The New Zealand 1986 very low birth weight cohort as young adults: mapping the road ahead

Romantic and sexual relationships of young adults born very preterm: An individual participant data meta-analysis

AIM

To compare romantic and sexual relationships between adults born very preterm (VP; <32 weeks of gestation) or with very low birth weight (VLBW; <1500 g) and at term, and to evaluate potential biological and environmental explanatory factors among VP/VLBW participants.

METHODS

This individual participant data (IPD) meta-analysis included longitudinal studies assessing romantic and sexual relationships in adults (mean sample age ≥ 18 years) born VP/VLBW compared with term-born controls. Following PRISMA-IPD guidelines, 11 of the 13 identified cohorts provided IPD from 1606 VP/VLBW adults and 1659 term-born controls. IPD meta-analyses were performed using one-stage approach.

RESULTS

Individuals born VP/VLBW were less likely to be in a romantic relationship (OR 0.49; 95% CI 0.31-0.76), to be married/cohabiting (OR 0.70, 95% CI 0.53-0.92), or to have had sexual intercourse (OR 0.21, 95% CI 0.09-0.36) than term-born adults. If sexually active, VP/VLBW participants were more likely to experience their first sexual intercourse after the age of 18 years (OR 1.93, 95% CI 1.24-3.01) than term-born adults. Among VP/VLBW adults, males, and those with neurosensory impairment were least likely to experience romantic relationships.

CONCLUSIONS

These findings reflect less optimal social functioning and may have implications for socioeconomic and health outcomes of adults born VP/VLBW.

DNA methylation patterns at birth predict health outcomes in young adults born very low birthweight

Background

Individuals born very low birthweight (VLBW) are at increased risk of impaired cardiovascular and respiratory function in adulthood. To identify markers to predict future risk for VLBW individuals, we analyzed DNA methylation at birth and at 28 years in the New Zealand (NZ) VLBW cohort (all infants born < 1500 g in NZ in 1986) compared with age-matched, normal birthweight controls. Associations between neonatal methylation and cardiac structure and function (echocardiography), vascular function and respiratory outcomes at age 28 years were documented.

Results

Genomic DNA from archived newborn heel-prick blood (n = 109 VLBW, 51 controls) and from peripheral blood at ~ 28 years (n = 215 VLBW, 96 controls) was analyzed on Illumina Infinium MethylationEPIC 850 K arrays. Following quality assurance and normalization, methylation levels were compared between VLBW cases and controls at both ages by linear regression, with genome-wide significance set to p < 0.05 adjusted for false discovery rate (FDR, Benjamini-Hochberg). In neonates, methylation at over 16,400 CpG methylation sites differed between VLBW cases and controls and the canonical pathway most enriched for these CpGs was Cardiac Hypertrophy Signaling (p = 3.44E⁻¹¹). The top 20 CpGs that differed most between VLBW cases and controls featured clusters in ARID3A, SPATA33, and PLCH1 and these 3 genes, along with MCF2L, TRBJ2-1 and SRC, led the list of 15,000 differentially methylated regions (DMRs) reaching FDR-adj significance. Fifteen of the 20 top CpGs in the neonate EWAS showed associations between methylation at birth and adult cardiovascular traits (particularly LnRHI). In 28-year-old adults, twelve CpGs differed between VLBW cases and controls at FDR-adjusted significance, including hypermethylation in EBF4 (four CpGs), CFI and UNC119B and hypomethylation at three CpGs in HIF3A and one in KCNQ1. DNA methylation GrimAge scores at 28 years were significantly greater in VLBW cases versus controls and weakly associated with cardiovascular traits. Four CpGs were identified where methylation differed between VLBW cases and controls in both neonates and adults, three reversing directions with age (two CpGs in EBF4, one in SNAI1 were hypomethylated in neonates, hypermethylated in adults). Of these, cg16426670 in EBF4 at birth showed associations with several cardiovascular traits in adults.

Conclusions

These findings suggest that methylation patterns in VLBW neonates may be informative about future adult cardiovascular and respiratory outcomes and have value in guiding early preventative care to improve adult health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-023-01463-3.

Self-reported executive function problems in adults born very low birthweight

BACKGROUND

Executive function difficulties are common among children born very preterm and/or very low birthweight (<1500 g; VLBW), but little is known about whether they persist into adulthood.

