The intrauterine environment is a strong determinant of glucose tolerance during the neonatal period, even in prematurity

Early supplementation of folate and vitamin B12 improves insulin resistance in intrauterine growth retardation rats

BACKGROUND

Insulin sensitivity is changed during the neonatal period in small for gestational age (SGA) infants. Yet, the interventional strategies are still limited. We aimed to investigate the effects of supplementation with high folate and vitamin B12 diets in the early postnatal period on the changes in insulin sensitivity in an intrauterine growth retardation (IUGR) rat model.

METHODS

IUGR rat model was established by both low-protein diet feeding and daily diet restriction. High folate and vitamin B12 diet was supplied in IUGR as nutritional interventional group (IUGR-I), otherwise, the non-intervened IUGR group (IUGR-NI). In this study, male rats were studied in order to avoid hormonal and gender influence. At 21, 60 and 120 days, fasting plasma glucose, insulin, triglyceride, cholesterol, and homocysteine levels were measured among the control, IUGR-I, and IUGR-NI groups. Pearson analysis was used to evaluate the correlation between homocysteine and fasting blood glucose, insulin, HOMA-IR, triglyceride, and cholesterol levels.

RESULTS

We established IUGR rat model by both low protein and restricted diet feeding during pregnancy and the incidence of IUGR pups was 93.33%. There was no difference in fasting glucose, insulin, HOMA-IR, triglyceride and cholesterol levels between the control, the IUGR-NI and the IUGR-I group at day 21. At day 60, insulin, HOMA-IR and triglyceride levels in the IUGR-I group were remarkably lower than those in the IUGR-NI group, but still higher than those in the control group (F=38.34, P=0.02; F=49.48, P=0.02; F=17.93, P<0.001, respectively). At day 120, glucose, insulin, HOMA-IR and Hcy levels in the IUGR-I group were obviously lower than those in the IUGR-NI group, although still higher than those in the control group (F=21.60, P<0.001; F=164.46, P<0.001; F=75.15, P<0.001; F=35.46, P<0.001, respectively). There were no significant differences in triglyceride and cholesterol levels between the IUGR-I group and the control group at day 120. At 120-day, homocysteine in IUGR-I group was highly positively correlated with fasting glucose and HOMA-IR (r=0.863, P=0.006; r=0.725, P=0.042, respectively); Only homocysteine was positively correlated with fasting glucose in IUGR-NI group (r=0.721, P=0.044).

CONCLUSIONS

Early supplementation of folate and vitamin B12 improved insulin resistance and lipid levels in IUGR rats to some extent, along with decreasing homocysteine levels, but not enough to completely repair glucose and lipid metabolism.

The impact of intrauterine and extrauterine weight gain in premature infants on later body composition

BackgroundThe impact of intrauterine and extrauterine growth on later insulin resistance and fat mass (FM) in very low birth weight (VLBW) infants is not well established. The aim of our study was to evaluate the effects of intrauterine and early/late extrauterine growth on later insulin resistance and body composition in VLBW infants from 6 months' corrected age (CA) to 36 months.MethodsProspective measurements of body composition by dual-energy X-ray absorptiometry and insulin resistance by homeostasis model assessment insulin resistance (HOMA-IR) along with other fasting plasma biochemistries were made in 95 VLBW infants at 6, 12, 18, and 24 months' CA and 36 months' postnatal age. Mixed-effect models were used to evaluate the effects of age, sex, maturation status, and Δweight SD score on percentage FM (PFM), FM index (FMI), fat-free mass index (FFMI), and HOMA-IR.ResultsPFM and FMI were negatively associated with a decrease in weight-SD scores from birth to 36 weeks' postmenstrual age (PMA; P=0.001) and from 36 weeks' PMA to 6 months' CA (P=0.003). PFM and FMI were higher in AGA than in small for gestational age (SGA) infants. HOMA-IR was not associated with the Δweight-SD scores in either period.ConclusionsCatch-down growth in terms of weight is associated with persistently lower adiposity but not insulin resistance up to 36 months of age.

Long-term metabolic risk among children born premature or small for gestational age

Accumulating evidence suggests that both the intrauterine environment and growth during early life can influence the development of chronic noncommunicable diseases, such as type 2 diabetes mellitus and cardiovascular disease, in adulthood. Here, we review the available human data supporting increased metabolic risk among children born premature or small for gestational age; the adrenal and pubertal modifications that contribute to this risk; metabolic changes that occur during adolescence and early adulthood; and approaches to potentially modify or decrease risk of metabolic disease. The risks associated with delivery at term or preterm are compared for each period of life. Knowledge of these associations is fundamental for the paediatric community to develop preventive strategies early during postnatal life.

Premature birth and insulin resistance in infancy: A prospective cohort study

OBJECTIVE

This study was done to determine the role of prematurity and other variables to predict insulin sensitivity in infancy.

