Glucose regulation in young adults with very low birth weight

Optimum feeding and growth in preterm neonates

Approximately 10% of all babies worldwide are born preterm, and preterm birth is the leading cause of perinatal mortality in developed countries. Although preterm birth is associated with adverse short- and long-term health outcomes, it is not yet clear whether this relationship is causal. Rather, there is evidence that reduced foetal growth, preterm birth and the long-term health effects of both of these may all arise from a suboptimal intrauterine environment. Further, most infants born preterm also experience suboptimal postnatal growth, with potential adverse effects on long-term health and development. A number of interventions are used widely in the neonatal period to optimise postnatal growth and development. These commonly include supplementation with macronutrients and/or micronutrients, all of which have potential short-term risks and benefits for the preterm infant, whereas the long-term health consequences are largely unknown. Importantly, more rapid postnatal growth trajectory (and the interventions required to achieve this) may result in improved neurological outcomes at the expense of increased cardiovascular risk in later life.

Post-receptor crosstalk between growth hormone and insulin signal in rats born small for gestational age with catch-up growth

Objective

Insulin resistance has been observed in individuals born small for gestational age (SGA) with catch-up growth (CUG), yet the mechanisms involved remain unclear. This study examined the role of GH and insulin signaling crosstalk in insulin resistance of SGA rats with CUG.

Design and Methods

SGA rats were developed by dietary restriction in pregnant rats. GH receptor inhibition was performed on four-week old CUG-SGA and AGA rats. Phosphorylation of IRS-1, AKT, and ERK, and expression of SOCS3 in the skeletal muscle were determined via immunoblot analysis at baseline and after insulin stimulation in CUG-SGA, NCUG-SGA and AGA groups.

Results

Compared to AGA controls, phosphorylation of IRS-1 and AKT in response to insulin stimulation in CUG-SGA rats was significantly blunted (P<0.05), and phosphorylation of ERK at baseline was dramatically activated (P<0.05). SOCS3 expression was significantly increased in CUG-SGA compared to AGA (P = 0.001) and NCUG-SGA (P = 0.006) rats, and was significantly suppressed following GHR inhibition (P<0.05). Furthermore, phosphorylation of IRS-1 and AKT in response to insulin stimulation increased after GHR inhibition (P<0.05).

Conclusions

Insulin resistance in CUG-SGA rats is associated with impairment of IRS-1-PI3K-AKT signaling, which may result from GH signaling-induced up-regulation of SOCS3.

Why we should transfer frozen instead of fresh embryos: the translational rationale

Epidemiologic studies have shown an increased rate of adverse perinatal outcomes, including small for gestational age (SGA) births, in fresh in vitro fertilization (IVF) cycles compared with frozen embryo transfer cycles. This increase is not seen in the donor oocyte population, suggesting that it is the peri-implantation environment created after superovulation that is responsible for these changes. During a fresh IVF cycle, multiple corpora lutea secrete high levels of hormones and other factors that can affect the endometrium and the implanting embryo. In this review, we discuss both animal and human data demonstrating that superovulation has significant effects on the endometrium and embryo. Additionally, potential mechanisms for the adverse effects of gonadotropin stimulation on implantation and placental development are proposed. We think that these data, along with the growing body of epidemiologic evidence, support the proposal that frozen embryo transfer should be considered preferentially, particularly in high responders, as a means to potentially decrease at least some of the adverse perinatal outcomes associated with IVF.

Advanced sleep-wake rhythm in adults born prematurely: confirmation by actigraphy-based assessment in the Helsinki Study of Very Low Birth Weight Adults

OBJECTIVE

Previous studies have suggested a propensity towards morningness in teenagers and adults born preterm. We set out to study sleep in a subsample from The Helsinki Study of Very Low Birth Weight Adults cohort, with emphasis on sleep timing, duration, and quality. We compared young adults who were born prematurely at very low birth weight (VLBW; <1500 g) with controls born at term.

METHODS

We measured sleep by actigraphy in young adults aged 21-29 years. A total of 75 individuals (40 VLBW and 35 controls) provided adequate data. Group differences in sleep parameters were analyzed using t-test and linear regression models.

RESULTS

VLBW adults woke up on average 40 min earlier [95% confidence interval (CI), 9-70] and reported 40 min earlier get up time (95% CI, 8-71) than did the controls. The difference remained after adjustment for confounders. We found no group difference in sleep duration or measures of sleep quality.

CONCLUSION

Our findings of earlier rising in the VLBW group are suggestive of an advanced sleep phase in that group. These results reinforce previous suggestions that chronotype may be programmed early during life.

Is very preterm birth a risk factor for adult cardiometabolic disease?

The first infants to experience modern pre- and neonatal care are now in their thirties, an age at which the incidence of cardiometabolic disease is low. However, data from cohorts born preterm prior to the introduction of modern care suggest an increased risk of type 2 diabetes. For young adult cohorts of former very small or very preterm infants, there is accumulating evidence of increased risk factors for later cardiovascular disease, including higher blood pressure, lower lean body mass, impaired glucose regulation, and perhaps a more atherogenic lipid profile. Regarding lifestyle, adults born very small or very preterm undertake less non-conditioning physical activity and may have a lower intake of fruit and milk products. Any intervention reducing risk factors, in particular blood pressure and low physical activity, would have a substantial potential to reduce the lifetime disease burden in small preterm infants. There are now enough data to warrant an expert evaluation of the level of evidence for cardiometabolic disease in individuals born very small or very preterm, which has possible public health implications.

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.

Functional outcomes of very premature infants into adulthood

The outcomes of very low birth weight survivors born in the early post-neonatal intensive care era have now been reported to young adulthood in several longitudinal cohort studies, and more recently from large Scandinavian national databases. The latter reports corroborate the findings that despite disabilities, a significant majority of very low birth weight survivors are leading productive lives, and are functioning better than expected. This is reassuring, but there are still concerns about future psychopathology, cardiovascular and metabolic problems as they approach middle age. Although these findings may not be directly applicable to the current survivors of modern neonatal intensive care, they do provide a yardstick by which to project the outcomes of future survivors until more contemporaneous data are available.

Long-term growth and general health for the tiniest or most immature infants

Given the improving survival rates of extremely preterm (EP, gestational age <28 weeks) infants, there is a need to understand their general growth and health outcomes not only in childhood, but also into adulthood. EP children are shorter and lighter compared with term children at term-equivalent age; with time, the weight disadvantage diminishes but the height disadvantage remains relatively unchanged. EP children and young adults also have higher rates of reported health concerns, medical conditions and visual impairment. Hospital readmissions are higher in early childhood, mostly attributed to respiratory illness. Individuals born EP have reduced bone health and are at increased risk for metabolic disorders. Increased rates of conditions such as diabetes or pathological fractures are not reported in the literature, although follow-up studies so far have only tracked EP individuals into young adulthood. Consequently, health care utilization and costs are increased in EP children and young adults. A thorough knowledge of the health risks related to EP birth is essential in planning surveillance and intervention strategies to optimize their health and wellbeing. Despite the increased risk of health problems, EP young adults generally report their quality of life to be similar to that reported in their term counterparts.

