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.

Rationale: Population-based data regarding the consequences of very low birth weight (VLBW) and bronchopulmonary dysplasia (BPD) on adult exercise capacity are 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 and function using echocardiography. Data on self-reported physical activity were collected. Measurements and Main Results: Compared with controls, adults with VLBW demonstrated reduced oxygen uptake, work rate, and oxygen pulse at peak exercise (9.3%, 10.7%, and 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, and DlCO), altered left ventricular structure and function (reduced mass, size, stroke volume, and cardiac output), and reduced right atrial and ventricular size. Adjustment for the combination of three sets of covariates (physical activity with body mass index, lung function, and cardiac structure and function) explained most of the exercise group differences. Beyond the effects of physical activity and body mass index, lung function and cardiac structure and function contributed approximately equally. BPD with other prematurity-related perinatal factors (ventilation, antenatal steroids, extremely low birth weight, and extreme preterm) were not associated with a reduced exercise capacity. Conclusions: Exercise capacity was significantly reduced in adults with VLBW, which we speculate is from combined effects of impaired lung function, altered heart structure and function, and reduced physical activity. Perinatal factors including BPD were not associated with a reduced exercise capacity.

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.

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Background and objectiveThe bronchodilation and cardiovascular effects of bronchodilators may alter alveolar ventilation and perfusion distribution, which could subsequently affect single-breath diffusing capacity of the lungs for carbon monoxide (D-L,CO) measurements. The aim of this study was to investigate the effect of salbutamol on D-L,CO in subjects with and without airway obstruction and reversibility.MethodsSixty subjects were investigated with 20 in each of the three groups: normal spirometry; irreversible obstruction; and reversible obstruction. Baseline spirometry, plethysmographic lung volumes, D-L,CO, pulse rate and arterial blood gases were measured. The same testing sequence was repeated after administration of a placebo inhaler and again after 400g salbutamol.ResultsSalbutamol did not affect the mean alveolar volume (V-A) (P>0.05), transfer coefficient for carbon monoxide (D-L,CO/V-A, KCO) (P>0.05) or D-L,CO (P>0.05) in the normal and irreversible obstruction groups. In the reversible obstruction group, salbutamol caused an increase in the mean V-A compared with placebo (P<0.001). However, the mean KCO was reduced (P<0.001). The mean change in D-L,CO was not significant (P>0.05). A considerable reduction in D-L,CO was found after salbutamol in four subjects in the reversible group as a result of a minor increase in V-A and substantial decrease in KCO. No statistical difference in pulse rate or arterial blood gases values was detected.ConclusionsSalbutamol had no effect on the mean D-L,CO in any group. However, salbutamol may considerably reduce D-L,CO in some individuals with reversibility secondary to its effects on V-A and KCO.