SUBJECTS AND METHODS

In this prospective study, 36 preterm appropriate for gestational age (AGA), 11 preterm small for gestational age (SGA), and 17 term SGA included as study cohort and 36 term AGA as control cohort. Detailed anthropometry assessment was performed at birth, 3, 6, and 9 months and at 9 months, fasting plasma glucose and serum insulin was done. Insulin resistance was determined by using homeostasis model assessment version 2.

RESULTS

It is found that preterm AGA (mean difference 0.617, 95% confidence interval [CI]; 0.43-0.80, P = 0.0001), preterm SGA (mean difference 0.764, 95% CI; 0.44-1.09, P = 0.0001), and term AGA (mean difference 0.725, 95% CI; 0.49-0.96, P = 0.0001) group had significantly higher insulin resistance than control. There was no significant difference in between preterm SGA and preterm AGA (mean difference 0.147 95% CI; -0.13-0.42, P = 0.927). In multiple regression models, SGA status (β =0.505) was more significant predictor of insulin resistance index than gestational age (β = -0.481), weight-for-length (β =0.315), and ponderal index (β = -0.194).

CONCLUSION

Preterm birth is a risk factor for the future development of insulin resistance which may develop as early as infancy.

Racial Disparities in the Pathogenesis of Type 2 Diabetes and its Subtypes in the African Diaspora: A New Paradigm

The global epidemic of diabetes has extended to the developing countries including Sub-Sahara Africa. In this context, blacks with type 2 diabetes in the African Diaspora continue to manifest 1.5-2 times higher prevalent rates than in their white counterparts. Previous studies have demonstrated that blacks with and without type 2 diabetes have alterations in hepatic and peripheral insulin sensitivity, beta-cell function, and hepatic insulin clearance as well as hepatic glucose dysregulation when compared to whites. In addition, non-diabetic blacks in the African Diaspora manifest multiple metabolic mediators that predict type 2 diabetes and its subtypes. These pathogenic modifiers include differences in subclinical inflammation, oxidative stress burden, and adipocytokines in blacks in the African Diaspora prior to clinical diagnosis. Consequently, blacks in the African Diaspora manifest subtypes of type 2 diabetes, including ketosis-prone diabetes and J type diabetes. Given the diversity of type 2 diabetes in blacks in the African Diaspora, we hypothesize that blacks manifest multiple early pathogenic defects prior to the diagnosis of type 2 diabetes and its subtypes. These metabolic alterations have strong genetic component, which appears to play pivotal and primary role in the pathogenesis of type 2 diabetes and its subtypes in blacks in the African Diaspora. However, environmental factors must also be considered as major contributors to the higher prevalence of type 2 diabetes and its subtypes in blacks in the African Diaspora. These multiple alterations should be targets for early prevention of type 2 diabetes in blacks in the African Diaspora.

Long-term renal consequences of preterm birth

The normal development of the kidney may be affected by several factors, including abnormalities in placental function, resulting in fetal growth restriction, exposure to maternal disease states, including hypertension and diabetes, antenatal steroids, chorioamnionitis, and preterm delivery. After preterm birth, several further insults may occur that may influence nephrogenesis and renal health, including exposure to nephrotoxic medications, postnatal growth failure, and obesity after growth restriction. In this review article, common clinical neonatal scenarios are used to highlight these renal risk factors, and the animal and human evidence on which these risk factors are based are discussed.

Preterm birth and subsequent insulin sensitivity: a systematic review

OBJECTIVE

The incidence of preterm birth is increasing worldwide. Evidence suggests that in later life these children are at increased risk of 'metabolic syndrome', which is itself associated with reduced insulin sensitivity (IS). We carried out a systematic review to examine whether preterm birth is associated with later changes in IS and whether a difference exists between those born small-for-gestational age (SGA) and appropriate-for-gestational age (AGA).

METHODS

We used the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidance to structure our review with a priori data extraction criteria to answer the questions posed and then carried out our literature search. Only papers which included preterm infants in their study population and specifically assessed IS were included. Findings are reported by age group to enable change over the life course to be examined, even though the studies were mostly cross-sectional, observation studies.

RESULTS

We identified and reviewed 26 suitable publications representing 20 separate cohorts, of which 16 had a term control group. The heterogeneity of the methods used to measure IS precluded meta-analysis. In infancy and early childhood there is a measurable association between IS and preterm birth. In later childhood and adulthood the strength of this association reduces, and current body composition becomes the variable most strongly associated with IS.

CONCLUSIONS

There is an association between preterm birth and IS throughout the life course, but the data are conflicting and associations are likely to be affected by the heterogeneity of each study population and multiple confounding factors that may change over time. While the optimal nutritional strategy for preterm infants remains to be determined, standard public health guidance to avoid obesogenic lifestyle factors remains equally important to individuals born preterm.

Early determinants of chronic disease in developing countries

The prevalence of non-communicable diseases (NCDs) is rising in developing countries. The extent to which this is due to a nutritional mismatch in foetal and adult life is unknown however, studies in such countries show that the risk of chronic diseases is increased in low birthweight subjects who become obese adults. Immune dysfunction is also linked to low birthweight. Therefore, in countries where communicable diseases are prevalent, infection may be exacerbated by factors acting in utero. It is also possible that the foetal growth-retarding effects of maternal Human Immunodeficiency Virus (HIV) and malaria infection may contribute to an increased risk of NCDs later in life. Low birthweight and postnatal growth faltering followed by rapid weight gain define subjects who develop NCDs. Dietary interventions at specific time points in the life course may therefore be important for reducing disease risk.