OBJECTIVES

Examine the nature and pattern of self-reported executive functioning at 23 and 28 years of age using data from a national cohort study of adults born VLBW and a comparison group of same-age full-term (FT) born adults. Also examined were associations between executive function difficulties and socio-economic outcomes.

METHODS

All infants born VLBW in New Zealand during 1986 were prospectively included in an audit of retinopathy of prematurity (n = 413), with 250 (77% of survivors) followed to median age 28 years. A comparison group of FT adults was also recruited at age 23 and followed to 28 years (n = 100). Across both adult assessments, executive functioning was assessed using the Behaviour Rating Inventory of Executive Function-Adult Version (BRIEF-A) and analysed with semi-parametric models to examine the effects of age and group on executive function.

RESULTS

At 23 and 28 years, VLBW adults had increased risk of executive function impairment compared with FT adults in behaviour regulation (relative risk [CI] 2.37, 95% confidence interval (CI)1.27, 4.45), meta-cognition (RR 6.03, 95% CI 2.18, 16.78) and global functioning (RR 3.20, 95% CI 1.40, 7.28). Impaired global executive functioning was associated with lower socio-economic status (regression estimate [b] = -0.43, 95% CI -0.59, -0.27) and a reduced likelihood of home ownership by age 28 years (RR 0.98, 95% CI 0.96, 1.00), even after controlling for sex, ethnicity and parental socio-economic backgrounds for both groups.

CONCLUSION(S)

VLBW-born adults continue to experience more executive function difficulties in their everyday life relative to term controls at age 28 years. These difficulties were negatively associated with their socio-economic opportunities as young adults.

Little evidence for long-term harm from antenatal corticosteroids in a population-based very low birthweight young adult cohort

BACKGROUND

Antenatal corticosteroids (ACS) given to mothers with anticipated very preterm delivery are widely used and improve infant outcomes. Follow-up studies of the first trials of ACS have shown no adverse effects, but recently there have been concerns about possible longer-term harms.

OBJECTIVES

We aimed to assess the relationship of ACS therapy to a range of physical health and welfare measures in a cohort of very low birthweight (VLBW; <1500 g) young adults.

METHODS

Population-based cohort follow-up study. All VLBW infants born in New Zealand in 1986 were included in a prospective audit of retinopathy of prematurity. Perinatal data collection included information on ACS. At 26-30 years, 250 of 323 (77%) survivors participated, 58% having received ACS, with 229 assessed in one centre, including cardiovascular, metabolic, respiratory and neurocognitive measures. Differences in outcome between those receiving/not receiving ACS were summarised by the mean difference for continuous outcomes supplemented by Cohen's d as a standardised measure of effect size (ES), and risk ratios (RRI) for dichotomous outcomes, adjusted for relevant covariates using generalised linear regression methods.

RESULTS

There were no or minimal adverse effects of receipt of ACS versus no receipt across a range of health and welfare outcomes, both for the full cohort (adjusted ES range d = 0.01-0.23; adjusted RR range 0.78-2.03) and for individuals with gestation <28 weeks (extremely preterm; EP), except for a small increase in rates of major depression. In EP adults, receipt of ACS was associated with a higher incidence of hypertension, but might have a small benefit for IQ.

CONCLUSIONS

In this population-based VLBW cohort, we detected minimal adverse outcomes associated with exposure to ACS by the third decade of life, a similar result to the 30-year follow-up of participants in the first ACS trial. However, further follow-up is warranted.

Visuospatial working memory of children and adults born very preterm and/or very low birth weight

BACKGROUND

This paper examines the visuospatial working memory (WM) performance of children and adults born very preterm (VPT) and/or very low birth weight (VLBW) relative to their full-term (FT)-born peers. Of interest was the nature and severity of observed impairments, as well associations with educational/occupational functioning at each age point.

METHODS

Participants were drawn from two prospective cohort studies: (1) a regional cohort of 110 VPT (<32 weeks' gestation and <1500 g) and 113 FT born children assessed at age 12 years; (2) a national cohort of 229 VLBW (<1500 g) and 100 FT born adults assessed at age 28 years. Visuospatial WM was assessed using a four-span/difficulty-level computerized task.

RESULTS

Both children and adults born VPT/VLBW had poorer visuospatial WM than FT controls, with their performance less accurate, slower (correct trials), and less efficient with increasing task difficulty (Cohen's d = 0.27-0.51; p < 0.05). Adults had better visuospatial WM than children, but between-group differences were highly similar across ages, before and after adjustment for confounding social background and individual factors. Poorer WM was associated with lower levels of educational and occupational/socioeconomic achievement.

