Association of vitamin D deficiency with acute lower respiratory tract infections in newborns

Dietary patterns and micronutrients in respiratory infections including COVID-19: a narrative review

BACKGROUND

COVID-19 is a pandemic caused by nCoV-2019, a new beta-coronavirus from Wuhan, China, that mainly affects the respiratory system and can be modulated by nutrition.

METHODS

This review aims to summarize the current literature on the association between dietary intake and serum levels of micronutrients, malnutrition, and dietary patterns and respiratory infections, including flu, pneumonia, and acute respiratory syndrome, with a focus on COVID-19. We searched for relevant articles in various databases and selected those that met our inclusion criteria.

RESULTS

Some studies suggest that dietary patterns, malnutrition, and certain nutrients such as vitamins D, E, A, iron, zinc, selenium, magnesium, omega-3 fatty acids, and fiber may have a significant role in preventing respiratory diseases, alleviating symptoms, and lowering mortality rates. However, the evidence is not consistent and conclusive, and more research is needed to clarify the mechanisms and the optimal doses of these dietary components. The impact of omega-3 and fiber on respiratory diseases has been mainly studied in children and adults, respectively, and few studies have examined the effect of dietary components on COVID-19 prevention, with a greater focus on vitamin D.

CONCLUSION

This review highlights the potential of nutrition as a modifiable factor in the prevention and management of respiratory infections and suggests some directions for future research. However, it also acknowledges the limitations of the existing literature, such as the heterogeneity of the study designs, populations, interventions, and outcomes, and the difficulty of isolating the effects of single nutrients from the complex interactions of the whole diet.

A Prospective Cross-Sectional Study on the Vitamin D Status of Neonates and the Impact of Neonates' Standard Vitamin D Supplementation on Neonatal Morbidities

(1) Background: This study aimed to determine whether standard-dose vitamin D supplementation could provide adequate levels in exclusively breastfed infants born with different cord 25(OH)D levels and to evaluate related neonatal morbidities. (2) Methods: A prospective cross-sectional study was designed in term infants. Three groups were formed based on cord 25(OH)D levels; Group1 Deficiency:25(OH)D < 12 ng/mL, Group2 Insufficiency:25(OH)D = 12-19 ng/mL, and Group3 Optimum:25(OH)D = 20-100 ng/mL. Cord and 1st month 25(OH)D levels, after receiving standard-dose vitamin D prophylaxis, neonatal outcomes and anthropometric measurements were compared. (3) Results: The study involved 86 infants. Group1 Deficiency had also significantly lower 25(OH)D levels at 1st month compared to the others (p < 0.001). There was a significant positive correlation between cord and 1st month 25(OH)D levels (r = 0.78, p < 0.001). Despite the fact that the mother's age and clothing style were similar, Group1 Deficiency mothers had higher parity numbers and used less vitamin D during pregnancy (p = 0.03, p = 0.04). Neonatal outcomes analysis revealed that newborns in Group1 Deficiency experienced more respiratory distress, transient tachypnea, and early-onset sepsis, as well as more and longer hospital stays in the first-month of life (p < 0.05). (4) Conclusions: Infants with low cord 25(OH)D levels had also lower 25(OH)D values in the 1st month of life and experienced higher rates of neonatal morbidities. Given its numerous biological activities and impact on neonatal morbidities, determining an individualized dose of vitamin D supplementation may be more accurate than using the standard approach.

Risk factors associated with vitamin D deficiency in preterm neonates: a single-center step-wise regression analysis

BACKGROUND

Vitamin D deficiency is particularly concerning in pregnant women, leading to various health-related issues in mothers and their babies, especially those born prematurely, including neonatal skeletal and respiratory disorders. In addition, there have been several reports indicating the presence of multiple impactful factors in the development of vitamin D deficiency. Therefore, we aimed to evaluate the vitamin D level in very preterm and moderately preterm newborns and investigate its association with presumed influential factors.

METHODS

This cross-sectional descriptive study was performed on 54 mothers and their preterm neonates with gestational ages less than 34 weeks at delivery (i.e., very preterm and moderately preterm). After the serum vitamin D levels were determined from samples obtained in the first 24 h after birth, the babies were divided into two groups based on the presence or absence of deficiency. The relationship between several factors and the neonatal serum vitamin D level was investigated separately and in a linear step-wise regression model.

RESULTS

The differences between the groups regarding maternal age, gestational age, neonate's gender, birth weight, and delivery method with neonatal vitamin D levels were not statistically significant. However, maternal vitamin D levels strongly correlated with neonatal vitamin D levels (P-value < 0.001, r = 0.636). The regression model also yielded a strong predictive capability (P-value < 0.001, Adjusted R² = 0.606), with the maternal vitamin D level demonstrating a significant impact.

CONCLUSIONS

Low vitamin D levels in pregnant mothers correlate with deficient levels in their preterm neonates. Therefore, as vitamin D deficiency significantly affects both the mother's and newborn's health, it is recommended that healthcare providers provide comprehensive plans for vitamin D supplementation during pregnancy.

Serum 25-Hydroxy Vitamin D Levels in Children with Acute Respiratory Infections Caused by Respiratory Virus or Atypical Pathogen Infection

We aimed to clarify the involvement of vitamin D status in virus or atypical pathogens infection in children with acute respiratory infections (ARIs). In this retrospective study, 295 patients with ARIs were attacked by a respiratory virus or a single atypical pathogen; 17 patients with ARIs induced by two pathogens, and 636 healthy children were included. Serum 25(OH)D levels of all children were measured. Oropharyngeal samples of the patients for viruses or atypical pathogens were studied by polymerase chain reaction (PCR) or reverse transcription-polymerase chain reaction (RT-PCR). In our studies, 58.98% of the 295 single-infected subjects and 76.47% of the 17 co-infected subjects had 25(OH)D levels below the recommended 50.0 nmol/L; the mean 25(OH)D levels were 48.48 ± 19.91 nmol/L and 44.12 ± 12.78 nmol/L. Low serum 25(OH)D levels were remarkable in patients with one of seven viruses or atypical pathogens infected. These results were significantly different from those in the healthy group. There were no significant differences in 25(OH)D levels between single infection and co-infection groups. There were no differences in severity among means of 25(OH)D levels. Female or >6-year-old children patients with low serum 25(OH)D levels were more vulnerable to pathogenic respiratory pathogens. However, serum 25(OH)D levels may be related to the recovery of ARIs. These findings provide additional evidence for the development of strategies to prevent ARIs in children.

