Arterial Structure and Stiffness Are Altered in Young Adults Born Preterm

From premature birth to premature kidney disease: does accelerated aging play a role?

As the limits of fetal viability have increased over the past 30 years, there has been a growing body of evidence supporting the idea that chronic disease should be taken into greater consideration in addition to survival after preterm birth. Accumulating evidence also suggests there is early onset of biologic aging after preterm birth. Similarly, chronic kidney disease (CKD) is also associated with a phenotype of advanced biologic age which exceeds chronologic age. Yet, significant knowledge gaps remain regarding the link between premature biologic age after preterm birth and kidney disease. This review summarizes the four broad pillars of aging, the evidence of premature aging following preterm birth, and in the setting of CKD. The aim is to provide additional plausible biologic mechanisms to explore the link between preterm birth and CKD. There is a need for more research to further elucidate the biologic mechanisms of the premature aging paradigm and kidney disease after preterm birth. Given the emerging research on therapies for premature aging, this paradigm could create pathways for prevention of advanced CKD.

Effect of preterm birth on blood pressure in later life: A systematic review and meta-analysis

Introduction

Preterm birth is linked to various complications in both infancy and adulthood. We assessed the association between preterm birth and hypertension in adulthood.

Materials and Methods

PubMed, EMBASE, and Cochrane CENTRAL Register were searched for randomized controlled trials (RCT) comparing systolic and diastolic blood pressures in individuals born preterm and those born full-term, from inception till April 11th, 2022. Data were extracted, pooled, and analyzed. Forest plots were created for a visual demonstration.

Results

Twenty-eight studies were included in our meta-analysis. SBP and DBP across all categories (Mean, Ambulatory, Daytime, and Nighttime) were higher in the preterm group compared to the term group. Mean SBP, mean ambulatory SBP, mean daytime SBP and mean nighttime SBP were 4.26 mmHg [95% CI: 3.09-5.43; P < 0.00001], 4.53 mmHg [95% CI: 1.82-7.24; P = 0.001], 4.51 mmHg [95% CI: 2.56-6.74; P < 0.00001], and 3.06 mmHg [95% CI: 1.32-4.80; P = 0.0006] higher in the preterm group, respectively. Mean DBP, mean ambulatory DBP, mean daytime DBP, and mean nighttime DBP were 2.32 mmHg [95% CI: 1.35-3.29; P < 0.00001], 1.54 mmHg [95% CI 0.68-2.39; P = 0.0004], 1.74 mmHg [95% CI: 0.92-2.56; P < 0.0001], and 1.58 mmHg [95% CI: 0.34-2.81; P = 0.01] higher in the preterm group, respectively.

Conclusion

Our observations suggest that individuals who were born preterm may have higher blood pressures as compared to those who were born full-term.

Accelerated Aging and the Life Course of Individuals Born Preterm

Individuals born preterm have shorter lifespans and elevated rates of chronic illness that contribute to mortality risk when compared to individuals born at term. Emerging evidence suggests that individuals born preterm or of low birthweight also exhibit physiologic and cellular biomarkers of accelerated aging. It is unclear whether, and to what extent, accelerated aging contributes to a higher risk of chronic illness and mortality among individuals born preterm. Here, we review accelerated aging phenotypes in adults born preterm and biological pathways that appear to contribute to accelerated aging. We highlight biomarkers of accelerated aging and various resiliency factors, including both pharmacologic and non-pharmacologic factors, that might buffer the propensity for accelerated aging among individuals born preterm.

