Race differences in the association between multivitamin exposure and wheezing in preterm infants

Prematurity-associated wheeze: current knowledge and opportunities for further investigation

Prematurity-associated wheeze is a common complication of preterm birth, with significant impact on the health and healthcare utilization of former preterm infants. This wheezing phenotype remains poorly understood and difficult to predict. This review will discuss the current state of the literature on prematurity-associated wheeze. We will discuss etiology and pathophysiology, and offer two conceptual models for the pathogenesis of this complex condition. This review will also identify current methods of ascertainment, and discuss the strengths and limitations of each. We will explore research-backed approaches to prevention and management, and finally suggest both pre-clinical and clinical avenues for investigation. An in-depth understanding of prematurity-associated wheeze will aid clinicians in its diagnosis and management, and inspire scientists to pursue much-needed further study into causes and prevention of this common and impactful condition. IMPACT: There is no recent, concise review on the current state of research on prematurity-associated wheeze, which is a rapidly evolving area of study. This article highlights causal models of wheeze, methods of ascertainment, management strategies for the clinician, and opportunities for further research for the physician scientist.

Early Oral Nutritional Supplements in the Prevention of Wheezing, Asthma, and Respiratory Infections

Wheezing, asthma, and respiratory infections (RTI) are among the most common causes of morbidity in children and their economic and social burden could be significantly reduced by specific prevention strategies. Epidemiological studies suggest that lower levels of some nutrients are associated with higher prevalence of these conditions, but the possible protective effect of early supplementation with these nutrients has not yet been established. Aim of our review is to synthetize the available scientific evidence on the role of supplementation with pre- and probiotics, vitamin D, fish and poly-unsaturated fatty acids (PUFA), vitamin A, C, and E, given during the first year of life, in the prevention of wheezing, asthma and RTI. We searched studies published on this topic in the PubMed database between January 2000 and September 2021. As for pre- and probiotics, most of the studies showed that an early supplementation had no protective effect toward the development of asthma and wheezing, while conflicting results were reported on their role in the reduction of RTI. As for vitamin D, the available data suggest that early and regular (on a daily or weekly base) supplementation of vitamin D during infancy could have a role in the prevention of RTI, while most studies showed no effect in the prevention of wheezing or asthma. Finally, early introduction of fish in the diet in most studies has proved protective toward wheezing and asthma development.

Correlations between oxygen and positive pressure exposure in the neonatal intensive care unit and wheezing in preterm infants without bronchopulmonary dysplasia

BACKGROUND

Oxygen exposure has been associated with increased wheezing and respiratory morbidity after discharge in extremely preterm infants and those with bronchopulmonary dysplasia. More mature preterm infants with less severe disease are also at risk for pulmonary complications, including rehospitalization for respiratory illnesses and wheezing disorders. Our aim was to evaluate associations between respiratory support and morbidity in preterm infants without bronchopulmonary dysplasia.

METHODS

A secondary analysis was performed on 300 infants born at 28-34 weeks gestation without bronchopulmonary dysplasia. Exposure included oxygen or positive pressure, (continuous positive airway pressure or mechanical ventilation). The primary outcome was recurrent wheezing. Secondary outcomes were respiratory medications, emergency room visits, and hospitalizations.

RESULTS

50% of infants who received oxygen experienced recurrent wheezing compared to 42.4% of infants who did not (OR 1.15 CI 0.72-1.85 adjusted OR 1.15 CI 0.67-1.98). 51.1% of infants who received positive pressure experienced recurrent wheezing compared to 38.1% who did not (OR 1.57 CI 0.97-2.53 adjusted OR 1.58 CI 0.90-2.77). There were no significant associations between oxygen and positive pressure exposure and any primary or secondary outcomes in the adjusted analyses.

CONCLUSIONS

After adjustment for known risk factors the analyses showed no significant associations between oxygen and positive pressure with respiratory morbidity in this population. Further study of infants with mild disease is needed.

Maternal Black Race and Persistent Wheezing Illness in Former Extremely Low Gestational Age Newborns: Secondary Analysis of a Randomized Trial

OBJECTIVE

To evaluate the relationship between maternal self-reported race/ethnicity and persistent wheezing illness in former high-risk, extremely low gestational age newborns, and to quantify the contribution of socioeconomic, environmental, and biological factors on this relationship.

STUDY DESIGN

We assessed persistent wheezing illness determined at 18-24 months corrected (for prematurity) age in survivors of a randomized trial. Parents/caregivers were surveyed for wheeze and inhaled asthma medication use quarterly to 12 months, and at 18 and 24 months. We used multivariable analysis to evaluate the relationship of maternal race to persistent wheezing illness, and identified mediators for this relationship via formal mediation analysis.

RESULTS

Of 420 infants (25.2 ± 1.2 weeks of gestation and 714 ± 166 g at birth, 57% male, 34% maternal black race), 189 (45%) had persistent wheezing illness. After adjustment for gestational age, birth weight, and sex, infants of black mothers had increased odds of persistent wheeze compared with infants of nonblack mothers (OR = 2.9, 95% CI 1.9, 4.5). Only bronchopulmonary dysplasia, breast milk diet, and public insurance status were identified as mediators. In this model, the direct effect of race accounted for 69% of the relationship between maternal race and persistent wheeze, whereas breast milk diet, public insurance status, and bronchopulmonary dysplasia accounted for 8%, 12%, and 10%, respectively.

