BURDEN AND SUBTYPES OF EARLY-LIFE INFECTIONS INCREASE THE RISK OF ASTHMA

BACKGROUND

Early-life respiratory tract infections have been linked to the development of asthma, but studies on burden and subtypes of common infections in asthma development are sparse.

OBJECTIVE

The study aimed to examine the association between burden of early-life infections, including subtypes, with risk of asthma from ages 3-10 years and lung function at age 10 years.

METHODS

We included 662 children from the COPSAC2010 birth cohort, where infections, i.e., colds, acute tonsillitis, acute otitis media (AOM), pneumonia, gastroenteritis, and fever were registered prospectively in daily diaries at age 0-3 years, and asthma was diagnosed longitudinally from ages 3-10 years. The association between infection burden and subtypes and risk of asthma was analysed by generalized estimating equations.

RESULTS

The children experienced a median of 16 [IQR=12-23] infections age 0-3 years. Children with a high burden of infections (above median) had an increased risk of asthma age 3-10: aOR=3.61 (2.39-5.45), p<0.001, which was driven by colds, pneumonia, gastroenteritis, and fever episodes (p-values<0.05), but not by AOM and tonsillitis. Lower lung function measures age 10 were associated with burden of pneumonia, but not the overall infection burden. The association between colds and risk of asthma was significantly higher in children with allergic rhinitis at age 6 (p-interaction=0.032).

CONCLUSION

High burden of early-life infections in terms of colds, pneumonia, gastroenteritis, and fever is associated with increased risk of developing asthma, particularly in children with respiratory allergy. Strategies to diminish these early-life infections could potentially offer a path for primary prevention of childhood asthma.

Key risk factors of asthma-like symptoms are mediated through infection burden in early childhood

BACKGROUND

Risk factors of asthma-like symptoms in childhood may act through an increased infection burden because infections often trigger these symptoms.

OBJECTIVE

We sought to investigate whether the effect of established risk factors of asthma-like episodes in early childhood is mediated through burden and subtypes of common infections.

METHODS

The study included 662 children from the Copenhagen Prospective Studies on Asthma in Childhood 2010 mother-child cohort, in which infections were registered prospectively in daily diaries from age 0 to 3 years. The association between established risk factors of asthma-like episodes and infection burden was analyzed by quasi-Poisson regressions, and mediation analyses were performed for significant risk factors.

RESULTS

In the first 3 years of life, the children experienced a median of 16 (interquartile range, 12-23) infectious episodes. We found that the infection burden significantly (PACME < .05) mediated the association of maternal asthma (36.6% mediated), antibiotics during pregnancy (47.3%), siblings at birth (57.7%), an asthma exacerbation polygenic risk score (30.6%), and a bacterial airway immune score (80.2%) with number of asthma-like episodes, whereas the higher number of episodes from male sex, low birth weight, low gestational age, and maternal antibiotic use after birth was not mediated through an increased infection burden. Subtypes of infections driving the mediation were primarily colds, pneumonia, gastroenteritis, and fever, but not acute otitis media or acute tonsillitis.

CONCLUSIONS

Several risk factors of asthma-like symptoms in early childhood act through an increased infection burden in the first 3 years of life. Prevention of infectious episodes may therefore be beneficial to reduce the burden of asthma-like symptoms in early childhood.

Vitamin D Primary Prevention of Respiratory Infections and Asthma in Early Childhood: Evidence and Mechanisms

Respiratory infections are a leading cause of child morbidity worldwide, and asthma is the most common chronic disorder in childhood. Both conditions associate with high socioeconomic costs and are major reasons for medication prescriptions and hospitalizations in children. Vitamin D deficiency has concomitantly increased with asthma prevalence and is hypothesized to play a key role in the development. Current evidence suggests that high prenatal and early childhood vitamin D could be protective against respiratory infections and asthma in some studies where several mechanisms are proposed. However, other studies have reported no effects on these outcomes. Therefore, future large intervention studies on this topic are warranted. Mechanistic studies have shown that vitamin D holds antimicrobial properties by inducing production of several peptides through altered gene expression. Others have shown a complex interplay between asthma risk genotypes, the sphingolipid pathway, and prenatal vitamin D in early childhood asthma. Vitamin D has also been suggested to change both airway immune and microbiota profiles, which are directly related to asthma risk. Finally, systemic low-grade inflammation seems to be regulated by vitamin D exposure. This review presents the current literature of the primary preventive effect of vitamin D on early childhood asthma and respiratory infections. Mechanisms of actions are discussed, and gaps in knowledge are highlighted to facilitate planning of future intervention trials.

High-dose vitamin D3 supplementation in pregnancy and risk of neurodevelopmental disorders in the children at age 10: A randomized clinical trial

BACKGROUND

Vitamin D deficiency in pregnancy may increase the risk of autism and attention deficit hyperactivity disorder (ADHD).

OBJECTIVE

The objective of this study was to estimate the effect of vitamin D3 supplementation in pregnancy on risk of autism and ADHD.