Cerebrovascular and ischemic heart disease in young adults born preterm: a population-based Swedish cohort study

Preterm birth is associated with overall cardiovascular mortality in young adulthood, but which specific conditions that underlie this association is unknown. We studied mortality and morbidity from cerebrovascular and ischemic heart disease in individuals born preterm. In a nationwide Swedish study, we included 1,306,943 individuals without congenital malformations born between 1983 and 1995, followed from 15 years of age to December 31st, 2010. Of these, 73,489 (5.6 %) were born preterm (<37 weeks of gestation). Cox proportional hazards regression analysis was used to calculate hazard ratios (HR) with 95 % confidence intervals (CI), after adjusting for maternal characteristics and birth weight for gestational age. Of 955 incident cases of cerebrovascular disease, 58 (6.1 %) occurred in preterm born subjects. The corresponding numbers of ischemic heart disease cases were 180 and 13 (7.2 %), respectively. Birth before 32 weeks was associated with a nearly twofold increased risk of cerebrovascular disease; adjusted HR, (95 % CI) = 1.89 (1.01-3.54) compared to term born individuals, whereas individuals born at 32-36 weeks were not at increased risk. Preterm birth was not associated with later ischemic heart disease; no cases of ischemic heart disease were recorded among those born before 32 weeks and the HR (95 % CI) for those born at 32-36 weeks of gestation was 1.45 (0.81-2.57), compared to term-born individuals. Birth before 32 weeks is associated with increased risk of cerebrovascular disease in young adulthood. Our data suggest that cardiovascular health promotion in follow-up programs after very preterm birth may be beneficial.

Preterm birth and random plasma insulin levels at birth and in early childhood

IMPORTANCE

Although previous reports have linked preterm birth with insulin resistance in children and adults, it is not known whether altered insulin homeostasis is detectable at birth and tracks from birth through childhood.

OBJECTIVE

To investigate whether preterm birth is associated with elevated plasma insulin levels at birth and whether this association persists into early childhood.

DESIGN, SETTING, AND PARTICIPANTS

A prospective birth cohort of 1358 children recruited at birth from 1998 to 2010 and followed-up with prospectively from 2005 to 2012 at the Boston Medical Center in Massachusetts.

MAIN OUTCOMES AND MEASURES

Random plasma insulin levels were measured at 2 time points: at birth (cord blood) and in early childhood (venous blood). The median age was 1.4 years (interquartile range [IQR], 0.8-3.3) among 4 gestational age groups: full term (≥39 wk), early term (37-38 wk), late preterm (34-36 wk), and early preterm (<34 wk).

RESULTS

The geometric mean of insulin levels at birth were 9.2 µIU/mL (95% CI, 8.4-10.0) for full term; 10.3 µIU/mL (95% CI, 9.3-11.5) for early term; 13.2 µIU/mL (95% CI, 11.8-14.8) for late preterm; and 18.9 µIU/mL (95% CI, 16.6-21.4) for early preterm. In early childhood, these levels were 11.2 µIU/mL (95% CI, 10.3-12.0) for full term; 12.4 µIU/mL (95% CI, 11.3-13.6) for early term; 13.3 µIU/mL (95% CI, 11.9-14.8) for late preterm; and 14.6 µIU/mL (95% CI, 12.6-16.9) for early preterm. Insulin levels at birth were higher by 1.13-fold (95% CI, 0.97-1.28) for early term, 1.45-fold (95% CI, 1.25-1.65) for late preterm, and 2.05-fold (95% CI, 1.69-2.42) for early preterm than for those born full term. In early childhood, random plasma insulin levels were 1.12-fold (95% CI, 0.99-1.25) higher for early term, 1.19-fold (95% CI, 1.02-1.35) for late preterm, and 1.31-fold (95% CI, 1.10-1.52) for early preterm than those born full term. The association was attenuated after adjustment for postnatal weight gain and was not significant after adjustment for insulin levels at birth. Infants ranked in the top insulin tertile at birth were more likely to remain in the top tertile (41.2%) compared with children ranked in the lowest tertile (28.6%) in early childhood.

CONCLUSIONS AND RELEVANCE

There was an inverse association between gestational age and elevated plasma insulin levels at birth and in early childhood. The implications for future development of insulin resistance and type 2 diabetes warrant further investigation.

Trajectory and correlates of growth of extremely-low-birth-weight adolescents

BACKGROUND

Catch-up growth may predispose to obesity and metabolic sequelae. We sought to examine the trajectory and correlates of growth and catch up among extremely-low-birth-weight (ELBW) (<1 kg) adolescents.

METHODS

A cohort study of 148 neurologically normal ELBW children and 115 normal-birth-weight (NBW) controls born during the period 1992-1995 was conducted. Longitudinal measures of gender-specific growth of ELBW children from birth, in addition to growth and measures of obesity of ELBW and NBW children at 14 y, were evaluated.

RESULTS

Following neonatal growth failure, ELBW children had accelerated growth, but at 8 y, they still had lower weight and height z scores than NBW children. By 14 y, ELBW boys had caught up in growth to their NBW controls, but ELBW girls remained significantly smaller. ELBW children, however, did not differ from their controls in measures of obesity. In hierarchical multiple regression analyses, only maternal BMI and weight gain during infancy and childhood predicted the ELBW children's 14-y weight z scores, BMI z scores, and abdominal circumference. Perinatal risk factors, including intrauterine growth, only predicted growth up to 20 mo.

CONCLUSION

Maternal BMI and rate of growth, rather than perinatal factors, predict 14-y obesity among neurologically normal ELBW adolescents.

Maternal morbidity and preterm birth in 22 low- and middle-income countries: a secondary analysis of the WHO Global Survey dataset

Background

Preterm birth (PTB) (<37weeks) complicates approximately 15 million deliveries annually, 60% occurring in low- and middle-income countries (LMICs). Several maternal morbidities increase the risk of spontaneous (spPTB) and provider-initiated (piPTB) preterm birth, but there is little data from LMICs.

Method

We used the WHO Global Survey to analyze data from 172,461 singleton deliveries in 145 facilities across 22 LMICs. PTB and six maternal morbidities (height <145 cm, malaria, HIV/AIDS, pyelonephritis/UTI, diabetes and pre-eclampsia) were investigated. We described associated characteristics and developed multilevel models for the risk of spPTB/piPTB associated with maternal morbidities. Adverse perinatal outcomes (Apgar <7 at 5 minutes, NICU admission, stillbirth, early neonatal death and low birthweight) were determined.

Results

8.2% of deliveries were PTB; one-quarter of these were piPTB. 14.2% of piPTBs were not medically indicated. Maternal height <145 cm (AOR 1.30, 95% CI 1.10–1.52), pyelonephritis/UTI (AOR 1.16, 95% CI 1.01–1.33), pre-gestational diabetes (AOR 1.41, 95% CI 1.09–1.82) and pre-eclampsia (AOR 1.25, 95% CI 1.05–1.49) increased odds of spPTB, as did malaria in Africa (AOR 1.67, 95%CI 1.32-2.11) but not HIV/AIDS (AOR 1.17, 95% CI 0.79-1.73). Odds of piPTB were higher with maternal height <145 cm (AOR 1.47, 95% CI 1.23-1.77), pre-gestational diabetes (AOR 2.51, 95% CI 1.81-3.47) and pre-eclampsia (AOR 8.17, 95% CI 6.80-9.83).

Conclusions

Maternal height <145 cm, diabetes and pre-eclampsia significantly increased odds of spPTB and piPTB, while pyelonephritis/UTI and malaria increased odds of spPTB only. Strategies to reduce PTB and associated newborn morbidity/mortality in LMICs must prioritize antenatal screening/treatment of these common conditions and reducing non-medically indicated piPTBs where appropriate.

Blunted hypothalamic-pituitary-adrenal axis and insulin response to psychosocial stress in young adults born preterm at very low birth weight

BACKGROUND

Young adults born preterm at very low birth weight (VLBW, ≤1500 g) have higher levels of cardiovascular risk factors, including impaired glucose regulation, than their term-born peers. This could be mediated through altered hypothalamic-pituitary-adrenal axis (HPAA) response to stress.

OBJECTIVE

To compare HPAA, glucose and insulin responses provoked by psychosocial stress in VLBW subjects versus a comparison group of term-born controls.