CONCLUSIONS

Visuospatial WM difficulties persist into adulthood raising concerns for the longer-term cognitive and adaptive functioning of VPT survivors.

IMPACT

Both children and adults born very preterm have poorer visuospatial working memory than their term-born peers. They are less accurate, take longer to respond correctly and are less efficient, with test performance declining with increasing cognitive demand. Similar differences in visuospatial working memory are observed between VPT/VLBW and full-term individuals during both childhood and adulthood, with these differences remaining even after covariate adjustment. Individuals with poorer visuospatial working memory have lower levels of educational achievement and occupational/socioeconomic success. Visuospatial working memory difficulties persist into adulthood and appear to continue to impact everyday functioning and life-course opportunities.

The association between low birth weight and dental caries among 11-to-13-year-old school age children in Ningbo, China

Background

The association between low birth weight (LBW) and dental caries is currently unclear. The aim of this study was to investigate the association of LBW with dental caries in permanent teeth in children of Ningbo city.

Methods

A total of 1975 children aged 11-to-13 years in Ningbo, China were enrolled in this cross-sectional study. LBW was defined as a birthweight< 2500 g. Ten dentists assessed the status of dental caries in permanent teeth in line with the World Health Organization (WHO) criteria and guidelines. Decayed, missing or filled teeth were considered to have dental caries. Parental questionnaires were used to collect child information. Non-conditional logistic regression analysis was used to estimate odds ratios (ORs) and the corresponding 95% confidence intervals (CIs).

Results

Dental caries in permanent teeth was found in 610 children (30.9%), with a mean DMFS of 2.09 (SD = 1.2). The adjusted ORs for dental caries in permanent teeth was 1.46 (95% CI 1.00, 2.13) for LBW.

Conclusions

LBW was not associated with dental caries in permanent teeth in the study population.

Right Ventricular Structure and Function in Young Adults Born Preterm at Very Low Birth Weight

Being born preterm (PT, <37 weeks gestation) or at very low birth weight (VLBW, <1500 g) is associated with increased rates of cardiopulmonary disorders in childhood. As survivors age, late cardiac effects, including right ventricular (RV) remodelling and occult pulmonary hypertension are emerging. In this population-based study, we aimed to investigate right heart structure and function in young adults born PT at VLBW compared to normal-weight term-born controls. The New Zealand VLBW Study has followed all infants born in 1986 with birth weight <1500 g. All were born preterm from 24 to 37 weeks. A total of 229 (71% of survivors) had echocardiograms aged 26–30 years which were compared to age-matched, term-born, normal-weight controls (n = 100). Young adults born preterm at very low birth weight exhibited smaller RV dimensions compared to term-born peers. Standard echocardiographic measures of RV function did not differ, but mildly reduced function was detected by RV longitudinal strain. This difference was related to birth weight and gestational age but not lung function or left ventricular function. Echocardiographic strain imaging may be an important tool to detect differences in RV function preterm and VLBW.

Visuospatial functions in preterm schoolchildren without cognitive delay: Using Pascual's Graphomotor test as a screening method

BACKGROUND

Preterm children obtain worse scores in tests that evaluate visuospatial functions. Pascual's graphomotor test (PGMt) assesses maturity in copying drawings in childhood, quickly evaluating the graphomotor aptitude that is a partial aspect of non-verbal intelligence.

AIMS

To evaluate visuospatial functions in preterm children compared to full-term children. To assess the capacity of the Pascual graphomotor test (PGMt) to detect visuospatial disorders more specifically than non-verbal intelligence quotient (IQ).

STUDY DESIGN AND SUBJECTS

case and control study.

CASES

preterm children between 5 and 11 years of age without cognitive delay; controls: full-term children with the same characteristics. For each child clinical history, neurological examination, language-free intelligence test Toni 2 (IQ) and Pascual's graphomotor test (PGMt) were carried out.