DESIGN

This randomized clinical trial was part of the COpenhagen Prospective Study on Neuro-PSYCHiatric Development (COPYCH) project nested within the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC2010) cohort comprising a population-based sample of 700 healthy mother-child pairs enrolled at week 24 of pregnancy. Maternal 25-hydroxy-vitamin D (25(OH)D) was measured at inclusion and 623 mothers were randomized 1:1 to either high-dose (2800 IU/d) or standard dose (400 IU/d) vitamin D3 until 1 wk postpartum (315 received high-dose, 308 standard dose). At age 10, diagnoses and symptom load of autism and ADHD, respectively, were established using the Kiddie-Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version.

RESULTS

The psychopathologic evaluation was completed by 591 children aged 10 y, and 16 children (2.7%) were diagnosed with autism and 65 (11.0%) with ADHD. Hereof, 496 children participated in the vitamin D3 trial (246 received high-dose, 250 standard dose). Of these, 12 children (2.4%) were diagnosed with autism and 58 (11.7%) with ADHD. Higher maternal preintervention 25(OH)D levels were associated with a decreased risk of autism [odd ratio (OR) per 10 nmol/L: 0.76 (0.59,0.97); P = 0.034], lower autistic symptom load [β per 10 nmol/L: -0.03 (-0.05,0.00); P = 0.024), and decreased risk of ADHD diagnosis (OR per 10 nmol/L: 0.88 (0.78,0.99); P = 0.033]. High-dose vitamin D3 supplementation was not associated with risk of autism or ADHD.

CONCLUSIONS

Higher maternal preintervention 25(OH)D was associated with a decreased risk of autism, lower autistic symptom load, and decreased risk of ADHD diagnosis, but high-dose vitamin D3 supplementation in pregnancy had no effect on risk of autism and ADHD. This trial was registered at clinicaltrials.gov as NCT00856947.

Maternal Diet Associates with Offspring Bone Mineralization, Fracture Risk and Enamel Defects in Childhood and Influences the Prenatal Effect of High-Dose Vitamin D Supplementation

We previously demonstrated a beneficial effect of high-dose vitamin D in pregnancy on offspring bone and dental health. Here, we investigated the effect of maternal dietary patterns during pregnancy on the risk of bone fractures, bone mineralization and enamel defects until age 6 years in the offspring. Further, the influence of diet on the effect of high-dose vitamin D was analyzed in the COPSAC2010 mother-child cohort including 623 mother-child pairs. A weighted network analysis on FFQs revealed three specific maternal dietary patterns that associated (Bonferroni p < 0.05) with both offspring bone and dental health. The effect of prenatal high-dose (2800 IU/day) vs. standard-dose (400 IU/day) vitamin D on offspring bone mineral content (adjusted mean difference (aMD): 33.29 g, 95% CI: 14.48-52.09, p < 0.001), bone mineral density (aMD: 0.02 g/cm2 (0.01-0.04), p < 0.001), fracture risk (adjusted incidence rate ratio: 0.36 (0.16-0.84), p = 0.02), and enamel defects in primary (adjusted odds ratio (aOR): 0.13 (0.03-0.58), p < 0.01) and permanent molars (aOR: 0.25; (0.10-0.63), p < 0.01) was most pronounced when mothers had lower intake of fruit, vegetables, meat, eggs, sweets, whole grain, offal and fish. This study suggests that prenatal dietary patterns influence offspring bone and dental development, and should be considered in order to obtain the full benefits of vitamin D to enhance personalized supplementation strategy.

Maternal vitamin D-related metabolome and offspring risk of asthma outcomes

BACKGROUND

Gestational vitamin D deficiency is implicated in development of respiratory diseases in offspring, but the mechanism underlying this relationship is unknown.

OBJECTIVE

We sought to study the link between gestational vitamin D exposure and childhood asthma phenotypes using maternal blood metabolomics profiling.

METHODS

Untargeted blood metabolic profiles were acquired using liquid chromatography-mass spectrometry at 1 week postpartum from 672 women in the Copenhagen Prospective Studies on Asthma in Childhood2010 (COPSAC2010) mother-child cohort and at pregnancy weeks 32 to 38 from 779 women in the Vitamin D Antenatal Asthma Reduction Trial (VDAART) mother-child cohort. In COPSAC2010, we employed multivariate models and pathway enrichment analysis to identify metabolites and pathways associated with gestational vitamin D blood levels and investigated their relationship with development of asthma phenotypes in early childhood. The findings were validated in VDAART and in cellular models.

RESULTS

In COPSAC2010, higher vitamin D blood levels at 1 week postpartum were associated with distinct maternal metabolome perturbations with significant enrichment of the sphingomyelin pathway (P < .01). This vitamin D-related maternal metabolic profile at 1 week postpartum containing 46 metabolites was associated with decreased risk of recurrent wheeze (hazard ratio [HR] = 0.92 [95% CI 0.86-0.98], P = .01) and wheeze exacerbations (HR = 0.90 [95% CI 0.84-0.97], P = .01) at ages 0 to 3 years. The same metabolic profile was similarly associated with decreased risk of asthma/wheeze at ages 0 to 3 in VDAART (odds ratio = 0.92 [95% CI 0.85-0.99], P = .04). Human bronchial epithelial cells treated with high-dose vitamin D3 showed an increased cytoplasmic sphingolipid level (P < .01).

CONCLUSIONS

This exploratory metabolomics study in 2 independent birth cohorts demonstrates that the beneficial effect of higher gestational vitamin D exposure on offspring respiratory health is characterized by specific maternal metabolic alterations during pregnancy, which involves the sphingomyelin pathway.