The impact of birth weight and maternal history on acne, hirsutism, and menstrual disorder symptoms in Turkish adolescent girls

The aim of the study was to determine the association between birthweight, maternal medical history and acne, hirsutism, and menstrual disorder symptoms in Turkish adolescent population. Self-administered questionnaires were distributed to all volunteer female students at 15 secondary schools. The subjects' body mass index, birthweight, age at menarche, pattern of menstrual cycle, and presence of acne or hirsutism problems were recorded. Maternal obstetric parameters, menstrual cycle, presence of acne or hirsutism at present and at adolescent period were also asked. The impact of birthweight and maternal history on acne, hirsutism, and menstrual disorder symptoms was evaluated. The results of the study showed that after exclusion of subjects born prematurely, total of 1,309 students filled the questionnaires properly and included in the study. Of these students, 174 had low birthweight (LBW) (<2,500 g), 925 had appropriate (2,500-4,000 g), and 210 had high birthweight (>4,000 g). LBW students had higher incidence of menstrual disorder and acne problems (P = 0.032 and P = 0.011, respectively). Maternal acne and hirsutism problems were significantly often in LBW group. Multivariate analysis showed that LBW was a predictor of acne, hirsutism, and menstrual disorder at adolescent period (P = 0.001; P = 0.01, and 0.02, respectively). In addition, maternal menstrual disorder was also a predictor of menstrual disorder (P = 0.035). We concluded that LBW is a good predictor of acne, hirsutism, and menstrual disorder problems in Turkish adolescent population.

Benefits of supplemented preterm formulas on insulin sensitivity and body composition after discharge from the neonatal intensive care unit

OBJECTIVE

To evaluate body composition and fasting insulin level in preterm infants receiving preterm formulas (higher protein plus docosahexaenoic acid) for longer periods compared with a recent historical cohort receiving these formulas for shorter periods.

STUDY DESIGN

A total of 95 infants fed preterm formula for 6 months or longer (postdischarge formula group) and 87 infants fed preterm formula only during their hospital stay (hospital formula group) were included in this arm of the study.

RESULTS

Bone mineral density, content, and lean mass were not different at 1 year and 2 years. However, in the postdischarge formula group, total fat mass (%) was lower by the second year (19.3% ± 5.3% vs 21.7% ± 4.2%; P < .01), trunk fat was lower by the first year (14.7% ± 5.0% vs 16.9% ± 4.9%; P < .005) and at the second year (14.1% ± 5.7% vs 17.2% ± 4.7%; P < .001), and fasting insulin was lower by the first year (13.2% ± 7.1% vs 17.2% ± 13.6% mIU/L; P = .06) and at the second year (13.6% ± 6.1% vs 26.4% ± 14.2%; P < .001).

CONCLUSION

Preterm infants fed formulas enriched with docosahexaenoic acid may have a better subsequent metabolic profile.

Prematurity and insulin sensitivity

Nowadays, an increased number of premature infants survive. The medical challenge is to reduce their postnatal morbidities with a special focus towards a decrease in metabolic risks. In this manuscript, we will examine available evidence of perinatal, infancy, and childhood consequences of prematurity on insulin sensitivity and glucose homeostasis. Moreover, we add some recent data on how nutritional intervention could modify these risks.

Changes in serum adiponectin levels from birth to term-equivalent age are associated with postnatal weight gain in preterm infants

BACKGROUND

Adiponectin, one of the adipocytokines, is postulated to play a key role in fetal growth, probably enhancing the growth-promoting effect of insulin through insulin-sensitizing action.

OBJECTIVES AND METHODS

To examine how different intrauterine or postnatal growth patterns relate to adiponectin secretion, we measured serum adiponectin concentrations in 30 appropriate-for-gestational-age (AGA) and 19 small-for-gestational-age (SGA) preterm infants on the first day of life and at term-equivalent age.

RESULTS

The serum levels of adiponectin increased significantly in all preterm infants from birth to term-equivalent age. The adiponectin levels at term-equivalent age were significantly higher in the AGA than in the SGA group [mean (SD) 40.4 (12.3) vs. 28.4 (10.4) μg/ml; p < 0.01] after adjustment for gestational age or term-equivalent body weight. The increase in adiponectin levels from birth to term-equivalent age was significantly higher in the AGA than in the SGA group, and was positively correlated with the weight gain rate (g/kg/day) in the combined groups (r = 0.37, p < 0.01). A multiple regression analysis with the adiponectin increase from birth to term-equivalent age as the dependent variable for all the subjects revealed that only weight gain rate was independently associated with the adiponectin increase.

