Is vitamin d deficiency a risk factor for respiratory distress syndrome?

Risk factors and outcomes of vitamin D deficiency in very preterm infants

BACKGROUND

Vitamin D is essential for bone health and immune system. Vitamin D deficiency (VDD) poses a high-risk to very preterm (VP) infants. This study aimed to evaluate the risk factors associated with VDD in VP infants and its potential clinical outcomes.

METHODS

A retrospective cohort study was conducted on VP infants admitted to the neonatal intensive care unit of a specialized tertiary hospital in Seoul, Republic of Korea, between January 2018 and June 2022. Serum 25-hydroxyvitamin D (25(OH)D) levels and other biochemical parameters were measured between 4 and 6 weeks of age. VDD was defined as a serum 25(OH)D level <20 ng/mL. Prenatal and postnatal risk factors and clinical outcomes were compared between the VDD and non-VDD groups.

RESULTS

Of the 82 VP infants analyzed, 27 (32.9%) were diagnosed with VDD. The VDD group exhibited a significantly longer duration of parenteral nutrition (PN) compared to the non-VDD group (adjusted odds ratio [OR] = 1.12; 95% confidence interval [CI]: 1.008-1.245). Breast milk intake was lower in the VDD group than in the non-VDD group (adjusted OR = 0.976, 95% CI, 0.955-0.999). Notably, calcium levels were significantly lower in the VDD group, while parathyroid hormone levels were significantly higher, compared with the non-VDD group. Additionally, the rickets severity score was higher in the VDD group than in the non-VDD, although the difference was not statistically significant.

CONCLUSIONS

Prolonged PN duration and low breast milk intake significantly increased the risk of VDD in VP infants.

Implications of maternal vitamin D administration for the neonatal respiratory distress syndrome: A randomized clinical trial

BACKGROUND

Vitamin D deficiency has been suggested to be a risk factor for neonatal respiratory distress syndrome (RDS). This study aimed to evaluate the effect of 25 (OH) D administrations in pregnant women with findings of preterm labor on the incidence of RDS in their preterm neonates.

MATERIALS AND METHODS

A randomized controlled clinical trial was conducted on pregnant mothers with gestational age (GA) of less than 34 weeks at risk of preterm delivery. 175 subjects were randomly assigned into two groups, including intervention (intramuscular injection of 50,000 units of 25(OH) D during 72 hours before delivery) and control (no injections). Serum concentrations of 25(OH) D were measured shortly after birth in both mothers and neonates. Then, clinical and laboratory results of mothers and their offspring were recorded (in a checklist). Short-term outcomes and the need for respiratory support were also assessed. Data were analyzed by independent t-test, Mann-Whitney U test, Fisher's exact test, and chi-square test.

RESULTS

Even though gestational age, birth weight, delivery method, and serum vitamin D levels are consistent among both groups, 45% of neonates in the control group and 20% in the intervention group developed respiratory distress syndrome (P = 0.05). The mean 25(OH) D level in neonates was 17.7±10.5 and 19.29±9.94 ng/mL in the intervention and control groups, respectively (P > 0.05).

CONCLUSION

A single dose of 50,000 units of intramuscular 25(OH)D in pregnant women at risk of preterm labor can lower the risk of RDS in the infant.

Association between vitamin D level and respiratory distress syndrome: A systematic review and meta-analysis

BACKGROUND

Growing evidence suggests an association between the vitamin D levels and respiratory outcomes of preterm infants. The objective of this systematic review and meta-analysis was to explore whether premature neonates with a vitamin D deficiency have an increased risk of respiratory distress syndrome (RDS).

METHODS

We searched PubMed, EMBASE, and the Cochrane Library up through July 20, 2021. The search terms were 'premature infant', 'vitamin D', and 'respiratory distress syndrome'. We retrieved randomized controlled trials and cohort and case-control studies. For statistical analysis, we employed the random-effects model in Comprehensive Meta-Analysis Software ver. 3.3. We employed the Newcastle-Ottawa Scales for quality assessment of the included studies.

RESULTS

A total of 121 potentially relevant studies were found, of which 15 (12 cohort studies and 3 case-control studies) met the inclusion criteria; the studies included 2,051 preterm infants. We found significant associations between RDS development in such infants and vitamin D deficiency within 24 h of birth based on various criteria, thus vitamin D levels < 30 ng/mL (OR 3.478; 95% CI 1.817-6.659; p < 0.001), < 20 ng/mL (OR 4.549; 95% CI 3.007-6.881; p < 0.001), < 15 ng/mL (OR 17.267; 95% CI 1.084-275.112; p = 0.044), and < 10 ng/ml (OR 1.732; 95% CI 1.031-2.910; p = 0.038), and an even lower level of vitamin D (SMD = -0.656; 95% CI -1.029 to -0.283; p = 0.001).

CONCLUSION

Although the vitamin D deficiency definitions varied and different methods were used to measure vitamin D levels, vitamin D deficiency or lower levels of vitamin D within 24 h of birth were always associated with RDS development. Monitoring of neonatal vitamin D levels or the maintenance of adequate levels may reduce the risk of RDS.

Immunomodulatory Effects of Vitamin D and Prevention of Respiratory Tract Infections and COVID-19

Little is known about potential protective factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), referred to as COVID-19. Suboptimal vitamin D status is a risk factor for immune dysfunction, respiratory tract infections (RTIs), and viral infections. Supplementation of vitamin D (2000-4000 IU) has decreased incidence and complications from RTIs, respiratory distress syndrome, and pneumonia and may be beneficial in high-risk populations. Given the possible link between low vitamin D status and RTIs, such as COVID-19, this review examined whether vitamin D supplementation can be supported as a nutritional strategy for reducing risk of infection, complications, and mortality from COVID-19 and found that the relationship between vitamin D and RTIs warrants further exploration.

