Thinness at birth and insulin resistance in adult life

Determinants of birthweight: gender based analysis

The objective of this cross sectional study is to look at determinants of birth weight and their association with the gender of the baby in 2,795 full term children living in the occupied Palestinian territory, derived from a stratified random sample of 2,994 households in the West Bank and 2,234 households in the Gaza Strip. The response rate was 85%. Multivariable analysis using analysis of variance for mixed models showed that sex and birth order, maternal age and education and to a lesser extent region were determinants of birth weight for all children. The effect of maternal education on birth weight differed for female and male infants, tending to be relatively unchanged for male infants and with mean birth weights increasing with maternal education in female infants. The effect of birth order differed by maternal age, with mean birth weight increasing with maternal age for first and second births; but being unaffected by maternal age for infants of birth order greater than two. We conclude that birth weight is influenced by common biological determinants across cultures, but is also influenced by social, ethnic, and environmental factors that are culture specific, of which some might be gender related.

Obesity and household roles: gender and social class in Morocco

Often referred to as the developing world's new burden of disease, obesity constitutes a major and growing health epidemic in Morocco, in particular for women (22% of women versus 8% of men). Through an analysis of qualitative data, I demonstrate how gender roles influence obesity risk in the Moroccan context. Current social and economic theories, including the nutrition transition theory, are inadequate in explaining the persistent gender differentials in health status across time and place. I suggest that Moroccan women's higher prevalence of obesity is predominantly the outcome of different risks acquired from their distinct roles. In the Moroccan context, we can gain insight into how men and women divide household labour and how the overall non-egalitarian nature of social roles may deleteriously affect women's health. I hypothesise that marital status, age and socioeconomic status determine Moroccan women's household roles and help to explain why women are more likely to be obese than men. The main findings support this hypothesis and demonstrate the interactive relationship between culture and structure in influencing obesity risk.

Peri-implantation and late gestation maternal undernutrition differentially affect fetal sheep skeletal muscle development

Poor prenatal nutrition is associated with a greater risk of adult glucose intolerance and insulin insensitivity in the offspring. Skeletal muscle is the primary tissue for glucose utilization, and insulin resistance in muscle is the earliest identifiable abnormality in the pre-diabetic patient. We investigated the effect of early and late gestation undernutrition on structure and markers of growth and glucose metabolism regulation in the fetal triceps brachii (TB, slow- and fast-twitch myofibres) and soleus (slow-twitch myofibres) muscles. Pregnant sheep were fed 100% nutrient requirements (C, n = 8) or a restricted diet peri-implantation (PI, n = 9; 40%, 1-31 days gestation (dGA) (term approximately 147)) or in late gestation (L, n = 6; 50%, 104-127 dGA). At 127 +/- 1 dGA we measured myofibre and capillary density in the fetal TB and soleus muscles, and mRNA levels in the TB of insulin receptor (InsR), glucose transporter-4 (GLUT-4) and type 1 insulin-like growth factor receptor (IGF-1R). Total myofibre and capillary densities were lower in the TB, but not the soleus, of PI and L fetuses. The predominant effect in the L group was on slow-twitch myofibres. In TB, InsR, GLUT-4 and IGF-1R mRNA levels were greater in L group fetuses. Our finding of reduced myofibre density is consistent with a redistribution of resources at the expense of specific peripheral tissues by early and late gestation undernutrition which may be mediated by a decrease in capillary density. The increase in key regulatory components of glucose uptake following late gestation undernutrition may constitute a short-term compensation to maintain glucose homeostasis in the face of fewer type I (insulin-sensitive) myofibres. However, together these adaptations may influence the risk of later metabolic disease and thus our findings have implications for future strategies aimed at improving maternal diet.

A life course of adiposity and dementia

Adiposity, commonly measured as body mass index (BMI), may influence or be influenced by brain structures and functions involved in dementia processes. Adipose tissue changes in degree and intensity over the lifespan, and has been shown to influence brain development in relationship to early and late measures of cognitive function, intelligence, and disorders of cognition such as dementia. A lower BMI is associated with prevalent dementia, potentially due to underlying brain pathologies and correspondingly greater rates of BMI or weight decline observed during the years immediately preceding clinical dementia onset. However, high BMI during mid-life or at least approximately 5-10 years preceding clinical dementia onset may increase risk. The interplay of adiposity and the brain occurring over the course of the lifespan will be discussed in relationship to developmental origins, mid-life sequelae, disruptions in brain structure and function, and late-life changes in cognition and dementia. Characterizing the life course of adiposity among those who do and do not become demented enhances understanding of biological underpinnings relevant for understanding the etiologies of both dementia and obesity and their co-existence.

Independent effects of prematurity on metabolic and cardiovascular risk factors in short small-for-gestational-age children

CONTEXT

Both small-for-gestational-age (SGA) and preterm birth have been associated with an increased incidence of adult cardiovascular disease and diabetes mellitus type 2. However, it is unclear whether preterm birth has an additional effect on cardiovascular risk factors in short children born SGA.

OBJECTIVE

Our objective was to investigate whether prematurity has an independent influence on several cardiovascular risk factors within a population of short SGA children.

DESIGN

A cross-sectional observational study was performed.

PATIENTS

A total of 479 short SGA children (mean age 6.8 yr), divided into preterm (<36 wk) and term (> or =36 wk) children, was included in the study.

OUTCOME MEASURE

Insulin sensitivity, beta-cell function, body composition, and lipid levels were studied in subgroups, and blood pressure (BP), anthropometry at birth and during childhood in the total group.

RESULTS

Preterm SGA children were significantly lighter and shorter at birth after correction for gestational age than term SGA children (P < 0.001) but had a comparable head circumference. In preterm SGA children, we found a significantly higher systolic (P = 0.003) and diastolic BP sd score (P = 0.026), lower percent body fat sd score (P = 0.011), and higher insulin secretion (P = 0.033) and disposition index (P = 0.021), independently of the degree of SGA. Insulin sensitivity, serum lipid levels, muscle mass, and body fat distribution were comparable for preterm and term SGA children.

CONCLUSIONS

Within a population of short SGA children, preterm birth has divergent effects on several cardiovascular risk factors. Whereas preterm SGA children had a higher systolic and diastolic BP, they also had a lower percent body fat and a higher insulin secretion and disposition index than term SGA children.

Adipose Tissue: A Metabolic Regulator. Potential Implications for the Metabolic Outcome of Subjects Born Small for Gestational Age (SGA)

Adipose tissue is involved in the regulation of glucose and lipid metabolism, energy balance, inflammation and immune response. Abdominal obesity plays a key role in the development of insulin resistance because of the high lipolytic rate of visceral adipose tissue and its secretion of adipocytokines. Low birth weight subjects are prone to central redistribution of adipose tissue and are at high risk of developing metabolic syndrome, type 2 diabetes and cardiovascular disease. Intrauterine adipogenesis may play a key role in the fetal origin of the pathogenesis of metabolic syndrome, type 2 diabetes and cardiovascular disease. Therefore, knowledge of the behavior of visceral adipose tissue-derived stem cells could provide a greater understanding of the metabolic risk related to intrauterine growth retardation, with potential clinical implications for the prevention of long-term metabolic alterations.