DESIGN AND PARTICIPANTS

We studied 54 unimpaired young adults, aged 19-27 years, born at VLBW and a comparison group of 40 adults born at term, group-matched for age, sex and birth hospital, from one regional centre in southern Finland. The participants underwent a standardized psychosocial stress test (Trier Social Stress Test, TSST).

MEASUREMENTS

In conjunction with TSST, we measured salivary cortisol, plasma ACTH, cortisol, glucose and insulin. Data were analysed with mixed-effects model and multiple linear regression analyses.

RESULTS

Baseline concentrations for cortisol, ACTH, insulin and glucose were similar in VLBW and comparison groups. During TSST, analysed with mixed-effects model, overall concentrations of plasma cortisol were 17·2% lower (95% CI; 3·5 to 28·9) in the VLBW group. The VLBW group also had lower salivary (P = 0·04) and plasma cortisol (P = 0·02) responses to TSST. Insulin and glucose concentrations correlated with changes in cortisol concentrations. Accordingly, VLBW subjects had 26·5% lower increment in insulin (95% CI; 9·8-40·1). Analyses were adjusted for age, sex, body mass index, hormonal contraception, menstrual cycle phase, time of day and parental education.

CONCLUSIONS

VLBW adults have lower HPAA responses to psychosocial stress than term-born controls. This is accompanied by a lower insulin response.

Long-term impact of preterm birth on exercise capacity in healthy young men: a national population-based cohort study

Background

Increasing numbers of survivors of preterm birth are growing into adulthood today. Long-term health-effects of prematurity are still poorly understood, but include increased risk for diabetes, obesity and cardiovascular diseases in adult life. To test if reduced physical fitness may be a link in the causal chain of preterm birth and diseases in later life, the association of preterm birth and adult exercise capacity was investigated. The hypothesis was that preterm birth contributes independently of other risk factors to lower physical fitness in adulthood.

Methods and Findings

Population-based national cohort study of all males conscripting for military service in 1993–2001 and born in Sweden 1973–1983, n = 218,820. Data were retrieved from the Swedish Conscript Register, the Medical Birth Register and the Population and Housing Census 1990. Primary outcome was the results from maximal exercise test (W_max in Watt) performed at conscription. Association to perinatal and socioeconomic risk factors, other co-variates and confounders were analysed. General linear modelling showed that preterm birth predicted low W_max in a dose-response related pattern, with 25 Watt reduction in W_max for the lowest gestational ages, those born ≤27 weeks. Low birth weight for gestational age also independently predicted low W_max compared to normal and high birth weight (32 Watt reduction for those with a birth weight Standard Deviation Score <2). Low parental education was significantly associated with reduced W_max (range 17 Watt), as well as both low and high current BMI, with severe obesity resulting in a 16 Watt deficit compared to W_max top performance.

Conclusion

Being born preterm as well as being born small for gestational age predicts low exercise capacity in otherwise healthy young men. The effect size of being born preterm equal or exceed that of other known risk factors for unfitness in adults, such as low parental education and overweight.

Psychosocial outcomes of young adults born very low birth weight

OBJECTIVE

To assess the early adult health, education, and social functioning of a national cohort of very low birth weight (VLBW) infants born in 1986 in New Zealand compared with a control group of young adults born the same year. The impact of neurodevelopmental disability at age 7 to 8 years on young adult outcomes was examined.

METHODS

Participants underwent a comprehensive face-to-face interview that included standardized assessment tools and previously used custom written survey items.

RESULTS

We interviewed 230 VLBW young adults (71% of survivors) and 69 controls at age 22 to 23 years. VLBW young adults were 5.6 kg lighter and 4.2 cm shorter than controls, had lower rates of tertiary education/training (percentage difference [95% confidence interval]: -13.1 [-21.6 to -1.8]) and university degree completion (-15.6 [-28.0 to -4.8]), had more often been welfare dependent (23.5 [10.2 to 35.0]), had few or no friends (20.5 [7.2 to 32.2]), and more often had wheeze in the past year (20.1 [9.0 to 28.6]). However, in many areas there were no differences between the VLBW cohort and controls, and VLBW adults rated their overall quality of life and behavioral functioning similarly to their peers. Those with previous disability had poorer social, occupational, and physical functioning than other VLBW young adults.

CONCLUSIONS

Despite some evidence of health, educational, and social difficulties, former VLBW young adults obtained similar scores across many aspects of health and social functioning as their same age peers, with some differences largely confined to those with previous disability.

Increased adiposity in adults born preterm and their children

Background

Preterm birth is associated with abnormalities in growth, body composition, and metabolism during childhood, but adult data are scarce and none exist for their offspring. We therefore aimed to examine body composition and cardiovascular risk factors in adults born preterm and their children.

Methods

A cohort of 52 adults (aged 35.7 years, 54% female, 31 born preterm) and their term-born children (n=61, aged 8.0 years, 54% female, 60% from a preterm parent) were studied. Auxology and body composition (whole-body dual-energy X-ray absorptiometry) were measured, and fasting blood samples taken for metabolic and hormonal assessments.

Results

Adults born preterm had greater abdominal adiposity, displaying more truncal fat (p=0.006) and higher android to gynoid fat ratio (p=0.004). Although women born preterm and at term were of similar weight and BMI, men born preterm (n=8) were on average 20 kg heavier (p=0.010) and of greater BMI (34.2 vs 28.4 kg/m²; p=0.021) than men born at term (n=16). Adults born preterm also displayed a less favourable lipid profile, including lower HDL-C concentrations (p=0.007) and greater total cholesterol to HDL-C ratio (p=0.047). Children of parents born preterm tended to have more body fat than the children of parents born at term (21.3 vs 17.6%; p=0.055). Even after adjustment for mean parental BMI, children of parents born preterm had altered fat distribution, with more truncal fat (p=0.048) and greater android to gynoid fat ratio (p=0.009).

Conclusions

Adults born preterm, particularly men, have markedly increased fat mass and altered fat distribution. A similar increase in abdominal adiposity was observed in the term born offspring of parents born preterm, indicating that adverse outcomes associated with preterm birth may extend to the next generation.

Born too soon: preterm birth matters

Urgent action is needed to address preterm birth given that the fi rst country-level estimates show that globally 15 million babies are born too soon and rates are increasing in most countries with reliable time trend data. As the fi rst in a supplement entitled “Born Too Soon”, this paper focuses on the global policy context. Preterm birth is critical for progress on Millennium Development Goal 4 (MDG) for child survival by 2015 and beyond, and gives added value to maternal health (MDG 5) investments also linking to non-communicable diseases. For preterm babies who survive, the additional burden of prematurity-related disability may aff ect families and health systems. Prematurity is an explicit priority in many high-income settings; however, more attention is needed especially in low- and middle-income countries where the invisibility of preterm birth as well as its myths and misconceptions have slowed action on prevention and care. Recent global attention to preterm birth hit a tipping point in 2012, with the May 2 publication of Born Too Soon: The Global Action Report on Preterm Birth and with the 2nd annual World Prematurity Day on November 17 which mobilised the actions of partners in many countries to address preterm birth and newborn health. Interventions to strengthen preterm birth prevention and care span the continuum of care for reproductive, maternal, newborn and child health. Both prevention of preterm birth and implementation of care of premature babies require more research, as well as more policy attention and programmatic investment.

Maternal preeclampsia and bone mineral density of the adult offspring

OBJECTIVE

Preterm birth at very low birthweight (<1500 g) is associated with cardiometabolic risk factors and reduced bone mineral density in the adult offspring. Preeclampsia is a frequent cause of preterm birth and is also associated with cardiometabolic risk factors in the offspring. Whether it is associated with bone mineral density is not known.

STUDY DESIGN

We evaluated skeletal health in participants of the Helsinki Study of Very Low Birthweight Adults: 144 born at very low birthweight and 139 born at term. From the very low birthweight and term offspring a respective 32 and 11 were born from pregnancy complicated by preeclampsia. We measured bone mineral density at age 18.5 to 27.1 years by dual X-ray absorptiometry.