Atopic heredity modifies the association between maternal vitamin D status in pregnancy and the risk of atopic disease in childhood: an observational study

Background

The relationship between maternal vitamin D status in pregnancy and the development of atopic diseases in the offspring has been frequently studied, but with contradictory results. Previous studies have found an inverse relation between maternal vitamin D in pregnancy and the risk of atopic diseases in the child. In contrast, others have found a higher maternal 25OHD to be related to a higher risk of atopic diseases. Thus, the aim was to investigate the associations between maternal vitamin D status and intake in pregnancy with asthma, eczema and food allergies in the children up to 5 years. In addition, effect modification by reported atopic heredity was studied.

Methods

Participants in the GraviD study had 25-hydroxyvitamin D (25OHD) analyzed in serum in early (T1) and late (T3) pregnancy. Maternal dietary vitamin D intake was estimated from a short food frequency questionnaire and supplement use by questionnaires. At 5 years of age the child´s history of asthma, eczema and food allergy, including atopic heredity, was reported by questionnaire. Multivariable logistic regression was used.

Results

The cumulative incidence of asthma was 13%, eczema 22%, and food allergy 18%. Only among children without reported atopic heredity, maternal 25OHD of 50–75 nmol/L in T1 was associated with lower odds of asthma (OR 0.271, 95% CI 0.127–0.580), compared to maternal 25OHD > 75 nmol/L. Additionally in these children, maternal 25OHD in T3 (continuous) was associated with asthma (OR 1.014, 95% CI 1.002–1.009), and dietary vitamin D intake with eczema (OR 1.141, 95% CI 1.011–1.288).

Conclusions

Among children without reported atopic heredity, higher maternal vitamin D status and intake during pregnancy was associated with increased risk of reported atopic disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-022-00787-9.

Questioning the adequacy of standardized vitamin D supplementation protocol in very low birth weight infants: a prospective cohort study

OBJECTIVES

Preterm infants are at increased risk for vitamin D deficiency (VDD). We aimed to assess the adequacy of standardized vitamin D supplementation protocol in very low birth weight (VLBW) infants. Additionally, vitamin D status of mother/infant couples and the associations between vitamin D status at birth and morbidities of the infants were investigated.

METHODS

In this single-center, prospective cohort study blood samples were collected from 55 mothers just before delivery and from their infants at birth and on the 30th day of life (DOL) for 25 hydroxy vitamin D (25OHD) measurements. Vitamin D was initiated in dose of 160 IU/kg by parenteral nutrition on the first DOL and oral vitamin D supplementation (400 IU/day) was administered when enteral feedings reached 50% of total intake or on the 15th DOL.

RESULTS

The median 25OHD levels of the infants were 16.12 (9.14-20.50) in cord blood and 36.32 (31.10-44.44) in venous blood on the 30th DOL (p<0.01). In 98% of the VLBW infants 25OHD reached sufficient levels on the 30th DOL. None of the mothers had sufficient vitamin D levels (25OHD >30 ng/mL). Maternal 25OHD levels were correlated with the 25OHD levels of the infants in cord blood (r=0.665, p<0.001). There was a significant difference in mean cord 25OHD levels between winter (13.65 ± 5.69 ng/mL) and summer seasons (19.58 ± 11.67 ng/mL) (p=0.021). No association was found between neonatal morbidity and vitamin D status.

CONCLUSIONS

The results clearly show that by utilizing the current supplementation protocol, the majority of VLBW infants with deficient/insufficient serum 25OHD levels reached sufficient levels on the 30th DOL. Furthermore, vitamin D levels in mother/infant couples were found to be highly correlated.

Association between vitamin D deficiency at one month of age and bronchopulmonary dysplasia

Vitamin D deficiency is common and increases the likelihood of neonatal morbidities in preterm infants. This study assessed vitamin D levels at 1 month of age after 4 weeks of vitamin D supplementation and determined the association between vitamin D levels and neonatal morbidities.This retrospective study included preterm infants with birth weight <1500 g or gestational age <32 weeks born in our hospital between January 2018 and December 2019. They were administered 400 IU of oral vitamin D supplementation after birth according to our policy. The infants were then divided into sufficient (≥20 ng/mL) and deficient (<20 ng/mL) groups according to their serum vitamin D levels at 1 month of age.The vitamin D deficient and sufficient groups included 49 and 41 patients, respectively. The mean gestational age and birth weight. GHT in the vitamin D deficient group were 29.1 ± 2.1 weeks and 1216.1 ± 308.1 g, respectively, and 30.0 ± 1.7 weeks and 1387.6 ± 350.8 g, respectively, in the sufficient group. No significant differences were observed between the 2 groups in demographic and clinical outcomes except for bronchopulmonary dysplasia (BPD), which occurred significantly more often in the vitamin D-deficient group (odds ratio 2.21; 95% confidence interval, 1.85-2.78; P = .02).The results of our study suggest that vitamin D deficiency at 1 month of age is associated with BPD in preterm infants.

The potential effects of vitamin D deficiency on respiratory distress syndrome among preterm infants

INTRODUCTION

Vitamin D deficiency is one of the most commonly deficient vitamins worldwide. Preterm infants usually suffer from different complications. However, the relationship between vitamin D levels and RDS prevalence has been emerging in the last few years.