Assessment of Vascular Indices by Abdominal Aortic Ultrasonography in Preterm Neonates with Bronchopulmonary Dysplasia

Preterm infants with bronchopulmonary dysplasia (BPD) frequently encounter systemic hypertension, yet the underlying cause remains elusive. Given the absence of prior investigations concerning the correlation between systemic hypertension and aortic thickness, we undertook this study to assess and juxtapose diverse vascular indices amidst preterm neonates with BPD, preterm neonates lacking BPD, and healthy neonates, utilizing abdominal aorta ultrasonography. This cross-sectional study encompassed 20 preterm neonates, 20 preterm neonates with BPD, and 20 healthy neonates, meticulously matched for sex and postnatal age. Comprehensive demographic, anthropometric, and clinical evaluation data were documented. The neonates underwent abdominal aortic ultrasonography for comparative evaluation of aortic wall thickness and vasomotor function across the three groups. The study revealed that neonates with BPD exhibited a notably higher average systolic blood pressure than preterm and term neonates (P < 0.05). Conversely, echocardiographic parameters such as input impedance, and arterial wall stiffness index displayed no substantial variance among the three groups (P > 0.05). The mean (SD) aortic intima-media thickness (aIMT) for preterm neonates with BPD, preterm neonates, and term neonates were 814 (193.59) μm, 497.50 (172.19) μm, and 574.00 (113.20) μm, correspondingly (P < 0.05). Furthermore, the mean (SD) pulsatile diameter for preterm neonates with BPD, preterm neonates, and term neonates were 1.52 (0.81) mm, 0.91 (0.55) mm, and 1.34 (0.51) mm, respectively (P < 0.05). Following adjustment for birth weight, sex, and gestational age at birth, the study identified a noteworthy correlation between aIMT and BPD. The investigation concluded that the mean aortic intima-media thickness (aIMT) was significantly elevated in preterm neonates with BPD, signifying a potential early indicator of atherosclerosis and predisposition to future heightened blood pressure and cardiovascular ailments. Consequently, the study postulates that aIMT could be a consistent and well-tolerated marker for identifying BPD patients at risk of developing these health complications.

Birth weight and subclinical cardiovascular and renal damage in a population-based study (the STANISLAS cohort study)

OBJECTIVE

Although preterm-born and low-birth-weight individuals have an increased risk of cardiovascular diseases in adulthood, little is known regarding early cardiovascular and renal damage (CVRD) or hypertension in adulthood. Our study investigated the association of birth weight with early CVRD markers as well as the heritability of birth weight in an initially healthy family-based cohort.

METHODS

This study was based on 1028 individuals from the familial longitudinal STANISLAS cohort (399 parents/629 children) initiated in 1993-1995, with a fourth examination conducted in 2011-2016. Analyses performed at the fourth visit included pulse-wave velocity, central pressure, ambulatory blood pressure, hypertension status, diastolic dysfunction/distensibility, left ventricular mass indexed (LVMI), carotid intima-media thickness and kidney damage. The family structure of the cohort allowed birth weight heritability estimation.

RESULTS

Mean (±SD) birth weight was 3.3 ± 0.6 kg. Heritability was moderate (42-44%). At the fourth visit, individuals were 37 years old (32.0-57.0), 56% were women and 13% had antihypertensive treatment. Birth weight was strongly and negatively associated with hypertension [odds ratio (OR) 95% confidence interval (CI) 0.61 (0.45-0.84)]. A nonlinear association was found with LVMI, participants with a birth weight greater than 3 kg having a higher LVMI. A positive association ( β 95% CI 5.09 (1.8-8.38)] was also observed between birth weight and distensibility for adults with normal BMI. No associations were found with other CVRD.

CONCLUSION

In this middle-aged population, birth weight was strongly and negatively associated with hypertension, and positively associated with distensibility in adults with normal BMI and with LVMI for higher birth weights. No associations were found with other CVRD markers.

Microvascular and oxidative stress responses to acute high-altitude exposure in prematurely born adults