RESULTS

Very low birthweight adults exposed to maternal preeclampsia had higher lumbar spine Z score (mean -0.44, compared with -1.07 in very low birthweight unexposed adults, P = .002), femoral neck Z score (-0.05 vs -0.53, P = .003) and whole body bone mineral density Z score (-0.14 vs -0.72, P = .001). Corresponding Z scores for those born at term were -0.02 (preeclampsia) and -0.45 (no preeclampsia) for lumbar spine (P = .2), 0.78 and 0.08 for femoral neck (P = .02) and 0.02 and -0.31 for whole body bone mineral density Z score (P = .08). The results survived adjustment for offspring current height, body mass index, leisure time physical activity, socioeconomic position, smoking, and maternal smoking during pregnancy, and maternal prepregnancy body mass index.

CONCLUSION

Young adults exposed to maternal preeclampsia have higher bone mineral density than those not exposed. This difference is seen among those born at very low birthweight and seems also to be present among those born at term.

Transient neonatal high oxygen exposure leads to early adult cardiac dysfunction, remodeling, and activation of the renin-angiotensin system

Perinatal conditions (such as preterm birth) can affect adult health and disease, particularly the cardiovascular system. Transient neonatal high O(2) exposure in rat in adulthood (a model of preterm birth-related complications) leads to elevated blood pressure, vascular rigidity, and dysfunction with renin-angiotensin system activation. We postulate that neonatal hyperoxic stress also affects myocardial structure, function, and expression of renin-angiotensin system components. Sprague-Dawley pups were kept with their mother in 80% O(2) or in room air (control) from days 3 to 10 of life. Left ventricular function was assessed in 4-, 7-, 12-week-old (echocardiography) and in 16-week-old (intraventricular catheterization) male O(2)-exposed versus control rats. At 16 weeks, hearts from O(2)-exposed rats showed cardiomyocyte hypertrophy, enhanced fibrosis, and increased expression of transforming growth factor-β1, senescence-associated proteins p53 and Rb, upregulation of angiotensin II type 1 (AT1) receptor expression (protein and AT1a/b mRNA), and downregulation of AT2 receptors. At 4 weeks (before blood pressure increase), the expression of cardiomyocyte surface area, fibrosis, p53, and AT1b was significantly increased and AT2 decreased in O(2)-exposed animals. After 4 weeks of continuous angiotensin II infusion (starting at 12 weeks), O(2)-exposed rats developed severe heart failure, with impaired myocardial mechanical properties compared with saline-infused rats. Transient neonatal O(2) exposure in rats leads to left ventricular hypertrophy, fibrosis and dysfunction, and increased susceptibility to heart failure under pressure overload. These results are relevant to the growing population of individuals born preterm who may be at higher risk of cardiac dysfunction when faced with increased peripheral resistance associated with hypertension, vascular diseases, and aging.

Relative intima-media thickening after preterm birth

AIM

Preterm infants are at increased risk of early arterial growth arrest and cardiovascular mortality. We assessed intima-media thickness (IMT) - an early marker of accelerated vascular ageing - in very preterm infants.

METHODS

Longitudinal cohort study of 21 very preterm and 29 term infants, all with appropriate birthweights. Intima-media thickness was assessed by M-Mode ultrasound of the aorta and carotid arteries at three occasions during a 6-month period corresponding to the third trimester of pregnancy and ending 3 months after term equivalent age.

RESULTS

No differences in absolute aortic or carotid IMT were found. However, in relation to vessel lumen diameter, the IMT switched from being narrower in preterm infants, compared with foetuses at 28 weeks of gestation, to being significantly thicker in both the aorta and carotid artery in older infants born preterm, compared with term controls of equivalent postmenstrual age. Although the aortic and carotid artery diameters increased significantly with postnatal age, IMT did not.

CONCLUSION

In relation to vessel diameter, subjects born preterm show thicker intima-media in the great arteries than infants born at term. It remains to be established whether this relative intima-media thickening persists and may be a risk marker for future cardiovascular disease.

Birth weight and time spent in outdoor physical activity during adolescence

PURPOSE

We investigated the association between birth parameters (weight, length, and head circumference) and time spent in physical activity (outdoor and indoor) and screen time (TV viewing, computer, and videogame usage) among adolescents.

METHODS

A longitudinal cohort study surveyed 1794 children in 2004-2005 (median age = 12.7 yr), and 752 were resurveyed 5 yr later in 2009-2010 (age = 17-18 yr). Adolescents completed detailed activity questionnaires. Parents extracted birth parameter data from their child's health record booklet.

RESULTS

After adjusting for age, sex, ethnicity, gestational age, parental education, home ownership, exposure to passive smoking, and body mass index, 12-yr-old children in the highest compared with the lowest quartile of birth weight spent on average approximately 56 and 62 min more in total (Ptrend = 0.02) and outdoor physical activity (Ptrend = 0.02) per week, respectively. Similarly, 12-yr-old children in the high (>4000 g) versus very low (<2000 g) birth weight group spent approximately 1.3 h·wk more in outdoor activity (Ptrend = 0.02). Among those age 17-18 yr, increasing birth weight (lowest to highest quartile) was associated with greater time spent in outdoor physical activity (∼1 h·wk-1, Ptrend = 0.04). Significant associations were not observed between all birth parameters and recreational screen time. Also, no associations were observed between head circumference or birth length with physical activity and screen time.

CONCLUSIONS

Birth weight could be a potential determinant of physical activity, but not of screen time during adolescence. Hence, this could be part of the underlying mechanism between prenatal influences and future disease risk and could have possible clinical implications.

Repeat antenatal steroid exposure and later blood pressure, arterial stiffness, and metabolic profile

OBJECTIVE

To determine the relationship between repeat courses of antenatal corticosteroids (ACS) and risk factors for cardiovascular disease in adolescents and young adults.

STUDY DESIGN

We assessed body mass index, blood pressure, arterial stiffness, blood lipids, and insulin resistance (IR) in a Swedish population-based cohort (n = 100) at a median age of 18 (range 14-26) years. Fifty-eight subjects (36 males) had been exposed to 2-9 weekly courses of antenatal betamethasone and 42 (23 males) were unexposed subjects matched for age, sex, and gestational age (GA).

RESULTS

There were no significant differences between the groups regarding body mass index, systolic or diastolic blood pressures, arterial stiffness measured by augmentation index, blood lipids, IR, or morning cortisol levels either in simple regression or in multivariable models. However, more subjects with elevated augmentation index had been exposed to repeat courses of ACS (n = 7) compared with unexposed subjects (n =1, P = .06), and glucose, insulin, and IR correlated inversely to GA at start of ACS (P < .01).

CONCLUSIONS

Repeat courses of ACS did not correlate to adverse cardiovascular risk profile in adolescence and young adulthood, but long-standing effects on the arterial tree and glucose metabolism, the latter dependent on GA at ACS exposure, cannot be excluded. These observations have clinical implications for the ongoing discussion on short-term benefits and long-term safety of repeat ACS treatment.