Influence of primiparity on size at birth, growth, the somatotrophic axis and fertility in dairy heifers

Epidemiological studies in humans suggest that small size at birth is a predictor of some adult diseases. Nutritional constraint experienced in utero may result in fetal adaptations, which alter subsequent body structure and physiology. Size at birth is influenced by maternal age and parity. Most dairy cows are bred for the first time at about 60% of their mature body weight and therefore carry their first pregnancy whilst still growing. We hypothesized that this might alter the nutritional environment in utero and thus influence the development of the calf. This study compared birth size, growth rates and fertility in consecutively born heifer offspring of 45 primiparous (PP) and 71 multiparous (MP) dairy cows on one farm. Measures of the somatotrophic axis (GH, insulin, IGF-I and glucose) were compared in blood samples collected at the start of the first lactation. Offspring of PP cows were significantly smaller at birth (weight, length, height, girth, P<0.01) than those born to MP dams. The ponderal index (weight/height(3)) was similar, showing that growth restriction was proportional. These differences were no longer apparent at 3 months, indicative of early catch up growth. The PP offspring conceived more rapidly during their first service period as nulliparous heifers (P<0.02). They experienced a greater weight loss postpartum (P<0.002) and had lower concentrations of IGF-I and insulin following their first calving (P<0.05). Fertility in the first lactation was, however, similar between the two groups. We conclude that having a primiparous dam resulted in a smaller size at birth and influenced the somatotrophic axis around calving. Fertility was generally better in offspring of PP than MP dams.

Constraint, pathology, and adaptation: how can we tell them apart?

Adaptation is a central concept of modern evolutionary biology, but remains a difficult one nevertheless. Definitions of adaptation are often confounded with definitions of natural selection, rendering them somewhat circular and difficult to operationalize. Williams introduced a definition that avoids such tautology and a strategy for testing adaptive claims against chance as an alternative explanation for design complexity. Gould and Lewontin ([1979]: Proc R Soc Lond B Biol Sci 205:581-598) challenged this strategy for pitting adaptation against a straw alternative, and argued that constraint is often the cause of design complexity. The field of Darwinian medicine has underscored the fact that adaptation can also be difficult to discriminate from pathology, which can also produce design complexity. We suggest that an updated version of Williams' strategy is to consider any claim of adaptation against constraint and pathology as alternatives. We use an example drawn from the intersection of human reproductive ecology and developmental biology to illustrate how this updated strategy can be applied. Where we can generate distinct predictions for the three alternative hypotheses, constraint, pathology, and adaptation, we have a better situation in which to evaluate adaptive claims with a real possibility of falsification. We view this strategy as an improvement over Williams' original suggestion, but not as a definitive strategy. Further advances, however, will likely also be based on a sound understanding of the concept of adaptation and the identification of the strongest competing alternatives to it.

Regulation of skeletal muscle PPAR delta mRNA expression in twins

Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors regulating the expression of genes involved in lipid and glucose metabolism in a complex and to some extent unknown manner. Our aim was to study the impact of different factors on PPARdelta mRNA expression in human skeletal muscle on one side, and the impact of PPARdelta mRNA expression on these factors, including glucose and lipid metabolism, aerobic capacity, fibre type composition and lipid profile, on the other side. PPARdelta mRNA levels were quantified by real-time PCR in muscle biopsies from 176 young and elderly monozygotic and dizygotic twins. Young twins had significantly increased PPARdelta mRNA levels compared with elderly twins. A 2 h hyperinsulinaemic euglycaemic clamp had no significant effect on PPARdelta mRNA levels. Biometric models were calculated for basal PPARdelta mRNA expression to estimate the degree of genetic versus environmental influence. In both young and elderly twins there was a substantial genetic component influencing basal PPARdelta mRNA levels. In a regression model, the muscle PPARdelta mRNA expression was correlated to birth weight, central adiposity and age. The level of PPARdelta mRNA was also positively correlated with markers for oxidative muscle fibres. However, in this apparently healthy study population, we found no correlations between PPARdelta mRNA expression and aerobic capacity, lipid profile or glucose and lipid metabolism. In conclusion, we provide evidence that mRNA expression of PPARdelta in human skeletal muscle is under genetic control but also influenced by factors such as age, birth weight and central adiposity.

Free/dissociable insulin-like growth factor (IGF)-I, not total IGF-I, correlates with growth response during growth hormone treatment in children born small for gestational age

CONTEXT

IGF-I plays an important role in pre- and postnatal growth. Its serum levels are regulated by metabolic and genetic factors. Mean total IGF-I in short, small for gestational age (SGA) children is reduced, but within the normal range. Free/dissociable IGF-I is the bioactive form of IGF-I.

OBJECTIVES

The aim of the study was to investigate changes in free IGF-I during GH treatment in short SGA children and to evaluate whether free IGF-I levels contribute to predicting first-year growth response and/or adult height. DESIGN, SETTING, AND INTERVENTION: We conducted a randomized, double-blind GH dose-response study with a GH dose of either 1 mg/m(2).d (group A) or 2 mg/m(2).d (group B). Free IGF-I, total IGF-I, and IGF binding protein (IGFBP)-3 were determined at baseline, after 1 and 5 yr, at stop, and 6 months after GH discontinuation.

PATIENTS

We studied 73 (46 male) short SGA children (36 group A) with a baseline mean age of 7.7 (2.2) yr and a mean GH duration of 8.2 (2.1) yr.

MAIN OUTCOME MEASURES

Untreated SGA children had a mean free IGF-I sd score (SDS) of -0.2 (1.2), not related to total IGF-I. During GH therapy, free IGF-I significantly increased to 1.6 (0.7) SDS, as did total IGF-I and IGFBP-3 [2.0 (0.8) and 1.3 (0.9), respectively]. Multiple regression analysis showed that baseline free IGF-I and IGFBP-3 were negatively correlated with adult height SDS, whereas baseline bone age delay, target height SDS, baseline height SDS, and GH dose were positively correlated. Free IGF-I was also negatively correlated with first-year growth response.

CONCLUSIONS

Circulating baseline free IGF-I and IGFBP-3 were better predictors for adult height in GH-treated SGA children than total IGF-I, or total IGF-I to IGFBP-3 ratio. This suggests a possible role for free IGF-I measurement in predicting the effect of GH therapy in short SGA children.

Why might South Asians be so susceptible to central obesity and its atherogenic consequences? The adipose tissue overflow hypothesis

The rates of coronary disease have accelerated dramatically amongst South Asians, driven to an important extent by the atherogenic dyslipidemia and type 2 diabetes that have become so common amongst them. These precursors of vascular disease appear at lower absolute amounts of adipose tissue in South Asians than in whites. In this paper, we set out a new hypothesis--the adipose tissue overflow hypothesis--to account for these findings. The adipose tissue mass within our bodies can be divided into three different compartments: superficial subcutaneous adipose tissue, deep subcutaneous adipose tissue and visceral adipose tissue. The superficial subcutaneous adipose tissue compartment is the primary compartment, is present throughout the body, and constitutes the vast majority of the adipose tissue in the lower limb. With energy excess, the secondary adipose tissue compartments--the deep subcutaneous (mainly upper body) and the visceral adipose tissue compartments--become more prominent. Superficial subcutaneous adipose tissue is relatively inert metabolically, whereas the other two compartments are characterized by higher transmembrane fatty acid flux rates and thus are more closely linked to dyslipidemia and dysglycemia. We hypothesize that the superficial subcutaneous adipose tissue compartment is larger in whites than in South Asians. If so, as obesity develops, South Asians exhaust the storage capacity of their superficial subcutaneous adipose tissue compartment before whites do and that is why they develop the metabolic complications of upper body obesity at lower absolute masses of adipose tissue than white people.

Reduced maternal corticosteroid-binding globulin and cortisol levels in pre-eclampsia and gamete recipient pregnancies

OBJECTIVE

To measure and contrast maternal cortisol and corticosteroid-binding globulin (CBG) levels in pregnancies with normal outcomes, pre-eclampsia, intrauterine growth restriction (IUGR) and in gamete recipients.