Role of Vitamin D Deficiency in Increased Susceptibility to Respiratory Infections Among Children: A Systematic Review

Vitamin D has several roles in the immune system besides its effects on bone metabolism. Acute respiratory infections are common infections in children. Severe lower respiratory tract infections (LRTIs) even cause death in children, especially in those less than five years of age. Our study aims to examine whether children with vitamin D deficiency are susceptible to respiratory infections and to study the association between vitamin D deficiency and the severity of respiratory infections. We comprehensively searched research articles in PubMed, ScienceDirect, and Cochrane library databases. The main keywords were vitamin D deficiency, respiratory infections, and children. We used Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines to conduct this systematic review. The initial search showed 16,120 papers. A meticulous screening of research articles using the eligibility criteria and quality appraisal tools was done. Finally, 10 research articles qualified for this systematic review, including eight case-control studies, one randomized controlled trial (RCT), and one cohort study. Seven of 10 research studies reviewed found that children with low vitamin D levels are susceptible to respiratory infections. Five studies discussed the severity of respiratory infections and low vitamin D levels. This systematic review concluded that children with low vitamin D levels are prone to developing respiratory infections. But we could not find a conclusive association between the severity of respiratory infections and low vitamin D levels.

Vitamin D status in very low birth weight infants and response to vitamin D intake during their NICU stays: a prospective cohort study

OBJECTIVE

To evaluate vitamin D status in very low birth weight (VLBW) infants and response to vitamin D intake.

STUDY DESIGN

In this prospective cohort study of VLBW infants, 25-hydroxyvitamin D [25(OH)D] was measured regularly starting at birth. Daily vitamin D intake was estimated from parenteral and enteral sources.

RESULTS

Of the included 83 infants born between November 2016 and March 2018, 44 (53%) had 25(OH)D < 30 ng/mL at birth but achieved vitamin D sufficiency (VDS) by 3 weeks while receiving 120-400 IU/day. Twenty-three (27.7%) infants had at least one 25(OH)D level >100 ng/mL during the study period. Infants whose intake was > 600 IU/day had higher prevalence of vitamin D excess (VDE).

CONCLUSION

In our study, low 25(OH)D was common in VLBW infants at birth. Vitamin D intake of 120-260 IU/day from parenteral and 200-400 IU/day from enteral route was appropriate for VLBW infants to achieve VDS. Doses > 600 IU/day increased risk of VDE.

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.

Relationship between bronchopulmonary dysplasia, long-term lung function, and vitamin D level at birth in preterm infants

BACKGROUND

We aimed to investigate the relationship between the level of serum 25 hydroxyvitamin D [25-(OH)D] at birth and the complications of bronchopulmonary dysplasia (BPD), as well as the long-term lung function of preterm infants.

METHODS

A total of 286 premature infants who were admitted to the neonatal ward of Haikou Maternal and Child Health Hospital from January 2018 to December 2020 and met the inclusion criteria were selected as the research objects. The level of serum 25(OH)D at birth was detected. The children were divided into a BPD group (79 cases) and a non-BPD group (207 cases). The case information and basic data of the children were recorded. The children were followed up 6 months after correcting the gestational age of 40 weeks, and their long-term lung function development was reported. Logistic regression analysis was used to evaluate the high-risk factors of BPD in preterm infants.

RESULTS

The 1- and 5-minute Apgar scores of preterm infants in the BPD group were significantly lower than those in the non-BPD group. Also, the combined neonatal pneumonia, neonatal asphyxia, hospital stay, and total oxygen therapy time in the BPD group were substantially higher than those in the non-BPD group. The mean value of serum 25-(OH)D at birth in the BPD group (33.7±15.1 nmol/L) was significantly lower than that in the non-BPD group (49.5±19.6 nmol/L). Compared with the non-BPD group, the respiratory rate (RR) in the BPD group increased significantly, while the tidal volume (VT), inspiratory to expiratory ratio (TI/TE), ratio of time to peak tidal expiratory flow to total expiratory time (TPEF/TE), and 25% tidal expiratory flow rate (TEF25%) decreased markedly (P<0.05). Total oxygen therapy time, neonatal pneumonia, neonatal asphyxia, and serum 25-(OH)D level at birth were identified as independent risk factors for BPD in preterm infants.

CONCLUSIONS

The level of serum 25-(OH)D in preterm infants at birth is closely related to the occurrence of BPD and long-term lung function damage, and is affected by multiple high-risk factors. This study provides a theoretical basis for the individualized treatment of preterm infants and the early prevention of BPD.

A Spatio-Temporal Analysis of the Environmental Correlates of COVID-19 Incidence in Spain

The novel SARS-CoV2 has disrupted health systems and the economy, and public health interventions to slow its spread have been costly. How and when to ease restrictions to movement hinges in part on whether SARS-CoV2 will display seasonality due to variations in temperature, humidity, and hours of sunshine. Here, we address this question by means of a spatio-temporal analysis in Spain of the incidence of COVID-19, the disease caused by the virus. Use of spatial Seemingly Unrelated Regressions (SUR) allows us to model the incidence of reported cases of the disease per 100,000 population as an interregional contagion process, in addition to a function of temperature, humidity, and sunshine. In the analysis we also control for GDP per capita, percentage of older adults in the population, population density, and presence of mass transit systems. The results support the hypothesis that incidence of the disease is lower at higher temperatures and higher levels of humidity. Sunshine, in contrast, displays a positive association with incidence of the disease. Our control variables also yield interesting insights. Higher incidence is associated with higher GDP per capita and presence of mass transit systems in the province; in contrast, population density and percentage of older adults display negative associations with incidence of COVID-19.

A Spatio-Temporal Analysis of the Environmental Correlates of COVID-19 Incidence in Spain

The novel SARS-CoV2 has disrupted health systems and the economy, and public health interventions to slow its spread have been costly. How and when to ease restrictions to movement hinges in part on whether SARS-CoV2 will display seasonality due to variations in temperature, humidity, and hours of sunshine. Here, we address this question by means of a spatio-temporal analysis in Spain of the incidence of COVID-19, the disease caused by the virus. Use of spatial Seemingly Unrelated Regressions (SUR) allows us to model the incidence of reported cases of the disease per 100,000 population as an interregional contagion process, in addition to a function of temperature, humidity, and sunshine. In the analysis we also control for GDP per capita, percentage of older adults in the population, population density, and presence of mass transit systems. The results support the hypothesis that incidence of the disease is lower at higher temperatures and higher levels of humidity. Sunshine, in contrast, displays a positive association with incidence of the disease. Our control variables also yield interesting insights. Higher incidence is associated with higher GDP per capita and presence of mass transit systems in the province; in contrast, population density and percentage of older adults display negative associations with incidence of COVID-19.

Vitamin D Status and Its Influence on the Health of Preschool Children in Hangzhou

Objective: Vitamin D deficiency and insufficiency in children are global public health problems. However, few studies have focused on vitamin D status in healthy preschool children, especially in Asia. This study aimed to investigate vitamin D status and host-related factors in healthy preschool children in Hangzhou to analyze the impact of low vitamin D levels (<30 ng/mL) on health outcomes (obesity, early childhood caries, and respiratory tract infections).

Methods: A total of 1,510 healthy children aged 24–72 months from 15 kindergartens in Hangzhou were included. Data on the children's gender, age, body mass index (BMI), caries, and blood samples available for vitamin D analysis were collected from June to August 2018. A total of 325 children aged 36–48 months took part in a survey on the frequency of respiratory tract infections in the last year.