Direct measurement of the permeability of human cervical tissue

The mechanical integrity of the uterine cervix is critical for a pregnancy to successfully reach full term. It must be strong to retain the fetus throughout gestation and then undergo a remodeling and softening process before labor for delivery of the fetus. It is believed that cervical insufficiency (CI), a condition in pregnancy resulting in preterm birth (PTB), is related to a cervix with compromised mechanical strength which cannot resist deformation caused by external forces generated by the growing fetus. Such PTBs are responsible for infant developmental problems and in severe cases infant mortality. To understand the etiologies of CI, our overall research goal is to investigate the mechanical behavior of the cervix. Permeability is a mechanical property of hydrated collagenous tissues that dictates the time-dependent response of the tissue to mechanical loading. The goal of this study was to design a novel soft tissue permeability testing device and to present direct hydraulic permeability measurements of excised nonpregnant (NP) and pregnant (PG) human cervical tissue from women with different obstetric histories. Results of hydraulic permeability testing indicate repeatability for specimens from single patients, with an order of magnitude separating the NP and PG group means (2.1 ± 1.4×10(-14) and 3.2 ± 4.8×10(-13)m(4)/N[middle dot]s, respectively), and large variability within the NP and PG sample groups. Differences were found between samples with similar obstetric histories, supporting the view that medical history may not be a good predictor of permeability (and therefore mechanical behavior) and highlighting the need for patient-specific measurements of cervical mechanical properties. The permeability measurements from this study will be used in future work to model the constitutive material behavior of cervical tissue and to develop in vivo diagnostic tools to stage the progression of labor.

Diet and nutrient intake in young adults born preterm at very low birth weight

OBJECTIVE

To assess dietary intake in young adults born preterm at very low birth weight (VLBW) (≤ 1500 g).

STUDY DESIGN

We studied 151 young adults aged 19-27 years who were born at VLBW and 156 term-born controls, group-matched for age, sex, and birth hospital. Participants completed a 3-day food record, which was checked by a nutritionist. Food and nutrient intakes were calculated with use of a dietary analysis program. Data were analyzed by multiple linear regression, adjusted for age, sex, body mass index, height, living at parental home, daily smoking, and highest parental education.

RESULTS

Compared with controls, VLBW subjects had lower mean (SD) daily intake of vegetables, fruits, and berries (183 [150] g vs 241 [168] g, P = .002] and milk products (343 [242] g vs 427 [316] g, P = .003). Energy intake from carbohydrates, protein, and fat was similar, as was salt intake. VLBW participants had lower daily intake of calcium (858 [389] mg vs 1080 [514] mg, P < .0001), vitamin D (3.7 [2.6] μg vs 4.4 [3.6] μg, P = .02), and cholesterol (189 [74] mg vs 227 [105] mg, P = .002], whereas intake of essential fatty acids was higher (4.3 [1.5] mg vs 4.0 [1.5] mg, P = .01).

CONCLUSIONS

Lower consumption of vegetables, fruits, berries, and milk products combined with lower calcium and vitamin D intake in VLBW participants offers a target for reducing the risk of osteoporosis and cardiovascular diseases in persons of VLBW.

Altered Methylation of IGF2 Locus 20 Years after Preterm Birth at Very Low Birth Weight

Introduction

People born preterm at very low birth weight (VLBW, ≤1500g) have higher rates of risk factors for adult-onset diseases, including cardiovascular diseases and type 2 diabetes. These risks may be mediated through epigenetic modification of genes that are critical to normal growth and development.

Methods

We measured the methylation level of an imprinted insulin-like-growth-factor 2 (IGF2) locus (IGF2/H19) in young adults born preterm at VLBW and in their peers born at term. We studied 158 VLBW and 161 control subjects aged 18 to 27 years from the Helsinki Study of Very Low Birth Weight Adults. Methylation fraction at two IGF2 differentially methylated regions (DMRs) – IGF2 antisense transcript (IGF2AS, also known as IGF2 DMR0) and last exon of IGF2 (IGF2_05, also known as IGF2 DMR2) – were measured with Sequenom Epityper. We used linear regression and adjustment for covariates to compare methylation fractions at these DMRs between VLBW and control subjects.

Results

At one IGF2AS CpG site, methylation was significantly lower in VLBW than in control subjects, mean difference −0.017 (95% CI; −0.028, −0.005), P = 0.004. Methylation at IGF2_05 was not different between the groups.

Conclusions

Methylation of IGF2AS is altered 20 years after preterm birth at VLBW. Altered methylation may be a mechanism of later increased disease risk but more data are needed to indicate causality.

Localization of a major susceptibility locus influencing preterm birth

Preterm birth (PTB) is a complex trait, but little is known regarding its major genetic determinants. The objective of this study is to localize genes that influence susceptibility to PTB in Mexican Americans (MAs), a minority population in the USA, using predominantly microfilmed birth certificate-based data obtained from the San Antonio Family Birth Weight Study. Only 1302 singleton births from 288 families with information on PTB and significant covariates were considered for genetic analysis. PTB is defined as a childbirth that occurs at <37 completed weeks of gestation, and the prevalence of PTB in this sample was 6.4%. An ∼10 cM genetic map was used to conduct a genome-wide linkage analysis using the program SOLAR. The heritability of PTB was high (h(2) ± SE: 0.75 ± 0.20) and significant (P = 4.5 × 10(-5)), after adjusting for the significant effects of birthweight and birth order. We found significant evidence for linkage of PTB (LOD = 3.6; nominal P = 2.3 × 10(-5); empirical P = 1.0 × 10(-5)) on chromosome 18q between markers D18S1364 and D18S541. Several other chromosomal regions (2q, 9p, 16q and 20q) were also potentially linked with PTB. A strong positional candidate gene in the 18q linked region is SERPINB2 or PAI-2, a member of the plasminogen activator system that is associated with various reproductive processes. In conclusion, to our knowledge, perhaps for the first time in MAs or US populations, we have localized a major susceptibility locus for PTB on chromosome 18q21.33-q23.

Total and carboxylated osteocalcin associate with insulin levels in young adults born with normal or very low birth weight

OBJECTIVE

Osteocalcin (OC), a bone-derived protein, has been implicated in the regulation of glucose and energy metabolism. Young adults born with very low birth weight (VLBW) have altered glucose regulation and lower bone mineral density (BMD) compared with those born at term. The aim of this study was to explore the association between bone and glucose metabolism in healthy young adults born prematurely or at term.

METHODS

The cohort of this cross-sectional study comprised 332 non-diabetic young adults (age 18 to 27 years) born either preterm with VLBW (n = 163) or at term (n = 169). OC, carboxylated osteocalcin (cOC) and markers of glucose metabolism were measured at fasting and after a 75-g oral glucose tolerance test (OGTT).

RESULTS

VLBW adults were shorter, had lower BMD (p<0.001) and higher fasting OC (p = 0.027) and cOC (p = 0.005) than term-born subjects. They also had higher 2-hour insulin (p = 0.001) and glucose (p = 0.037) concentrations. OGTT induced a significant reduction in OC (p<0.001), similar in both groups. OC reduction was not associated with OGTT-induced increases in insulin (p = 0.54). However, fasting total OC and cOC correlated negatively with fasting insulin after adjustment for age, gender, BMD and VLBW status (r = -0.182, p = 0.009 and r = -0.283, p<0.001, respectively).

CONCLUSION

Adults born with VLBW have higher OC and cOC than their peers born at term. This may in part reflect the mechanisms that underlie their lower BMD and decreased insulin sensitivity. Serum OC appears to be negatively associated with long-term glucose regulation whereas acute changes during OGTT may be mediated via other mechanisms.

Lipoprotein subclass profiles in young adults born preterm at very low birth weight

BACKGROUND

Adults born preterm at very low birth weight (VLBW ≤ 1500g) have increased risk factors for cardiovascular diseases including high blood pressure and impaired glucose regulation. Non-optimal lipoprotein profile is generally also likely to affect the increased cardiovascular risk, but lipoprotein subclass level data on adults born at VLBW are sparse.

SUBJECTS AND METHODS

We studied 162 subjects born at VLBW and 169 term-born controls, aged 19 to 27 years. Total lipid, triglyceride and cholesterol concentrations of 14 lipoprotein subclasses were determined by proton nuclear magnetic resonance spectroscopy in the fasting state and in 2-hour serum samples from an oral glucose tolerance test.