RESULTS

135 children were enrolled (59 cases vs. 79 controls). The mean age was 7.4 years. 55% were male. The mean gestational age of cases was 30.5 weeks with 34% extremely preterm. Cases obtained worse mean scores in both tests. The mean IQ scores were: cases 117.4, controls 125.0 (p = 0.004). The mean graphomotor quotient (GQ) scores were statistically and clinically significant (cases 76.8; controls 98.3, p = 0.001). Although we have found a positive correlation between IQ and GQ scores (cc = 0.31 p = 0.01), the differences found in the GQ between groups have been maintained regardless of the IQ in the multivariate analysis (GQ: cases 78.3 (SD 14.8), controls 98.3 (SD 12.5), p = 0.04).

CONCLUSIONS

GQ is a useful tool for screening for visuospatial anomalies. GQ more specifically measures the visuoperceptive disorder regardless of non-verbal cognitive level.

Reduced Exercise Capacity in Adults Born Very Low Birth Weight: A Population-Based Cohort Study

RATIONALE

Population-based data regarding the consequences of very low birth weight (VLBW) and bronchopulmonary dysplasia (BPD) on adult exercise capacity is limited.

OBJECTIVES

To compare exercise capacity in a national VLBW cohort with term-born controls and explore factors contributing to the differences.

METHODS

At 26-30 years of age, 228 VLBW survivors and 100 controls underwent lung function tests, cardiopulmonary exercise testing and assessment of resting cardiac structure/function using echocardiography. Data on self-reported physical activity were collected.

MEASUREMENTS AND MAIN RESULTS

Compared with controls, VLBW adults demonstrated reduced oxygen uptake, work rate and oxygen pulse at peak exercise (9.3%, 10.7%, 10.8% lower, respectively) and earlier anaerobic threshold (all p<0.0001), with all mean values within normal range. VLBW survivors showed reduced physical activity, impaired lung function (reduced FEV1, FEV1/FVC, DLCO), altered left ventricular structure/function (reduced mass, size, stroke volume, cardiac output) and reduced right atrial/ventricular size. Adjustment for the combination of three sets of covariates (physical activity with BMI, lung function, cardiac structure/function) explained most of the exercise group-differences. Beyond the effects of physical activity and BMI, lung function and cardiac structure/function contributed approximately equally. BPD with other prematurity-related perinatal factors (ventilation, antenatal steroids, extremely low birth weight, extreme preterm) were not associated with a reduced exercise capacity.

CONCLUSIONS

Exercise capacity was significantly reduced in VLBW adults, which we speculate is from combined effects of impaired lung function, altered heart structure/function and reduced physical activity. Perinatal factors including BPD were not associated with a reduced exercise capacity.

Biomarkers of ageing in New Zealand VLBW young adults and controls

BACKGROUND

There is individual variation in physiological ageing. Former very low birthweight (VLBW; birthweight < 1500 g) young adults may have less satisfactory measurements on some physiological parameters than term controls. We hypothesized that a summation score of physiological biomarkers that change with age would show VLBW adults to have a more advanced physiologic age than controls.

METHODS

VLBW adults (229; 71% survivors of a national VLBW cohort) and term-born controls (100) were clinically assessed at 26-30 years. Ten measured physiological biomarkers were selected and measurements converted to z-scores using normative reference data. Between-group comparisons were tested for statistical significance for individual biomarker z-scores and a summation score.

RESULTS

Nine of 10 biomarkers showed a mean z-score suggestive of older physiological age in the VLBW group versus controls. The observed mean difference in the summation score was highly significant (p < 0.001), representing a mean shift of 0.47 SD in the distribution of test scores for VLBW relative to controls.

CONCLUSIONS

Utilizing a 10-biomarker score, VLBW young adults have a score indicative of poorer physiological functioning than term-born controls. Repeating these measures after an interval could provide insights into the comparative pace of ageing between VLBW and term-born adults.

IMPACT

A summation score of 10 physiological biomarkers that are known to change with age shows that former very low birthweight adults have significantly poorer physiological functioning by the end of their third decade than term-born controls. This result adds to existing literature showing very preterm and very low birthweight young adults often have physiological and metabolic test results that are less satisfactory than those from term controls, despite mostly being in the normal range for age; for instance, higher systolic blood pressure. Although the pace of ageing in later years is yet to be established, the implications of this study are that preventative measures and lifestyle choices that impact on physiological ageing might have even greater importance for very preterm and very low birthweight graduates.

Perinatal and childhood predictors of general cognitive outcome at 28 years in a very-low-birthweight national cohort

AIM

To determine IQ at 26 to 30 years in very-low-birthweight (VLBW) adults compared with term-born controls; and to examine the stability of IQ in VLBW individuals between 7 to 8 years and 26 to 30 years, identify perinatal and social predictors of IQ, and assess the contribution of brain volume to IQ.