CONCLUSIONS

Our results suggest that the change in serum adiponectin levels may reflect postnatal growth from birth to term-equivalent age in preterm infants.

Effects of birth weight on anti-mullerian hormone serum concentrations in infant girls

CONTEXT

We previously demonstrated that low birth weight (BW) infant girls show increased serum anti-Müllerian hormone (AMH) concentrations and poststimulated estradiol levels compared to normal-BW infants, suggesting an altered follicular development. However, the impact of high BW on reproductive function is less known.

OBJECTIVE

To evaluate the effect of BW on AMH, we determined the concentrations of this hormone in low-BW, normal-BW, and high-BW female infants during the first 3 months of life.

DESIGN

Twenty-seven low-BW, 29 normal-BW, and 28 high-BW infant girls were studied. We measured serum gonadotropins, steroid hormones, AMH, glucose, insulin, free fatty acids, IGF-I, and adiponectin in a fasting blood sample. In addition, in a subgroup of normal-BW (n = 23) and high-BW infants (n = 10), a GnRH analog leuprolide acetate test was performed.

RESULTS

Serum concentrations of AMH were higher in low-BW and high-BW infants compared to normal-BW infants (P = 0.028 and 0.022, respectively). In addition, in high-BW infants, adiponectin concentrations were lower (P = 0.018), and poststimulated FSH and estradiol levels were higher compared to normal-BW infants (P = 0.024 and 0.047, respectively).

CONCLUSIONS

Serum AMH and poststimulated estradiol concentrations are increased in low-BW and high-BW female infants, suggesting that these girls may show evidence of an altered follicular development. However, the increased poststimulated FSH levels and low adiponectin concentrations observed in high-BW infants suggest that ovarian function is perturbed through a different mechanism from that in low-BW infants.

Influence of catch-up growth on glucose tolerance and beta-cell function in 7-year-old children: results from the birth to twenty study

OBJECTIVE

The aim of this study was to investigate the effect of catch-up growth occurring at different stages of childhood on glucose levels and beta-cell function at 7 years of age.

METHODS

Oral glucose tolerance tests were performed on 152 7-year-old children. Anthropometric data were available from birth to 7 years of age. Children were split into catch-up, catch-down, and normal-growth groups on the basis of growth rates between birth and 1 year, birth and 5 years, and birth and 7 years. Fasting and 30- and 120-minute blood samples collected during the oral glucose tolerance tests were assayed for glucose, insulin, proinsulin, and des-31,32-proinsulin levels, and area-under-the-curve values were calculated.

RESULTS

Children with catch-up growth between birth and 5 years or birth and 7 years had greater area-under-the-curve insulin levels than the children with catch-down growth. Children with catch-up growth only between birth and 7 years exhibited higher proinsulin levels and a greater insulin secretory response to glucose than those who experienced catch-up growth between both birth and 1 year and birth and 7 years of age. Low birth weight children with no catch-up growth between birth and 7 years had the highest glucose and lowest insulinogenic index levels, whereas children with high birth weight and catch-up growth had the highest insulin levels.

CONCLUSIONS

Extremes of birth weight in conjunction with extremes of postnatal growth are all detrimental to childhood metabolism. The negative metabolic effects of catch-up growth between birth and 7 years may be attenuated if catch-up growth also occurs between birth and 1 year of age.

Size at birth, obesity and blood pressure at age five

BACKGROUND

The fetal origins hypothesis indicates that morphometric evidence of fetal nutritional deprivation is predictive of excessive weight gain/obesity, insulin resistance, and cardiovascular disease after birth. However, it is unclear whether these effects are present in offspring with "normal" birth weights in contemporary Western society, whether they are population specific, and how early in life they appear. This study was designed to examine these questions in a select populace of morphometrically diverse offspring to test the null hypothesis that morphometric evidence of nutritional restriction in utero has no effect on the presence of either obesity or increased blood pressure at ages 5 and 6.

METHODS

We present a prospective study of 101 offspring born of well-nourished, middle and upper socioeconomic-class women who participated in studies of diet and exercise during pregnancy. At birth and age 5 to 6 the offspring underwent morphometric evaluation with the additional measurement of blood pressure at age 5 to 6.

RESULTS

There were no significant negative correlations between neonatal morphometrics and either blood pressure or obesity at age 5 to 6. There were, however, direct positive correlations between birth weight and both weight and BMI at age 5 to 6 (p < 0.0001).

CONCLUSIONS

In this specific populace, morphometrics at age 5 to 6 correlated with size at birth. However, there was no relationship between mophometric evidence of in utero nutritional deprivation at birth and either blood pressure or obesity at age 5 to 6.

Adiponectin levels measured in dried blood spot samples from neonates born small and appropriate for gestational age

OBJECTIVE

Adiponectin levels measured in neonatal dried blood spot samples (DBSS) might be affected by both prematurity and being born small for gestational age (SGA). The aim of the study was to measure adiponectin levels in routinely collected neonatal DBSS taken on day 5 (range 3-12) postnatal from infants.

DESIGN

A retrospective case-control study.