FINDINGS

In comparison to controls, VLBW subjects had significantly higher fasting concentration of triglycerides in chylomicrons and largest very-low-density lipoprotein particles [XXL-VLDL-TG, difference 0.026 (95% CI: 0.004 to 0.049), P=0.024], and of triglycerides in small high-density lipoprotein particles [S-HDL-TG, 0.026 (95% CI: 0.002 to 0.051), P=0.037]. The seemingly important role of triglycerides was further supported by principal component analysis in which the first component was characterized by multiple lipoprotein triglyceride measures.

CONCLUSIONS

Young adults born at VLBW and their peers born at term had triglyceride-related differences in both VLDL and HDL subclasses. These differences suggest that the increased risk factors for cardiovascular diseases among the VLBW individuals in adulthood may partly relate to impaired triglyceride metabolism.

Prematurity and programming: contribution of neonatal Intensive Care Unit interventions

Contemporary clinical practice for the care of the prematurely born babies has markedly improved their rates of survival so that most of these babies are expected to grow up to live a healthy functional life. Since the clinical follow-up is of short duration (years), only limited data are available to relate non-communicable diseases in adult life to events and interventions in the neonatal period. The major events that could have a programming effect include: (1) intrauterine growth restriction; (2) interruption of pregnancy with change in redox and reactive oxygen species (ROS) injury; (3) nutritional and pharmacological protocols for clinical care; and (4) nutritional care in the first 2 years resulting in accelerated weight gain. The available data are discussed in the context of perturbations in one carbon (methyl transfer) metabolism and its possible programming effects. Although direct evidence for genomic methylation is not available, clinical and experimental data on impact of redox and ROS, of low protein intake, excess methionine load and vitamin A, on methyl transfers are reviewed. The consequences of antenatal and postnatal administration of glucocorticoids are presented. Analysis of the correlates of insulin sensitivity at older age, suggests that premature birth is the major contributor, and is compounded by gain in weight during infancy. We speculate that premature interruption of pregnancy and neonatal interventions by affecting one carbon metabolism may cause programming effects on the immature baby. These can be additive to the effects of intrauterine environment (growth restriction) and are compounded by accelerated growth in early infancy.

Preterm birth and the metabolic syndrome in adult life: a systematic review and meta-analysis

BACKGROUND

Preterm birth is associated with features of the metabolic syndrome in later life. We performed a systematic review and meta-analysis of studies reporting markers of the metabolic syndrome in adults born preterm.

METHODS

Reports of metabolic syndrome-associated features in adults (≥18 years of age) born at <37-week gestational age and at term (37- to 42-week gestational age) were included. Outcomes assessed were BMI, waist-hip ratio, percentage fat mass, systolic (SBP) and diastolic (DBP) blood pressure, 24-hour ambulatory SBP and DBP, flow-mediated dilatation, intima-media thickness, and fasting glucose, insulin, and lipid profiles.

RESULTS

Twenty-seven studies, comprising a combined total of 17,030 preterm and 295,261 term-born adults, were included. In adults, preterm birth was associated with significantly higher SBP (mean difference, 4.2 mm Hg; 95% confidence interval [CI], 2.8 to 5.7; P < .001), DBP (mean difference, 2.6 mm Hg; 95% CI, 1.2 to 4.0; P < .001), 24-hour ambulatory SBP (mean difference, 3.1 mm Hg; 95% CI, 0.3 to 6.0; P = .03), and low-density lipoprotein (mean difference, 0.14 mmol/L; 95% CI, 0.05 to 0.21; P = .01). The preterm-term differences for women was greater than the preterm-term difference in men by 2.9 mm Hg for SBP (95% CI [1.1 to 4.6], P = .004) and 1.6 mm Hg for DBP (95% CI [0.3 to 2.9], P = .02).

CONCLUSIONS

For the majority of outcome measures associated with the metabolic syndrome, we found no difference between preterm and term-born adults. Increased plasma low-density lipoprotein in young adults born preterm may represent a greater risk for atherosclerosis and cardiovascular disease in later life. Preterm birth is associated with higher blood pressure in adult life, with women appearing to be at greater risk than men.

Embryo-transfer of the F2 postnatal calorie restricted female rat offspring into a control intra-uterine environment normalizes the metabolic phenotype

OBJECTIVE

Postnatal calorie and growth restriction (PNGR) in the first generation (F1) rat female offspring causes a lean and glucose tolerant phenotype associated with hypoinsulinemia and reduced glucose-stimulated insulin secretion (GSIS). Despite the absence of gestational hyperglycemia in the F1 PNGR female, naturally born second generation (F2) PNGR female adult offspring reportedly exhibit obesity, hyperglycemia with insulin resistance. The objective of this study was to determine the role of the intrauterine environment on the heritability of the trans-generational phenotypic expression in the F2 PNGR female adult offspring.

MATERIALS/METHODS

We performed embryo transfer (ET) of the F2 embryos from the procreating F1 pregnant PNGR or control (CON) females to gestate in control recipient rat mothers. Employing stable isotopes glucose metabolic kinetics was determined.

RESULTS

Birth weight, postnatal growth pattern and white adipose tissue in female F2 ET-PNGR were similar to ET-CON. Similarly, no differences in basal glucose and insulin concentrations, GSIS, glucose futile cycling and glucose clearance were seen. When compared to F2 ET-CON, F2 ET-PNGR showed no overall difference in glucose or hepatic glucose production (HGP) AUCs with minimal hyperglycemia (p<0.04) as a result of unsuppressed endogenous HGP (p<0.02) observed only during the first phase of IVGTT.

CONCLUSIONS

We conclude that the lean, glucose tolerant and hypoinsulinemic phenotype with reduced GSIS in the F1 generation is nearly normalized when the embryo-transferred F2 offspring gestates in a normal metabolic environment. This observation supports a role for the intra-uterine environment in modifying the heritability of the trans-generational PNGR phenotype.

Early-term birth (37-38 weeks) and mortality in young adulthood

BACKGROUND

Early-term birth (gestational age, 37-38 weeks) has been associated with increased infant mortality relative to later-term birth, but mortality beyond infancy has not been studied. We examined the association between early-term birth and mortality through young adulthood.

METHODS

We conducted a national cohort study of 679,981 singleton births in Sweden in 1973-1979, followed up for all-cause and cause-specific mortality through 2008 (ages 29-36 years).

RESULTS

There were 10,656 deaths in 21.5 million person-years of follow-up. Among those still alive at the beginning of each age range, early-term birth relative to those born at 39-42 weeks was associated with increased mortality in the neonatal period (0-27 days: adjusted hazard ratio = 2.18 [95% confidence interval = 1.89-2.51]), postneonatal period (28-364 days: 1.66 [1.44-1.92]), early childhood (1-5 years: 1.29 [1.10-1.51]), and young adulthood (18-36 years: 1.14 [1.05-1.24]), but not in late childhood/adolescence (6-17 years: 0.97 [0.84-1.12]). In young adulthood, early-term birth was strongly associated with death from congenital anomalies and endocrine disorders, especially diabetes (2.89 [1.54-5.43]).

CONCLUSIONS

In this large national cohort study, early-term birth was independently associated with increased mortality in infancy, early childhood, and young adulthood. Lowest short-term and long-term mortality was among those born at 39-42 weeks.

Leptin may enhance hepatic insulin sensitivity in children and women born small for gestational age

OBJECTIVE

Children born small for gestational age (SGA) are at risk for developing type 2 diabetes. Lipodystrophy leads to early type 2 diabetes and leptin reverses the metabolic consequences of the disease. Low IGF-binding protein 1 (IGFBP1) can predict the development of type 2 diabetes. The aim of this study was to determine leptin, insulin, and IGFBP1 in children and adult women born preterm or SGA to evaluate the role of leptin as a compensatory mechanism in insulin resistance development.