STUDY DESIGN

Prospective study of 93 women at high risk of pre-eclampsia, including gamete recipients (n = 22) and 33 controls. Plasma total and free cortisol and CBG were measured every 2 weeks from 16 weeks' gestation until delivery.

RESULTS

Forty-two per cent of the high-risk group had complications, including pre-eclampsia (n = 11), gestational hypertension (n = 16) and small-for-gestational-age (SGA) neonates (n = 12). There were no complications in the controls. In all groups, plasma CBG concentrations increased progressively across gestation (P < 0.05), in parallel to total cortisol, but fell significantly from 36 weeks' gestation onwards, with a corresponding rise in free cortisol concentrations. In pre-eclampsia and gestational hypertension, plasma CBG, and total and free cortisol concentrations were lower from 36 weeks onwards (P < 0.05). In IUGR, plasma CBG concentrations were suppressed from 28 weeks' gestation until delivery (P < 0.05), but with no significant difference in plasma total and free cortisol. Gamete recipients had significantly lower plasma CBG from 20 weeks' gestation onwards, and plasma total and free cortisol were reduced at 24 and 32 weeks onwards, respectively.

CONCLUSIONS

Maternal plasma CBG, total and free cortisol concentrations are reduced in pre-eclampsia/gestational hypertension, and markedly reduced in gamete recipients. Low CBG may be due to reduced synthesis or enhanced inflammation-driven degradation. Low maternal cortisol may be due to a lack of placental corticotropin-releasing hormone or reduced maternal ACTH, driving cortisol production. Low maternal cortisol may influence the foetal hypothalamic-pituitary-adrenal axis and disease patterns later in life following complicated pregnancy.

Gender-based differences in endocrine and reproductive toxicity

Basic differences in male versus female reproductive physiology lead to differentials in their respective susceptibilities to chemical insult as evidenced by a variety of observations. As individuals undergo maturation from prenatal sex differentiation through pubertal development, these susceptibilities become evident in each gender. Gender bias occurs in human populations for birth defects and for the acceleration of the onset of puberty. Data on gender bias in fetal origins of adult disease are more complex. Useful for understanding reproductive and developmental effects in animals are a range of standard methodological procedures including the multigeneration testing protocol and the National Toxicology Program (NTP) Reproductive Assessment by Continuous Breeding (RACB). Examples of gender-based differences seen in reproductive toxicology studies on animals include teratogenic effects, reproductive effects in adult males and females, and effects on pubertal development. It is clear that gender biases exist in the reproductive and developmental toxicity, and the biological bases for these differences need to be explored.

Epidemiology, genes and the environment: lessons learned from the Helsinki Birth Cohort Study

Nonoptimal growth during fetal life and infancy is associated with an increased risk of coronary heart disease and type 2 diabetes later in life. This early pattern of growth is associated with an increased disease risk especially when followed by a relative gain in body size later in childhood. Genetic factors are closely involved in growth and disease pathogenesis and gene-early life environmental interactions will be described affecting adult health outcomes. This overview will primarily focus upon findings from the Helsinki Birth Cohort Study consisting of 15846 subjects born 1924-1944 on whom growth data and information on adult health are available.

Experimental IUGR and later diabetes

It is widely accepted that an association exists between the intrauterine environment in which a fetus grows and develops and the subsequent development of type 2 diabetes. Any disturbance in maternal ability to provide nutrients and oxygen to the fetus can lead to fetal intrauterine growth restriction (IUGR). Here we will review IUGR in rodent models, in which maternal metabolism has been experimentally manipulated to investigate the molecular basis of the relationship between IUGR and development of type 2 diabetes in later life, and the identification of the molecular derangements in specific metabolically - sensitive organs/tissues.

Altered skeletal muscle fiber composition and size precede whole-body insulin resistance in young men with low birth weight

CONTEXT

Low birth weight (LBW), a surrogate marker of an adverse fetal milieu, is linked to muscle insulin resistance, impaired insulin-stimulated glycolysis, and future risk of type 2 diabetes. Skeletal muscle mass, fiber composition, and capillary density are important determinants of muscle function and metabolism, and alterations have been implicated in the pathogenesis of insulin resistance.

OBJECTIVE

The aim of this study was to investigate whether an adverse fetal environment (LBW) induces permanent changes in skeletal muscle morphology, which may contribute to the dysmetabolic phenotype associated with LBW.

DESIGN AND SUBJECTS

Vastus lateralis muscle was obtained by percutaneous biopsy from 20 healthy 19-yr-old men with birth weights at 10th percentile or lower for gestational age (LBW) and 20 normal birth weight controls, matched for body fat, physical fitness, and whole-body glucose disposal. Myofibrillar ATPase staining was used to classify muscle fibers as type I, IIa, and IIx (formerly type IIb), and double immunostaining was performed to stain capillaries (LBW, n=8; normal birth weight, n=12).

RESULTS

LBW was associated with increased proportion of type IIx fibers (+66%; P=0.03), at the expense of decreased type IIa fibers (-22%; P=0.003). No significant change was observed in proportion of type I fibers (+16%; P=0.11). In addition, mean area of type IIa fibers was increased (+29%; P=0.01) and tended to be increased for type I fibers as well (+17%; P=0.08). Capillary density was not significantly different between groups.

CONCLUSION

Alterations in fiber composition and size may contribute to development of type 2 diabetes in individuals with LBW.

Small for gestational age: short stature and beyond

Depending on the definitions used, up to 10% of all live-born neonates are small for gestational age (SGA). Although the vast majority of these children show catch-up growth by 2 yr of age, one in 10 does not. It is increasingly recognized that those who are born SGA are at risk of developing metabolic disease later in life. Reduced fetal growth has been shown to be associated with an increased risk of insulin resistance, obesity, cardiovascular disease, and type 2 diabetes mellitus. The majority of pathology is seen in adults who show spontaneous catch-up growth as children. There is evidence to suggest that some of the metabolic consequences of intrauterine growth retardation in children born SGA can be mitigated by ensuring early appropriate catch-up growth, while avoiding excessive weight gain. Implicitly, this argument questions current infant formula feeding practices. The risk is less clear for individuals who do not show catch-up growth and who are treated with GH for short stature. Recent data, however, suggest that long-term treatment with GH does not increase the risk of type 2 diabetes mellitus and the metabolic syndrome in young adults born SGA.

The effects of maternal protein restriction on the growth of the rat fetus and its amino acid supply

Maternal protein deficiency causes fetal growth retardation which has been associated with the programming of adult disease. The growth of the rat fetus was examined when the mothers were fed on diets containing 180, 90 and 60 g protein/kg. The numbers of fetuses were similar in animals fed on the 180 and 90 g protein/kg diets but the number was significantly reduced in the animals fed on the 60 g protein/kg diet. The fetuses carried by the mothers fed on the 90 g protein/kg diet were 7·5% heavier than those of mothers fed on 180 g protein/kg diet on day 19 of gestation, but by day 21 the situation was reversed and the fetuses in the protein-deficient mothers were 14% smaller. Analysis of the free amino acids in the maternal serum showed that on day 19 the diets containing 90 and 60 g protein/kg led to threonine concentrations that were reduced to 46 and 20% of those found in animals fed on the control (180 g/kg) diet. The other essential amino acids were unchanged, except for a small decrease in the branched-chain amino acids in animals fed on the 60 g protein/kg diet. Both low-protein diets significantly increased the concentrations of glutamic acid+glutamine and glycine in the maternal serum. On day 21 the maternal serum threonine levels were still reduced by about one third in the group fed on the 90 g protein/kg diet. Dietary protein content had no effect on serum threonine concentrations in non-pregnant animals. Analysis of the total free amino acids in the fetuses on day 19 showed that feeding the mother on a low-protein diet did not change amino acid concentrations apart from a decrease in threonine concentrations to 45 and 26% of the control values at 90 and 60 g protein/kg respectively. The results suggest that threonine is of particular importance to the protein-deficient mother and her fetuses. Possible mechanisms for the decrease in free threonine in both mother and fetuses and the consequences of the change in amino acid metabolism are discussed.