CONCLUSIONS

Among former high-risk extremely low gestational age newborns, infants of black mothers have increased odds of developing persistent wheeze. A substantial proportion of this effect is directly accounted for by race, which may reflect unmeasured environmental influences, and acquired and innate biological differences.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01022580.

Effect of Vitamin D Supplementation on Recurrent Wheezing in Black Infants Who Were Born Preterm: The D-Wheeze Randomized Clinical Trial

IMPORTANCE

Black infants born preterm face high rates of recurrent wheezing throughout infancy. Vitamin D supplementation has the potential to positively or negatively affect wheezing through modulation of the pulmonary and immune systems.

OBJECTIVE

To assess the effectiveness of 2 vitamin D dosing strategies in preventing recurrent wheezing.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial enrolled 300 black infants born at 28 to 36 weeks' gestation between January 2013 and January 2016 at 4 sites in the United States, and followed them up through March 2017. Randomization was stratified by site and maternal milk exposure.

INTERVENTIONS

Patients were enrolled prior to discharge from the neonatal intensive care unit or newborn nursery and received open-label multivitamin until they were consuming 200 IU/d of cholecalciferol from formula or fortifier added to human milk, after which they received either 400 IU/d of cholecalciferol until 6 months of age adjusted for prematurity (sustained supplementation) or placebo (diet-limited supplementation). One-hundred fifty three infants were randomized to the sustained group, and 147 were randomized to the diet-limited group.

MAIN OUTCOMES AND MEASURES

Recurrent wheezing by 12 months' adjusted age was the primary outcome.

RESULTS

Among 300 patients who were randomized (mean gestational age, 33 weeks; median birth weight, 1.9 kg), 277 (92.3%) completed the trial. Recurrent wheezing was experienced by 31.1% of infants in the sustained supplementation group and 41.8% of infants in the diet-limited supplementation group (difference, -10.7% [95% CI, -27.4% to -2.9%]; relative risk, 0.66 [95% CI, 0.47 to 0.94]). Upper and lower respiratory tract infections were among the most commonly reported adverse events. Upper respiratory infections were experienced by 84 of 153 infants (54.9%) in the sustained group and 83 of 147 infants (56.5%) in the diet-limited group (difference, -1.6% [95% CI, -17.1% to 7.0%]). Lower respiratory infections were experienced by 33 of 153 infants (21.6%) in the sustained group and 37 of 147 infants (25.2%) in the diet-limited group (difference, -3.6% [95% CI, -16.4% to 4.4%]).

CONCLUSIONS AND RELEVANCE

Among black infants born preterm, sustained supplementation with vitamin D, compared with diet-limited supplementation, resulted in a reduced risk of recurrent wheezing by 12 months' adjusted age. Future research is needed to better understand the mechanisms and longer-term effects of vitamin D supplementation on wheezing in children born preterm.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01601847.

The problems of moderate preterm infants

Moderate preterm infants are the largest group of preterm infants but are an understudied population. Care practices are adapted from studies of full term infants or extremely preterm infants. Studies are needed to tailor treatments for this vulnerable population. The NRN began investigation in this population with a registry of characteristics, and neonatal outcomes of these infants. This work compares outcomes of MPR with those of full term infants reported in the literature.

Have Changing Palivizumab Administration Policies Led to More Respiratory Morbidity in Infants Born at 32-35 Weeks?

OBJECTIVES

To determine differences in the incidence of respiratory morbidity during the first year of life among infants born 32(0/7)-34(6/7) weeks' gestational age (GA) before and after the administration policy for palivizumab, as written by the American Academy of Pediatrics, was updated in 2009.

STUDY DESIGN

Secondary analysis of the dataset collected for the Gastrointestinal Risk Factors for Wheezing in Premature Infants study, which enrolled preterm infants without bronchopulmonary dysplasia and followed them by parental questionnaires at 3, 6, 9, and 12 months adjusted age for prematurity. Participants were included if they were enrolled in Gastrointestinal Risk Factors for Wheezing in Premature Infants, born 32(0/7)-34(6/7) weeks' GA, and completed the 12-month questionnaire. We compared rates of recurrent wheezing, respiratory medication use, and health care use before (Epoch 1) and after (Epoch 2) the 2009 administration policy change.

RESULTS

A total of 165 infants met inclusion criteria. There was a significant increase in recurrent wheezing in Epoch 2 (46.2%) vs Epoch 1 (28.8%) (OR 2.22 [95% CI 1.08-4.53], P = .03). There was a nonsignificant increase in visits to the emergency department in Epoch 2 (27.4%) vs Epoch 1 (15.3%) (OR 2.12 [95% CI 0.91-4.96], P = .08). There were no differences in hospital admissions or respiratory medication use.

CONCLUSIONS

Infants born 32(0/7)-34(6/7) weeks' GA treated after the American Academy of Pediatrics administration policy change in 2009 had a greater incidence of recurrent wheezing than those treated according to the previous policy. It will be important to track rates of recurrent wheezing after the 2014 administration policy, because it may be an important factor in future cost-effectiveness analyses.