METHODS

Seventy-six children (8.5-10 years, 41 girls and 35 boys) and 45 women (23-30 years) were studied. The children comprised subjects born appropriate for gestational age (<30 gestational weeks) (n=22), born SGA at term (n=23), and full-term normal-weight controls (n=31). Among the women, the corresponding figures were, n=10, n=18, and n=17 respectively. Fasting levels of IGFBP1, leptin, insulin, and IGF1 were determined and total adiponectin only in women.

RESULTS

In girls and women, term SGA subjects had higher leptin levels in relation to BMI SDS (P=0.042 and P=0.03 respectively). More than half of IGFBP1 variability was explained by leptin and insulin in children. In term SGA women, IGFBP1 level was lower compared with controls (P=0.012) and the regression line of IGFBP1 on insulin was suppressed below -1 s.d. of a reference material.

CONCLUSION

Leptin levels were elevated in term SGA girls and women, in particular in adult women, but not found in preterm girls and women. IGFBP1 was lower in term SGA women. In children, leptin and insulin were strong suppressors of IGFBP1. We speculate that higher leptin levels could be a protective event to enhance hepatic insulin sensitivity.

Feeding preterm infants today for later metabolic and cardiovascular outcomes

Preterm birth continues to contribute disproportionately to neonatal morbidity and subsequent physical and neurodevelopmental disabilities. Epidemiologic studies have described additional long-term health consequences of preterm birth such as an increased risk of hypertension and insulin resistance in adult life. It is not known whether the influence of infant and childhood growth rates and early nutrition on long-term outcomes is the same or different among preterm infants and neonates with intrauterine growth restriction. Our goal is to review the effects of fetal growth, postnatal growth, and early nutrition on long-term cardiovascular and metabolic outcomes in preterm infants. Present evidence suggests that even brief periods of relative undernutrition during a sensitive period of development have significant adverse effects on later development. Our review suggests that growth between birth and expected term and 12-18 months post-term has no significant effect on later blood pressure and metabolic syndrome, whereas reduced growth during hospitalization significantly impacts later neurodevelopment. In contrast, growth during late infancy and childhood appears to be a major determinant of later metabolic and cardiovascular well being, which suggests that nutritional interventions during this period are worthy of more study. Our review also highlights the paucity of well-designed, controlled studies in preterm infants of the effects of nutrition during hospitalization and after discharge on development, the risk of developing hypertension, or insulin resistance.

Self- and parent-rated executive functioning in young adults with very low birth weight

BACKGROUND AND OBJECTIVE

Adults born preterm score lower on performance-based tests of executive functioning (EF) than their term-born peers. These test scores do not necessarily translate to application of these skills in an everyday environment. The objective of the study was to test differences between very low birth weight (VLBW; <1500 g) adults and their term-born peers in self- and parent-rated EF and examine concordance between self- and parent-rated EF and performance-based tests of EF.

METHODS

A longitudinal study of 90 VLBW adults and 93 term-born controls (aged 21-30 years) was performed. The young adults and their parents filled in the Behavioral Rating Inventory of Executive Functioning-Adult Version, and the adults underwent performance-based tests of EF.

RESULTS

VLBW young adults and especially those born appropriate for gestational age reported fewer problems in behavioral regulation and global EF than term-born controls; however, parents of VLBW adults born small for gestational age reported more problems for their children in all EF scales than parents of the controls. Compared with their parents, VLBW young adults reported fewer problems in behavioral regulation. Adults' ratings and their parents' ratings correlated significantly among VLBW and control groups. In the VLBW and VLBW/small-for-gestational-age groups, parent ratings of EF were correlated to performance-based tests, whereas among term-born adults, self-reports correlated.

CONCLUSIONS

These findings reveal that VLBW adults may have learned to compensate in the everyday environment for their EF deficits apparent in performance-based tests. Alternatively, VLBW adults may have positively skewed views of their abilities.

Response to an aerobic training intervention in young adults depends on ponderal index at birth

Poor fetal growth is associated with later-life changes in adult body composition and decrements in muscle strength and morphology. Few studies have investigated the association of poor fetal growth with whole-body exercise. The purpose of this study was to investigate the association of poor fetal growth with the maximal oxygen consumption (VO(2)max), lactate levels during exercise and the response to aerobic training. Thirty-six college-aged men and women (aged 20.8 ± 0.3 years), born to term (37-42 weeks gestation), were recruited to participate in an 8-week training program. Participants comprised two groups, high ponderal index (HIGHPI) and low ponderal index (LOWPI) (n = 18/group), identified as falling above and below the 10th percentile of the ponderal index (g/cm(3))-for-gestational age distribution, respectively. The HIGHPI and LOWPI were matched pair-wise on age, sex, body mass index and pre-study physical activity patterns. The LOWPI and HIGHPI did not differ significantly before training, after training or with a change (Δ) in training VO(2)max (l/min or ml/min kg/fat-free mass (FFM)). However, LOWPI had significantly lower pre-training lactate levels at similar levels of relative work output (P = 0.016), and significantly smaller decreases in lactate at a fixed level of absolute work after training (P = 0.044). These differences were independent of pre-training aerobic fitness, the change in fitness with training, diet and fuel substrate choice. The lower lactate of untrained LOWPI subjects during exercise could reflect metabolic reprograming due to intrauterine growth restriction, or could be secondary to muscle morphological and/or fiber-type distribution changes that also associate with poor fetal growth.

Pregnancy complications among women born preterm

BACKGROUND

Adults who were born with low birth weights are at increased risk of cardiovascular and metabolic conditions, including pregnancy complications. Low birth weight can result from intrauterine growth restriction, preterm birth or both. We examined the relation between preterm birth and pregnancy complications later in life.

METHODS

We conducted a population-based cohort study in the province of Quebec involving 7405 women born preterm (554 < 32 weeks, 6851 at 32-36 weeks) and a matched cohort of 16 714 born at term between 1976 and 1995 who had a live birth or stillbirth between 1987 and 2008. The primary outcome measures were pregnancy complications (gestational diabetes, gestational hypertension, and preeclampsia or eclampsia).

RESULTS

Overall, 19.9% of women born at less than 32 weeks, 13.2% born at 32-36 weeks and 11.7% born at term had at least 1 pregnancy complication at least once during the study period (p < 0.001). Women born small for gestational age (both term and preterm) had increased odds of having at least 1 pregnancy complication compared with women born at term and at appropriate weight for gestational age. After adjustment for various factors, including birth weight for gestational age, the odds of pregnancy complications associated with preterm birth was elevated by 1.95-fold (95% confidence interval [CI] 1.54-2.47) among women born before 32 weeks' gestation and 1.14-fold (95% CI 1.03-1.25) among those born at 32-36 weeks' gestation relative to women born at term.

INTERPRETATION

Being born preterm, in addition to, and independent of, being small for gestational age, was associated with a significantly increased risk of later having pregnancy complications.

Insulin sensitivity and β-cell function in adults born preterm and their children

We aimed to evaluate insulin secretion and insulin sensitivity in adults born preterm and their children. Subjects were adults born both preterm and at term, with their children aged 5-10 years born at term. Insulin sensitivity and secretion were assessed using hyperglycemic clamps in adults and frequently sampled intravenous glucose tolerance tests using Bergman minimal model in children. In total, 52 adults aged 34-38 years participated (31 born preterm, mean gestational age 33.3 weeks). Adults born preterm were less insulin sensitive than those born at term (19.0 ± 2.5 vs. 36.3 ± 5.2 mg · kg(-1) · min(-1)mU · L; P < 0.05) with compensatory increased first-phase insulin secretion (56.1 ± 8.5 vs. 25.3 ± 3.7 mU/L; P < 0.001) but similar disposition index indicating appropriate insulin secretion. These differences were independent of sex and remained when subjects born <32 weeks' gestation were excluded from analyses. In total, 61 children were studied (37 of preterm parents, mean age 7.9 ± 0.3 years). Children of parents born preterm had similar insulin sensitivity to children of parents born at term, but a correlation between parental and offspring insulin sensitivity was noted only among children of parents born preterm. In conclusion, adults born preterm have insulin resistance in midadulthood, but this was not associated with insulin resistance in their children.