Maternal food restriction in the second half of pregnancy affects vascular function but not blood pressure of rat female offspring

Food restriction during pregnancy in rats induces intrauterine growth retardation with consequences persisting into adulthood. In the present study we have investigated the hypothesis that malnutrition in pregnant rats may lead to altered cardiovascular function in adult female offspring. Perinatal growth retardation was induced by a 50 % reduction of normal dietary intake in rats during the second half of pregnancy. Systolic and diastolic blood pressure values and heart rate were recorded in conscious female offspring (100 d old) using a femoral artery probe. No significant differences in heart rate, or in systolic and diastolic blood pressures were recorded between control offspring and offspring of nutritionally deprived rats. In order to ascertain whether cardiovascular variables in the offspring were influenced by lactation, subgroups of offspring from food-restricted dams were fostered with lactating dams fed on a normal diet. Blood pressure and heart rate were also found to be normal in these offspring. The rise in blood pressure associated with NO inhibition was similar in all groups. Isolated resistance artery function was assessed in vitro in offspring (100–120 d old) of a second group of semi-starved dams. Small mesenteric arteries from these animals showed reduced endothelium-dependent relaxation (to acetylcholine and bradykinin), but enhanced sensitivity to exogenous NO (sodium nitroprusside). We conclude that food restriction during the second half of pregnancy and/or lactation does not induce hypertension in adult offspring, but may effect subtle changes in vascular function.

Raised saturated-fat intake worsens vascular function in virgin and pregnant offspring of streptozotocin-diabetic rats

Adult offspring of severely diabetic pregnant rats are insulin resistant and display cardiovascular dysfunction. When pregnant they develop mild hyperglycaemia. Diets high in saturated fat have been implicated in the development of cardiovascular disease and vascular dysfunction. In the present study we have determined vascular function in small mesenteric arteries from offspring of normal (OC) and diabetic (OD) rats fed standard chow and offspring of diabetic rats fed a diet high in saturated fats (OD-HF) from weaning to adulthood, and throughout their subsequent pregnancies. OD rats displayed an increased sensitivity to noradrenaline (P < 0·05) and impaired sensitivity to the endothelium-dependent vasodilator, acetylcholine. The component of acetylcholine-induced relaxation attributable to endothelium-derived hyperpolarizing factor was reduced in OD-HF rats. Pregnant OD rats also demonstrated impaired maximum relaxation to acetylcholine (pregnant OD rats v. pregnant OC rats P < 0·05). In pregnant OD-HF rats noradrenaline sensitivity was enhanced and endothelium-dependent relaxation further reduced (pregnant OD-HF rats v. pregnant OC rats P < 0·001). The isoprostane, 8-epi-prostaglandin F2α, a marker of oxidative stress, was increased in pregnant OD rats (pregnant OD rats v. pregnant OC rats P < 0·001) and further increased in pregnant OD-HF rats (pregnant OD-HF rats v. pregnant OD rats P < 0·05). We conclude that a high-saturated-fat diet leads to deterioration in specific components of vascular function in OD rats. When pregnant, vascular function of OD-HF rats is further compromised. Pregnancy in the OD rats is associated with a striking increase in a marker of oxidative stress, which increases further if the saturated fat intake is raised.

Obesity epidemic in India: intrauterine origins?

The epidemic of ‘obesity’ in India is not appreciated because BMI underestimates the adiposity of Indians. Specific adiposity measurements are necessary for recognition of the adiposity of ‘thin’ Indians. The origin of this adiposity is only beginning to be understood. In addition to a possible genetic predisposition, intrauterine ‘programming’ might be responsible, although in the ‘thrifty phenotype’ hypothesis the adiposity of the ‘thin’ fetus has not been appreciated. Dutch men who faced ‘winter hunger’ during the first trimester of their in utero life have become more obese as adults. Low birth weight predicts central obesity in some studies, including studies in urban children. It has also been shown that small and thin Indian newborns (weight 2·7?kg and ponderal index 2·4?kg\m3) have poor muscle and visceral mass but higher adiposity for a given weight compared with white Caucasian babies. This body composition is influenced by maternal adiposity before pregnancy and by aspects of maternal nutritional intake and circulating nutrient concentrations during pregnancy. There are no strong paternal determinants of adiposity at birth. Adiposity may be an integral part of the orchestrated adjustments made to support ‘brain preservation’ during intrauterine growth, because brain tissue is predominantly fat. Increased nutrition in the face of a genetic predisposition or multigenerational undernutrition increases maternal insulin resistance in late pregnancy and promotes fetal adiposity even in absence of marked hyperglycaemia. Further research is necessary to define the role of specific nutrients and metabolites in the intrauterine processes promoting adiposity before maternal interventions to curtail the epidemic of obesity and diabetes are planned.

Developmental programming of health and disease

The environment encountered in fetal and neonatal life exerts a profound influence on physiological function and risk of disease in adult life. Epidemiological evidence suggests that impaired fetal growth followed by rapid catch-up in infancy is a strong predictor of obesity, hypertension, non-insulin-dependent diabetes and CHD. Whilst these associations have been widely accepted to be the product of nutritional factors operating in pregnancy, evidence from human populations to support this assertion is scarce. Animal studies clearly demonstrate that there is a direct association between nutrient imbalance in fetal life and later disease states, including hypertension, diabetes, obesity and renal disease. These associations are independent of changes in fetal growth rates. Experimental studies examining the impact of micro- or macronutrient restriction and excess in rodent pregnancy provide clues to the mechanisms that link fetal nutrition to permanent physiological changes that promote disease. Exposure to glucocorticoids in early life appears to be an important consequence of nutrient imbalance and may lead to alterations in gene expression that have major effects on tissue development and function. Epigenetic mechanisms, including DNA methylation, may also be important processes in early-life programming.

Management of the child born small for gestational age through to adulthood: a consensus statement of the International Societies of Pediatric Endocrinology and the Growth Hormone Research Society

OBJECTIVE

Low birth weight remains a major cause of morbidity and mortality in early infancy and childhood. It is associated with an increased risk of health problems later in life, particularly coronary heart disease and stroke. A meeting was convened to identify the key health issues facing a child born small for gestational age (SGA) and to propose management strategies.

PARTICIPANTS

There were 42 participants chosen for their expertise in obstetrics, peri- and neonatal medicine, pediatrics, pediatric and adult endocrinology, epidemiology, and pharmacology.

EVIDENCE

Written materials were exchanged, reviewed, revised, and then made available to all. This formed the basis for discussions at the meeting. Where published data were not available or adequate, discussion was based on expert clinical opinions.

CONSENSUS PROCESS

Each set of questions was considered by all and then discussed in plenary sessions with consensus and unresolved issues identified. The consensus statement was prepared in plenary sessions and then edited by the group chairs and shared with all participants.

CONCLUSIONS

The diagnosis of SGA should be based on accurate anthropometry at birth including weight, length, and head circumference. We recommend early surveillance in a growth clinic for those without catch-up. Early neurodevelopment evaluation and interventions are warranted in at-risk children. Endocrine and metabolic disturbances in the SGA child are recognized but infrequent. For the 10% who lack catch-up, GH treatment can increase linear growth. Early intervention with GH for those with severe growth retardation (height sd score, <-2.5; age, 2-4 yr) should be considered at a dose of 35-70 microg/kg x d. Long-term surveillance of treated patients is essential. The associations at a population level between low birth weight, including SGA, and coronary heart disease and stroke in later life are recognized, but there is inadequate evidence to recommend routine health surveillance of all adults born SGA outside of normal clinical practice.

