Sex differences in preterm respiratory morbidity: A recent whole-population study

Sex differences in the risk of bronchopulmonary dysplasia and pulmonary hypertension: a Bayesian meta-analysis

BACKGROUND

Bronchopulmonary dysplasia (BPD) is generally considered to be more frequent in males than in females. We conducted a Bayesian model-averaged (BMA) meta-analysis of studies addressing sex differences in the risk of developing different severities of BPD and BPD-associated pulmonary hypertension (BPD-PH).

METHODS

We used BMA to calculate Bayes factors (BFs). The BF10 is the ratio of the probability of the data under the alternative hypothesis (presence of sex differences) over the probability of the data under the null hypothesis (absence of sex differences). BPD was classified as BPD28 (Supplementary oxygen at or during 28 days), BPD36 (moderate-to-severe BPD; oxygen at 36 weeks postmenstrual age), mild, moderate, and severe BPD.

RESULTS

We included 222 studies (541,826 infants). The BMA analysis showed evidence in favor of a male disadvantage in BPD28 (BF10 > 105), BPD36 (BF10 > 1021), and severe BPD (BF10 = 87.55), but not in mild BPD (BF10 = 0.28), or BPD-PH (BF10 = 0.54). The evidence for a male disadvantage in BPD decreased as the gestational age of the cohort decreased.

CONCLUSIONS

We confirmed the presence of a male disadvantage in moderate-to-severe BPD, but not in less severe forms of BPD or in BPD-PH. The male disadvantage in BPD is much less apparent in the more immature infants.

IMPACT

This Bayesian meta-analysis confirms that the risk of developing moderate to severe bronchopulmonary dysplasia (BPD) is approximately 20% higher in males than in females. Sex differences in BPD decrease with decreasing gestational age, are heterogeneous across geographic and sociodemographic settings, and have remained persistently stable over time. There is no evidence supporting sex differences in pulmonary hypertension associated with BPD. An important step in the process of individualizing the approach to BPD may be to consider the sex of the infant, as this information can be used to personalize care and potentially improve outcomes.

Physiological basis of non-invasive ventilation in the newborn

Non-invasive ventilation (NIV) is a form of respiratory support provided primarily to preterm born infants in an effort to avoid any endotracheal intubation or as a weaning step following invasive ventilation. In the context of the respiratory distress syndrome of the newborn, NIV could target and partially reverse specific pathophysiological phenomena, by improving alveolar recruitment and establishing adequate functional residual capacity. It can also assist in minimizing lung injury by avoiding excessive pressure delivery, which can be harmful for the developing lung. Non-invasive ventilation can unload the respiratory muscles and decrease the work of breathing as reported by studies that compare the measured work of breathing at increasing levels of non-invasive support. NIV can also be beneficial in moderating the frequency and intensity of apnea of prematurity. Unintended physiological effects of NIV include gaseous distension of the gastrointestinal tract and increased incidence of air-leak complications. During NIV there is also a lack of direct access to the trachea for suctioning and pulmonary toiletry. Insufficient non-invasive respiratory support could be associated with inadequate oxygenation and ventilation, insufficient gas exchange and atelectotrauma. Excessive provision of non-invasive support could be inefficient or harmful, as overdistention can be associated with decreased compliance of the respiratory system, impaired gas exchange and abnormal diaphragmatic function. An individualized physiological approach could, thus, aim to optimize the beneficial effects of non-invasive ventilation while avoiding inadequate or excessive levels of support.

Impact of sex, race, and social determinants of health on neonatal outcomes

Despite the global improvements in neonatal outcomes, mortality and morbidity rates among preterm infants are still unacceptably high. Therefore, it is crucial to thoroughly analyze the factors that affect these outcomes, including sex, race, and social determinants of health. By comprehending the influence of these factors, we can work towards reducing their impact and enhancing the quality of neonatal care. This review will summarize the available evidence on sex differences, racial differences, and social determinants of health related to neonates. This review will discuss sex differences in neonatal outcomes in part I and racial differences with social determinants of health in part II. Research has shown that sex differences begin to manifest in the early part of the pregnancy. Hence, we will explore this topic under two main categories: (1) Antenatal and (2) Postnatal sex differences. We will also discuss long-term outcome differences wherever the evidence is available. Multiple factors determine health outcomes during pregnancy and the newborn period. Apart from the genetic, biological, and sex-based differences that influence fetal and neonatal outcomes, racial and social factors influence the health and well-being of developing humans. Race categorizes humans based on shared physical or social qualities into groups generally considered distinct within a given society. Social determinants of health (SDOH) are the non-medical factors that influence health outcomes. These factors can include a person's living conditions, access to healthy food, education, employment status, income level, and social support. Understanding these factors is essential in developing strategies to improve overall health outcomes in communities.