SUBJECTS AND METHODS

One hundred and twenty-two infants: 62 very premature (34 SGA) and 60 mature infants (27 SGA). Adiponectin concentrations were determined in stored neonatal DBSS using a sandwich immunoassay based on flow metric Luminex xMap technology.

RESULTS

Adiponectin was measurable in all samples, and repeated measurements correlated significantly (r = 0.94). Adiponectin concentrations were negatively associated with both SGA (B = -0.283, P = 0.04) and prematurity (B = -2.194, P < 0.001), independently of each other. In the premature but not the mature group, adiponectin levels increased with increasing postnatal age at blood sampling (B = 0.175, P < 0.001).

CONCLUSIONS

Reliable quantification of adiponectin in stored DBSS is feasible and may be used to study large populations of routinely collected samples. Low levels of adiponectin in neonatal DBSS are associated with SGA as well as prematurity. Blood adiponectin levels increase with postnatal age in premature infants, suggesting a rapid yet unexplained metabolic adaptation to premature extrauterine life.

Circulating levels of adiponectin in preterm infants

OBJECTIVE

To determine circulating levels of adiponectin in preterm infants and examine possible associations with anthropometric measurements, weight gain, and leptin and insulin levels.

DESIGN

Prospective study.

SETTING

A university hospital neonatal care unit.

STUDY POPULATION

62 preterm (mean (SD) gestational age 32.0 (2.1) weeks) and 15 full-term infants (reference group).

INTERVENTIONS

Blood samples taken at discharge (40.9 (14.8) days of life) from the preterm infants and at a comparable postnatal age in full-term infants. All infants were fed the same commercial formula, but in nine preterms the formula contained long-chain polyunsaturated fatty acids (LCPUFAs).

MAIN OUTCOME MEASURES

Serum levels of adiponectin, leptin and insulin. Associations of adiponectin levels were tested only in the preterm group.

RESULTS

Serum levels of adiponectin were lower in preterm (40.9 (14.8) microg/ml) than full-term infants (53.1 (16.0) microg/ml, p<0.01). However, after adjustment for body weight, the influence of prematurity on adiponectin levels was no longer significant. In preterm infants, adiponectin levels independently correlated with being born small for gestational age (SGA) (beta=-0.35, p=0.01), weight gain (beta=0.28, p=0.03) and LCPUFA-supplemented formula (beta=0.34, p=0.009). Serum adiponectin levels did not correlate with insulin or leptin levels. However, insulin levels were higher in preterm than in full-term infants after adjustment for body weight.

CONCLUSIONS

Adiponectin levels are lower in preterm infants at discharge than full-term infants probably due to decreased adiposity. The levels are influenced by being born SGA, weight gain and, possibly, by dietary LCPUFAs. The importance of these findings in the development of insulin or leptin resistance in children born prematurely needs to be further studied.

The impact of early nutrition in premature infants on later childhood insulin sensitivity and growth

OBJECTIVES

Children born prematurely have decreased insulin sensitivity. The etiology of this insulin resistance is unknown. The aim of this study was to evaluate infant nutrition and its influence on insulin sensitivity and postnatal growth in children born < or = 32 weeks' gestation.

METHODS

A total of 56 healthy, developmentally normal, prepubertal children, aged 4 to 10 years were recruited. Thirty-seven were born < or = 32 weeks' gestation, and 19 were control subjects born at term with a birth weight > 10th percentile. Insulin sensitivity (10(-4) min(-1) microU/mL) was calculated from a 90-minute frequently sampled intravenous glucose tolerance test. Perinatal, nutritional, and growth data were obtained retrospectively from both neonatal and early infancy records in the premature cohort.

RESULTS

Children born prematurely had decreased insulin sensitivity when compared with those born at term (13.8 vs 30.6). Neonatal nutrition was not correlated with insulin sensitivity; however, all of the infants had inadequate protein in the first month followed by excessive fat intake thereafter. Premature children with greater weight gain had lower insulin sensitivity. Higher carbohydrate intake in the first month of life was associated with greater weight gain from birth. No relationship was seen between weight gain and either protein or lipid intake.

CONCLUSIONS

Prematurely born children are insulin resistant and have suboptimal neonatal nutrition. Greater childhood weight gain magnifies this reduction in insulin sensitivity and seems to be associated with early nutrition. We speculate that a high carbohydrate neonatal diet may lead to greater weight gain and a greater reduction in insulin sensitivity in this group.

A Thin Phenotype Is Protective for Impaired Glucose Tolerance and Related to Low Birth Weight in Mice

BACKGROUND

Low birth weight is an independent risk factor for impaired glucose tolerance (IGT) and diabetes in adult life. This risk extends to both preterm and term infants, a particularly important finding given the increased survival of low-birth-weight infants with improvements in neonatal care. One potential strategy for prevention of low-birth-weight-associated glucose intolerance is postnatal nutritional modification and prevention of early postnatal weight gain. To determine the efficacy of this approach, we utilized our mouse model of low birth weight related to maternal undernutrition during the third week of pregnancy.