Coexistence of maternal central adiposity and child stunting in Mexico

OBJECTIVE

To assess the coexistence of maternal adiposity and child stunting (CS) in Mexico, estimate its national prevalence and identify the associated socio-demographic factors.

METHODS

A secondary analysis from the Mexican Nutrition Survey 1999, a nationally representative survey, was conducted. Mother and children subsamples were matched and a total of 6225 mother/child pairs were obtained. Stunting was defined as height-for-age z-scores <-2.0. Maternal body mass index (BMI) was classified according to World Health Organization recommended cutoff points. Waist-to-hip ratio (WHR) was calculated by dividing waist by hip circumferences. Logistic regression models were fitted to explore the coexistence of CS and maternal central adiposity (MCA) (WHR> or =0.85) while controlling for biological and socio-demographic factors.

RESULTS

A total of 5974 pairs had complete information. MCA coexisted with CS in 6.2% of the mother/child pairs. The phenomenon was more prevalent in rural locations, in the south region and among indigenous families (14.5, 12.5 and 23.9%). After controlling for child age and maternal BMI, a 78% increase in the likelihood of CS was related to maternal WHR > or =0.85 (odds ratio (OR)=1.78, 95% confidence interval (CI)=1.53, 2.10). After controlling for maternal height, the magnitude of the OR decreased (OR=1.33, 95%CI=1.13, 1.57), but remained significant. Therefore, it is suggested that women with a WHR approximately 1 have had twice the probability of having a stunted child as those with a WHR of 0.65.

CONCLUSION

Although MCA and CS are two conditions frequently regarded as result of opposite determinants, our observation suggests that this is not necessarily the case, particularly in populations undergoing the nutrition transition. MCA was associated not only to chronic diseases, but also to child stunting.

Risk factors for diabetes mellitus type 2 and metabolic syndrome are comparable for previously growth hormone-treated young adults born small for gestational age (sga) and untreated short SGA controls

CONTEXT

Low birth weight might increase risk of diabetes mellitus type 2 and metabolic syndrome (MS). GH has insulin-antagonistic properties. Therefore, long-term follow-up of GH-treated children born small for gestational age (SGA) is important.

OBJECTIVE AND PATIENTS

The objective of the study was to evaluate insulin sensitivity (Si) and disposition index (DI), all components of the MS and IGF-I and IGF binding protein (IGFBP)-3 levels in 37 previously GH-treated young SGA adults in comparison with 25 untreated short SGA controls.

RESULTS

GH-treated subjects were 22.3 (1.7) yr old. Mean duration of GH treatment had been 7.3 (1.3) yr. Mean period after discontinuation was 6.5 (1.4) yr. Si and DI were comparable for GH-treated and untreated SGA subjects. Fasting glucose and insulin levels increased during GH treatment but recovered after discontinuation. Body mass index, waist circumference, high-density lipoprotein cholesterol levels, and triglycerides were equivalent. Systolic and diastolic blood pressure and cholesterol were significantly lower in GH-treated subjects. Thirty-two percent of untreated controls vs. none of the GH-treated subjects had an increased blood pressure. GH-induced rises in IGF-I and IGFBP-3 levels had completely recovered after GH stop.

CONCLUSION

At 6.5 yr after discontinuation of long-term GH treatment, Si, DI, fasting levels of glucose and insulin, body mass index, waist circumference, and IGF-I and IGFBP-3 levels were equivalent for GH-treated and untreated young SGA adults. Systolic and diastolic blood pressure and serum cholesterol were even lower in GH-treated subjects. These data are reassuring because they suggest that long-term GH treatment does not increase the risk for diabetes mellitus type 2 and MS in young adults.

Nutritional challenges during development induce sex-specific changes in glucose homeostasis in the adult sheep

The early-life environment has implications for risk of adult-onset diseases, such as glucose intolerance, insulin insensitivity, and obesity, effects that may occur with or without reduced birth weight. We determined the consequences of nutrient restriction in early gestation and early postnatal life and their interactions on postnatal growth, body composition, and glucose handling. Ewes received 100% (C, n = 39) or 50% nutritional requirements (U, n = 41) from 1 to 31 days gestation and 100% thereafter. Male and female offspring (singleton/twin) from C and U ewes were then fed either ad libitum (CC n = 22, UC n = 19) or to reduce body weight to 85% of target from 12 to 25 wk of age (CU n = 17, UU n = 22) and ad libitum thereafter. At 1.5 and 2.5 yr, glucose handling was determined by area under the curve (AUC) for glucose and insulin concentrations following intravenous glucose (0.5 g/kg body wt). Insulin sensitivity was determined at 2.5 yr following intravenous insulin (0.5 IU/kg). In females, postnatal undernutrition reduced (P < 0.05) glucose AUC at both ages, regardless of prenatal nutrition. Postnatal undernutrition did not affect insulin secretion in females but enhanced insulin-induced glucose disappearance in singletons. Poor early postnatal growth was associated with increased fat in females. In males, glucose tolerance was unaffected by undernutrition despite changes in insulin AUC dependent on age, treatment, and single/twin birth. Nutrition in early postnatal life has long-lasting, sex-specific effects on glucose handling in sheep, likely due, in females, to enhanced insulin sensitivity. Improved glucose utilization may aid weight recovery but have negative implications for glucose homeostasis and body composition over the longer term.

Hyperglycemia in extremely low birth weight infants in a predominantly Hispanic population and related morbidities

OBJECTIVE

This study describes the incidence, correlates and subsequent morbidities of hyperglycemia, a highly prevalent condition in extremely low birth weight (ELBW) infants.

STUDY DESIGN

A retrospective chart review of 169 infants with birth weight (BW)<1000 g was conducted. Hyperglycemia was defined as plasma glucose level > or =150 mg/dl during the first 2 weeks of life. Data were analyzed by logistic regression, multivariate analysis and Fisher exact test.

RESULTS

Overall, 88% of the study sample developed hyperglycemia in the first 2 weeks of life. Both gestational age (GA) (odds ratio (OR) 0.11, 95% confidence interval (CI)=0.01-0.89) and chorioamnionitis (OR 0.10, 95% CI=0.01-0.64) were inversely associated with hyperglycemia, whereas BW, sepsis and postnatal steroid exposure were not. After adjusting for GA, BW and postnatal steroids, hyperglycemia was associated with a statistically significant increase in retinopathy of prematurity (ROP) (OR 4.6, 95% CI 1.12-18.9). No association was found with bronchopulmonary dysplasia, intraventricular hemorrhage, death or prolonged hospital stay.

CONCLUSION

Lower GA was identified as the main factor associated with hyperglycemia in ELBW infants during the first 2 weeks of life. Hyperglycemia was associated with an increased incidence of ROP; further studies need to determine if this association is causal.

Impact of parental smoking on diabetes, hypertension and the metabolic syndrome in adult men and women in the San Antonio Heart Study

AIMS/HYPOTHESIS

In the San Antonio Heart Study (SAHS) we investigated the effects of exposure to parental smoking on diabetes, hypertension and the metabolic syndrome in adult offspring aged 25-64 years.

SUBJECTS, MATERIALS AND METHODS

In a retrospective cohort study the parental smoking status during childhood, obtained through a postal questionnaire, determined a person's exposure status. Logistic regression models were used to calculate odds ratios for diabetes, hypertension and the metabolic syndrome at the baseline SAHS examination in relation to parental smoking status. All models were adjusted for age, sex, ethnicity, education years, personal smoking status (current, former or never-smoker), BMI and, in the case of diabetes, a family history of diabetes.