Results: The children's mean 25(OH)D level was 28.01 ± 7.29 ng/mL. A total of 11.4% of the children had vitamin D deficiency, and 52.6% had vitamin D insufficiency. Only 36.0% had vitamin D sufficiency. No significant difference was found by gender or BMI group. However, children in the obesity group had the highest prevalence of vitamin D deficiency and the lowest 25(OH)D levels. A significant negative correlation was found between the 25(OH)D level and child age (r = −0.144, p < 0.001). Regression analysis showed that the children’s 25(OH)D levels decreased by 0.17 ng/mL per month with age. In addition, children with low vitamin D levels might increase the risk of obesity and early childhood caries. Multiple linear regression indicated that the number of caries in children increased by 0.08 per 1-ng/mL decrease in the 25(OH)D level (β = −0.08, p < 0.001).

Conclusion: Vitamin D deficiency/insufficiency is a serious problem among healthy preschool children in Hangzhou. Public health policies or interventions should be implemented to ensure that preschool children have adequate vitamin D to reduce the risk of related diseases.

Vitamin D status in women with dichorionic twin pregnancies and their neonates: a pilot study in China

Background

Vitamin D deficiency is a global public health issue in women and children and is associated with adverse impacts on child growth, such as rickets. However, prior studies have mainly focused on measuring vitamin D levels in singleton pregnant women and their offspring, and very limited studies have revealed the prevalence of vitamin D deficiency in twin pregnant women and their offspring. The aim of this study was to investigate vitamin D levels in twin-pregnant women and their neonates. We also explored the correlation of maternal vitamin D levels with neonatal outcomes and infant growth.

Methods

A prospective subcohort investigation was carried out among 72 dichorionic, diamniotic twin-pregnant mothers and their twin offspring from the Longitudinal Twin Study. Peripheral blood was collected from the mothers in the third trimester, and cord blood was collected from neonates at birth to identify 25[OH]D levels. Data on the characteristics of the mothers and neonates were collected. Infant growth data and food sensitivities were also collected.

Results

The average maternal 25[OH]D level was 31.78 ng/mL, with 19.4% being deficient and 20.8% insufficient, while the average neonatal 25[OH]D level was 15.37 ng/mL, with 99.3% being deficiency or insufficient. A positive correlation was found between maternal and neonatal 25[OH]D levels (beta-value: 0.43, 95% CI: 0.37, 0.49). Interestingly, the higher the maternal 25[OH]D level was, the smaller the cotwin birthweight discordance (beta-value: -2.67, 95% CI: − 5.11, − 0.23). In addition, the infants of mothers with vitamin D deficiency were more likely to be allergic to foods at 6 months than those of mothers with vitamin D sufficiency.

Conclusions

Twin neonates were at high risk of vitamin D deficiency, although their mothers’ vitamin D deficiency partially improved. Higher maternal vitamin D levels were associated with smaller discordance of cotwin birthweight.

Trial registration

Chinese Clinical Trial Registry ChiCTR-OOC-16008203, 1st April 2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-03707-7.

Supplementation with vitamin D in the COVID-19 pandemic?

The coronavirus disease 2019 (COVID-19) pandemic was declared a public health emergency of international concern by the World Health Organization. COVID-19 has high transmissibility and could result in acute lung injury in a fraction of patients. By counterbalancing the activity of the renin-angiotensin system, angiotensin-converting enzyme 2, which is the fusion receptor of the virus, plays a protective role against the development of complications of this viral infection. Vitamin D can induce the expression of angiotensin-converting enzyme 2 and regulate the immune system through different mechanisms. Epidemiologic studies of the relationship between vitamin D and various respiratory infections were reviewed and, here, the postulated mechanisms and clinical data supporting the protective role of vitamin D against COVID-19-mediated complications are discussed.

Effects of vitamin D on neonatal sepsis: A systematic review and meta-analysis

Vitamin D deficiency is a major public health concern of pregnant women and neonates worldwide, affecting more than half of neonates. Studies report inconsistent and inconclusive effects of vitamin D treatment on neonatal sepsis. This study aimed to provide conclusive evidence regarding the effect of maternal and cord blood vitamin D levels on neonatal sepsis. Data were retrieved from the electronic database (Web of Science, Scopus, CINAHL [EBSCOhost], ProQuest, EMBASE [Ovid], PubMed, Emcare, MEDLINE [Ovid], and gray literature sources [World cat, Mednar, Google scholar and Google]). Joanna Briggs Institute quality assessment tool was utilized for quality assessment while analysis was performed using Open Meta-analyst, Comprehensive Meta-analysis version 3.3.070, and Review Manager version 5.3 software. From the 18 studies included in the study, the overall prevalence of vitamin D deficiency among neonates was 61% (95% CI: 44.3, 77.7); 79.4% (95% CI: 71.6, 87.3) of neonates with sepsis were vitamin D deficient as were 43.7% (23.4, 63.9) of sepsis-free neonates. Neonates born from mothers with low vitamin D levels were at greater risk of developing neonatal sepsis with a weighed mean difference of -8.57 ng/ml (95% CI: -13.09, -4.05). Similarly, neonates with low cord vitamin D levels were at risk for neonatal sepsis with a mean difference of -8.78 ng/ml (95% CI:-11.58, -5.99). The incidence of EONS in full-term newborns was significantly associated with low maternal and cord blood vitamin D levels with weighed mean differences of -11.55ng/ml (95% CI: -17.63, -5.46) & -11.59 ng/ml (95% CI:-16.65, -6.53), respectively. Low levels of vitamin D both in the cord blood and maternal blood were significantly associated with neonatal sepsis. Hence, vitamin D supplementation for pregnant women and newborns could decrease neonatal sepsis.

Association Between Vitamin D and Novel SARS-CoV-2 Respiratory Dysfunction - A Scoping Review of Current Evidence and Its Implication for COVID-19 Pandemic

OBJECTIVES

To assess the association between vitamin D deficiency and increased morbidity/mortality with COVID-19 respiratory dysfunction.

DESIGN

Scoping review.

DATA SOURCES

Ovid MEDLINE (1946 to 24 of April 2020) and PubMed (2020 to 17 of September 2020).

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

A search using the search terms: [(cholecalciferol or ergocalciferol or vitamin D2 or vitamin D3 or vitamin D or 25OHD) and (SARS-CoV-2 or coronavirus or COVID or betacoronavirus or MERS-CoV or SARS-CoV or respiratory infection or acute respiratory distress syndrome or ARDS)]m.p. was conducted on the 24/04/2020 (Search A) and 17/09/2020 (Search B).

RESULTS

91 studies were identified as being concerned with Acute Respiratory Infection (ARI)/Acute Respiratory Distress Syndrome (ARDS) and vitamin D, and 25 publications specifically explored the role of vitamin D deficiency in the development and progression of SARS-CoV-2/COVID-19 related ARDS. Search "A" identified three main themes of indirect evidence supporting such an association. Consistent epidemiological evidence exists linking low vitamin D levels to increased risk and severity of respiratory tract infections. We also report on plausible biological processes supporting such an association; and present weaker evidence supporting the benefit of vitamin D supplementation in reducing the risk and severity of ARIs. Uncertainty remains about what constitutes an appropriate dosing regimen in relation to reducing risk/severity of ARI/ARDS. More recent evidence (Search B) provided new insights into some direct links between vitamin D and COVID-19; with a number of cohort and ecological studies supporting an association with PCR-positivity for SARS-CoV-2 and vitamin D deficiency. The exact efficacy of the vitamin D supplementation for prevention of, or as an adjunct treatment for COVID-19 remains to be determined; but a number of randomized control trials (RCTs) currently underway are actively investigating these potential benefits.