METHODS

We studied three experimental groups of offspring mice: controls (C), undernutrition with low birth weight (UN) fed ad lib postnatally, and undernutrition with food restriction continued in postnatal life (UN-UN). Mean birth weight was significantly reduced in both groups of undernutrition offspring in utero (C: 1.86 +/- 0.03 vs. UN: 1.37 +/- 0.04 and UN-UN: 1.32 +/- 0.06, p <0.001). As expected, and in accord with human data, differences in weight between C and UN mice disappeared by week 2 of life, indicating catch-up growth in the UN group.

RESULTS

Body weight was similar in all groups until 4 months of age, after which the UN-UN group had reduced body weight as compared with controls (p <0.05 at 6 months). Insulin tolerance test (1 U/kg), glucose tolerance test (2 g/kg) and glucose-stimulated insulin secretion test (3 g/kg) at 2 months of age were identical among C, UN, and UN-UN groups. By age 6 months, IGT had developed in the UN mice (p <0.05 vs. C). By contrast, UN offspring with caloric restriction postnatally (UN-UN) were protected from the development of glucose intolerance, with glucose levels identical to that of control mice. These differences appeared to be related to improved insulin sensitivity in the UN-UN mice as compared with UN mice, although data did not reach statistical significance.

CONCLUSIONS

Our data suggest that alterations in early postnatal nutrition are associated with prevention of weight gain and the development of IGT in low-birth-weight mice.

Prematurity – Another Example of Perinatal Metabolic Programming?

Low birth weight is associated with both later adult diseases such as type 2 diabetes mellitus and a number of metabolic abnormalities, the foremost of which is insulin resistance. Indeed the link between an adverse perinatal environment, manifested by low birth weight, and adult life pathology may be an early, permanent reduction in insulin sensitivity. A reduction in insulin sensitivity has been demonstrated in small for gestational age (SGA), term subjects from childhood through to adulthood. Less is known about children born premature into an adverse neonatal environment. We present data demonstrating that premature infants also have metabolic abnormalities similar to those observed in term, SGA children and that these occur irrespective of whether they are SGA or appropriate for gestational age (AGA).

Prematurity and insulin sensitivity

Premature infants of low and extremely low birth weight represent a challenge for neonatal intensive care units and paediatricians. These neonates may be at increased risk of insulin resistance and diabetes perinatally and during childhood. During the first week of postnatal life, infants born prematurely are at risk of abnormalities in glucose homeostasis. Additionally, there are major differences in their glucose/insulin homeostasis compared with infants born at term. Preterm infants are at risk of hypoglycaemia, due to decreases in deposits of glycogen and fat that occur during the third trimester, and also to transient hyperinsulinaemia. Hyperglycaemia may also be observed in preterm infants during the perinatal period. These infants are unable to suppress glucose production within a large range of glucose and insulin concentrations, insulin secretory response is inappropriate, insulin processing is immature and there is an increased ratio of the glucose transporters Glut-1/Glut-2 in fetal tissues, which limits sensitivity and hepatocyte reaction to increments in glucose/insulin concentration during hyperglycaemia. In addition, increased concentrations of tumour necrosis factor alpha present in intrauterine growth retardation (IUGR) and induce insulin resistance. It has been proposed that the reduced insulin sensitivity may result from adaptation to an adverse in utero environment during a critical period of development. We have investigated postnatal insulin resistance in 60 children born with very low birth weight and either small for gestational age or at an appropriate size for gestational age. This study showed that IUGR, rather than low birth weight itself, was associated with increased fasting insulin levels. As poor fetal growth may be associated with the development of obesity, type 2 diabetes and the metabolic syndrome in later life, it is important that we continue to increase our understanding of the effects of IUGR on postnatal growth and metabolism.

Laboratory tests and measurements in children born small for gestational age (SGA)

Children born small for gestational age are at high risk of developing insulin resistance, type 2 diabetes, hyperlipidemia, hypertension and cardiovascular disease in adulthood. In addition, approximately 10% of SGA children do not achieve a normal adult height. Studies performed in SGA children to evaluate markers of metabolic disease in prepubertal, pubertal and adolescent subjects, indicate a higher prevalence of subtle endocrine and metabolic abnormalities that may precede the onset of overt disease in adulthood. At present, however, there are no conclusive data supporting the need of systematic close monitoring of GH-IGF, hypothalamus-pituitary-adrenal and hypothalamus-pituitary-gonadal axes, as well as insulin sensitivity, glucose homeostasis, and lipid metabolism. Monitoring of metabolic parameters should probably be reserved to SGA children with genetic predisposition to type 2 diabetes and hyperlipidemia, as early identification of metabolic alterations might prompt effective preventive interventions and, ultimately, reduce cardiovascular risk.

Determinants of insulin concentrations in healthy 1-week-old babies in the community: applications of a bloodspot assay

BACKGROUND

Epidemiological research into insulin secretion and insulin action would be helped by improved ability to measure insulin concentrations in large groups of healthy babies in the neonatal period. Such research is often restricted by the invasive nature of blood sampling.