RESULTS

Of the 2,371 participants who returned the mailing, 44.5, 5.4, 20.0 and 30.1% reported that their father, mother, both or neither parent smoked, respectively. Participants reporting that both parents smoked were 1.60 (95% CI: 0.95-2.69) times more likely to have diabetes, 1.55 (95% CI: 1.05-2.28) times more likely to have hypertension, and 1.46 (95% CI: 1.01-2.10) times more likely to have the metabolic syndrome than participants reporting that neither parent smoked during their childhood. Odds ratios, after limiting the population to younger participants (i.e. <or=50 years) to reduce survivor bias, were 2.53 (95% CI: 1.21-5.31), 1.29 (95% CI: 0.78-2.16), and 1.41 (95% CI: 0.89-2.22) for diabetes, hypertension and the metabolic syndrome, respectively.

CONCLUSIONS/INTERPRETATION

These results provide evidence that early exposure to parental smoking may be associated with an increased risk of diabetes and perhaps hypertension and the metabolic syndrome.

Intimal thickness of the coronary arteries in low-birthweight infants

BACKGROUND

Intimal thickening is considered to be an early manifestation of developing atherosclerosis in healthy young adults and children. Low birthweight correlates with increased incidence of cardiovascular diseases.

AIM

To test the hypothesis that low birthweight is associated with relatively thickened intima at birth.

METHODS

The coronary arteries of 175 children were screened from serial cross-sections for maximal intimal thickening and measured morphometrically. The area of intima and media and the length of internal elastic lamina were measured. The intimal to medial area ratio and calculated thicknesses of intima were used in statistical comparisons. Only children who died within 30 d after birth (n=111) were included.

RESULTS

There was a significant positive correlation between intimal thickness and birthweight in low-birthweight children (p<0.006). Neither the relative thickness of the intima nor the ratio of intimal to medial area increased with increasing growth restriction. The sum of the thicknesses of arterial media and intima had a significant positive correlation with birthweight in these infants.

CONCLUSION

Intimal thickness present at birth in small-for-date children does not seem to be an aetiological factor for the increased risk of coronary heart disease later in life.

Wheezing and eczema in relation to infant anthropometry: evidence of developmental programming of disease in childhood

Early life factors and, in particular, the fetal environment have been suggested to programme risk of allergic disease in later life. Diversion of nutrients away from immune organs towards the brain, a process termed brain sparing, has been proposed as a mechanism underpinning this association. The study population was a group of 256 seven-year old children from the UK recruited from two general practitioner surgeries. Historical anthropometric data from birth to age three and current anthropometry were assessed as predictors of parent-reported wheeze and eczema. Eczema at seven years was not related to any anthropometric indices at birth or during infancy. A smaller head circumference at 10-15 days of age was noted in children with current wheeze at age 7 years (P = 0.018) and this relationship persisted after adjustment for current anthropometry and confounders. Comparison of children with head circumference over 36.5 cm at 10-15 days with those with head circumference under 35.5 cm, showed reduced odds for wheeze at 7 years (OR 0.12, 95% CI 0.03-0.44, P(trend) = 0.009). These data suggest that factors that determine fetal growth may be associated with wheeze in childhood and support the developmental origins of health and disease hypothesis. Brain sparing does not appear to play a role in this early life programming.

Fatness at birth predicts adult susceptibility to ovarian suppression: an empirical test of the Predictive Adaptive Response hypothesis

Poor fetal environments are thought to produce adaptive changes in human developmental trajectories according to the Predictive Adaptive Response hypothesis. Although many studies have demonstrated correlations between indicators of fetal environment and negative adult health outcomes, the adaptive significance of these outcomes is unclear. Our study explicitly tests the adaptive nature of fetal programming in humans. We show that differences in nutritional status at birth are associated with adaptive differences in the sensitivity of adult ovarian function to energetic stress. Women who were born as relatively fat babies do not exhibit ovarian suppression in response to moderate levels of physical activity at adulthood, in contrast to women who were born as skinnier babies. The levels of estradiol in women born in the highest tertile of ponderal index (an indicator of neonatal nutritional status) were 37% and 46% higher, respectively, than levels of estradiol in women born in the low and middle ponderal index tertiles. These findings suggest that fetal programming of reproductive function results in developmentally plastic, but essentially adaptive, shifts in set points of ovarian response to energetic stress, such that women who were gestated under conditions of energetic constraint show greater sensitivity to energetic stress in adulthood. Our results have practical implications in terms of behavioral strategies for reducing the risk of breast cancer. We suggest that the amount of activity necessary to reduce levels of estrogen, which may in turn reduce cancer risk, can depend on a woman's nutritional status at birth.

Assessing newborn body composition using principal components analysis: differences in the determinants of fat and skeletal size

Background

Birth weight is a composite of skeletal size and soft tissue. These components are likely to have different growth patterns. The aim of this paper is to investigate the association between established determinants of birth weight and these separate components.

Methods

Weight, length, crown-rump, knee-heel, head circumference, arm circumference, and skinfold thicknesses were measured at birth in 699 healthy, term, UK babies recruited as part of the Exeter Family Study of Childhood Health. Corresponding measurements were taken on both parents. Principal components analysis with varimax rotation was used to reduce these measurements to two independent components each for mother, father and baby: one highly correlated with measures of fat, the other with skeletal size.

Results

Gestational age was significantly related to skeletal size, in both boys and girls (r = 0.41 and 0.52), but not fat. Skeletal size at birth was also associated with parental skeletal size (maternal: r = 0.24 (boys), r = 0.39 (girls) ; paternal: r = 0.16 (boys), r = 0.25 (girls)), and maternal smoking (0.4 SD reduction in boys, 0.6 SD reduction in girls). Fat was associated with parity (first borns smaller by 0.45 SD in boys; 0.31 SD in girls), maternal glucose (r = 0.18 (boys); r = 0.27 (girls)) and maternal fat (r = 0.16 (boys); r = 0.36 (girls)).

Conclusion

Principal components analysis with varimax rotation provides a useful method for reducing birth weight to two more meaningful components: skeletal size and fat. These components have different associations with known determinants of birth weight, suggesting fat and skeletal size may have different regulatory mechanisms, which would be important to consider when studying the associations of birth weight with later adult disease.

Insulin sensitivity and insulin secretion at birth in intrauterine growth retarded infants

AIM

To study insulin sensitivity, secretion and relation of insulin levels with birth weight and ponderal index in intrauterine growth retarded (IUGR) infants at birth.

METHODS

We studied 30 IUGR and 30 healthy newborns born at term by vaginal delivery in Jipmer, Pondicherry, India. Cord blood was collected at the time of delivery for measurement of plasma glucose and insulin.

RESULTS

When compared with healthy newborns, IUGR newborns had lower plasma glucose levels (mean 2.3+/-0.98 versus 4.1+/-0.51 mmol/L, p<0.001); lower plasma insulin levels (mean 4.5+/-2.64 versus 11.03+/-1.68 microU/L, p<0.001); higher insulin sensitivity calculated using G/I ratio (mean 11.6+/-5.1 versus 6.7+/-0.31, p<0.001), HOMA IS (mean 5.5+/-6.0 versus 0.53+/-0.15, p<0.001), and QUICKI (mean 0.47+/-0.12 versus 0.34+/-0.02, p<0.001); and decreased pancreatic beta-cell function test measured as I/G (mean 0.10+/-0.037 versus 0.15+/-0.006, p<0.001). A positive correlation was identified between insulin levels and birth weight in both the healthy control group (r2 = 0.17, p = 0.024) and IUGR group (r2 = 0.13, p = 0.048). However correlation of insulin levels with ponderal index was much more confident in both healthy control (r2 = 0.90, p<0.001) and IUGR groups (r2 = 0.28, p = 0.003). Insulin status correlated both with birth weight and ponderal index more confidently in control group than in IUGR group.