AIM

This study aimed to assess the severity of respiratory distress syndrome in preterm infants who are ≤34 weeks GA, with a birth weight of ≤2 kg, and its relation to their serum blood level of vitamin D.

MATERIALS AND METHODS

This is a multicenter study conducted at Neonatal Intensive Care Unit (NICU) at King Fahad Medical City (KFMC), Riyadh, Saudi Arabia, and Maternity and Children Hospital (MCH), Qassim, Saudi Arabia. We observed prospectively all preterm babies who were ≤34 weeks GA with 25-hydroxyvitamin D (25OHD) serum level ≤30 ng/ml at 24 h of life or less. Included infants were divided into 2 groups; infants with 25-hydroxyvitamin D level of ≤30 ng/ml were the deficient group and those with >30 ng/ml were considered in the normal group.

RESULTS

174 preterm infants were included in this study with an average gestational age of 30.2 ± 2.7 weeks. The mean vitamin D level was 30.5 (SD 19.5). Vitamin D deficiency was detected among 99 infants (56.9%). Of the deficient infants, 26.3% were severe, 42.4% moderate and 31.3% were mild. Pneumothorax was 2.9% and mortality rates were recorded among 14 cases (8%).

CONCLUSION

Vitamin D deficiency was widely prevalent among preterm neonates. Pneumothorax, surfactant doses, oxygen, and mechanical ventilation requirements were statistically significant at vitamin D deficiency.

Vitamin D Status and Factors Associated with Vitamin D Deficiency during the First Year of Life in Preterm Infants

We aimed to investigate the changes in vitamin D levels and factors associated with vitamin D deficiency (VDD) during the first year of life in Korean preterm infants. We enrolled 333 preterm infants who were born at Kyungpook National University Children’s Hospital between March 2013 and December 2019. 25-hydroxyvitamin D (25-OHD) levels and medical records were collected at birth, 6 months, and 12 months of age. The mean gestational age was 33.4 ± 2.3 weeks and mean 25-OHD levels at birth were 18.2 ± 13.5 ng/mL. The incidence of VDD was 82.8%, 30.6%, and 27.0% at birth, 6 months, and 12 months, respectively. The incidence of severe VDD (25-OHD < 10 ng/mL) was 31.5%, 1.5%, and 0%, at birth, 6 months, and 12 months, respectively. Among infants with severe VDD, the deficiency persisted in 49.6% at 6 months, and 35.3% at 12 months. The strongest predictor of VDD during follow-up was 25-OHD concentration at birth. Vitamin D supplementation at 400 IU/day did not affect vitamin D levels during the first year of life. Therefore, it is important to prevent neonatal VDD through maternal vitamin D supplementation during pregnancy. Further research is needed to determine the optimal vitamin D supplementation dose for Korean preterm infants.

Association of vitamin D status at birth with pulmonary disease morbidity in very preterm infants

OBJECTIVE

We aimed to assess whether serum 25-hydroxyvitamin D (25(OH)D) levels at birth are associated with pulmonary disease morbidities in very preterm infants.

METHODS

This prospective cohort analysis included 93 infants born before 32 weeks of gestation in the Second Xiangya Hospital of Central South University between March 2016 and February 2017. Participants were classified into three groups according to their 25(OH)D levels at birth. The groups were compared in terms of demographic variables and pulmonary disease morbidities.

RESULTS

The mean serum 25(OH)D level at birth was 35.7 ± 19.1 nmol/L, and 38 (40.9%), 31 (33.3%), and 24 (25.8%) infants had 25(OH)D levels of less than 25 nmol/L, 25-50 nmol/L, and more than or equal to 50 nmol/L, respectively. There was a statistically significant difference in neonatal respiratory distress syndrome (RDS) rates among the three groups (43.6% vs. 35.9% vs. 20.5%, p = .029). The rates of bronchopulmonary dysplasia, apnea, respiratory failure, persistent pulmonary hypertension, and pulmonary hemorrhage did not differ significantly among the groups. Logistic analysis, adjusted for gestational age and birth weight, showed that a low serum 25(OH)D level (<50 nmol/L) was a risk factor for RDS (odds ratio, 0.195; p = .017).

CONCLUSION

There was a high prevalence of low 25(OH)D levels (<50 nmol/L) and an association between vitamin D status and RDS in very preterm infants. However, more research on this association is required.

Association Between Vitamin D Level and Neonatal Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

In recent years, vitamin D in the occurrence of lung diseases has gradually become a hot topic. Although the role of vitamin D in normal lung development has been confirmed, the correlation between vitamin D level and neonatal respiratory distress syndrome (NRDS) is not clear.

OBJECTIVE

To evaluate the association between vitamin D level and NRDS.

METHODS

We performed a comprehensive search of the following electronic databases: PubMed, Embase, Cochrane Library, Web of Science, and China National Knowledge Infrastructure (CNKI). Literature screening and quality assessment were performed according to inclusion and exclusion criteria. The Newcastle-Ottawa Scale was used to assess the methodological components of each study, and Stata 15.1 software to perform the Meta-analysis.

RESULTS

A total of nine case-control studies were included, with 653 infants with NRDS and 501 infants without NRDS. The Meta-analysis showed no heterogeneity across all studies(I²=0.0%, P=0.583). The fixed-effect model showed that 25 hydroxy vitamin D level of children in the NRDS group was significantly lower than that of the non-NRDS group(SMD = -0.51, 95%CI: -0.63 to -0.39, p ≤ 0.05).