Atopic and non-atopic effects of fish oil supplementation during pregnancy

BACKGROUND

We recently conducted a double-blinded randomised controlled trial showing that fish-oil supplementation during pregnancy reduced the risk of persistent wheeze or asthma in the child by 30%. Here, we explore the mechanisms of the intervention.

METHODS

736 pregnant women were given either placebo or n-3 long-chain polyunsaturated fatty acids (LCPUFAs) in the third trimester in a randomised controlled trial. Deep clinical follow-up of the 695 children in the trial was done at 12 visits until age 6 years, including assessment of genotype at the fatty acid desaturase (FADS) locus, plasma fatty acids, airway DNA methylation, gene expression, microbiome and metabolomics.

RESULTS

Supplementation with n-3 LCPUFA reduced the overall risk of non-atopic asthma by 73% at age 6 (relative risk (RR) 0.27 (95% CI 0.06 to 0.85), p=0.042). In contrast, there was no overall effect on asthma with atopic traits (RR 1.42 (95% CI 0.63 to 3.38), p=0.40), but this was significantly modified by maternal FADS genotype and LCPUFA blood levels (interaction p<0.05), and supplementation did reduce the risk of atopic asthma in the subgroup of mothers with FADS risk variants and/or low blood levels of n-3 LCPUFA before the intervention (RR 0.31 (95% CI 0.11 to 0.75), p=0.016). Furthermore, n-3 LCPUFA significantly reduced the number of infections (croup, gastroenteritis, tonsillitis, otitis media and pneumonia) by 16% (incidence rate ratio 0.84 (95% CI 0.74 to 0.96), p=0.009).

CONCLUSIONS

n-3 LCPUFA supplementation in pregnancy showed protective effects on non-atopic asthma and infections. Protective effects on atopic asthma depended on maternal FADS genotype and n-3 LCPUFA levels. This indicates that the fatty acid pathway is involved in multiple mechanisms affecting the risk of asthma subtypes and infections.

TRIAL REGISTRATION NUMBER

NCT00798226.

Associations of pre- and postnatal exposures with optic nerve status in young adults

PURPOSE

We aimed to explore the effect of multiple pre- and postnatal exposures on optic nerve status in young adults due to this critical period for development.

METHODS

We analysed peripapillary retinal nerve fibre layer (RNFL) status and macular thickness at age 18 years in the Copenhagen Prospective Studies on Asthma in Childhood 2000 (COPSAC2000 ) cohort in relation to several exposures.

RESULTS

Of the 269 participants (median (IQR) age, 17.6 (0.6) years; 124 boys), 60 participants whose mothers had smoked during pregnancy had a thinner RNFL: adjusted mean difference -4.6 μm (95% CI -7.7; -1.5 μm, p = 0.004) compared with participants whose mothers had not smoked during pregnancy. A total of 30 participants who were exposed to tobacco smoke both during foetal life and childhood had thinner RNFL: -9.6 μm (-13.4; -5.8 μm, p < 0.001). Smoking during pregnancy was also associated with a macular thickness deficit: -4.7 μm (-9.0; -0.4 μm, p = 0.03). Higher indoor concentrations of particulate matter 2.5 (PM2.5) was associated with thinner RNFL: -3.6 μm (-5.6; -1.6 μm, p < 0.001) and a macular deficit: -2.7 μm (-5.3; -0.1 μm, p = 0.04) in the crude analyses, but not in the adjusted analyses. No difference was found among participants who smoked at age 18 years compared with non-smokers on RNFL or macular thickness.

CONCLUSIONS

We found that exposure to smoking during early life was associated with a thinner RNFL and macula at age 18 years. The absence of an association between active smoking at 18 years suggests that the vulnerability of the optic nerve is highest during prenatal life and early childhood.

Dietary prevention strategies for childhood asthma

Asthma is the most common chronic disease in childhood and a rise in prevalence has been observed concomitantly with changing dietary habits in the Western world. This change has favored a more Westernized diet characterized by high intake of processed food and fat in contrast to a Mediterranean diet high in fruit, vegetable and fish intake. This has resulted in a decreased intake of several antioxidants and micronutrients including n-3 long-chained polyunsaturated fatty acids and vitamin D that are speculated to have anti-inflammatory effects and hold immunoregulatory properties. Several observational studies have investigated associations between dietary intake and wheeze and asthma but only few large well-conducted randomized controlled trials (RCTs) have been performed investigating the primary preventive effect of micronutrient supplementations. Currently, the recommendations from the Global Initiative for Asthma (GINA) for primary prevention of asthma in children do not include maternal dietary changes or supplementations during pregnancy, although the most recent report mentions both specific dietary patterns and micronutrients as potential protective supplementation regimes. This review will present the current literature and future research needs focusing on primary and secondary prevention of both early and late childhood asthma from dietary intake during pregnancy and early childhood to highlight potential preventive effects of specific dietary patterns and micronutrient supplements, which may facilitate the planning of future clinical trials in search of a preemptive strategy.

The Impact of Baseline 25-Hydroxyvitamin D Level and Gestational Age on Prenatal Vitamin D Supplementation to Prevent Offspring Asthma or Recurrent Wheezing

BACKGROUND

Prenatal vitamin D deficiency is associated with asthma or recurrent wheezing in offspring. However, evidence from randomized trials on the efficacy of vitamin D supplementation is inconclusive.