The ontogeny of the endocrine pancreas in the fetal/newborn baboon

Erratic regulation of glucose metabolism including hyperglycemia is a common condition in premature infants and is associated with increased morbidity and mortality. The objective of this study was to examine histological and ultrastructural differences in the endocrine pancreas in fetal (throughout gestation) and neonatal baboons. Twelve fetal baboons were delivered at 125 days (d) gestational age (GA), 140d GA, or 175d GA. Eight animals were delivered at term (185d GA); half were fed for 5 days. Seventy-three nondiabetic adult baboons were used for comparison. Pancreatic tissue was studied using light microscopy, confocal imaging, and electron microscopy. The fetal and neonatal endocrine pancreas islet architecture became more organized as GA advanced. The percent areas of α-β-δ-cell type were similar within each fetal and newborn GA (NS) but were higher than the adults (P<0.05) regardless of GA. The ratio of β cells within the islet (whole and core) increased with gestation (P<0.01). Neonatal baboons, which survived for 5 days (feeding), had a 2.5-fold increase in pancreas weight compared with their counterparts killed at birth (P=0.01). Endocrine cells were also found in exocrine ductal and acinar cells in 125, 140 and 175d GA fetuses. Subpopulation of tissue that coexpressed trypsin and glucagon/insulin shows the presence of cells with mixed endo-exocrine lineage in fetuses. In summary, the fetal endocrine pancreas has no prevalence of a α-β-δ-cell type with larger endocrine cell percent areas than adults. Cells with mixed endocrine/exocrine phenotype occur during fetal development. Developmental differences may play a role in glucose homeostasis during the neonatal period and may have long-term implications.

Glucose metabolism soon after birth in very premature infants with small- and appropriate-for-gestational-age birth weights

The intrauterine environment affects the development of insulin resistance in adulthood. To determine the influence of foetal growth restriction on glucose metabolism, we assessed indices of insulin sensitivity soon after birth in very premature infants. Blood samples were collected at birth from 52 premature infants with a gestational age of ≤31 weeks, who were divided into a group whose birth weight was small for their gestational age (SGA group, n=19) and a group whose birth weight was appropriate for their gestational age (AGA group, n=33). Blood glucose, serum insulin and C-peptide immunoreactivity (CPR) levels were measured in both groups. Furthermore, the quantitative insulin check index (QUICKI) was also calculated. Correlations between these indices and glucose metabolism and the standard deviation (SD) score for birth weight were also determined. The levels of insulin and CPR were significantly (p<0.05) lower in the SGA group than in the AGA group. The QUICKI was significantly (p<0.05) higher in the SGA group compared with the AGA group. The SD score for birth weight was correlated with the QUICKI (p<0.01), the serum insulin level (p<0.05) and the CPR level (p<0.05) in all 52 infants.

CONCLUSION

In very premature infants, poor foetal growth may impair foetal insulin secretion and affect the QUICKI at birth.

Effect of sex and gestational age on neonatal body composition

To determine the effects of length of gestation and sex on infant body composition, air displacement plethysmography was performed in forty-six full-term neonates at 3 d of life and during the week prior to hospital discharge in 180 preterm neonates. Fat mass, as a percentage of body weight, was higher in preterm than in term infants (13·4 (sd 4·2) v. 10·1 (sd 3·7) %, respectively; P= 0·001). The absolute amount of fat mass did not differ between preterm and full-term newborns (323 (sd 126) v. 335 (sd 138) g; P= 0·58), whereas lean body mass was lower in preterm than in term infants (2055 (sd 280) v. 2937 (sd 259) g, respectively; P< 0·001). Among full-term infants, fat mass was higher in females than in males (11·1 (sd 3·7) v. 9·0 (sd 3·3) %, respectively; P= 0·047), whereas we did not observe any sex difference in preterm infants (13·5 (sd 4·1) v. 13·4 (sd 4·3) %; P= 0·89). Our data suggest that by the time they are discharged from hospital: (1) preterm infants have a higher percentage of body fat than term neonates and (2) this is presumably due to a lesser accretion in lean body mass in the first few weeks of extra-uterine life, particularly in boys.

Birth-weight, insulin levels, and HOMA-IR in newborns at term

Background

Recent studies have demonstrated that low and high birth-weight at birth are risk factors of developing diabetes. The aim of this study was to determine if the abnormal birth-weight is related with hyperinsulinemia and elevated index of the Homeostasis Model assessment for Insulin Resistance (HOMA-IR) at birth, in at term newborns.

Methods

Newborns with gestational age between 38 and 41 weeks, products of normal pregnancies of healthy mothers aged 18 to 39 years, were eligible to participate. Small-for-gestational age (SGA) and large-for-gestational age (LGA) newborns were compared with appropriate-for-gestational (AGA) age newborns. Incomplete or unclear data about mother’s health status, diabetes, gestational diabetes, history of gestational diabetes, hypertension, pre-eclampsia, eclampsia, and other conditions that affect glucose metabolism were exclusion criteria. Hyperinsulinemia was defined by serum insulin levels ≥13.0 μU/mL and IR by HOMA-IR ≥2.60. Multiple logistic regression analysis was used to determine the odds ratio (OR) that computes the association between birth-weight (independent variable) with hyperinsulinemia and HOMA-IR index (dependent variables).

Results

A total of 107 newborns were enrolled; 13, 22, and 72 with SGA, LGA, and AGA, respectively. Hyperinsulinemia was identified in 2 (15.4%), 6 (27.3%), and 5 (6.9%) with SGA, LGA, and AGA (p=0.03), whereas IR in 3 (23.1%), 8 (36.4%), and 10 (13.9%) newborns with SGA, LGA and AGA (p=0.06). The LGA showed a strong association with hyperinsulinemia (OR 5.02; CI 95%, 1.15-22.3; p=0.01) and HOMA-IR (OR 3.54; CI 95%, 1.03-12.16; p=0.02); although without statistical significance, the SGA showed a tendency of association with hyperinsulinemia (OR 2.43; CI 95%, 0.43-17.3 p=0.29) and HOMA-IR (OR 1.86; CI 95%, 0.33-9.37; p=0.41).

Conclusions

Our results suggest that LGA is associated with hyperinsulinemia and elevated HOMA-IR at birth whereas the SGA show a tendency of association.

Preterm birth and leisure participation: a synthesis of the literature

Leisure participation has been associated with happiness and well-being in children. Individuals born preterm are at greater risk for motor, cognitive and behavioral difficulties which may contribute to difficulties participating in leisure activities. This systematic review examined the current knowledge on participation in leisure activities in individuals born preterm throughout the lifespan as compared to term born controls. An electronic search of eight databases for articles published up to October 2011 was conducted. The quality of each study was assessed using a standardized checklist. Thirteen studies met the selection criteria. In school-age children, no significant differences were found in activity levels between children born prematurely and term born controls. In adolescents, leisure scores in social activities, hobbies and sports were statistically significantly lower compared to controls. In young adults, differences in frequency and intensity of physical activity were reported compared to term controls. Promoting participation in leisure activities should be encouraged at a young age and continued to adulthood by minimizing the gaps between capabilities and the demands of the tasks and the environment.

Impact of fetal programming, birth weight, and infant feeding on later hypertension

The concept of developmental origins of adult disease derives from both epidemiologic and basic sciences. This brief review considers the impact of the intrauterine milieu, intrauterine growth retardation, premature birth, and infant feeding on later hypertension and kidney disease.