CONCLUSION

This systematic review and meta-analysis study suggests that vitamin D deficiency is very likely to be a high-risk factor of NRDS, and reasonable vitamin D supplementation during pregnancy and after birth is of great significance.

Single nucleotide vitamin D receptor polymorphisms (FokI, BsmI, ApaI, and TaqI) in the pathogenesis of prematurity complications

The vitamin D receptor (VDR), coded by the VDR gene, plays a pivotal role in executing cellular functions when bound by the active form of vitamin D. Gene polymorphisms in this receptor have been increasingly associated with a heightened state of vulnerability to certain diseases. However, limited data is available concerning the role of VDR gene polymorphisms in preterm infant complications. In 114 premature infants (< 32 weeks gestation) we analyze four single nucleotide VDR polymorphisms (rs2228570 (FokI), rs1544410 (BsmI), rs797532 (ApaI), rs731236 (TaqI)) for their association with respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC) and retinopathy of prematurity (ROP). The results show that BPD was almost four times more likely in infants with the genotype CC of ApaI (rs7975232) (OR 3.845; p = 0.038). While both BPD and NEC were 2.1 times more likely to occur in preterm infants with the allele C of ApaI (rs7975232) (respectively: OR 2.111 and OR 2.129, p < 0.05). The ApaI VDR polymorphism appears to influence incidence of BPD and NEC in preterm infants. Considering VDR polymorphisms in future genetic investigations, in preterm complications, may prove clinically relevant.

[A comparative analysis of the efficacy of two vitamin D supplementation regimens in preterm infants: a prospective randomized controlled study]

OBJECTIVE

To study the effect of different vitamin D supplementation regimens on the nutritional status of vitamin D on day 28 after birth in preterm infants with a gestational age of <34 weeks.

METHODS

A total of 59 preterm infants with a gestational age of <34 weeks who were born from October 2018 to October 2019 were enrolled and divided into an observation group with 30 infants and a control group with 29 infants. The infants in the observation group received a single-dose intramuscular injection of vitamin D₃ (10 000 IU/kg), while those in the control group received oral vitamin D₃ drops (900 IU/d) for 25 days. Venous blood samples were collected within 48 hours after birth (before vitamin D₃ supplementation) and on day 28 after birth to measure the serum 25-hydroxyvitamin D [25(OH)D] level.

RESULTS

Within 48 hours after birth, the prevalence rate of vitamin D deficiency (≤15 ng/mL) was 78% among the 59 preterm infants. There were no significant differences in the serum 25(OH)D level and the prevalence rate of vitamin D deficiency between the two groups (P>0.05). Compared with the control group on day 28 after birth, the observation group had a significantly higher serum 25(OH)D level (P<0.05) and a significantly lower prevalence rate of vitamin D deficiency (P<0.05). There were no cases of vitamin D overdose or poisoning.

CONCLUSIONS

In preterm infants with a gestational age of <34 weeks, single-dose intramuscular injection of 10 000 IU/kg vitamin D₃ can significantly increase serum 25(OH)D level on day 28 after birth and safely and effectively reduce the prevalence rate of vitamin D deficiency.

Severe vitamin D deficiency in preterm infants: possibly no association with clinical outcomes?

Purpose: The primary objective of this study was to compare clinical outcomes of very low birth weight (VLBW) infants with 25-hydroxy vitamin D [25(OH)D] levels <25 nmol/l in umbilical cord blood versus VLBW infants with 25(OH)D levels in cord blood >25 nmol/l. The secondary objective was to evaluate umbilical cord vitamin D as a risk factor for respiratory distress syndrome (RDS) in preterm infants.Methods: We examined 25(OH)D levels in umbilical cord blood and in infants' serum at discharge from the neonatal intensive care unit. We evaluated the associations between severe vitamin D deficiency and various laboratory findings and clinical outcomes.Results: Eighty one infants with birth weight less than 1500 g met the entry criteria for this study and were divided to groups according to umbilical cord blood vitamin D [Group A: 25(OH)D < 25 nmol/l; 10 ng/ml and Group B: 25(OH)D > 25 nmol/l; 10 ng/ml]. Overall, 81.5% of the infants had a 25(OH)D level <50 nmol/L and 44.4% had a level <25 nmol/L. The laboratory findings and the subsequent clinical outcomes were comparable in infants in both groups (non-significant difference). Only the infants in the 25(OH)D 25 nmol/L group had a lower calcium in urine at age 28 d (p=.0272). In addition, we found in this study that umbilical cord vitamin D level does not lead to a higher or lower risk of RDS (odds ratio 1.044; 95% confidence interval 0.349-0.88; p=.0771).Conclusions: In our prospective cohort study, we found no significant association between vitamin D status and selected clinical outcomes when using a cut-off of 25 nmol/l (severe vitamin D deficiency) in preterm infants.