METHOD

At 26 to 30 years, 229 VLBW adults (71% survivors of prospectively enrolled national cohort) and 100 term-born controls were tested on the Wechsler Abbreviated Scale of Intelligence. For VLBW, IQ at 7 to 8 years, perinatal and social data were extracted from the data set, and 150 adults underwent volumetric cranial magnetic resonance imaging (MRI).

RESULTS

At 26 to 30 years, the mean adjusted difference between VLBW and controls for total IQ was 9.4 (95% CI 6.5-12.4) points. In VLBW individuals the correlation between IQ scores at 7 to 8 years and 26 to 30 years was 0.78. On multiple regression analysis, parental education was the strongest predictor of verbal and total IQ at both ages. Birthweight was a strong predictor of perceptual and total IQ. In VLBW individuals with MRI scans, the addition of brain volume as a variable increased the variance explained for perceptual and total IQ.

INTERPRETATION

VLBW adults have mean IQ scores 9 to 11 points below controls. Parental education and birthweight are the strongest predictors of IQ.

Dental status of young adults born with very low birthweight: A national cohort study

OBJECTIVES

Little is known about the oral health of very low birthweight (<1500 g: VLBW) young adults. This study compared the oral health and self-reported oral health in a 1986 birth cohort of VLBW young adults with that of term-born controls.

METHODS

Oral health interviews and dental examinations were conducted. The dental examinations were carried out in a dental clinic using the standardized examination protocols from the 2009 New Zealand Oral Health Survey. Participants were interviewed to obtain data on self-reported oral health, oral hygiene practices, use of dental health services and oral health-related quality of life using the OHIP-14 measure.

RESULTS

Interviews were completed by 250 VLBW participants and 226 (90.4%) of those underwent the dental examination. All 100 controls completed both the interview and dental examination. While there were few overall differences in clinical or self-reported oral health between the VLBW or control groups, proportionally fewer VLBW participants attended the dentist for regular check-ups or cleaned between their teeth than controls. The VLBW and controls did not differ in the prevalence of untreated dental caries or in the number of carious tooth surfaces after adjusting for confounders. However, participants in the control group had more teeth that had been restored due to caries (4.4 teeth) than did the VLBW group (3.4 teeth, P = .045), after adjusting for confounding.

CONCLUSIONS

Very low birthweight young adults showed poorer self-care than the control group when it came to oral health; they were less likely to regularly attend dental visits, had poorer oral hygiene and were less likely to have had their dental disease treated. VLBW young adults should be encouraged to attend regular dental check-up appointments and to carry out effective home oral hygiene care.

Cardiovascular Outcomes in Young Adulthood in a Population-Based Very Low Birth Weight Cohort

OBJECTIVES

To assess differences in left heart structure and function, and endothelial function in a national cohort of very low birth weight (VLBW) young adults and term-born controls.

STUDY DESIGN

The New Zealand VLBW study is a prospective, population-based, longitudinal cohort study which included all infants born <1500 g in 1986. The VLBW cohort (n = 229; 71% of survivors) and term-born controls (n = 100), were assessed at age 26-30 years. Measures of left heart structure and function were evaluated by echocardiography, vascular function was assessed using blood pressure, reactive hyperemia index, and arterioventricular coupling by calculating left ventricular (LV) and arterial elastance.

RESULTS

Compared with controls, those born VLBW had smaller LVs, even when indexed for body surface area (mean LV mass, 89.7 ± 19.3 g/m² vs 95.0 ± 22.3 g/m² [P = .03]; LV end-diastolic volume, 58.3 ± 10.9 mL/m² vs 62.4 ± 12.4 mL/m² [P = .002]; and LV end-systolic volume, 20.8 ± 4.9 mL/m² vs 22.6 ± 5.8 mL/m² [P = .004]). VLBW participants had lower stroke volume (median, 37.2 mL/m² [IQR, 33-42 mL/m²] vs median, 40.1 mL/m² [IQR, 34-45 mL/m²]; P = .0059) and cardiac output (mean, 4.8 ± 1.2 L/min vs 5.1 ± 1.4 L/min; P = .03), but there was no difference in ejection fraction. The VLBW group had higher LV elastance (3.37 ± 0.88 mm Hg/mL vs 2.86 ± 0.75 mm Hg/mL; P < .0001) and arterial elastance (1.84 ± 0.4 vs 1.6 ± 0.4; P < .0001) and lower reactive hyperemia index (0.605 ± 0.28 vs 0.688 ± 0.31; P = .041). These measures were influenced by birth weight and sex, but we found limited associations with other perinatal factors.