AIMS

We assessed the use of an assay that can measure insulin from bloodspots taken during routine Guthrie testing 7 days after delivery.

STUDY DESIGN AND SUBJECTS

Insulin and glucose were measured in 366 seven-day-old infants from heel-prick bloodspots. Time since last feed and type of feed were recorded.

RESULTS

Bloodspot insulin concentrations in normal 7-day-old infants were much lower (median (IQR): 15.4 pmol/l (<10-28.5)) than fasting insulin concentrations in adult males (44.3 pmol/l (30.6-72.6)) (p<0.001). Insulin and glucose concentrations were correlated (r=0.33, p<0.001). Insulin and glucose fell significantly with time from feed. Bottle fed infants had higher insulin concentrations but similar glucose concentrations compared to breast fed infants. Detailed analysis to account for confounders was limited due to the skewed distribution of time since feed and the lower limit of the assay leading to non-continuous insulin data.

CONCLUSIONS

In the largest study of normal 7-day-old children to date we have shown insulin concentrations are low compared to adults and vary with glucose, time from feed, and type of feed. This validates the use of the bloodspot insulin assay as a potential research tool for large-scale epidemiological studies. However, careful study design would be required in future use to reduce the variation caused by timing and type of feeding and the problem of one third of values being at or below the lower limit of this assay.

Birth weight in offspring of mothers with polycystic ovarian syndrome

BACKGROUND

A relationship between reduced fetal growth and the polycystic ovary syndrome (PCOS) has been proposed in girls with PCOS. However, the birth weight in the offspring of PCOS mothers has not been systematically investigated. The aim of this study was to establish the birth weight of newborns of mothers with PCOS and to compare it with a control group of newborns of normal women matched by age and weight at the beginning of pregnancy.

METHODS

The birth weight of 47 infants born from singleton pregnancies in women with well-documented PCOS was compared with 180 infants born from singleton pregnancies in healthy controls.

RESULTS

The prevalence of small for gestational age (SGA) infants was significantly higher in the PCOS group compared to the control group (12. 8% versus 2.8%, respectively, P<0.02). Moreover, SGA infants born to PCOS mothers were smaller than those born to control mothers (P<0.05). The prevalence of large for gestational age infants (LGA) was similar in both groups, but birth length of LGA newborns was greater in PCOS women than controls (P<0.05).

CONCLUSIONS

PCOS mothers showed a significantly higher prevalence of SGA newborns which cannot be completely attributed to pregnancy complications, and seems to be more related to the PCOS condition of the mother.

Premature birth and later insulin resistance

BACKGROUND

Term infants who are small for gestational age appear prone to the development of insulin resistance during childhood. We hypothesized that insulin resistance, a marker of type 2 diabetes mellitus, would be prevalent among children who had been born prematurely, irrespective of whether they were appropriate for gestational age or small for gestational age.

METHODS

Seventy-two healthy prepubertal children 4 to 10 years of age were studied: 50 who had been born prematurely (32 weeks' gestation or less), including 38 with a birth weight that was appropriate for gestational age (above the 10th percentile) and 12 with a birth weight that was low (i.e., who were small) for gestational age, and 22 control subjects (at least 37 weeks' gestation, with a birth weight above the 10th percentile). Insulin sensitivity was measured with the use of paired insulin and glucose data obtained by frequent measurements during intravenous glucose-tolerance tests.

RESULTS

Children who had been born prematurely, whether their weight was appropriate or low for gestational age, had an isolated reduction in insulin sensitivity as compared with controls (appropriate-for-gestational-age group, 14.2x10(-4) per minute per milliunit per liter [95 percent confidence interval, 11.5 to 16.2]; small-for-gestational-age group, 12.9x10(-4) per minute per milliunit per liter [95 percent confidence interval, 9.7 to 17.4]; and control group, 21.6x10(-4) per minute per milliunit per liter [95 percent confidence interval, 17.1 to 27.4]; P=0.002). There were no significant differences in insulin sensitivity between the two premature groups (P=0.80). As compared with controls, both groups of premature children had a compensatory increase in acute insulin release (appropriate-for-gestational-age group, 2002 pmol per liter [95 percent confidence interval, 1434 to 2432] [corrected]; small-for-gestational-age group, 2253 pmol per liter [95 percent confidence interval, 1622 to 3128]; and control group, 1148 pmol per liter [95 percent confidence interval, 875 to 1500]; P<0.001).

CONCLUSIONS

Like children who were born at term but who were small for gestational age, children who were born prematurely have an isolated reduction in insulin sensitivity, which may be a risk factor for type 2 diabetes mellitus.

Plasma adiponectin levels in newborns are higher than those in adults and positively correlated with birth weight

OBJECTIVE

The aim of this study was to examine plasma adiponectin concentrations during perinatal the period and their correlations with fetal anthropometric parameters and other hormones.