Nutrients and Microbiota in Lung Diseases of Prematurity: The Placenta-Gut-Lung Triangle

Cardiorespiratory function is not only the foremost determinant of life after premature birth, but also a major factor of long-term outcomes. However, the path from placental disconnection to nutritional autonomy is enduring and challenging for the preterm infant and, at each step, will have profound influences on respiratory physiology and disease. Fluid and energy intake, specific nutrients such as amino-acids, lipids and vitamins, and their ways of administration -parenteral or enteral-have direct implications on lung tissue composition and cellular functions, thus affect lung development and homeostasis and contributing to acute and chronic respiratory disorders. In addition, metabolomic signatures have recently emerged as biomarkers of bronchopulmonary dysplasia and other neonatal diseases, suggesting a profound implication of specific metabolites such as amino-acids, acylcarnitine and fatty acids in lung injury and repair, inflammation and immune modulation. Recent advances have highlighted the profound influence of the microbiome on many short- and long-term outcomes in the preterm infant. Lung and intestinal microbiomes are deeply intricated, and nutrition plays a prominent role in their establishment and regulation. There is an emerging evidence that human milk prevents bronchopulmonary dysplasia in premature infants, potentially through microbiome composition and/or inflammation modulation. Restoring antibiotic therapy-mediated microbiome disruption is another potentially beneficial action of human milk, which can be in part emulated by pre- and probiotics and supplements. This review will explore the many facets of the gut-lung axis and its pathophysiology in acute and chronic respiratory disorders of the prematurely born infant, and explore established and innovative nutritional approaches for prevention and treatment.

Vitamin D status in preterm neonates and the effects of its supplementation on respiratory distress syndrome

AIM

The aim of this study was to investigate the status and effects of vitamin D supplement as adjuvant therapy in the management of respiratory distress syndrome (RDS) in preterm infants.

PATIENT AND METHODS

Vitamin D was prospectively studied in 196 preterm neonates, 96 of them developed RDS, which further subdivided into three subgroups (subgroup received just conventional therapy, subgroup received conventional therapy plus vitamin D 400 IU/day, and subgroup received conventional therapy plus vitamin D 800 IU/day). The patient selection for each treatment subgroup was done by computed randomization, and all the patients had the same treatment protocols assigned for each subgroup.

RESULTS

The preterm group who developed RDS had lower vitamin D concentrations than the preterm group without RDS (*P < .001). Also, the subgroups supplemented with vitamin D had lower Downes Respiratory Distress score and PaCO₂ levels, less duration of hospitalization, and complications rates than the subgroup without vitamin D supplementation. The subgroup supplemented with 800 IU/day vitamin D showed also significantly improvement, less hospitalization duration, and less complications than those supplemented with 400 IU/day.

CONCLUSIONS

25-hydroxyvitamin D concentration was deficient in most preterm babies especially those who developed RDS. Administration of 800 IU/day vitamin D as an adjuvant therapy in cases of RDS was associated with significant decreased in severity, rate of complications, and duration of hospital stay in preterm neonates with RDS.

Perinatal Undernutrition, Metabolic Hormones, and Lung Development

Maternal and perinatal undernutrition affects the lung development of litters and it may produce long-lasting alterations in respiratory health. This can be demonstrated using animal models and epidemiological studies. During pregnancy, maternal diet controls lung development by direct and indirect mechanisms. For sure, food intake and caloric restriction directly influence the whole body maturation and the lung. In addition, the maternal food intake during pregnancy controls mother, placenta, and fetal endocrine systems that regulate nutrient uptake and distribution to the fetus and pulmonary tissue development. There are several hormones involved in metabolic regulations, which may play an essential role in lung development during pregnancy. This review focuses on the effect of metabolic hormones in lung development and in how undernutrition alters the hormonal environment during pregnancy to disrupt normal lung maturation. We explore the role of GLP-1, ghrelin, and leptin, and also retinoids and cholecalciferol as hormones synthetized from diet precursors. Finally, we also address how metabolic hormones altered during pregnancy may affect lung pathophysiology in the adulthood.

Association between vitamin D level at birth and respiratory morbidities in very-low-birth-weight infants

Purpose

This study aimed to evaluate vitamin D status at birth in very-low-birth-weight infants (VLBWIs: <1,500 g) and to determine the association between vitamin D level and respiratory morbidity.

Methods

A retrospective study was conducted at Soonchunhyang University Bucheon Hospital between November 2013 and November 2017. We collected blood samples and data on respiratory morbidity from 230 VLBWIs on the first day of life. Patients who were transferred to other hospitals (n=19), died before 36 weeks of gestational age (n=18), or whose blood samples were not collected immediately after birth (n=5) were excluded. Finally, 188 patients were enrolled. VLBWIs with different vitamin D levels were compared with respect to demographic features, maternal diseases, respiratory morbidities, and other neonatal diseases.

Results

The mean serum vitamin D level, as measured by 25-hydroxyvitamin D (25(OH)D), was 13.4± 9.3 ng/mL. The incidence of vitamin D deficiency (<20 ng/mL) was 79.8%, and 44.1% of preterm infants had severe vitamin D deficiency (<10 ng/mL). Logistic analysis shows that a low serum 25(OH)D level (<20 ng/mL) was a risk factor for respiratory distress syndrome (odds ratio [OR], 4.32; P=0.010) and bronchopulmonary dysplasia (OR, 4.11; P=0.035).

Conclusion

The results showed that 79.8% of preterm infants in this study had vitamin D deficiency at birth. Low vitamin D status was associated with respiratory morbidity, but the exact mechanism was unknown. Additional studies on the association between vitamin D level and neonatal morbidity are required.