OBJECTIVES

We aimed to examine the differential efficacy of prenatal vitamin D supplementation based on the maternal baseline vitamin D status and the starting time of supplementation to prevent early life asthma or recurrent wheezing.

METHODS

We conducted a secondary analysis of the Vitamin D Antenatal Asthma Reduction Trial (VDAART), a randomized double-blind trial of prenatal vitamin D supplementation initiated at 10-18 weeks (wks) of gestation (4400 IU of intervention/day compared with 400 IU of placebo/day) to prevent offspring asthma or recurrent wheezing by the age of 6 years. We assessed the effect of modification of supplementation by maternal baseline vitamin D status at enrollment and the timing of initiation of supplementation.

RESULTS

An inverse relationship was observed between maternal 25-hydroxyvitamin D (25(OH)D) levels at trial entry and 25(OH)D levels during late pregnancy (32-38 wks of gestation) in both supplementation arms (P < 0.001). Overall, supplementation efficacy was not dependent on the maternal baseline 25(OH)D status. However, a trend toward the reduction of asthma or recurrent wheezing was observed across the baseline groups in the intervention arm (P = 0.01), with the greatest reduction observed in the most severely vitamin D-deficient women (25(OH)D < 12 ng/mL; adjusted odds ratio [aOR] = 0.48; confidence interval [CI]: 0.17, 1.34). Gestational age at trial enrollment modified supplementation efficacy, showing a greater reduction of offspring asthma or recurrent wheezing with earlier intervention during pregnancy (aOR = 0.85; CI = 0.76, 0.95), particularly in women who were 9-12 wk pregnant (aOR = 0.45; CI = 0.24, 0.82).

CONCLUSIONS

Pregnant women with severe vitamin D deficiency show the greatest 25(OH)D improvement because of supplementation. In these women, a vitamin D dose of 4400 IU might have a preventive role in the development of early life offspring asthma or recurrent wheezing. Gestational age is suggested to modify the efficacy of prenatal vitamin D supplementation, showing the highest beneficial effect if supplementation is started during the first trimester of pregnancy. This study is an ancillary analysis from the VDAART, which is registered in ClinicalTrials.gov as NCT00902621.

Risk Factors and Age-Related Patterns of Asthma-Like Symptoms in Early Childhood

BACKGROUND

Episodes of asthma-like symptoms in young children are common, but little is known about risk factors and their patterns for the daily symptom burden.

OBJECTIVE

We investigated a variety of possible risk factors and their age-related impact on the number of asthma-like episodes during age 0 to 3 years.

METHODS

The study population included 700 children from the Copenhagen Prospective Studies on Asthma in Childhood2010 mother-child cohort followed prospectively from birth. Asthma-like symptoms were recorded until age 3 by daily diaries. Risk factors were analyzed by quasi-Poisson regressions, and interaction with age was explored.

RESULTS

Diary data were available in 662 children. Male sex, maternal asthma, low birth weight, maternal antibiotic use, high asthma exacerbation polygenic risk score, and high airway immune score were associated with a higher number of episodes in a multivariable analysis. Maternal asthma, preterm birth, caesarean section, and low birth weight showed an increasing impact with age, whereas sibling(s) at birth showed a decreased association with age. The remaining risk factors had a stable pattern during age 0 to 3 years. For every additional clinical risk factor (male sex, low birth weight, and maternal asthma) a child had, we found 34% more episodes (incidence rate ratio: 1.34, 95% confidence interval: 1.21-1.48; P < .001).

CONCLUSION

Using unique day-to-day diary recordings, we identified risk factors for the burden of asthma-like symptoms in the first 3 years of life and described their unique age-related patterns. This provides novel insight into the origin of asthma-like symptoms in early childhood that potentially pave a path for personalized prognostics and treatment.

Supplementation With Fish Oil in Pregnancy Reduces Gastroenteritis in Early Childhood

BACKGROUND

We hypothesized that insufficient intake of fish oil-derived omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs) during pregnancy is a contributing factor to gastroenteritis in early childhood. We examined the effect of n-3 LCPUFA supplementation on gastroenteritis symptoms in the offspring's first 3 years of life.

METHODS

This was a double-blinded, randomized controlled trial whereby 736 mothers were administered n-3 LCPUFA or control from pregnancy week 24 until 1 week after birth. We measured the number of days with gastroenteritis, number of episodes with gastroenteritis, and the risk of having a gastroenteritis episode in the first 3 years of life.

RESULTS

A median reduction of 2.5 days with gastroenteritis (P = .018) was shown, corresponding to a 14% reduction in the n-3 LCPUFA group compared with controls in the first 3 years of life (P = .037). A reduction in the number of gastroenteritis episodes (P = .027) and a reduced risk of having an episode (hazard ratio, 0.80 [95% confidence interval, .66-.97]; P = .023) were also shown.

CONCLUSIONS

Fish oil supplementation from the 24th week of pregnancy led to a reduction in the number of days and episodes with gastroenteritis symptoms in the first 3 years of life. The findings suggest n-3 LCPUFA supplementation as a preventive measure against gastrointestinal infections in early childhood.