Premature birth is associated with endothelial and mitochondrial dysfunction, and chronic oxidative stress, which might impair the physiological responses to acute altitude exposure. We assessed peripheral and oxidative stress responses to acute high-altitude exposure in preterm adults compared to term born controls. Post-occlusive skeletal muscle microvascular reactivity and oxidative capacity from the muscle oxygen consumption recovery rate constant (k) were determined by Near-Infrared Spectroscopy in the vastus lateralis of seventeen preterm and seventeen term born adults. Measurements were performed at sea-level and within 1 h of arrival at high-altitude (3375 m). Plasma markers of pro/antioxidant balance were assessed in both conditions. Upon acute altitude exposure, compared to sea-level, preterm participants exhibited a lower reperfusion rate (7 ± 31% vs. 30 ± 30%, p = 0.046) at microvascular level, but higher k (6 ± 32% vs. -15 ± 21%, p = 0.039), than their term born peers. The altitude-induced increases in plasma advanced oxidation protein products and catalase were higher (35 ± 61% vs. -13 ± 48% and 67 ± 64% vs. 15 ± 61%, p = 0.034 and p = 0.010, respectively) and in xanthine oxidase were lower (29 ± 82% vs. 159 ± 162%, p = 0.030) in preterm compared to term born adults. In conclusion, the blunted microvascular responsiveness, larger increases in oxidative stress and skeletal muscle oxidative capacity may compromise altitude acclimatization in healthy adults born preterm.

Higher blood pressure in adolescent boys after very preterm birth and fetal growth restriction

BACKGROUND

Although preterm birth predisposes for cardiovascular disease, recent studies in children indicate normal blood pressure and arterial stiffness. This prospective cohort study therefore assessed blood pressure and arterial stiffness in adolescents born very preterm due to verified fetal growth restriction (FGR).

METHODS

Adolescents (14 (13-17) years; 52% girls) born very preterm with FGR (preterm FGR; n = 24) and two control groups born with appropriate birth weight (AGA), one in similar gestation (preterm AGA; n = 27) and one at term (term AGA; n = 28) were included. 24-hour ambulatory blood pressure and aortic pulse wave velocity (PWV) and distensibility by magnetic resonance imaging were acquired.

RESULTS

There were no group differences in prevalence of hypertension or in arterial stiffness (all p ≥ 0.1). In boys, diastolic and mean arterial blood pressures increased from term AGA to preterm AGA to preterm FGR with higher daytime and 24-hour mean arterial blood pressures in the preterm FGR as compared to the term AGA group. In girls, no group differences were observed (all p ≥ 0.1).

CONCLUSIONS

Very preterm birth due to FGR is associated with higher, yet normal blood pressure in adolescent boys, suggesting an existing but limited impact of very preterm birth on cardiovascular risk in adolescence, enhanced by male sex and FGR.

IMPACT

Very preterm birth due to fetal growth restriction was associated with higher, yet normal blood pressure in adolescent boys. In adolescence, very preterm birth due to fetal growth restriction was not associated with increased thoracic aortic stiffness. In adolescence, very preterm birth in itself showed an existing but limited effect on blood pressure and thoracic aortic stiffness. Male sex and fetal growth restriction enhanced the effect of preterm birth on blood pressure in adolescence. Male sex and fetal growth restriction should be considered as additional risk factors to that of preterm birth in cardiovascular risk stratification.

Association of Gestation and Fetal Growth Restriction on Cardiovascular Health in Preterm-Born Children

OBJECTIVES

To prospectively evaluate the associations of early and current life factors, including gestational age and fetal growth restriction in preterm-born subjects, on cardiovascular health including measures of central and peripheral blood pressure and arterial stiffness and assess cardiovascular changes before and after acute exercise in preterm- and term-born school-aged children.

STUDY DESIGN

From 240 children, aged 7-12 years, 204 (141 preterm-born and 63 term-born) had satisfactory data. An oscillometric device recorded cardiovascular measures before and after cycle ergometer exercise testing. Data were analyzed with multivariable linear regression and mediation.

RESULTS

Central systolic blood pressure (SBP) was 6.4 mmHg (95% CI, 1.2, 11.6) higher in preterm-born children with fetal growth restriction and 3.4 mmHg (0.02, 6.8) higher in those without fetal growth restriction when compared with term controls. Augmentation index was 4.1% (0.7, 7.4) higher in the preterm fetal growth restriction group when compared with those without fetal growth restriction but was similar between the latter group and term controls. Regression modelling showed gestational age, female sex, and antenatal smoking, but not fetal growth restriction, were significantly associated with SBP. In contrast, fetal growth restriction and fat mass index, but not gestation, were significantly associated with augmentation index. Cardiovascular exercise responses were similar between all 3 groups studied.