Updates on the Status of Vitamin D as a Risk Factor for Respiratory Distress Syndrome

To update the guidelines regarding vitamin D status in respiratory distress syndrome, we reviewed recent human and animal studies on the benefits of vitamin D in respiratory distress. We searched PubMed and ProQuest for studies on the use of vitamin D from 2009 to 2017. The common parameters in these studies included the use of lung tissue, phospholipids, blood, and plasma to assess the effects of vitamin D on respiratory syndrome. The metabolized form of vitamin D used in these studies was 1,25(OH)₂D₃ in animal studies and 25(OH)D in human studies. Vitamin D supplementation decreases the risk of respiratory distress syndrome, improves the quality of life, and is relatively effective and safe for preterm neonates as well as during lung maturation. However, although vitamin D supplementation may offer benefits for respiratory distress syndrome, the optimal dosing strategies for specific types of risk factors in the lungs must be clarified to confirm the therapeutic efficacy.

Vitamin D deficiency and respiratory morbidity among African American very low birth weight infants

BACKGROUND

Very low birth weight infants (VLBWI) have unexplained variation in respiratory morbidity, including respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD). We examined a potential association to serum 25-hydroxyvitamin D (s-25OHD) on day one.

STUDY DESIGN

Prospective, observational study on 89 VLBWI (≤1250 g). S-25OHD (day one and 21) and respiratory severity score (RSS) (day one) were examined. Other respiratory morbidities including BPD were compared between infants with s-25OHD ≤ 10 ng/ml (deficient) versus >10 ng/ml (adequate).

RESULTS

Eighty one neonates (91%) were African Americans. The mean (SD) birthweight was 868 (229) g, gestational age 27 (2) weeks. On day one, mean (SD) s-25OHD was 15.48 (8.31) ng/ml, with 32 (37%) being vitamin D deficient. The deficiency and adequate VLBWI groups had similar birthweight; 860 (262) vs 873 (210) g, and gestational age; 27 (2) vs 27 (2) weeks. In 78 survivors, s-25OHD rose from 15.48 (8.31) ng/ml day one to 52.36 (22.49) ng/ml day 21 after supplementation, p < 0.001. On day one, increasing RSS was inversely related to s-25OHD, trend p = 0.054. Compared to the adequate group, the deficiency group had higher RSS (5.0 ± 2.7 vs 3.6 ± 1.9), required surfactant therapy more frequently (91% vs 72%), and needed home oxygen therapy more often (48% vs 26%), p ≤ 0.05 for all. Among infants with BPD, the severity of disease was inversely related to s-25OHD, trend p < 0.09.

CONCLUSION

Lower levels of s-25OHD were associated with increased severity of RDS and BPD among a cohort of mostly African American VLBWI.

Serum level of vitamin D in preterm infants and its association with premature-related respiratory complications: a case-control study

Background and aim

Prematurity and related problems, especially respiratory distress, are one of the main challenges for neonatal medicine. The aim of this study was to compare vitamin D levels in preterm infants with, and those without respiratory distress.

Methods

This case-control study was conducted in Ghaem and Emam Reza Hospitals in Mashhad (Iran) from 2015 to 2016. In this study, we examined 160 preterm infants weighing less than 2000 grams and born at less than 34 weeks' gestation. Serum vitamin D levels were measured in preterm infants without- and those with respiratory distress, and their mothers. Neonatal characteristics, including age, sex, birth weight, gestational age, Apgar score and needs for oxygen, resuscitation, ventilation and surfactant were documented. The data were analyzed using SPSS version 16.0.

Results

Means serum level of maternal vitamin D in control and case groups were 16.66±14.29 ng/dl and 21.23±15.19 ng/dl, respectively (p=0.029). In addition, mean serum level of neonatal vitamin D in control and case groups were 11.69±8.66 ng/dl 17.9±12.55 ng/dl, respectively (p=0.001). Vitamin D levels in premature neonates without respiratory distress and their mothers were significantly different from other preterm neonates with respiratory distress (p=0.029). There was a direct correlation with neonatal and maternal vitamin D levels (r=0.713, p=0.001). The duration of hospitalization (p=0.001), gestational age (p=0.073), birth weight (p=0.001), one- and (p=0.001) five-minute (p=0.001) Apgar scores and head circumference (p=0.002) had significant relation with vitamin D levels in neonates. Death (12.5%) and pneumothorax (7.5%) were the main complications among cases with respiratory distress.

Conclusion

According to the results of present research, neonatal vitamin D levels have a significant association with respiratory distress syndrome and maternal vitamin D levels.

Multi-dose vitamin d supplementation in stable very preterm infants: Prospective randomized trial response to three different vitamin D supplementation doses

BACKGROUND

Preterm newborns are born with lower vitamin D stores. Although vitamin D supplementation is recommended there is no consensus regarding the adequate dose of supplementation for preterm infants.

AIMS

To assess the effect of three different doses of vitamin D supplementation (400, 800 and 1000IU/d) in preterm infants ≤32weeks gestation on the prevalence of vitamin D deficiency and 25(OH) D levels at 36weeks postmenstrual age (PMA).

STUDY DESIGN

Prospective randomized trial.

SUBJECTS

121 preterm infants with gestational age of 24-32weeks were randomly allocated to receive 400, 800 or 1000IU/d vitamin D.

OUTCOME MEASURES

Serum concentration of 25(OH) D and the prevalence of vitamin D deficiency at 36weeks PMA. Vitamin D deficiency was defined as serum 25(OH) D concentrations <20ng/ml.

RESULTS

Of the 121 infants 72% had deficient vitamin D levels before supplementation. The average 25(OH) vitamin D concentrations at 36weeks PMA were significantly higher in 800IU (40±21.4ng/ml) and 1000IU group (43±18.9ng/ml) when compared to 400IU group (29.4±13ng/ml). The prevalence of vitamin D deficiency (2.5 vs 22.5; RR: 0.09; CI:0.01-0.74) and insufficiency (30 vs 57.5; RR:0.32; CI:0.13-0.80) was significantly lower in 1000IU group when compared to 400IU group at 36weeks PMA.