CONCLUSIONS

Being born preterm and VLBW is associated with differences in cardiovascular structure and function in adulthood. This population may be more vulnerable to cardiovascular pathology as they age.

TRIAL REGISTRATION

Australian Clinical Trials Registry ACTRN12612000995875.

Lung Function of Adults Born at Very Low Birth Weight

BACKGROUND

Much remains unknown about the consequences of very low birth weight (VLBW) and bronchopulmonary dysplasia (BPD) on adult lungs. We hypothesized that VLBW adults would have impaired lung function compared with controls, and those with a history of BPD would have worse lung function than those without.

METHODS

At age 26 to 30 years, 226 VLBW survivors of the New Zealand VLBW cohort and 100 term controls born in 1986 underwent lung function tests including spirometry, plethysmographic lung volumes, diffusing capacity of the lung for carbon monoxide, and single-breath nitrogen washout (SBN₂).

RESULTS

An obstructive spirometry pattern was identified in 35% VLBW subjects versus 14% controls, with the majority showing mild obstruction. Compared with controls, VLBW survivors demonstrated significantly lower forced expiratory volume in 1 second (FEV₁), FEV₁/forced vital capacity (FVC) ratio (FEV₁/FVC), forced expiratory flow at 25% to 75% of FVC and higher residual volume (RV), RV/total lung capacity (TLC) ratio (RV/TLC), decreased diffusing capacity of the lung for carbon monoxide, and increased phase III slope for SBN₂. The differences persisted after adjustment for sex and smoking status. Within the VLBW group, subjects with BPD showed significant reduction in FEV₁, FEV₁/FVC, and forced expiratory flow at 25% to 75% of FVC, and increase in RV, RV/TLC, and phase III slope for SBN₂, versus subjects without. The differences remained after adjustment for confounders.

CONCLUSIONS

Adult VLBW survivors showed a higher incidence of airflow obstruction, gas trapping, reduced gas exchange, and increased ventilatory inhomogeneity versus controls. The findings suggest pulmonary effects due to VLBW persist into adulthood, and BPD is a further insult on small airway function.

Dilated hypertrophy: a distinct pattern of cardiac remodeling in preterm infants

BACKGROUND

Young adults born preterm have remodeled hearts, i.e., altered cardiac shape and size with impaired cardiac function. At present, the natural history and pattern of prematurity related cardiac remodeling are not clearly established. The aim of this study was to compare the left ventricle (LV) geometry and function of preterm infants at 36 weeks postmenstrual age (PMA) with gestation matched newborn infants.

METHODS

LV end diastolic volume index (LV EDVI), LV mass index (LVMI), relative wall thickness (RWT), and sphericity index (SI) were prospectively obtained with echocardiography. LV geometry was classified according to the Gaasch method. LV function was assessed by determining ejection fraction (EF), longitudinal strain (LS), mitral annulus systolic motion (s'), and estimated LV filling pressure (E/e').

RESULTS

Eighty-three preterm infants between 23 and 29 weeks gestation, and 40 infants of 36 weeks gestation at birth were analysed. LV EDVI, LVMI, SI, LS, s', and E/e' were higher in preterm group while RWT and EF were comparable between groups. LV showed normal geometry in 55.4%, physiological enlargement in 23% and dilated hypertrophy in 21.6% preterm infants.

CONCLUSION

At 36 week, preterm infants have significantly dilated, hypertrophied, and more spherical LV with impaired diastolic function compared with PMA matched newborn infants.