CONCLUSION

At birth, IUGR infants are hypoglycaemic, hypoinsulinaemic and display increased insulin sensitivity and decreased pancreatic beta-cell function. Insulin levels correlate with ponderal index much more confidently than with birth weight.

Impaired insulin secretion after prenatal exposure to the Dutch famine

OBJECTIVE

We previously reported that people prenatally exposed to famine during the Dutch Hunger Winter of 1944-1945 have higher 2-h glucose concentrations after an oral glucose tolerance test in later life. We aimed to determine whether this association is mediated through alterations in insulin secretion, insulin sensitivity, or a combination of both.

RESEARCH DESIGN AND METHODS

We performed a 15-sample intravenous glucose tolerance test in a subsample of 94 normoglycemic men and women from the Dutch Famine Birth Cohort. We used the disposition index, derived as the product of insulin sensitivity and the first-phase insulin response to glucose as a measure of the activity of the beta-cells adjusted for insulin resistance. In all analyses, we adjusted for sex and BMI.

RESULTS

Glucose tolerance was impaired in people who had been prenatally exposed to famine compared with people unexposed to famine (difference in intravenous glucose tolerance test K(g) value -21% [95% CI -41 to -4]). People exposed to famine during midgestation had a significantly lower disposition index (-53% [-126 to -3]) compared with people unexposed to famine. Prenatal exposure to famine during early gestation was also associated with a lower disposition index, but this difference did not reach statistical significance.

CONCLUSIONS

Impaired glucose tolerance after exposure to famine during mid-gestation and early gestation seems to be mediated through an insulin secretion defect.

Does estrogen affect the development of abnormal vascular function in offspring of rats fed a low-protein diet in pregnancy?

It is established that there are gender-related differences in the effects on offspring blood pressure induced by maternal protein restriction in animal studies. Since such effects may depend on estrogen levels, we hypothesized that lower estrogen would induce an earlier onset of hypertension caused by maternal under-nutrition. Wistar rats were fed a diet containing either 18% (C) or 9% (R) casein throughout pregnancy. Half of the offspring in both C and R groups were ovariectomized on day 50 (CX, RX), and the other half underwent a sham operation (CO, RO). On d 175, offspring were killed for small artery reactivity and histologic investigation. Birth weight and later growth were not significantly different between C and R. RX had higher systolic blood pressure than CX on d125, but no difference was seen between RO and CO. On d 175, systolic blood pressure was higher in R than in C, whether or not ovariectomized. Dilator responses to acetylcholine and bradykinin in small mesenteric arteries were significantly attenuated in RX, although responses to SNP and isoprenaline showed no attenuation in R. The ratio of coronary peri-vascular fibrosis to total vascular area was higher in R, and the fibrosis became prominent in ovariectomized rats. These findings suggest that estrogen plays an important role in limiting the elevation of offspring blood pressure induced by maternal under-nutrition, possibly via BK-mediated mechanisms. The processes may underlie gender and life course patterns of hypertension and also the developmental origins of this disease.

The association of low birthweight and chronic renal failure among Medicaid young adults with diabetes and/or hypertension

OBJECTIVE

The purpose of this study was to assess the effect of low birthweight on chronic renal failure among young Medicaid patients with diabetes and/or hypertension.

METHODS

The study included Caucasian and African American young adults, aged 18-50, who enrolled in the Medicaid program from 1993 to 1996 in South Carolina and were diagnosed with diabetes and/or hypertension. The odds of chronic renal failure by low birthweight (< 2,500 grams) was estimated using logistic regression.

RESULTS

Of the 7,505 Medicaid patients with diabetes and/or hypertension, 179 (2.4%) were diagnosed with chronic renal failure. These patients were younger (mean age of 33.9 vs. 37.6, p = 0.0024) and had a higher proportion of low birthweight (15.1% vs. 11.4%, p = 0.07) compared with the 7,326 patients without renal failure. The odds ratio of chronic renal failure for low birthweight was significantly higher compared with normal birthweight (2,500-3,999 grams) (adjusted odds ratio [OR] 1.56, 95% confidence interval [95% CI] 1.0, 2.4). The association between low birthweight and chronic renal failure was stronger among the 888 patients with both diabetes and hypertension (OR 2.6, 95% Cl 1.3, 5.7) than the 1,812 diabetes or the 4,805 hypertension patients.

CONCLUSIONS

The odds of chronic renal failure by low birthweight was highest in patients with both diabetes and hypertension, suggesting that the mechanism(s) involved in the disease progression to chronic renal failure may have a fetal early life origin.

[Accuracy of ultrasonic fetal weight estimation using head and abdominal circumference and femur length]

INTRODUCTION

Former investigations have shown that the accuracy of fetal weight estimation is significantly higher if several ultrasonic fetal parameters are measured, because the total body mass depends on the size of fetal head, abdominal circumference and femur length. The aim of this investigation was to establish the best regression model, that is a number of combinations of fetal parameters providing the most accurate fetal weight estimation in utero in our population.

MATERIAL AND METHODS

This prospective study was carried out at the Gynecology and Obstetrics Clinic of the Clinical Center Novi Sad. It included 270 pregnant women with singleton pregnancies within 72 hours of delivery who underwent ultrasound measurements of the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL).

RESULTS

In regard to fetal weight estimation formulas, the deviation was lowest using regression models that simultaneously analyzed four fetal parameters (0. 55%) with SD +/- 7.61%. In these models the estimates of fetal weights were within +/- 5% of actual birth weight in 48.89%, and within +/- 10% of actual birth weight in 81.48%. Good results were also obtained using AC, FL measurements (0.92% +/- 8.20) as well as using AC, HC, FL measurements (-1.45% +/- 7.81). In our sample the combination of AC and FL model gave better results in fetal weight estimation (0.92 +/- 8.20%) than the one using BPD and AC (2.97 +/- 8.83%). Furthermore, the model using parameters AC, HC and FL showed a lower error in accuracy (-1.45 +/- 7.81%) than the model using BPD, AC and FL (2.51 +/- 7.82%).

CONCLUSION

This investigation has confirmed that the accuracy of fetal weight estimation increases with the number of measured ultrasonic fetal parameters. In our population the greatest accuracy was obtained using BPD, HC, AC and FL model. In cases when fast estimation of fetal weight is needed, AC, HC, FL model may be appropriate, but if fetal head circumference cannot be measured (amnion rupture and/or fetal head already in the pelvis) the AC, FL model should be used.

Long-term metabolic consequences of being born small for gestational age

During the last 15 years, a number of long-term health risks associated with reduced fetal growth have been identified, including cardiovascular diseases and the insulin-resistance syndrome or one of its components: hypertension, dyslipidemia, impaired glucose tolerance or Type 2 diabetes. A common feature of these conditions is the presence of high insulin levels, which are thought to play a pathogenic role. However, despite abundant data in the literature, it is still difficult to trace the pathway by which fetal events, environmental or not, may lead to the increased morbidity later in life. To explain this association, several hypotheses have been proposed pointing to the critical role of either a detrimental fetal environment or a genetic susceptibility, or indicating interaction of both. Clearly, not all subjects born small for gestational age are at the same risk of developing these complications. It appears that individuals at particular risk are those who were thin at birth and had a subsequent catch-up in body mass index, irrespective of the degree of adiposity in adulthood. It is suggested that this particular dynamic change in adiposity has a critical role in the development of long-term metabolic complications. Therefore, it is important to consider the relative impact of early postnatal events in relation to fetal growth to the diseases risk throughout life in forming health policy strategies towards eventual early interventions.

