bone resorption marker), and markedly lower (8 %) total body BMC than summer-born newborn infants. Infant total body BMC was positively correlated with cord serum 25-OHD and inversely correlated with ICTP, which was also negatively correlated with vitamin D status. In three separate studies on North American neonates we found markedly lower (8-12 %) BMC in summer newborn infants compared with winter newborn infants, the opposite of the findings for Korean neonates. The major reason for the conflicting BMC results might be the markedly different maternal vitamin D status of the North American and Korean subjects. Recently, we found evidence of decreased bone formation rates in infants who were small-for-gestational age (SGA) compared with infants who were appropriate-for-gestational age; we reported reduced BMC, cord serum osteocalcin (a marker of bone formation) and 1,25-dihydroxyvitamin D (the active metabolite of vitamin D), but no alterations in indices of fetal bone collagen metabolism. In theory, reduced utero-placental blood flow in SGA infants may result in reduced transplacental mineral supply and reduced fetal bone formation. Infants of diabetic mothers (IDM) have low BMC at birth, and infant BMC correlated inversely with poor control of diabetes in the mother, specifically first trimester maternal mean capillary blood glucose concentration, implying that factors early in pregnancy might have an effect on fetal BMC. The low BMC in IDM may be related to the decreased transplacental mineral transfer. Cord serum ICTP concentrations were higher in IDM than in control subjects, implying increased intrauterine bone resorption. BMC is consistently increased with increasing body weight and length in infants. Race and gender differences in BMC appear in early life, but not at birth. Ethanol consumption and smoking by the mother during pregnancy affect fetal skeletal development.

Macrosomia revisited: ponderal index and leptin delineate subtypes of fetal overgrowth

OBJECTIVES

We sought to reanalyze the concept of fetal macrosomia with regard to the ponderal index and to investigate the role of insulin, insulinlike growth factor I, leptin, and maternal factors on birth size in a population of infants with nondiabetic mothers.

STUDY DESIGN

Venous cord blood levels of insulin, insulinlike growth factor I, insulinlike growth factor binding protein 3, and leptin were measured in 28 large-for-gestational-age and 21 appropriate-for-gestational-age newborns.

RESULTS

Large-for-gestational-age newborns can be divided into symmetric and asymmetric subtypes according to the ponderal index. Mean leptin concentrations in cord blood were significantly higher in asymmetric than in symmetric large-for-gestational-age newborns (P =.01). A positive correlation was observed between leptin and the ponderal index (r = 0.53, P =.001) and between leptin and insulin concentrations in cord blood (r = 0.53, P =.008).

CONCLUSION

Our results strongly suggest that macrosomia should not be classified on the basis of birth weight and gestational age alone. We also show that asymmetric macrosomic infants with nondiabetic mothers have abnormal leptin and insulin concentrations.

Methods for measuring body composition in newborns--a comparative analysis

The complexity of nutritional support in infants now makes it necessary to use body-composition methods for accurate nutritional assessment. For this goal a variety of methods of determining body composition have been introduced in research on human nutrition. The purpose of this paper is to review the background and to describe the precision of established techniques, focusing on the results obtained in newborns and infants. The ideal method for assessing newborns' and infants' body composition should be non-invasive, reproducible, accurate, and also relatively inexpensive. In addition, we summarize in this paper data on body composition obtained in normal and pathological newborns by using dual X-ray absorptiometry, one of the reference techniques.