Altered grey matter volume, perfusion and white matter integrity in very low birthweight adults

This study examined the long-term effects of being born very-low-birth-weight (VLBW, <1500 g) on adult cerebral structural development using a multi-method neuroimaging approach. The New Zealand VLBW study cohort comprised 413 individuals born VLBW in 1986. Of the 338 who survived to discharge, 229 were assessed at age 27–29 years. Of these, 150 had a 3 T MRI scan alongside 50 healthy term-born controls. The VLBW group included 53/57 participants born <28 weeks gestation. MRI analyses included: a) structural MRI to assess grey matter (GM) volume and cortical thickness; b) arterial spin labelling (ASL) to quantify GM perfusion; and c) diffusion tensor imaging (DTI) to measure white matter (WM) integrity. Compared to controls, VLBW adults had smaller GM volumes within frontal, temporal, parietal and occipital cortices, bilateral cingulate gyri and left caudate, as well as greater GM volumes in frontal, temporal and occipital areas. Thinner cortex was observed within frontal, temporal and parietal cortices. VLBW adults also had less GM perfusion within limited temporal areas, bilateral hippocampi and thalami. Finally, lower fractional anisotropy (FA) and axial diffusivity (AD) within principal WM tracts was observed in VLBW subjects. Within the VLBW group, birthweight was positively correlated with GM volume and perfusion in cortical and subcortical regions, as well as FA and AD across numerous principal WM tracts. Between group differences within temporal cortices were evident across all imaging modalities, suggesting that the temporal lobe may be particularly susceptible to disruption in development following preterm birth. Overall, findings reveal enduring and pervasive effects of preterm birth on brain structural development, with individuals born at lower birthweights having greater long-term neuropathology.

•

Very-low-birth-weight adults had smaller GM volumes and thinner cortex than controls.

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VLBW adults also showed regions of larger grey matter volumes and thicker cortex.

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Several small regions showed lower cerebral perfusion in VLBW adults than in controls.

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Diffusion tensor MRI suggested poorer WM integrity in VLBW adults than in controls.

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Within VLBW adults, all MRI measures showed positive associations with birthweight.

Metabolic Syndrome in Very Low Birth Weight Young Adults and Controls: The New Zealand 1986 VLBW Study

OBJECTIVE

To assess the physical well-being and components of the metabolic syndrome in a national cohort of very low birth weight (VLBW) young adults and same age controls.

STUDY DESIGN

The New Zealand VLBW Study cohort prospectively included all infants with birth weight <1500 g born in 1986, with 338 (82%) surviving to discharge home. Height and weight were measured at age 7-8 years. The VLBW cohort (n = 229; 71% alive) and term-born controls (n = 100) aged 27-29 years were clinically assessed in a single center over 2 days, including assessment for components of the metabolic syndrome.

RESULTS

Compared with controls, both male and female VLBW adults were significantly shorter (P < .001), but only females were lighter (P < .001) and had lower mean body mass index (P = .044), fat mass, and body fat percentage. Males, but not females, had significantly higher systolic blood pressure (P = .028), but there were no significant differences in other components of the metabolic syndrome. There was no difference in the prevalence of the metabolic syndrome in VLBW adults compared with controls (males, 22.2% vs 11.1%; P = .15: females, 12.8% vs 13.1%; P = .95). Examining the VLBW cohort with logistic regression, male sex, gestational age <28 weeks, Māori/Pacific Island ethnicity, and body mass index >90th percentile at age 7-8 years were significant predictors for the metabolic syndrome at age 27-29 years, with ORs of 2-4.

CONCLUSIONS

Systolic blood pressure in males was the only component of the metabolic syndrome that was significantly elevated in VLBW adults compared with controls. Extreme prematurity (<28 weeks) and body mass index >90th percentile at age 7-8 years were significant predictors of the metabolic syndrome at age 27-29 years.

TRIAL REGISTRATION

Registered at the Australian Clinical Trials Registry: ACTRN12612000995875.

Unrecognised and unmet physical health problems in a national cohort of very low birthweight young adults and controls