CONCLUSION

Our rapid review of literature supports the need for observational studies with COVID-19 infected populations to measure and assess vitamin D levels in relation to risk/severity and outcomes; alongside RCTs designed to evaluate the efficacy of supplementation both in preventive and therapeutic contexts. The overlap in the vitamin D associated biological pathways with the dysregulation reported to drive COVID-19 outcomes warrants further investigation.

The Role of Micronutrients in Support of the Immune Response against Viral Infections

Viral infections are a leading cause of morbidity and mortality worldwide, and the importance of public health practices including handwashing and vaccinations in reducing their spread is well established. Furthermore, it is well known that proper nutrition can help support optimal immune function, reducing the impact of infections. Several vitamins and trace elements play an important role in supporting the cells of the immune system, thus increasing the resistance to infections. Other nutrients, such as omega-3 fatty acids, help sustain optimal function of the immune system. The main aim of this manuscript is to discuss of the potential role of micronutrients supplementation in supporting immunity, particularly against respiratory virus infections. Literature analysis showed that in vitro and observational studies, and clinical trials, highlight the important role of vitamins A, C, and D, omega-3 fatty acids, and zinc in modulating the immune response. Supplementation with vitamins, omega 3 fatty acids and zinc appears to be a safe and low-cost way to support optimal function of the immune system, with the potential to reduce the risk and consequences of infection, including viral respiratory infections. Supplementation should be in addition to a healthy diet and fall within recommended upper safety limits set by scientific expert bodies. Therefore, implementing an optimal nutrition, with micronutrients and omega-3 fatty acids supplementation, might be a cost-effective, underestimated strategy to help reduce the burden of infectious diseases worldwide, including coronavirus disease 2019 (COVID-19).

Preoperative serum 25-hydroxyvitamin D3 and the incidence of early pulmonary infection after pediatric living donor liver transplantation

BACKGROUND

Pulmonary infection is a common complication in pediatric living donor liver transplantation (LDLT) recipients. It has been suggested that vitamin D has a role in immune defense against infection. Therefore, we investigated the effect of preoperative serum 25-hydroxyvitamin D₃ (25(OH)D₃ ) on the risk of pneumonia in hospitalized patients undergoing LDLT.

MATERIALS AND METHODS

This study was a retrospective review of patient records. Fifty consecutive pediatric patients (aged < 14 years) who underwent LDLT from January 2017 to December 2017 were included. Pulmonary infection in the early postoperative period was diagnosed using clinical, radiological, or laboratory criteria. Preoperative serum 25(OH)D₃ level, demographic characteristics, primary diagnosis, ascites, time to extubation, length of intensive care unit stay, and perioperative laboratory values were recorded. Vitamin D deficiency, insufficiency, and sufficiency were defined as a serum 25(OH)D₃ concentration of less than 10, 10 to 20, and more than 20 ng/mL, respectively. Associations between serum 25(OH)D₃ levels and pulmonary infection were analyzed.

RESULTS

Of 50 pediatric patients who underwent LDLT, 19 (38%) developed pulmonary infections in the early postoperative period. The mean serum 25(OH)D₃ level in these subjects was 18.7 ± 17.2 ng/mL (range, 3.0-70.0 ng/mL). Twenty patients (40%) had severe vitamin D deficiency (<10 ng/mL). The mean serum 25(OH)D₃ level was significantly decreased (9.3 ± 7.4 vs 24.5 ± 19.1 ng/mL, P = .002) in patients with pulmonary infection compared with those without pulmonary infection. Serum 25(OH)D₃ level as a continuous variable (odds ratio [OR], 0.90, 95% confidence interval [CI], 0.84-0.97, P = .008) and a classification variable (≤10 ng/mL) (OR, 7.42, 95% CI, 2.06-26.79, P = .002) were significantly associated with pulmonary infection in univariate analysis. After adjusting for other significant predictors (age, weight, and pediatric end-stage liver disease score), severe 25(OH)D₃ deficiency at presentation was independently associated with a higher risk of developing pulmonary infection in the early postoperative period (OR, 5.11, 95% CI, 1.30-20.16, P = .02).

CONCLUSIONS

25(OH)D₃ deficiency is common and inversely correlated with pulmonary infection within the first month after pediatric LDLT. Our results indicate that preoperative serum 25(OH)D₃ deficiency is a potential biomarker for early pulmonary infection after pediatric LDLT.

Vitamin D Status in Neonatal Pulmonary Infections: Relationship to Inflammatory Indicators

AIM

The study aimed to evaluate serum vitamin D concentrations among neonates with pneumonia.

METHODS

This case-control study enrolled 33 neonates with pneumonia in addition to 30 healthy controls. CBC, CRP, Serum vitamin D and Pentraxin 3 levels were measured for all participants.

RESULTS

There was significant difference between patients and controls regarding Hemoglobin levels, TLC and CRP (p value < 0.01, = 0.002, < 0.01 respectively). Patients with pneumonia showed significant lower levels of Vit. D (9 ± 2.1) compared to controls (14.1 ± 2.8), P value < 0.01. However, patient group had significant higher levels of Pentraxin 3 (29.1 ± 4.8) compared with controls (12.6 ± 3), P value < 0.01. Moreover, mechanically ventilated patients revealed significant lower vit D (7.7 ± 1.8) and higher pentraxin 3 (32.2 ± 2.6) compared to patients on free oxygen (9.1 ± 2.1, 26.4 ± 3.7 respectively), P value = 0.05, 0.02 respectively. Regarding hospital stay, it had significant positive correlation with serum pentraxin 3 (r = 0.6, P value < 0.01) and significant negative correlation with serum vit D (r = -0.4, P value = 0.04). Finally a significant negative correlation between serum levels of vitamin D and Pentraxin 3 was found (r = -0.4, P value = 0.01).

CONCLUSION

Lower concentration of serum vitamin D may be significantly associated with neonatal pneumonia. It also can predict the need for mechanical ventilation and duration of hospital stay in neonatal pneumonia. Similarly, higher levels of Pentraxin 3 may be used as an indicator for mechanical ventilation need and a longer hospital stay in neonates with pneumonia.

The association between vitamin D status and infectious diseases of the respiratory system in infancy and childhood

PURPOSE

Respiratory tract infections (RTIs) are a major cause of illness worldwide and the most common cause of hospitalization for pneumonia and bronchiolitis. These two diseases are the leading causes of morbidity and mortality among children under 5 years of age. Vitamin D is believed to have immunomodulatory effects on the innate and adaptive immune systems by modulating the expression of antimicrobial peptides, like cathelicidin, in response to both viral and bacterial stimuli. The aim of this review is to summarize the more recently published data with regard to potential associations of 25-hydroxyvitamin D [25(OH)D] with infectious respiratory tract diseases of childhood and the possible health benefits from vitamin D supplementation.