DESIGN

Venous cord blood samples were obtained from 59 full-term healthy newborns (36 males and 23 females, gestational age 37.0-41.4 weeks, birth weight 2,146-4,326 g, birth length 44.0-54.5 cm). The blood samples were also obtained from 15 neonates (postnatal day 3-7) whose cord blood had already been collected and the changes in adiponectin concentrations were examined.

MEASUREMENTS

The adiponectin concentration was determined by enzyme-linked immunosorbent assay. The leptin concentration was determined by radioimmunoassay. Insulin, GH and IGF-1 concentrations were determined by immunoradiometric assays.

RESULTS

The plasma adiponectin concentrations in cord blood ranged from 6.0 to 55.8 microg/ml (median 22.4 microg/ml), which were much higher than those in normal-weight adults (P < 0.0001). In contrast to the findings in adults, these values were positively correlated with birth weight (r = 0.43, P = 0.0005), body mass index (r = 0.44, P = 0.0005), birth weight/birth length ratio (r = 0.46, P = 0.0002) and the leptin concentrations (r = 0.39, P = 0.004). When the effects of fat mass-related anthropometric parameters such as the birth weight/birth length ratio were controlled, plasma adiponectin concentrations had a significant inverse correlation with insulin concentrations (r = -0.35, P = 0.01). There was no significant gender difference in adiponectin concentrations among newborns. The adiponectin concentrations in neonates (postnatal day 3-7) did not change significantly compared with those in cord blood.

CONCLUSIONS

In contrast to the findings in adults, these results suggest that the adiponectin concentration increases with the mass of fetal fat.

Insulin sensitivity in children born small for gestational age (SGA)

In the past decade, several epidemiological studies have shown a relationship between intrauterine growth retardation and insulin resistance, type 2 diabetes and cardiovascular disease in adulthood. Although the biological mechanisms underlying this association are still largely unknown, different explanatory hypotheses have been proposed. It seems likely that the various pathways may interact with each other, all contributing at different degrees to the development of the metabolic disturbances.

The metabolic consequences of prematurity

An association between low birth weight, commonly a reflection of an adverse in utero environment, and the subsequent development of diseases such as type 2 diabetes and hypertension in later life is now generally accepted - as is an association between an adverse perinatal environment and a permanent reduction in insulin sensitivity. This and other metabolic abnormalities have been demonstrated from childhood through to adulthood in subjects who were born full-term but small for gestational age (SGA). Less is known about children born prematurely into an adverse neonatal environment. We present data demonstrating that premature infants also have metabolic abnormalities similar to those observed in full-term, SGA children, and that these occur irrespective of whether the premature infants are SGA or appropriate for gestational age (AGA).

Insulin sensitivity and cardiovascular risk factors in hypertensive and normotensive native Ghanaians

AIMS/HYPOTHESIS

The objective of this study was to examine the relationships among insulin and insulin sensitivity and risk factors for cardiovascular diseases in native Ghanaians with and without hypertension.

METHODS

We measured the anthropometric parameters, systolic and diastolic blood pressure, fasting serum triglycerides, cholesterol and high-density lipoprotein cholesterol and fasting and stimulated glucose, insulin and C-peptide of 200 Ghanaian subjects, who were between 25 to 74 years of age, and residing in the Accra Metropolitan area. Serum glucose, C-peptide and insulin concentrations were measured at baseline (fasting) and also 2 h after 75 gm oral glucose drink. Homeostasis model assessment was used to measure insulin resistance. Hypertension was defined as a blood pressure higher than 140/90 mmHg.

RESULTS

There were 53 subjects with hypertension (HBP) and 147 subjects with normal blood pressure (NBP). The mean BMI, waist circumference and waist-to-hip circumference ratio for HBP and NBP subjects were 27.4+/-0.8, 24.8+/-0.4 kg/m(2); 89.8+/-11.7, 81.1+/-0.9 cm; and 0.87+/-0.08, 0.82+/-0.08 respectively, (p<0.05). The fasting and 2-h plasma glucose concentrations in HBP and NBP subjects were 5.5+/-0.2, 7.2+/-0.3 mmol/l and 5.2+/-01, 6.8+/-0.2 mmol/l respectively (p>0.05). The corresponding fasting and 2-h insulin concentrations were 10.0+/-0.7, 8.0+/-0.4 uU/ml and 47.3+/-3.7, 37.3+/-2.5 uU/ml respectively (p<0.05). The insulin resistance index (HOMA-IR) in the HBP and the NBP groups were 2.49+/-0.2 and 1.95+/-0.13 (p<0.05). The two groups had similar fasting and stimulated C-peptide, lipids and HDL concentrations. Correlations were found between blood pressure and the concentrations of lipids, HDL, fasting and stimulated insulin and C-peptide, and between fasting insulin and HOMA-IR with lipids and HDL concentrations. On multiple regression analysis, fasting insulin and HOMA-IR did not influence blood pressure variations significantly.

CONCLUSIONS/INTERPRETATION

We found clustering of hyperinsulinaemia, insulin resistance and truncal obesity in hypertensive Ghanaian subjects but dissociation between insulin resistance, hypertension and atherogenic lipid and lipoprotein profile.