CONCLUSIONS

Our data show the differential associations of prematurity and fetal growth restriction on central SBP and augmentation index. Cardiovascular responses to exercise were similar in all 3 groups. Preterm-born children with and without fetal growth restriction are at an increased risk of cardiovascular disease in adult life.

TRIAL REGISTRATION

URL: https://www.clinicaltrialsregister.eu/ctr-search/trial/2015-003712-20/GB: RHiNO, EudraCT: 2015-003712-20.

Cardiopulmonary Exercise Testing in Childhood in Late Preterms: Comparison to Early Preterms and Term-Born Controls

Background: Late preterm (340−366 weeks gestational age [GA]) infants may have abnormal pulmonary development and possible exercise physiology parameters. We aim to assess the effect of late prematurity on exercise capacity in childhood and to compare it to early preterm (EP) (born < 300 GA), and to term healthy control (TC) (>370 week GA). Methods: Late preterm and early preterm (7−10 years) completed a cardiopulmonary exercise test (CPET) and spirometry and were compared to EP and to TC. Results: Eighty-four children (age 9.6 ± 1.0 years, 48% girls) participated. Twenty-one former LP were compared to 38 EP (15 with Bronchopulmonary dysplasia (BPD) [EP+], 23 without BPD [EP−]) and to 25 TC children. Peak oxygen uptake (peakV̇O2) was statistically lower than in the TC, but within the normal range, and without difference from the EP (LP 90.2 ± 15.1%, TC 112.4 ± 16.9%, p < 0.001; EP+ 97.3 ± 25.5%, EP− 85.4 ± 20.8%, p = 0.016 and p < 0.001, respectively, when compared with TC). Lung function (FEV1) was lower than normal only in the EP+ (75.6 ± 14.9% predicted, compared with 12.5 ± 87.8 in EP−, 87.5 ± 16.9 in LP and 91.0 ± 11.7 in TC). Respiratory and cardiac limitations were similar between all four study groups. Conclusions: This study demonstrated lower exercise capacity (peakV̇O2) in former LP children compared with healthy term children. Exercise capacity in LP was comparable to that of EP, with and without BPD. However, the exercise test parameters, specifically peakV̇O2, were within the normal range, and no significant physiological exercise limitations were found.

Diagnosing Arterial Stiffness in Pregnancy and Its Implications in the Cardio-Renal-Metabolic Chain

Cardio-renal and metabolic modifications during gestation are crucial determinants of foetal and maternal health in the short and long term. The cardio-renal metabolic syndrome is a vicious circle that starts in the presence of risk factors such as obesity, hypertension, diabetes, kidney disease and ageing, all predisposing to a status dominated by increased arterial stiffness and alteration of the vascular wall, which eventually damages the target organs, such as the heart and kidneys. The literature is scarce regarding cardio-renal metabolic syndrome in pregnancy cohorts. The present paper exposes the current state of the art and emphasises the most important findings of this entity, particularly in pregnant women. The early assessment of arterial function can lead to proper and individualised measures for women predisposed to hypertension, pre-eclampsia, eclampsia, and diabetes mellitus. This review focuses on available information regarding the assessment of arterial function during gestation, possible cut-off values, the possible predictive role for future events and modalities to reverse or control its dysfunction, a fact of crucial importance with excellent outcomes at meagre costs.

Arterial stiffness and nocturnal hypertension in preterm children and adolescents

BACKGROUND AND OBJECTIVES

Preterm birth has been associated with increased risk for developing hypertension and other chronic diseases during childhood and adulthood. The aim of the current prospective case-control study was to investigate the associations of preterm birth with ambulatory blood pressure (BP) levels and arterial stiffness during childhood and adolescence.

METHODS

The study population included 52 children and adolescents born preterm and 26 healthy children born full term with similar age. The participants underwent ambulatory BP monitoring (ABPM) and assessment of carotid-femoral pulse wave velocity (PWV).