METHODS

The literature search was conducted by using the PubMed, Scopus, and Google Scholar databases, with the following keywords: vitamin D, respiratory tract infection, tuberculosis, influenza, infancy, and childhood.

RESULTS

Several studies have identified links between inadequate 25(OH)D concentrations and the development of upper or lower respiratory tract infections in infants and young children. Some of them also suggest that intervention with vitamin D supplements could decrease both child morbidity and mortality from such causes.

CONCLUSIONS

Most studies agree in that decreased vitamin D concentrations are prevalent among most infants and children with RTIs. Also, normal to high-serum 25(OH)D appears to have some beneficial influence on the incidence and severity of some, but not all, types of these infections. However, studies with vitamin D supplementation revealed conflicting results as to whether supplementation may be of benefit, and at what doses.

Importance of vitamin D in acute and critically ill children with subgroup analyses of sepsis and respiratory tract infections: a systematic review and meta-analysis

OBJECTIVES

To estimate the prevalence of 25-hydroxyvitamin D (25(OH)D) deficiency and investigate its association with mortality in children with acute or critical conditions.

DESIGN

Systematic review and meta-analysis of observational studies.

DATA SOURCES

PubMed, OVID, Google Scholar and the Cochrane Library searched until 21 December 2018.

ELIGIBILITY CRITERIA

Studies of children hospitalised with acute or critical conditions who had blood 25(OH)D levels measured.

DATA EXTRACTION AND SYNTHESIS

We obtained pooled prevalence estimates of 25(OH)D deficiency and ORs for mortality. We calculated 95% CI and prediction intervals and investigated heterogeneity and evidence of small-study effects.

RESULTS

Fifty-two studies were included. Of 7434 children, 3473 (47.0%) were 25(OH)D deficient (<50 nmol/L). The pooled prevalence estimate of 25(OH)D deficiency was 54.6% (95% CI 48.5% to 60.6%, I²=95.3%, p<0.0001). Prevalence was similar after excluding smaller studies (51.5%). In children with sepsis (18 studies, 889 total individuals) prevalence was 64.0% (95% CI 52.0% to 74.4%, I²=89.3%, p<0.0001) and 48.7% (95% CI 38.2% to 59.3%; I²=94.3%, p<0.0001) in those with respiratory tract infections (RTI) (25 studies, 2699 total individuals). Overall, meta-analysis of mortality (18 cohort studies, 2463 total individuals) showed increased risk of death in 25(OH)D deficient children (OR 1.81, 95% CI 1.24 to 2.64, p=0.002, I²=25.7%, p=0.153). Four (22.0%) of the 18 studies statistically adjusted for confounders. There were insufficient studies to meta-analyse sepsis and RTI-related mortality.

CONCLUSIONS

Our results suggest that 25(OH)D deficiency in acute and critically ill children is high and associated with increased mortality. Small-study effects, reverse causation and other biases may have confounded results. Larger, carefully designed studies in homogeneous populations with confounder adjustment are needed to clarify the association between 25(OH)D levels with mortality and other outcomes.

PROSPERO REGISTRATION NUMBER

CRD42016050638.

Vitamin D status of very low birth weight infants at birth and the effects of generally recommended supplementation on their vitamin D levels at discharge

Purpose: To evaluate vitamin D status in mothers and their very low birth weight infants (VLBW) at birth (umbilical cord blood) and at discharge with currently recommended supplementation of vitamin D.Methods: Ninety-four infants with birth weight less than 1500 g completed the study. The total daily vitamin D intake was 800-1000 IU. We examined 25-hydroxyvitamin-D [25(OH)D] levels in maternal serum before labor, in cord blood, and in infants' serum at discharge.Results: Median (IQR) serum 25(OH)D was 21 (14-36) nmol/l [8 (6-15) ng/ml] in cord blood, and 46 (37-60) nmol/l [18 (15-24) ng/ml] at discharge. Serum 25(OH)D was <50 nmol/L in 71.3% of mothers, in 91.5% of cord blood samples, and in almost 60% of preterm newborns at discharge (after 8 weeks of supplementation). Serum 25(OH)D was <75 nmol/L in 88.3% of mothers, in 97.9% of cord blood samples, and in 91.4% of preterm newborns at discharge.Conclusions: In our cohort, we found that due to the very high prevalence of 25(OH)D deficiency among mothers, the current generally recommended dose of vitamin D (800-1000 IU per day) for VLBW infants was unable to improve vitamin D levels above the desired 50 or even 75 nmol/L before discharge.

Maternal and neonatal vitamin D deficiency and transient tachypnea of the newborn in full term neonates

AIM

To investigate the association between maternal and neonatal serum 25-hydroxyvitamin D (25-OHD) levels and development of transient tachypnea of the newborn (TTN) in full term infants.

METHODS

This was a prospective case-control study carried out on 30 neonates with TTN and their mothers and 30 control neonates and their mothers. Levels of 25-OHD were measured in maternal and neonatal blood samples that were obtained in the first 12-24 h of postnatal age.

RESULTS

Both maternal and neonatal 25-OHD levels in the TTN group were significantly lower compared to the control group (P=0.0001). A negative correlation was observed between neonatal 25-OHD level and average hospital stay (P=0.0001).

CONCLUSION

We observed that lower maternal and neonatal vitamin 25-OHD levels were associated with TTN development in full term infants.

Vitamin D: Immunomodulatory Aspects

Vitamin D is a group of liposoluble prohormones consisting of 5 different vitamins, the most important forms being vitamin D2 and vitamin D3. The ergocalciferol (vitamin D2) is less efficacious and derives from irradiated fungi, while colecalciferol (vitamin D3), derived from cholesterol, is synthesized via ultraviolet B rays in animal organisms. Only the ultraviolet B rays (290 to 315 nm) portion of the solar ray photolyzes 7-dehydrocholesterol in the skin to previtamin D3, which is converted subsequently to vitamin D3. Moreover, the skin makes little vitamin D from the sun at latitudes above 37 degrees north or below 37 degrees south of the equator. Calcidiol [25(OH)D] is the more stable metabolite of vitamin D in serum and the best indicator of the vitamin D status. Optimal values range are >30 ng/mL. Calcitriol [1,25(OH)2D] is the active hormone form of vitamin D. The 1,25(OH)2D binds to its nuclear receptor (vitamin D receptor), expressed in many tissues, regulating the expression of genes involved in calcium metabolism, cell differentiation, apoptosis, and immunity. About immunity, calcitriol stimulates innate immune responses by enhancing the chemotactic and phagocytotic responses of macrophages as well as the production of antimicrobial peptides. 1,25(OH)2D strongly enhances production of interleukine-10 by stimulating T regulatory cells and inhibiting Th1 and Th17 cell differentiation. Furthermore, several studies suggest that lower 25(OH)D serum levels are associated with an increased risk of respiratory infection at all ages in a dose-response manner.