CLINICAL TRIALS REGISTRATION

NCT00798226.

Furan fatty acid metabolite in newborns predicts risk of asthma

BACKGROUND

Intake of fish-oil and fatty fish during pregnancy has been shown to reduce the risk of childhood asthma but biomarkers of such intake are lacking.

OBJECTIVE

To establish biomarkers of prenatal fish-oil exposure from newborn dry blood spot metabolomics profiles and assess their relevance for childhood asthma risk stratification.

METHODS

The Danish COPSAC₂₀₁₀ mother-child cohort was utilized to investigate the effect of a double-blinded randomized controlled trial of fish-oil supplementation during pregnancy on dry blood spot liquid-chromatography mass spectrometry-based metabolomics profiles of 677 newborns. We thereafter investigated the association between fish-oil associated biomarkers in the newborn and development of asthma-related outcomes. Replication was sought in the independent observational COPSAC₂₀₀₀ cohort with 387 newborn metabolomics profiles.

RESULTS

The newborn metabolomics profiles differed between children in the fish-oil vs. placebo group in COPSAC₂₀₁₀ (area under the receiver operator curve = 0.94 ± 0.03, p < .001). The fish-oil metabolomics profile and the top biomarker, 3-carboxy-4-methyl-5-propyl-2-furan propanoic acid (CMPF) were both associated with a decreased risk of asthma by age 6 years (HR = 0.89, p = .002 and HR = 0.67, p = .005, respectively). In COPSAC₂₀₀₀ , newborn CMPF level was also inversely associated with asthma risk by age 6 years (HR = 0.69, p = .01). Troublesome lung symptoms and common infections in the first 3 years were also inversely associated with newborn CMPF levels in both cohorts.

CONCLUSIONS

Newborn children's blood levels of the furan fatty acid metabolite CMPF reflect fish-oil and fatty fish intake during pregnancy and are associated with a lower risk of asthma across two cohorts, which could aid newborn screening for childhood asthma.

Diet-associated vertically transferred metabolites and risk of asthma, allergy, eczema, and infections in early childhood

BACKGROUND

Evidence suggests maternal pregnancy dietary intake and nutrition in the early postnatal period to be of importance for the newborn child's health. However, studies investigating diet-related metabolites transferred from mother to child on disease risk in childhood are lacking. We sought to investigate the influence of vertically transferred metabolites on risk of atopic diseases and infections during preschool age.

METHODS

In the Danish population-based COPSAC2010 mother-child cohort, information on 10 diet-related vertically transferred metabolites from metabolomics profiles of dried blood spots (DBS) at age 2-3 days was analyzed in relation to the risk of childhood asthma, allergy, eczema, and infections using principal component and single metabolite analyses.

RESULTS

In 678 children with DBS measurements, a coffee-related metabolite profile reflected by principal component 1 was inversely associated with risk of asthma (odds ratio (95% CI) 0.78 (0.64; 0.95), p = .014) and eczema at age 6 years (0.79 (0.65; 0.97), p = .022). Furthermore, increasing stachydrine (fruit-related), 3-carboxy-4-methyl-5-propyl-2-furanpropanoate (fish-related), and ergothioneine (fruit-, green vegetables-, and fish-related) levels were all significantly associated with reduced risks of infections at age 0-3 years (p < .05).

CONCLUSION

This study demonstrates associations between pregnancy diet-related vertically transferred metabolites measured in children in early life and risk of atopic diseases and infections in childhood. The specific metabolites associated with a reduced disease risk in children may contribute to the characterization of a healthy nutritional profile in pregnancy using a metabolomics-based unbiased tool for predicting childhood health.

Fish Oil and Vitamin D Supplementations in Pregnancy Protect Against Childhood Croup

BACKGROUND

Croup is a prevalent respiratory disorder in early childhood most often caused by parainfluenza virus infections. There are no preventive strategies; therefore, we investigated the potential effects of prenatal micronutrient supplementations.

OBJECTIVE

To investigate the supplementation effects of (1) 2.4-g n-3 long-chained polyunsaturated fatty acid (n-3 LCPUFA) (fish oil) versus olive oil and (2) high-dose (2800 IU/d) versus standard-dose (400 IU/d) of vitamin D from pregnancy week 24 until 1 week after birth on the risk for offspring croup during the double-blinded first 3 years of life in a secondary analysis of a 2 × 2 factorial designed randomized controlled trial.

METHODS

The study was completed in the Danish population-based single-center Copenhagen Prospective Studies on Asthma in Childhood 2010 mother-child cohort, which included 736 pregnant women. Croup was diagnosed by physicians' clinical examinations and medical record checks. Potential mediating mechanisms were investigated using blood metabolomics, airway cytokines, and airway microbiome.

RESULTS

Of 695 children, 97 had croup before age 3 years (14%). The risk of croup was reduced in the n-3 LCPUFA (n_cases / n_total = 38/346; 11%) versus olive oil group (59 of 349 children; 17%) (hazard ratio = 0.62; 95% CI, 0.41-0.93; P = .02) and in the high-dose vitamin D group (32 of 295 children; 11%) versus the standard-dose group (51 of 286 children; 18%) (hazard ratio = 0.60; 95% CI, 0.38-0.93; P = .02). There was no evidence of interaction or additive effects between the supplements (P_interaction = .56). Furthermore, the results did not change when they were adjusted for each other, persistent wheeze, and lower respiratory tract infection.

