Exercise fitness at 14 years: Good news for antenatal corticosteroids

Abstract

The lungs of infants born with very low birth weight (VLBW) are not normal at term, even without a history of prematurity associated lung disease. Their lungs can continue to remodel for perhaps 20 years to be functionally close to normal, but the effects of aging on the previously preterm lung remain essentially unknown. Lung function of infants born at normal term can be categorized into quartiles from lower to higher function. Remarkably, the children, and subsequently the adults, track within each quartile to at least 30 years of age. And the lowest quartile has increased risk of asthma and chronic obstructive lung disease as adults. Virtually nothing is known about how the lung function of infants born preterm tracks across age. However, in early childhood, infants born preterm with a history of bronchopulmonary dysplasia (BPD) have several overlapping phenotypes that include large airway malacia, small airway disease, and parenchymal (alveolar and vascular) abnormalities. This mix of abnormalities likely also are present to lesser degrees in infants born VLBW without BPD. Within this context of respiratory outcomes in infants with VLBW, Nixon et al report that antenatal corticosteroid (ACS) use in a cohort of 14-year-old children improved peak oxygen uptake with maximal exercise in non-black males relative to black males or females. This result correlated with greater physical activity in non-black males. The result was contrary to their hypothesis that ACS would decrease exercise tolerance because ACS inhibit alveolar and vascular development in the premature lung. My concern is that the % predicted peak oxygen uptake values were 85 ± 19% for ACS exposed and 78 ± 19% for ACS unexposed children born VLBW. These children thus are in the lowest quartile for normal lung function. There must be concerns for how these lungs will age. At least ACS did not seem to aggravate the problem. Article page 98▸ Antenatal Steroid Exposure, Aerobic Fitness, and Physical Activity in Adolescents Born Preterm with Very Low Birth WeightThe Journal of PediatricsVol. 215PreviewTo determine whether antenatal corticosteroid exposure is associated with aerobic fitness or physical activity participation in adolescents born preterm with very low birth weight (VLBW). Full-Text PDF