ABSTRACT INTRODUCTIONYoung adults are often reluctant to seek medical attention. Compared with full-term controls, very low birthweight (&lt;1500 g; VLBW) young adults may have more health problems. AIMTo assess the frequency of unrecognised or unmet physical health needs during a comprehensive health and welfare assessment of a national cohort of VLBW adults born in 1986 compared with full-term controls. METHODSThe VLBW cohort (n = 229; 71% of those alive) and controls (n = 100) aged 27–29 years were assessed in one University Hospital over 2 days. Physical health assessments included growth, respiratory function, blood pressure, echocardiogram, renal function, blood tests and an interview. Cranial MRI scans were performed on 150 VLBW adults and 50 controls. Significant unrecognised or unmet health needs were defined as including a body mass index (BMI) &gt;30 plus raised fasting insulin &gt;80 pmol/L; any two of moderate respiratory obstruction, or reduced diffusing capacity, or being a regular smoker; cardiovascular: hypertension or abnormal echocardiogram. RESULTSAmong the VLBW cohort and controls; 61% versus 73% (P &lt; 0.05) rated their overall health as very good or excellent. A general practitioner (GP) referral letter was sent for 44% VLBW adults and 38% controls, concerning metabolic problems in 20% and 17% respectively; respiratory problems in 12% and 4% (P &lt; 0.05) respectively; cardiovascular problems in 14% and 12% respectively; abnormal renal function in 7% in both groups; and anaemia in 3% and 5% respectively. DISCUSSIONUnrecognised or unmet health needs were frequent in both VLBW young adults and controls. Respiratory problems and hypertension were more frequent in the former. Continuity of care is important for VLBW adults who require a regular GP. GPs should routinely ask about gestation and birthweight and VLBW graduates should volunteer this information.

New Insights into Cardiac and Vascular Natriuretic Peptides: Findings from Young Adults Born with Very Low Birth Weight

BACKGROUND

In community studies, plasma B-type natriuretic peptide (BNP) is positively associated with cardiovascular disorders. Those born with very low birth weight (VLBW) have increased risk of metabolic and vascular disorders in later life, but plasma concentrations of natriuretic peptides have not been studied. The objectives here were to evaluate BNP and C-type natriuretic peptide (CNP)—a putative marker of vascular risk—in young adults born with VLBW.

METHODS

In all, 220 VLBW cases and 97 matched controls were studied 28 years after birth during a 2-day period at 1 research center. Aminoterminal (NT) products (NTproBNP, NTproCNP) and a range of conventional vascular risk factors including echocardiographic indices were measured along with genetic polymorphisms known to increase plasma NTproBNP.

RESULTS

VLBW individuals were smaller, had smaller hearts, reduced stroke volume and endothelial function, and higher systolic blood pressure and arterial elastance. Of the many humoral vascular and metabolic risk factors measured, including NTproBNP, only plasma NTproCNP (higher in VLBW individuals) differed significantly. Across all individuals, associations of NTproCNP with each of 7 conventional risk factors, as well as with arterial elastance, were positive, whereas associations of NTproBNP with risk were all inverse. In multivariate analysis, the genetic variant rs198358 was independently associated with NTproBNP.

CONCLUSIONS

In young adults at increased risk of cardiovascular disease, higher NTproCNP likely reflects a compensatory vascular response to vascular stress, whereas the negative link with NTproBNP likely reflects beneficial genetic mutations. The ratio of NTproBNP to NTproCNP may provide a novel index of ideal cardiovascular health.

Vision in former very low birthweight young adults with and without retinopathy of prematurity compared with term born controls: the NZ 1986 VLBW follow-up study

Objective

There are few data on visual outcomes in adulthood of former very low birthweight (VLBW; <1500 g) infants. We aimed to assess vision at 27–29 years in a national cohort of VLBW infants born in 1986 and assessed for retinopathy of prematurity (ROP) when no treatment was available, compared with term born controls.

Methods

The cohort and controls attended a 2-day assessment in Christchurch as part of a larger study. Visual assessment included glasses prescription measured by focimeter, logarithm of the minimum angle of resolution (logMAR) distance visual acuity (VA), contrast sensitivity, autorefraction, retinal photographs and a questionnaire on vision-related everyday activities. Rates of reduced VA and myopia in the VLBW cohort at 27–29 were compared with the results of vision testing at 7–8 years.

Results

250 VLBW adults (77% those alive) gave study consent and 229 (45 with a history of ROP) were assessed in Christchurch, plus 100 term born controls. VLBW adults with ROP had reduced VA compared with no ROP and controls (mean logMAR score (SD); 0.003 (0.19), –0.021 (0.16), –0.078 (0.09), P=0.001). There were no differences in myopia (>2 D) between the groups but high myopia (>5 D) was confined to those with ROP. VLBW adults with ROP drove a car less often and had higher difficulties with everyday activities scores due to eyesight. Between 7–8 and 27–29 years rates of reduced VA were stable but myopia increased.

Conclusion

Former VLBW young adults with ROP have ongoing problems with vision affecting daily living and should continue in regular ophthalmological review.

Trial registration number

ACTRN12612000995875, Pre-results .