CONCLUSIONS

This analysis of the double-blinded period of the Copenhagen Prospective Studies on Asthma in Childhood 2010 randomized controlled trial of n-3 LCPUFA and high-dose vitamin D supplementation during pregnancy demonstrated a reduced risk of croup in early childhood.

Safety of High-Dose Vitamin D Supplementation Among Children Aged 0 to 6 Years: A Systematic Review and Meta-analysis

IMPORTANCE

Several health benefits of vitamin D have been suggested; however, the safety of high-dose supplementation in early childhood is not well described.

OBJECTIVE

To systematically assess the risk of adverse events after high-dose supplementation with vitamin D reported in published randomized clinical trials.

DATA SOURCES

PubMed and ClinicalTrials.gov were searched through August 24, 2021.

STUDY SELECTION

Randomized clinical trials of high-dose vitamin D supplementation in children aged 0 to 6 years, defined as greater than 1000 IU/d for infants (aged 0-1 year) and greater than 2000 IU/d for children aged 1 to 6 years.

DATA EXTRACTION AND SYNTHESIS

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline, 2 reviewers independently extracted the data from the eligible studies. Summary risk ratio (RR), 95% CI, and P values were derived from random-effects meta-analysis.

MAIN OUTCOMES AND MEASURES

Adverse events, serious adverse events (SAEs), and/or levels of 25-hydroxyvitamin D, calcium, alkaline phosphatase, phosphate, parathyroid hormone, and/or the ratio of urine calcium to creatinine levels.

RESULTS

A total of 32 randomized clinical trials with 8400 unique participants were included. Different clinical outcomes of children receiving high-dose vitamin D supplements ranging from 1200 to 10 000 IU/d and bolus doses from 30 000 IU/week to a single dose of 600 000 IU were evaluated. Eight studies with 4612 participants were eligible for meta-analysis using a control group receiving either low-dose vitamin D supplementation (≤400 IU/d) or placebo when investigating the risk of SAEs such as hospitalization or death. No overall increased risk of SAEs in the high-dose vitamin D vs control groups was found (RR, 1.01 [95% CI, 0.73-1.39]; P = .89, I2 = 0%). In addition, risk of hypercalcemia (n = 726) was not increased (RR, 1.18 [95% CI, 0.72-1.93]; P = .51). Clinical adverse events potentially related to the vitamin D supplementation reported in the studies were rare.

CONCLUSIONS AND RELEVANCE

This meta-analysis and systematic review found that high-dose vitamin D supplementation was not associated with an increased risk of SAEs in children aged 0 to 6 years, and that clinical adverse events potentially related to the supplementation were rare. These findings suggest that vitamin D supplementation in the dose ranges of 1200 to 10 000 IU/d and bolus doses to 600 000 IU to young children may be well tolerated.

Vertical Transfer of Metabolites Detectable from Newborn's Dried Blood Spot Samples Using UPLC-MS: A Chemometric Study

The pregnancy period and first days of a newborn's life is an important time window to ensure a healthy development of the baby. This is also the time when the mother and her baby are exposed to the same environmental conditions and intake of nutrients, which can be determined by assessing the blood metabolome. For this purpose, dried blood spots (DBS) of newborns are a valuable sampling technique to characterize what happens during this important mother-child time window. We used metabolomics profiles from DBS of newborns (age 2-3 days) and maternal plasma samples at gestation week 24 and postpartum week 1 from n=664 mother-child pairs of the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC2010) cohort, to study the vertical mother-child transfer of metabolites. Further, we investigated how persistent the metabolites are from the newborn and up to 6 months, 18 months, and 6 years of age. Two hundred seventy two metabolites from UPLC-MS (Ultra Performance Liquid Chromatography-Mass Spectrometry) analysis of DBS and maternal plasma were analyzed using correlation analysis. A total of 11 metabolites exhibited evidence of transfer (R>0.3), including tryptophan betaine, ergothioneine, cotinine, theobromine, paraxanthine, and N6-methyllysine. Of these, 7 were also found to show persistence in their levels in the child from birth to age 6 years. In conclusion, this study documents vertical transfer of environmental and food-derived metabolites from mother to child and tracking of those metabolites through childhood, which may be of importance for the child's later health and disease.

High-dose vitamin D supplementation in pregnancy and 25(OH)D sufficiency in childhood reduce the risk of fractures and improve bone mineralization in childhood: Follow-up of a randomized clinical trial

BACKGROUND

Exposure to vitamin D in early life has been associated with improved bone mineralization, but no studies have investigated the combined effect of pregnancy supplementation and childhood 25(OH)D concentrations on bone health.

METHODS

We analyzed the effect of serum 25(OH)D concentrations at age 6 months and 6 years and the combined effect with prenatal high-dose vitamin D (2800 vs. 400 IU/day) on bone mineral density (BMD) and content (BMC) assessed by dual-energy X-ray absorptiometry (DXA) scans at age 3 and 6 years and longitudinal risk of fractures in a double-blinded, randomized clinical trial in the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC₂₀₁₀) mother-child cohort with enrollment from March 4, 2009, to November 17, 2010, and clinical follow-up until January 31, 2019 (NCT00856947). All participants randomized to intervention and with complete data were included in the analyses.