RESULTS

Preterm children presented higher night SBP z score values compared to controls, but did not differ in other ABPM parameters, office peripheral and central SBPs. Nocturnal hypertension was found in 78% (7/9) of ex-preterm children with ambulatory BP hypertension. Preterm birth was an independent predictor of PWV z score adjusted for heart rate. Estimated marginal means for PWV z score adjusted for age, sex, presence of kidney disease at birth, office BPs, night BPs, central SBP, and BMI z scores were significantly higher in preterm individuals compared to controls (0.703, 95% confidence interval [CI] 0.431-0.975 versus -0.19, 95% CI -0.574-0.536, respectively, P  = 0.027). Preterm children who were overweight presented the highest values of night SBP and PWV z score.

CONCLUSION

Preterm birth is associated with higher nocturnal BP and increased arterial stiffness in childhood and adolescence. Increased awareness for detection of hypertension and prevention of obesity in childhood could prevent future adverse cardiovascular outcomes in preterm individuals.

Exposure to high levels of oxygen in neonatal rats induce a decrease in hemoglobin levels

BACKGROUND

Anemia of prematurity is common in extremely preterm neonates, and oxygen exposure may participate to anemia by inhibiting erythropoietin secretion. We aimed to determine whether hyperoxia exerts an independent role in the occurrence of the anemia of prematurity.

METHODS

Sprague-Dawley pups were exposed to 80% oxygen or room air from days 3 to 10 of life. Main outcome was the difference in hemoglobin and circulating erythropoietin levels in animals exposed to hyperoxia at 10 days of life. We performed a complete blood count analysis using fluorescent laser flow cytometry and measured circulating erythropoietin levels using ELISA.

RESULTS

We found lower hemoglobin in the hyperoxia group, compared to the normoxia group, both in males (70 ± 3 versus 78 ± 2 g/l) and in females (71 ± 2 versus 81 ± 3 g/l) at 10 days of life. Reticulocyte count was not increased in the hyperoxia group. Circulating erythropoietin levels were lower at 10 days of life in the animals exposed to hyperoxia, both in males (33 ± 7 versus 73 ± 6 pg/ml) and in females (37 ± 5 versus 66 ± 3 pg/ml), but were similar at 28 days of life.

CONCLUSION

Neonatal exposure to hyperoxia decreases hematopoiesis in rats.

IMPACT

Mechanisms leading to anemia of prematurity are not well known and their study in humans is complicated due to multiple confounders. This study shows for the first time that exposure to high concentrations of oxygen in the neonatal period decreases hematopoiesis in rats, providing insight on the pathophysiological mechanisms of the anemia of prematurity. This research paves the way for future therapeutic developments aiming to reduce the burden of anemia of prematurity and the necessity of red blood cell transfusions in extremely preterm neonates.

Current applications for measuring pediatric intima-media thickness

Intima-media thickness is a known subclinical radiologic marker of the early manifestations of atherosclerotic disease. It is the thickness of the vessel wall, most often the carotid artery. Intima-media thickness is measured on conventional US manually or automatically. Other measurement techniques include radiofrequency US. Because there is variation in its measurement, especially in children, several recommendations have been set to increase the measurement's validity and comparability among studies. Despite these recommendations, several pitfalls should be avoided, and quality control should be performed to avoid erroneous interpretation. This article summarizes current literature in relation to the clinical applications for intima-media thickness measurement in children with known risk factors such as obesity, liver steatosis, hypercholesterolemia, diabetes, hypertension, systemic inflammatory diseases, cancer survival, kidney and liver transplant, and sickle cell disease or beta thalassemia major. Most potential indications for intima-media thickness measurement remain in the research domain and should be interpreted combined with other markers. The objective of diagnosing an increased intima-media thickness is to start a multidisciplinary treatment approach to prevent disease progression and its sequelae in adulthood.