CONCLUSION

1000IU/d of vitamin D supplementation in preterm infants ≤32weeks gestation age effectively decreases the prevalence of vitamin D deficiency and leads to higher concentrations of 25(OH) vitamin D at 36weeks PMA TRIAL REGISTRATION: Clinical Trials.gov: NCT02941185.

Vitamin D levels in newborns and association with neonatal hypocalcemia

OBJECTIVE

Vitamin D has many important functions in our body. Especially in intrauterine and early infancy periods, Vitamin D plays a major role in bone development, growth, and the maturation of tissues such as lung and brain. Fetus is dependent on the mother in terms of Vitamin D and maternal Vitamin D deficiency results in a Vitamin D deficient newborn. The purpose of this study was to determine the levels of Vitamin D in newborns and to investigate the association between Vitamin D status of the baby and neonatal hypocalcemia.

METHOD

Vitamin D, calcium, and parathyroid hormone levels of 750 infants, born between 1 January 2014 and 30 June 2015 and followed in Ondokuz Mayıs University Neonatal Intensive Care Unit were analyzed retrospectively. Blood levels of Vitamin D were checked within 3 days after birth. A 25(OH)D3 level of <10 ng/ml indicated severe, levels between 10 and 20 ng/ml, which indicated moderate and levels between 20 and 30 ng/ml indicated mild Vitamin D deficiency. Serum calcium levels below 8 mg/dl in term infants and below 7 mg/dl in preterm infants were accepted as hypocalcemia. Hypocalcemia that developed within the first week after birth was defined as early, while hypocalcemia after one week were defined as late hypocalcemia.

RESULTS

A total of 44% of the infants in the study were girls, while 56% were boys; 38% were term and 62% were preterm. Average 25(OH)D3 level of all infants was 11.4 ± 10.2 (0-153) ng/ml. Only 30 (4%) infants had normal (>30 ng/ml) 25(OH)D3 levels; 68 (9%) had mild, 234 (31%) had moderate and 418 (56%) had severe vitamin D deficiency. No correlation was found between Vitamin D levels and gender, mother's age, gestational week or birth weight. In 79 (17.2%) preterms, neonatal hypocalcemia was observed. Vitamin D levels of the premature infants who had early neonatal hypocalcemia were statistically significantly lower when compared with those who did not have early neonatal hypocalcemia (p = .02). No significant difference was found between the Vitamin D levels of the term infants who had early neonatal hypocalcemia and those who did not (p= .29). No significant difference was found between the Vitamin D levels of the infants who had late neonatal hypocalcemia and those who did not (in preterm p = .27; in term p = .29).

CONCLUSIONS

Although lack of Vitamin D is preventable and curable, it is an important health problem for newborns in Turkey. In our study, 56% of the infants were found to have severe lack of Vitamin D and lack of Vitamin D was found to be associated with early neonatal hypocalcemia in preterm newborns. However, long-term effects of lack of Vitamin D in infancy are not fully known. In order to be able to prevent neonatal Vitamin D deficiency, 1200 IU/day vitamin D was supplemented to mothers from the 12th gestational week to 6th month of the birth, which was put into effect by the Ministry of Health in 2011, and should be applied by all health workers.

Protective effect of vitamin D against hyperoxia-induced lung injury in newborn rats

INTRODUCTION

Preterm infants have risks of developing vitamin D deficiency. Thus we aimed to investigate the effect of vitamin D on hyperoxia-induced lung injury in newborn rats.

METHODS

Full term rat pups were included in the study 12-24 hr after delivery. The pups were randomly divided into eight groups as follows: normoxia control group (NC), normoxia plus vitamin D group (ND1, 1 ng/gr/day vitamin D), normoxia plus vitamin D group (ND2, 3 ng/gr/day vitamin D), normoxia plus vitamin D group (ND3, 5 ng/gr/day vitamin D), hyperoxia control group (HC), hyperoxia plus vitamin D group (HD1, 1 ng/gr/day vitamin D), hyperoxia plus Vitamin D group (HD2, 3 ng/gr/day vitamin D), hyperoxia plus vitamin D group (HD3, 5 ng/gr/day vitamin D). The histopathological effects of vitamin D were assessed by alveolar surface area (with mean linear intercept (MLI) method), apoptosis index and proliferating cell nuclear antigen (PCNA) index.

RESULTS

MLI values were significantly lower among three groups (HD1: 83.93 ± 1.95 μm, HD2: 81.76 ± 1.68 μm, and HD3: 82.33 ± 1.87 μm) when compared with HC group (92.98 ± 2.09 μm) (P = 0.001, P = 0.0004, P = 0.002, respectively). Apoptotic cell index were significantly lower among three treatment groups (HD1: 1.455 ± 0.153, HD2: 0.575 ± 0.079, and HD3: 0.700 ± 0.105) when compared with HC group (2.500 ± 0.263) (P = 0.001, P = 0.001, P = 0.001, respectively). Although PCNA positive cell index did not change in HD1 group (0.132 ± 0.008) (P > 0.05), there were significant increases in HD2 (0.277  ± 0.026) and HD3 (0.266 ± 0.018) group when compared with HC group (0.142 ± 0.010) (HD2 P = 0.001, HD3 P = 0.001).