FINDINGS

At age 6 months, serum 25(OH)D concentration was measured in 93% (n = 541) of 584 children. Children with sufficient (≥ 75 nmol/l) vs. insufficient (< 75 nmol/l) concentrations did not have lower risk of fractures: incidence rate ratio (95% CI); 0.64 (0.37;1.11), p = 0.11. However, vitamin D sufficient children from mothers receiving high-dose supplementation during pregnancy had a 60% reduced incidence of fractures compared with vitamin D insufficient children from mothers receiving standard-dose: 0.40 (0.19;0.84), p = 0.02.At age 6 years, serum 25(OH)D concentration was measured in 83% (n = 318) of 383 children with available DXA data. Whole-body bone mineralization was higher in vitamin D sufficient children at age 6 years; BMD, adjusted mean difference (aMD) (95% CI): 0.011 g/cm² (0.001;0.021), p = 0.03, and BMC, aMD: 12.3 g (-0.8;25.4), p = 0.07, with the largest effect in vitamin D sufficient children from mothers receiving high-dose vitamin D supplementation; BMD, aMD: 0.016 g/cm² (0.002;0.030), p = 0.03, and BMC, aMD: 23.5 g (5.5;41.5), p = 0.01.

INTERPRETATION

Childhood vitamin D sufficiency improved bone mineralization and in combination with prenatal high-dose vitamin D supplementation reduced the risk of fractures.

FUNDING

The study was supported by The Lundbeck Foundation R16-A1694, The Danish Ministry of Health 903,516, The Danish Council for Strategic Research 0603-00280B and The European Research Council 946,228.

Maternal 17q21 genotype influences prenatal vitamin D effects on offspring asthma/recurrent wheeze

BACKGROUND

Prenatal vitamin D3 supplementation has been linked to reduced risk of early-life asthma/recurrent wheeze. This protective effect appears to be influenced by variations in the 17q21 functional single nucleotide polymorphism rs12936231 of the child, which regulates the expression of ORMDL3 (ORM1-like 3) and for which the high-risk CC genotype is associated with early-onset asthma. However, this does not fully explain the differential effects of supplementation. We investigated the influence of maternal rs12936231 genotype variation on the protective effect of prenatal vitamin D3 supplementation against offspring asthma/recurrent wheeze.

METHODS

We determined the rs12936231 genotype of mother-child pairs from two randomised controlled trials: the Vitamin D Antenatal Asthma Reduction Trial (VDAART, n=613) and the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC2010, n=563), to examine the effect of maternal genotype variation on offspring asthma/recurrent wheeze at age 0-3 years between groups who received high-dose prenatal vitamin D3 supplementation versus placebo.

RESULTS

Offspring of mothers with the low-risk GG or GC genotype who received high-dose vitamin D3 supplementation had a significantly reduced risk of asthma/recurrent wheeze when compared with the placebo group (hazard ratio (HR) 0.54, 95% CI 0.37-0.77; p<0.001 for VDAART and HR 0.56, 95% CI 0.35-0.92; p=0.021 for COPSAC2010), whereas no difference was observed among the offspring of mothers with the high-risk CC genotype (HR 1.05, 95% CI 0.61-1.84; p=0.853 for VDAART and HR 1.11, 95% CI 0.54-2.28; p=0.785 for COPSAC2010).

CONCLUSION

Maternal 17q21 genotype has an important influence on the protective effects of prenatal vitamin D3 supplementation against offspring asthma/recurrent wheeze.

High-dose vitamin D during pregnancy and pathway gene polymorphisms in prevention of offspring persistent wheeze

BACKGROUND

Randomized controlled trials (RCTs) suggest a protective effect of high-dose vitamin D supplementation in pregnancy on offspring risk of persistent wheeze, but only in some individuals, which might be explained by variations in vitamin D pathway genes. This study aimed to investigate the effect of vitamin D supplementation by maternal and offspring vitamin D receptor (VDR) genotype and GC genotype, encoding vitamin D binding protein (VDBP), in two RCTs.

METHODS

In the Copenhagen Prospective Studies on Asthma in Childhood (COPSAC₂₀₁₀ ) RCT, we analyzed the effect of high-dose vitamin D during pregnancy on the risk of persistent wheeze age 0-3 years by variants in single nucleotide polymorphisms (SNPs) in VDR (rs1544410, rs2228570, rs7975128, rs7975232) and GC (rs4588, rs7041). Replication was sought in the Vitamin D Antenatal Asthma Reduction Trial (VDAART).

RESULTS

In COPSAC₂₀₁₀ , VDR SNP rs1544410 influenced the effect of high-dose vitamin D: maternal P_interaction  = .049 and child P_interaction  = .001, with the largest effect in offspring from mothers with TT genotype: hazard ratio (95% CI), 0.26 (0.10-0.68), P = .006, and no effect among CT or CC genotypes: 0.85 (0.48-1.51), P = .58 and 0.94 (0.47-1.89), P = .87, respectively. However, these findings were not replicated in VDAART. There was no significant effect modification from maternal or offspring GC genotype in either COPSAC₂₀₁₀ or VDAART: all P_interaction  ≥ .17.