Preterm Birth, Kidney Function and Cardiovascular Disease in Children and Adolescents

Over recent decades, there has been a global increase in preterm birth rate, which constitutes about 11% of total births worldwide. The present review aims to summarize the current knowledge on the long-term consequences of prematurity on renal and cardiovascular development and function. Recent literature supports that prematurity, intrauterine growth restriction or low birth weight (LBW) may have an adverse impact on the development of multiple organ systems, predisposing to chronic diseases in childhood and adulthood, such as arterial hypertension and chronic kidney disease. According to human autopsy and epidemiological studies, children born preterm have a lower nephron number, decreased kidney size and, in some cases, affected renal function. The origin of hypertension in children and adults born preterm seems to be multifactorial as a result of alterations in renal, cardiac and vascular development and function. The majority of the studies report increased systolic and diastolic blood pressure (BP) in individuals born preterm compared to full term. The early prevention and detection of chronic non-communicable diseases, which start from childhood and track until adulthood in children with a history of prematurity or LBW, are important.

Educational Review: The Impact of Perinatal Oxidative Stress on the Developing Kidney

Oxidative stress occurs when there is an imbalance between reactive oxygen species/reactive nitrogen species and antioxidant systems. The interplay between these complex processes is crucial for normal pregnancy and fetal development; however, when oxidative stress predominates, pregnancy related complications and adverse fetal programming such as preterm birth ensues. Understanding how oxidative stress negatively impacts outcomes for the maternal-fetal dyad has allowed for the exploration of antioxidant therapies to prevent and/or mitigate disease progression. In the developing kidney, the negative impact of oxidative stress has also been noted as it relates to the development of hypertension and kidney injury mostly in animal models. Clinical research addressing the implications of oxidative stress in the developing kidney is less developed than that of the neurodevelopmental and respiratory conditions of preterm infants and other vulnerable neonatal groups. Efforts to study the oxidative stress pathway along the continuum of the perinatal period using a team science approach can help to understand the multi-organ dysfunction that the maternal-fetal dyad sustains and guide the investigation of antioxidant therapies to ameliorate the global toxicity. This educational review will provide a comprehensive and multidisciplinary perspective on the impact of oxidative stress during the perinatal period in the development of maternal and fetal/neonatal complications, and implications on developmental programming of accelerated aging and cardiovascular and renal disease for a lifetime.

Cumulative risks predict epigenetic age in adult survivors of extremely low birth weight

Long-term sequelae of extremely low birth weight (ELBW; ≤1000 g) may contribute to accelerated biological aging. This hypothesis was examined by analyzing a range of risk factors with a molecular age marker in adults born at ELBW or normal birth weight (NBW; ≥2500 g). DNAm age-the weighted average of DNA methylation at 353 cytosine-phosphate-guanine (CpG) sites from across the genome-was derived from a sample of 45 ELBW (M_age  = 32.35 years) and 47 NBW control (M_age  = 32.44 years) adults, using the Illumina 850k BeadChip Array. At two assessments undertaken 9 years apart (at 23 and 32 years), cumulative risks were summed from six domains with potential to affect physiological and psychological health: resting respiratory sinus arrhythmia, blood pressure, basal cortisol, grip strength, body mass index, and self-esteem. At age 32 years, cumulative risks were differentially associated with epigenetic age in ELBW survivors (interaction, p < 0.01). For each additional risk factor they possessed, ELBW survivors (B = 1.43) were biologically 2.16 years older than NBW adults (B = -0.73), by the fourth decade of life. Developmental change, epigenetic maintenance, and intervention targets are discussed.

Postnatal Expression Profile of MicroRNAs Associated with Cardiovascular Diseases in 3- to 11-Year-Old Preterm-Born Children