Association of vitamin D deficiency with an increased risk of late-onset neonatal sepsis

BACKGROUND

Vitamin D deficiency in mothers and neonates is being recognised increasingly as a leading cause of many adverse health effects in the newborn infant, including sepsis.

METHODS

A prospective observational study was conducted at a tertiary care Paediatric teaching hospital in northern India to assess vitamin D deficiency as a possible risk factor for late-onset sepsis (LOS) in term and late preterm neonates and also to examine the correlation between maternal and infant vitamin D levels during the neonatal period. Late-onset sepsis (LOS) was defined as the development of signs and symptoms of severe sepsis after 72 h of life and a positive sepsis screen. All term and late preterm neonates admitted with LOS between September 2015 and February 2016 who had not been previously admitted for >48 h and had not been prescribed antibiotics or vitamin D were included in the study. Matched controls were recruited from otherwise healthy neonates admitted with physiological hyperbilirubinaemia. Serum 25(OH) vitamin D was assessed in neonates in both groups and their mothers.

RESULTS

A total of 421 neonates were admitted to the neonatal intensive care unit during the study period, 120 of whom satisfied the inclusion criteria, and 60 were recruited as cases. Sixty neonates were recruited as controls who were similar in gender, gestational age, age at admission and anthropometry. The study group had significantly lower mean (SD) vitamin D levels [15.37 ng/ml (10.0)] than the control group [21.37 ng/ml (9.53)] (p = 0.001). The odds ratio was 1.7 (95% CI 0.52-5.51) for LOS in vitamin D-deficient neonates. Mothers of septic neonates also had significantly lower mean (SD) vitamin D levels [17.87 (11.89)] than the mothers of non-septic neonates [23.65 ng/ml (9.55)] (p = 0.004). Maternal vitamin D levels strongly correlated to neonatal vitamin D levels in both groups.

CONCLUSION

Neonates with vitamin D deficiency are at greater risk of LOS than those with sufficient vitamin D levels.

Vitamin D in pediatric age: consensus of the Italian Pediatric Society and the Italian Society of Preventive and Social Pediatrics, jointly with the Italian Federation of Pediatricians

Vitamin D plays a pivotal role in the regulation of calcium-phosphorus metabolism, particularly during pediatric age when nutritional rickets and impaired bone mass acquisition may occur.Besides its historical skeletal functions, in the last years it has been demonstrated that vitamin D directly or indirectly regulates up to 1250 genes, playing so-called extraskeletal actions. Indeed, recent data suggest a possible role of vitamin D in the pathogenesis of several pathological conditions, including infectious, allergic and autoimmune diseases. Thus, vitamin D deficiency may affect not only musculoskeletal health but also a potentially wide range of acute and chronic conditions. At present, the prevalence of vitamin D deficiency is high in Italian children and adolescents, and national recommendations on vitamin D supplementation during pediatric age are lacking. An expert panel of the Italian Society of Preventive and Social Pediatrics reviewed available literature focusing on randomized controlled trials of vitamin D supplementation to provide a practical approach to vitamin D supplementation for infants, children and adolescents.

Prenatal vitamin D status and respiratory and allergic outcomes in childhood: A meta-analysis of observational studies

BACKGROUND

Prenatal vitamin D status may influence offspring's respiratory and allergic outcomes; however, evidence is inconclusive. A systematic review and meta-analysis were conducted on the association between 25-hydroxyvitamin D [25(OH)D] levels in maternal blood in pregnancy or cord blood at birth with the risk of offspring's respiratory and allergic conditions.

METHODS

Two independent researchers conducted systematic searches for observational studies published until May 2017 using defined keywords on vitamin D and health outcomes, including respiratory tract infections (RTIs), wheeze, asthma, atopic eczema, allergic rhinitis, allergic sensitization, and lung function. Random-effects meta-analyses were conducted.

RESULTS

A total of 34 from 547 retrieved articles were included. Increased prenatal exposure to 25(OH)D was inversely associated with risk of RTIs. Comparing the highest with the lowest category of 25(OH)D levels, the pooled odds ratio was 0.64 (95% CI 0.47, 0.87). A positive borderline association was found for lung function at school age (FEV1 z-score coefficient 0.07, 95% CI -0.01, 0.15). No associations were found for wheeze, asthma, atopic eczema, allergic rhinitis, and allergic sensitization.

CONCLUSION

The introduction of public health measures to tackle vitamin D status in pregnancy may reduce the burden of RTIs in offspring. Current evidence does not support an impact on asthma and allergy.

[Predictive value of cord blood 25(OH)D3 for early infantile atopic dermatitis]

OBJECTIVE

To explore the predictive value of cord blood 25(OH)D₃ [25(OH)D₃] for infantile atopic dermatitis (AD), and to provide a reference for primary prevention of early infantile AD.

METHODS

The neonates born from July to September, 2015 were enrolled. The cord blood samples were collected at birth to measure the level of 25(OH)D₃. Outpatient follow-up was conducted for all the infants at 6 weeks, 3 months, and 6 months after birth. A survey was performed to investigate the incidence of AD.

RESULTS

A total of 67 neonates completed a 6-month follow-up. The incidence of AD was 34% (23/67), and 91% (21/23) of these cases occurred in the first month after birth. The 23 AD children had a significantly lower cord 25(OH)D₃ level than those without AD (P&lt;0.05). The children with a cord 25(OH)D₃ level <30 nmol/L showed a significantly higher incidence of AD than those with a cord 25(OH)D₃ level &ge;30 nmol/L (P&lt;0.05). The receiver operating characteristic (ROC) analysis showed that the area under the ROC curve of cord 25(OH)D₃ in predicting AD was 0.648 (standard error: 0.075; 95%CI: 0.502-0.795). Its sensitivity, specificity, positive predictive value, and negative predictive value were 52.2%, 79.5%, 57.1%, and 76.1%, respectively. Logistic regression analysis showed that low cord 25(OH)D₃ level, preference for seafood during pregnancy, atopic family history, and mixed feeding were risk factors for infantile AD (P&lt;0.05).

CONCLUSIONS

Cord 25(OH)D₃ level is inversely associated with the risk of infantile AD, but it has a low diagnostic value for this disease.

[Relationship between serum 25(OH)D levels at birth and respiratory distress syndrome in preterm infants]

OBJECTIVE

To investigate the relationship between serum 25-hydroxyvitamin D [25(OH)D] levels at birth and respiratory distress syndrome (RDS) in preterm infants.

METHODS

This retrospective study recruited preterm infants with gestational age of below 34 weeks who were born between January 2014 and December 2016. These preterm infants were divided into two groups: RDS (n=72) and control (n=40). Clinical data of the two groups were collected, including gestational age, birth weight, gender, delivery mode, Apgar scores at 1 minute and 5 minutes, incidence of maternal gestational diabetes mellitus, and use of prenatal steroid hormone. Peripheral blood samples were collected and 25(OH)D levels were measured by chemiluminescence immunoassay. The association between serum 25(OH)D levels at birth and RDS was analyzed by multivariate logistic regression.