CONCLUSIONS

We found that the effect of high-dose vitamin D supplementation during pregnancy on offspring risk of persistent wheeze was significantly influenced by VDR genotype in the COPSAC₂₀₁₀ RCT, but not VDAART, which may be due to population differences.

Characteristics and Mechanisms of a Sphingolipid-associated Childhood Asthma Endotype

Rationale: A link among sphingolipids, 17q21 genetic variants, and childhood asthma has been suggested, but the underlying mechanisms and characteristics of such an asthma endotype remain to be elucidated.Objectives: To study the sphingolipid-associated childhood asthma endotype using multiomic data.Methods: We used untargeted liquid chromatography-mass spectrometry plasma metabolomic profiles at the ages of 6 months and 6 years from more than 500 children in the COPSAC₂₀₁₀ (Copenhagen Prospective Studies on Asthma in Childhood) birth cohort focusing on sphingolipids, and we integrated the 17q21 genotype and nasal gene expression of SPT (serine palmitoyl-CoA transferase) (i.e., the rate-limiting enzyme in de novo sphingolipid synthesis) in relation to asthma development and lung function traits from infancy until the age 6 years. Replication was sought in the independent VDAART (Vitamin D Antenatal Asthma Reduction Trial) cohort.Measurements and Main Results: Lower concentrations of ceramides and sphingomyelins at the age of 6 months were associated with an increased risk of developing asthma before age 3, which was also observed in VDAART. At the age of 6 years, lower concentrations of key phosphosphingolipids (e.g., sphinganine-1-phosphate) were associated with increased airway resistance. This relationship was dependent on the 17q21 genotype and nasal SPT gene expression, with significant interactions occurring between the genotype and the phosphosphingolipid concentrations and between the genotype and SPT expression, in which lower phosphosphingolipid concentrations and reduced SPT expression were associated with increasing numbers of at-risk alleles. However, the findings did not pass the false discovery rate threshold of <0.05.Conclusions: This exploratory study suggests the existence of a childhood asthma endotype with early onset and increased airway resistance that is characterized by reduced sphingolipid concentrations, which are associated with 17q21 genetic variants and expression of the SPT enzyme.

Effect of High-Dose vs Standard-Dose Vitamin D Supplementation in Pregnancy on Bone Mineralization in Offspring Until Age 6 Years: A Prespecified Secondary Analysis of a Double-Blinded, Randomized Clinical Trial

IMPORTANCE

Studies suggest an association between maternal vitamin D status during pregnancy and offspring anthropometry and bone mineralization, but investigations are few and with mixed results.

OBJECTIVE

To investigate the effect of a high dose vs standard dose of vitamin D supplementation in pregnancy on anthropometric and bone outcomes until age 6 years in the offspring.

DESIGN, SETTING, AND PARTICIPANTS

A prespecified analysis of a double-blinded, randomized clinical trial in the Copenhagen Prospective Studies on Asthma in Childhood 2010 mother-child cohort that included 623 pregnant mothers and their 584 children. Data were analyzed between January 2019 and September 2019.

INTERVENTIONS

Vitamin D supplementation of 2800 IU/d (high-dose) vs 400 IU/d (standard-dose) from pregnancy week 24 until 1 week after birth.

MAIN OUTCOMES AND MEASURES

Longitudinal anthropometry assessments including length/height, weight, and body mass index until age 6 years and bone mineral content (BMC) and bone mineral density (BMD) at age 3 years and 6 years from dual-energy radiography absorptiometry scans.

RESULTS

At age 6 years, 517 children (89%) completed the clinical follow-up. All participants were Danish and white; 261 were boys and 256 were girls. A mixed-effects model analysis of dual-energy radiography absorptiometry scan outcomes from ages 3 years and 6 years showed that children in the vitamin D vs placebo group had higher whole-body BMC: mean difference adjusted (aMD) for age, sex, height, and weight was 11.5 g (95% CI, 2.3-20.7; P = .01); higher whole-body-less-head BMC aMD was 7.5 g (95% CI, 1.5-13.5; P = .01); and higher head BMD aMD was 0.023 g/cm2 (95% CI, 0.003-0.004; P = .03). The largest effect was in children from vitamin D-insufficient mothers (<30 ng/mL; to convert to nanomoles per liter, multiply by 2.496) and among winter births. In a post hoc analysis, we found borderline lower incidence of fractures in the vitamin D group (n = 23 vs n = 36; incidence rate ratio, 0.62 [95% CI, 0.37-1.05]; P = .08), but no differences in any anthropometric outcomes. Adjustment for a concomitant ω-3 polyunsaturated fatty acids intervention did not change the results.

CONCLUSIONS AND RELEVANCE

High-dose vitamin D supplementation in pregnancy improved offspring bone mineralization through age 6 years compared with the standard dose, suggesting an increased recommended gestational intake, which may influence peak bone mass, fracture risk, and risk of osteoporosis later in life. We found no supplementation effect on anthropometric outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00856947.

High-Dose Vitamin D Supplementation During Pregnancy and Asthma in Offspring at the Age of 6 Years

This long-term follow-up of a randomized trial reporting no apparent effect of high-dose vs standard-dose prenatal vitamin D supplementation on wheezing in children at the age of 3 years extends the findings an additional 3 years and describes asthma risk at the age of 6 years.