(1) Background: Preterm-born children have an increased cardiovascular risk with the first clinical manifestation during childhood and/or adolescence. (2) Methods: The occurrence of overweight/obesity, prehypertension/hypertension, valve problems or heart defects, and postnatal microRNA expression profiles were examined in preterm-born children at the age of 3 to 11 years descending from preterm prelabor rupture of membranes (PPROM) and spontaneous preterm birth (PTB) pregnancies. The whole peripheral blood gene expression of 29 selected microRNAs associated with cardiovascular diseases was the subject of our interest. (3) Results: Nearly one-third of preterm-born children (32.43%) had valve problems and/or heart defects. The occurrence of systolic and diastolic prehypertension/hypertension was also inconsiderable in a group of preterm-born children (27.03% and 18.92%). The vast majority of children descending from either PPROM (85.45%) or PTB pregnancies (85.71%) had also significantly altered microRNA expression profiles at 90.0% specificity. (4) Conclusions: Postnatal microRNA expression profiles were significantly influenced by antenatal and early postnatal factors (gestational age at delivery, birth weight of newborns, and condition of newborns at the moment of birth). These findings may contribute to the explanation of increased cardiovascular risk in preterm-born children. These findings strongly support the belief that preterm-born children should be dispensarized for a long time to have access to specialized medical care.

Left Ventricle Structure and Function in Young Adults Born Very Preterm and Association with Neonatal Characteristics

Preterm birth increases risk of cardiovascular disease and early death. A body of evidence suggests left ventricle (LV) echocardiographic alterations in children and adults born preterm. We aimed to determine if neonatal characteristics were associated with alterations in LV structure and function in preterm adults. We evaluated a cohort of 86 young adults born preterm below 30 weeks of gestation, and 85 full-term controls. We determined LV dimensions and function using tissue Doppler imaging, conventional and speckle tracking echocardiography (STE). Adults born preterm had smaller LV dimensions, but these differences did not remain after adjustment for body surface area (BSA), which was smaller in the preterm group. Stroke volume and cardiac output were reduced even after adjustment for BSA. We found a smaller e’ wave in the preterm group, but other markers of systolic and diastolic function did not differ. Use of antenatal steroids may be associated with a further reduced cardiac output in those born preterm. Adults born preterm show alterations in markers of LV dimensions and function. Identification of these markers may represent opportunities for early prevention of cardiovascular events in this at-risk population.

Vascular Endothelial Function Assessed by Flow-Mediated Vasodilatation in Young Adults Born Very Preterm or With Extremely Low Birthweight: A Regional Cohort Study

Background: Preterm birth and low birthweight have been associated with increased risk of cardiovascular disease in young adults. Endothelial dysfunction is established as an early marker for development of atherosclerotic cardiovascular disease. Previous studies of endothelial function in young adults born very preterm or with extremely low birthweight have, however, shown diverging results. Objective: We aimed to evaluate the risk of cardiovascular disease as measured by vascular endothelial function in young adults born very preterm (<29 weeks of gestation) or with extremely low birthweight (<1,000 g), compared with term-born controls. Methods: This study included 50 young adults born very preterm or with extremely low birthweight and 49 term-born controls born in Norway in the periods 1982-1985, 1991-1992, and 1999-2000 at mean age 28 (±6) years. The endothelial function was assessed by ultrasound measured flow-mediated dilatation (FMD) of the right brachial artery. The arterial diameter was measured at baseline, after release of 5 min of occlusion, and after sublingual administration of nitroglycerine. FMD was reported as absolute and percentage diameter change from baseline and relative to nitroglycerine-induced dilatation. Results: The participants were mainly normal weight non-smokers, without hypertension, diabetes, or established cardiovascular disease. The cases and controls had mean blood pressure 112/71 (SD 12/9) and 112/69 (SD 11/8) mmHg, body mass index 24.0 (SD 4.2) and 24.4 (SD 4.5) kg/m², and HbA1c 32.7 (SD 2.5) and 33.0 (SD 2.6) mmol/mol, respectively. For both groups, 4 (8%) were smokers. Mean FMD for the adults born very preterm or with extremely low birthweight was 0.17 mm (95% CI 0.14, 0.21) vs. 0.24 mm (95% CI 0.20, 0.28) for the controls (p = 0.01), corresponding to a percentage increase of 5.4% (95% CI 4.2, 6.6) and 7.6% (95% CI 6.2, 8.9), respectively (p = 0.02). The FMD relative to maximal nitroglycerine-induced dilatation was 20% and 31%, respectively (p = 0.001). Conclusions: Young adults born very preterm or with extremely low birthweight have significantly lower FMD compared with the term-born controls suggesting an increased risk of cardiovascular disease.