RESULTS

Apgar scores at 1 minute and 5 minutes and serum 25(OH)D levels in the RDS group were significantly lower than those in the control group (P<0.05), while the rates of neonatal asphyxia and vitamin D deficiency were significantly higher than those in the control group (P<0.05). Multivariate logistic regression analysis showed that neonatal asphyxia (OR=2.633, 95%CI: 1.139-6.085) and vitamin D deficiency (OR=4.064, 95%CI: 1.625-10.165) were risk factors for RDS in preterm infants.

CONCLUSIONS

Vitamin D deficiency might be associated with increased risk of RDS in preterm infants. Reasonable vitamin D supplementation during pregnancy might reduce the incidence of RDS in preterm infants.

Milk vitamin D in relation to the 'adequate intake' for 0-6-month-old infants: a study in lactating women with different cultural backgrounds, living at different latitudes

Breast-fed infants are susceptible to vitamin D deficiency rickets. The current vitamin D 'adequate intake' (AI) for 0-6-month-old infants is 10 µg/d, corresponding with a human milk antirachitic activity (ARA) of 513 IU/l. We were particularly interested to see whether milk ARA of mothers with lifetime abundant sunlight exposure reaches the AI. We measured milk ARA of lactating mothers with different cultural backgrounds, living at different latitudes. Mature milk was derived from 181 lactating women in the Netherlands, Curaçao, Vietnam, Malaysia and Tanzania. Milk ARA and plasma 25-hydroxyvitamin D (25(OH)D) were analysed by liquid-chromatography-MS/MS; milk fatty acids were analysed by GC-flame ionisation detector (FID). None of the mothers reached the milk vitamin D AI. Milk ARA (n; median; range) were as follows: Netherlands (n 9; 46 IU/l; 3-51), Curaçao (n 10; 31 IU/l; 5-113), Vietnam: Halong Bay (n 20; 58 IU/l; 23-110), Phu Tho (n 22; 28 IU/l; 1-62), Tien Giang (n 20; 63 IU/l; 26-247), Ho-Chi-Minh-City (n 18; 49 IU/l; 24-116), Hanoi (n 21; 37 IU/l; 11-118), Malaysia-Kuala Lumpur (n 20; 14 IU/l; 1-46) and Tanzania-Ukerewe (n 21; 77 IU/l; 12-232) and Maasai (n 20; 88 IU/l; 43-189). We collected blood samples of these lactating women in Curaçao, Vietnam and from Tanzania-Ukerewe, and found that 33·3 % had plasma 25(OH)D levels between 80 and 249·9 nmol/l, 47·3 % between 50 and 79·9 nmol/l and 19·4 % between 25 and 49·9 nmol/l. Milk ARA correlated positively with maternal plasma 25(OH)D (range 27-132 nmol/l, r 0·40) and milk EPA+DHA (0·1-3·1 g%, r 0·20), and negatively with latitude (2°S-53°N, r -0·21). Milk ARA of mothers with lifetime abundant sunlight exposure is not even close to the vitamin D AI for 0-6-month-old infants. Our data may point at the importance of adequate fetal vitamin D stores.

[Association between serum 25(OH)D levels at birth and bronchopulmonary dysplasia in preterm infants]

OBJECTIVE

To assess the association between serum 25-hydroxyvitamin D [25(OH)D] levels at birth and bronchopulmonary dysplasia (BPD) in preterm infants.

METHODS

This study recruited preterm infants with gestational age of below 34 weeks who were born between January 2014 and December 2016. These preterm infants were classified into two groups: BPD and control. The association between serum 25(OH)D levels at birth and BPD was analyzed.

RESULTS

Serum 25(OH)D levels in the BPD group was significantly lower than those in the control group [(37±17 nmol/L vs 47±20 nmol/L; P<0.05), and the rate of vitamin D deficiency was significantly higher than those in the control group (90.2% vs 74.0%; P<0.05). The level of serum 25(OH)D was negatively correlated with the incidence of BPD (r=-0.201, P=0.001).

CONCLUSIONS

Vitamin D deficiency at birth may be associated with BPD in preterm infants, but need to be further studied by multivariate analysis.

MOnitored supplementation of VItamin D in preterm infants (MOSVID trial): study protocol for a randomised controlled trial

Background

The pivotal role of vitamin D (vit D) in skeletal health is well known. Neonatal vit D storage at birth is dependent on maternal levels, and newborns receive 50–70% of their mother’s 25-hydroxyvitamin D [25(OH)D]. Deficiency of vit D can lead to prematurity bone disease, with an incidence of up to 55% in infants weighing < 1000 g. The aim of this study is to assess the effectiveness of monitored supplementation of vit D in a population of preterm infants.

Methods/design

Preterm infants born at 24–32 weeks of gestation will be recruited within the first 7 days of life. Depending on the type of feeding, and after reaching partial enteral feeding or at 7 days of life, vit D supplementation will consist of 500 IU and an additional 150–300 IU/kg included in human milk fortifiers (if fed exclusively with breast milk) or 190 IU/kg in milk formulas. Subjects will be randomised to either monitored (with an option of dose modification based on 25(OH)D levels as per protocol) or standard therapy up to 52 weeks of post-conceptional age (PCA). The primary outcome measure will be the number of neonates with deficiency or excess levels of 25(OH)D at 40  ±2 weeks of PCA. Additional 25(OH)D levels will be measured at birth, at 4 and 8 weeks of age, and/or at 35 and 52  ±2 weeks of PCA. Secondary objectives will include the incidence of osteopenia, nephrocalcinosis and nephrolithiasis. Serum parameters of calcium phosphorus metabolism will also be measured.

Discussion

Despite multiple years of research and numerous publications, there is still a lack of consensus in regard to how much vit D infants should receive and how long they should receive it. Because 80% of calcium and phosphorus placental transfer occurs between 24 and 40 weeks of gestation, preterm infants are especially prone to adverse effects of vit D insufficiency. However, both inadequate and excessive amounts of vit D may be unsafe and lead to serious health issues. The results of our study may shed new light on these concerns and contribute to optimising vit D supplementation.

Trial registration

ClinicalTrials.gov, NCT03087149. Registered on 15 March 2017.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2141-y) contains supplementary material, which is available to authorized users.

[Vitamin D level at birth and influencing factors in preterm infants]

OBJECTIVE

To investigate vitamin D level at birth and possible influencing factors in preterm infants.

METHODS

A total of 600 preterm infants were enrolled, and venous blood samples were collected within 24 hours after birth to measure the serum level of 25-hydroxyvitamin D [25(OH)D]. The effect of sex, birth weight, birth season, gestational age, mother's age, body mass index (BMI) in early pregnancy, delivery mode, and complications during pregnancy on serum 25(OH)D level was analyzed.