CONCLUSION

Vitamin D seems to protect hyperoxia-induced lung injury in newborn rats. Pediatr Pulmonol. 2017;52:69-76. © 2016 Wiley Periodicals, Inc.

Vitamin D and bronchopulmonary dysplasia in preterm infants

OBJECTIVE

Vitamin D deficiency is associated with asthma and reactive airway disease in childhood but its potential contribution to bronchopulmonary dysplasia (BPD) in preterm infants is unknown. Preterm infants have lower levels of 25-hydroxyvitamin D (25(OH)D) at birth and are at risk for nutritional deficiencies after birth. The objective of the study was to evaluate the association of 25(OH)D concentrations at birth and at 36 weeks' corrected gestational age with BPD in preterm infants born before 29 completed weeks of gestation.

STUDY DESIGN

We collected umbilical cord blood samples from 44 preterm infants (gestational age <29 weeks) delivered at Brigham and Women's Hospital in Boston. In addition, with parental consent we collected venous samples at 36 weeks' corrected age from 20 preterm infants born before 29 weeks' gestation (including 6 infants with previously collected cord blood). Samples were frozen at -80 °C until subsequent measurement of 25(OH)D levels by chemiluminescence. We used multivariable logistic models to adjust for gestational age and considered other confounding variables, including maternal race, age, mode of delivery and infant sex.

RESULTS

Among 44 infants, 41 (93.2%) survived and 3 (6.8%) died before 36 weeks' corrected age. Median 25(OH)D levels at birth were 30.4 ng ml(-1) in preterm infants who subsequently died or developed BPD and 33.8 ng ml(-1) in infants who survived without BPD (P=0.6). Median 25(OH)D levels at corrected age of 36 weeks were 59.0 ng ml(-1) among survivors without BPD and 64.2 ng ml(-1) among survivors with BPD (P=0.9). Neither cord blood nor 36 weeks' corrected 25(OH)D levels were associated with odds of death or BPD (adjusted odds ratio (OR) 1.00, 95% confidence interval (CI): 0.73 to 1.37; and OR 0.93, 95% CI: 0.61 to 1.43, respectively).

CONCLUSIONS

Among this population of extremely preterm infants neither cord blood nor the 36 weeks' corrected age 25(OH)D levels were associated with development of BPD. Notably, at the current level of supplementation, all extremely preterm infants in our cohort had achieved 25(OH)D levels >30 ng ml(-1) by 36 weeks' corrected age, which is thought to represent sufficiency in adult and pediatric populations.

A Comparison of 3 Vitamin D Dosing Regimens in Extremely Preterm Infants: A Randomized Controlled Trial

OBJECTIVE

To determine the optimal dose of vitamin D supplementation to achieve biochemical vitamin D sufficiency in extremely low gestational age newborns in a masked randomized controlled trial.

STUDY DESIGN

100 infants 23 0/7-27 6/7 weeks gestation were randomized to vitamin D intakes of placebo (n = 36), 200 IU (n = 34), and 800 IU/d (n = 30) (approximating 200, 400, or 1000 IU/d, respectively, when vitamin D routinely included in parenteral or enteral nutrition is included). The primary outcomes were serum 25-hydroxy vitamin D concentrations on postnatal day 28 and the number of days alive and off respiratory support in the first 28 days.

RESULTS

At birth, 67% of infants had 25-hydroxy vitamin D <20 ng/mL suggesting biochemical vitamin D deficiency. Vitamin D concentrations on day 28 were (median [25th-75th percentiles], ng/mL): placebo: 22 (13-47), 200 IU: 39 (26-57), 800 IU: 84.5 (52-99); P < .001. There were no differences in days alive and off respiratory support (median [25th-75th percentiles], days): placebo: 1 (0-11), 200 IU: 0 (0-8), and 800 IU: 0.5 (0-22); P = .63, or other respiratory outcomes among groups.

CONCLUSIONS

At birth, most extremely preterm infants have biochemical vitamin D deficiency. This biochemical deficiency is reduced on day 28 by supplementation with 200 IU/d and prevented by 800 IU/d. Larger trials are required to determine if resolution of biochemical vitamin D deficiency improves clinical outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01600430.

The impact of vitamin D on fetal and neonatal lung maturation. A systematic review

Respiratory distress syndrome (RDS) and bronchopulmonary dysplasia (BPD) are major complications to preterm birth. Hypovitaminosis D is prevalent in pregnancy. We systematically reviewed the evidence of the impact of vitamin D on lung development, surfactant synthesis, RDS, and BPD searching PubMed, Embase, and Cochrane databases with the terms vitamin D AND (surfactant OR lung maturation OR lung development OR respiratory distress syndrome OR fetal lung OR prematurity OR bronchopulmonary dysplasia). Three human studies, ten animal studies, two laboratory studies, and one combined animal and laboratory study were included. Human evidence was sparse, allowing no conclusions. BPD was not associated with vitamin D receptor polymorphism in a fully adjusted analysis. Animal and laboratory studies showed substantial positive effects of vitamin D on the alveolar type II cell, fibroblast proliferation, surfactant synthesis, and alveolarization. These data support the hypothesis of hypovitaminosis D as a frequent, modifiable risk factor of RDS and BPD, which should be tested in randomized controlled trials on pregnant women, those with threatening preterm delivery, or in the preterm neonates. Future experimental and human studies should aim to identify optimal time windows, vitamin D doses, and cut-off levels for 25-hydroxyvitamin D in interventions against RDS, BPD, and later adverse respiratory outcomes.