Does birth weight predict childhood diet in the Avon longitudinal study of parents and children?

STUDY OBJECTIVE

Low birth weight predicts cardiovascular disease in adulthood, and one possible explanation is that children with lower birth weight consume more fat than those born heavier. Therefore, the objective of this study was to investigate associations between birth weight and childhood diet, and in particular, to test the hypothesis that birth weight is inversely related to total and saturated fat intake.

DESIGN

Prospective cohort study.

SETTING

South west England.

PARTICIPANTS

A subgroup of children enrolled in the Avon longitudinal study of parents and children, with data on birth weight and also diet at ages 8, 18, 43 months, and 7 years (1152, 998, 848, and 771 children respectively).

MAIN RESULTS

Associations between birth weight and diet increased in strength from age 8 to 43 months, but had diminished by age 7 years. Fat, saturated fat, and protein intakes were inversely, and carbohydrate intake was positively associated with birth weight at 43 months of age, after adjusting for age, sex, and energy intake. After adjustment for other confounders, all associations were weakened, although there was still a suggestion of a relation with saturated fat (-0.48 (95% CI -0.97, 0.02) g/day per 500 g increase in birth weight. Similar patterns were seen in boys and girls separately, and when the sample was restricted to those with complete data at all ages.

CONCLUSIONS

A small inverse association was found between birth weight and saturated fat intake in children at 43 months of age but this was not present at 7 years of age. This study therefore provides little evidence that birth weight modifies subsequent childhood diet.

Small for Gestational Age and the Metabolic Syndrome: Which Mechanism Is Suggested by Epidemiological and Clinical Studies?

The metabolic and cardiovascular complications associated with in-utero undernutrition have been identified during the past 10 years. Reduced fetal growth is independently associated with an increased risk of development of cardiovascular diseases, the insulin-resistance syndrome or one of its components (i.e., hypertension, dyslipidaemia, impaired glucose tolerance and type 2 diabetes). Insulin resistance appears to be a key component underlying these metabolic complications. Although the mechanism remains unclear, several pieces of evidence support an active role of adipose tissue in the emergence of insulin resistance (an abnormal growth pattern and repartition, hypersensitivity to catecholamines, regulation of leptin and adiponectin secretion and modulation of peroxisome proliferator-activated receptor gamma). Among individuals born SGA, those who are more at risk of gaining excess adiposity are those who are thin at birth following a period of fetal growth restriction. This period of undernutrition is followed by a neonatal period of catch-up growth and renutrition. This pattern induces important modifications in adipose tissue, with long-term consequences, among which is a high risk of early development of insulin resistance. Not all individuals born SGA will show such modifications in adipose tissue, meaning that not all of those born SGA are at risk of insulin resistance and diabetes. From a broader point of view, several hypotheses have been proposed over the past 10 years to explain this unexpected association between being born SGA and the later development of disease. Each of them points to a detrimental fetal environment, to a genetic susceptibility or to interactions between these two components playing a critical role in this context. Although not confirmed, the hypothesis suggesting that this association could be the consequence of genetic/environmental interactions remains the most attractive.

Glucose tolerance at age 58 and the decline of glucose tolerance in comparison with age 50 in people prenatally exposed to the Dutch famine

AIMS/HYPOTHESIS

People who were small at birth have an increased risk of type 2 diabetes in later life. People who were in utero during the Dutch famine had decreased glucose tolerance and raised insulin concentrations at age 50. We aimed to evaluate whether prenatal famine exposure leads to more rapid progression of impaired glucose/insulin homeostasis with increasing age.

METHODS

We performed an OGTT in 702 men and women at age 50 and in 699 men and women at age 58, all born as term singletons immediately before, during or after the 1944-1945 Dutch famine.

RESULTS

People who had been exposed to famine in utero had significantly higher 120-min glucose concentrations at age 58 compared with people who had not been exposed to famine (difference=0.4 mmol/l, 95% CI 0.1 to 0.7, adjusted for sex and BMI). Glucose tolerance deteriorated between the age of 50 and 58. The unadjusted 120-min glucose concentrations rose by 0.2 mmol/l (95% CI 0.0 to 0.4), while 120-min insulin concentrations had increased by 64 pmol/l (95% CI 48 to 82). There were no differences in the rates of glucose and insulin level increase between the famine-exposed group and the unexposed group (p=0.28 for the difference in increase in glucose concentrations and p=0.09 for insulin concentrations).

CONCLUSIONS/INTERPRETATION

Although we confirmed that undernutrition during gestation is linked to decreased glucose tolerance, the effect does not seem to become more pronounced at age 58 as compared with age 50.

What makes a champion?

Variation in human athletic performance is determined by a complex interaction of socio-cultural, psychological, and proximate physiological factors. Human physiological trait variance has both an environmental and genetic basis, although the classic gene-environment dichotomy is clearly too simplistic to understand the full range of variation for most proximate determinants of athletic performance, e.g., body composition. In other words, gene and environment interact, not just over the short term, but also over the lifetime of an individual with permanent effects on the adult phenotype. To further complicate matters, gene and environment may also be correlated. That is, genetically gifted individuals may be identified as children and begin training pulmonary, cardiovascular, and muscle systems at an early critical age. This review covers evidence in support of a genetic basis to human athletic performance, with some emphasis on the recent explosion of candidate gene studies. In addition, the review covers environmental influences on athletic performance with an emphasis on irreversible environmental effects, i.e., developmental effects that may accrue during critical periods of development either before conception (epigenetic effects), during fetal life (fetal programming), or during childhood and adolescence. Throughout, we emphasize the importance of gene-environment interaction (G x E) as a means of understanding variation in human physiological performance and we promote studies that integrate genomics with developmental biology.

Developmental origins of diabetes: the role of oxidative stress

The "thrifty phenotype" hypothesis proposes that the fetus adapts to an adverse intrauterine milieu by optimizing the use of a reduced nutrient supply to ensure survival, but, by favoring the development of certain organs over that of others, this leads to persistent alterations in the growth and function of developing tissues. This concept has been somewhat controversial; however, recent epidemiological, clinical, and animal studies provide support for the developmental origins of disease hypothesis. Underlying mechanisms include reprogramming of the hypothalamic-pituitary-adrenal axis, islet development, and insulin signaling pathways. Emerging data suggest that oxidative stress and mitochondrial dysfunction may also play critical roles in the pathogenesis of type 2 diabetes in individuals who were growth retarded at birth.

Neonatal programming of body weight regulation and energetic metabolism

Programming is an epigenetic phenomena by which nutritional, hormonal, physical psychological and other stressful events acting in a critical period of life, such as gestation and lactation, modifies in a prolonged way certain physiological functions. This process was preserved by natural selection as an important adaptive tool for survival of organisms living in nutritional impaired areas. So, malnutrition during gestation and lactation turns on different genes that provide the organism with a thrifty phenotype. In the case of an abundant supply of nutrients after this period, those organisms that were adapted to a low metabolic waste and higher energy utilization will be in a higher risk of developing metabolic diseases, such as obesity, hyperlipidemia, diabetes mellitus and hypertension. The kind of malnutrition, duration and intensity are important for the type of programming obtained. We discuss some of the hormonal and metabolic changes that occur in gestation or lactation, when malnutrition is applied to the mothers and their offspring. Some of these changes, such as an increase of maternal triiodothyronine (T(3)), leptin and glucocorticoids (GC) and decrease in prolactin are by itself potential programming factors. Most of these hormones can be transfer through the milk that has other important macronutrients composition changes in malnourished dams. We discuss the programming effects of some of these hormones upon body weight and composition, leptin, thyroid and adrenal functions, and their effects on liver, muscle and adipose tissue metabolism and the consequences on thermogenesis.