RESULTS

The rates of vitamin D deficiency, insufficiency, and sufficiency were 42.0%, 38.7%, and 19.3% respectively. The preterm infants born in summer and autumn had a significantly higher serum 25(OH)D level than those born in winter (P<0.05) and a significantly lower incidence rate of vitamin D deficiency than those born in spring and winter (P<0.003). Compared with those whose mothers were aged <30 years, the infants whose mothers were aged ≥30 years had a significantly higher serum 25(OH)D level (P<0.05) and a significantly lower incidence rate of vitamin D deficiency (P<0.017). Compared with those whose mothers were overweight or had normal body weight, the infants whose mothers were obese had a significantly lower serum 25(OH)D level (P<0.05) and a significantly higher incidence rate of vitamin D deficiency (P<0.006). Compared with those whose mothers had no preeclampsia, the infants whose mothers had preeclampsia during pregnancy had a significantly lower serum 25(OH)D level (P<0.05) and a significantly higher incidence rate of vitamin D deficiency (P<0.017). The multivariate analysis showed that birth in winter and spring, mother's age <30 years, and early-pregnancy BMI ≥28 kg/m² were risk factors for vitamin D deficiency (P<0.05).

CONCLUSIONS

There is a high prevalence of vitamin D deficiency in preterm infants. Vitamin D supplementation should be given to the preterm infants with high-risk factors for vitamin D deficiency.

Vitamin D and its impact on maternal-fetal outcomes in pregnancy: A critical review

The role of vitamin D beyond its classical function in calcium homeostasis has been of significant interest in recent years. There has been expanding research on the pleiotropic role of vitamin D in pregnancy and the implications of its deficiency on maternal-fetal outcomes. Several studies have associated low maternal vitamin D status to adverse outcomes in pregnancy, including preeclampsia, gestational diabetes, preterm births, low birth weight, and others. Several randomized controlled clinical trials of Vitamin D supplementation during pregnancy have also been conducted. Though some of the studies found improvement in pregnancy outcomes with vitamin D supplementation, others have not shown any association. In this article, we have critically reviewed the observational and interventional studies, published primarily within the past two years (January 2014 to February 2016) on the influence of vitamin D deficiency on pregnancy and the impact of its supplementation. The potential underlying mechanisms of vitamin D in regulating each of the outcomes have also been discussed.

Maternal vitamin D levels during pregnancy and neonatal health: evidence to date and clinical implications

Low maternal vitamin D levels during pregnancy have been associated with a plethora of adverse neonatal outcomes, including small for gestational age and preterm births, detrimental effect on offspring bone and teeth development, and risk of infectious diseases. Although most observational studies indicate a significant linear relationship between maternal 25-hydroxyvitamin D and the above outcomes, some randomized controlled trials to date are inconclusive, mostly due to differences in study design and supplementation regimen. The currently available results indicate that vitamin D supplementation during pregnancy reduces the risk of preterm birth, low birth weight, dental caries of infancy, and neonatal infectious diseases such as respiratory infections and sepsis. This narrative review aims to summarize available trial results regarding the effect of low maternal vitamin D levels during pregnancy, in conjunction with neonatal outcomes on the field, with a discourse on the appropriate clinical approach of this important issue.

Maternal Vitamin D Level Is Associated with Viral Toll-Like Receptor Triggered IL-10 Response but Not the Risk of Infectious Diseases in Infancy

Reports on the effect of prenatal vitamin D status on fetal immune development and infectious diseases in childhood are limited. The aim of this study was to investigate the role of maternal and cord blood vitamin D level in TLR-related innate immunity and its effect on infectious outcome. Maternal and cord blood 25 (OH)D level were examined from 372 maternal-neonatal pairs and their correlation with TLR-triggered TNF-α, IL-6, and IL-10 response at birth was assessed. Clinical outcomes related to infection at 12 months of age were also evaluated. The result showed that 75% of the pregnant mothers and 75.8% of the neonates were vitamin deficient. There was a high correlation between maternal and cord 25(OH)D levels (r = 0.67, p < 0.001). Maternal vitamin D level was inversely correlated with IL-10 response to TLR3 (p = 0.004) and TLR7-8 stimulation (p = 0.006). However, none of the TLR-triggered cytokine productions were associated with cord 25(OH)D concentration. There was no relationship between maternal and cord blood vitamin D status with infectious diseases during infancy. In conclusion, our study had shown that maternal vitamin D, but not cord vitamin D level, was associated with viral TLR-triggered IL-10 response.

Working group reports: evaluation of the evidence to support practice guidelines for nutritional care of preterm infants-the Pre-B Project

The "Evaluation of the Evidence to Support Practice Guidelines for the Nutritional Care of Preterm Infants: The Pre-B Project" is the first phase in a process to present the current state of knowledge and to support the development of evidence-informed guidance for the nutritional care of preterm and high-risk newborn infants. The future systematic reviews that will ultimately provide the underpinning for guideline development will be conducted by the Academy of Nutrition and Dietetics' Evidence Analysis Library (EAL). To accomplish the objectives of this first phase, the Pre-B Project organizers established 4 working groups (WGs) to address the following themes: 1) nutrient specifications for preterm infants, 2) clinical and practical issues in enteral feeding of preterm infants, 3) gastrointestinal and surgical issues, and 4) current standards of infant feeding. Each WG was asked to 1) develop a series of topics relevant to their respective themes, 2) identify questions for which there is sufficient evidence to support a systematic review process conducted by the EAL, and 3) develop a research agenda to address priority gaps in our understanding of the role of nutrition in health and development of preterm/neonatal intensive care unit infants. This article is a summary of the reports from the 4 Pre-B WGs.

Vitamin D and respiratory tract infections in childhood

BACKGROUND

Respiratory tract infections (RTIs) remain among of the most important causes of morbidity and mortality among children. Several studies have associated vitamin D deficiency with an increased risk of RTIs, and vitamin D supplementation has been proposed as a possible preventive measure against RTIs in children. The main aim of this review is to summarize the current evidence from the literature about the link between vitamin D and RTIs in children.

DISCUSSION

Several recent studies have shown that vitamin D has different immunomodulatory properties associated with the risk of RTIs in childhood. In this regard, it is very important to understand the definition of deficiency and insufficiency of vitamin D and when and how to treat this condition. Unfortunately, there is no consensus, although a level of at least 10 ng/mL 25-hydroxycholecalciferol (25[OH]D) is thought to be necessary to promote bone mineralization and calcium homeostasis, and a concentration between 20 ng/mL and 50 ng/mL is considered adequate to provide an immunomodulatory effect. Available data support a role for vitamin D deficiency in the risk of pediatric tuberculosis, recurrent acute otitis media, and severe bronchiolitis, whereas further studies are needed to confirm an association in children with recurrent pharyngotonsillitis, acute rhinosinusitis and community-acquired pneumonia.

CONCLUSIONS

Maintenance of adequate vitamin D status may be an effective and inexpensive prophylactic method against some RTIs, but the supplementation regimen has not been clearly defined. Further clinical trials are needed to determine the 25(OH)D concentrations associated with an increased risk of RTIs and optimal vitamin D supplementation regimen according to the type of RTI while also taking into consideration vitamin D receptor polymorphisms.