Analysis of DNA methylation at birth and in childhood reveals changes associated with season of birth and latitude.

BACKGROUND: Seasonal variations in environmental exposures at birth or during gestation are associated with numerous adult traits and health outcomes later in life. Whether DNA methylation (DNAm) plays a role in the molecular mechanisms underlying the associations between birth season and lifelong phenotypes remains unclear. METHODS: We carried out epigenome-wide meta-analyses within the Pregnancy And Childhood Epigenetic Consortium to identify associations of DNAm with birth season, both at differentially methylated probes (DMPs) and regions (DMRs). Associations were examined at two time points: at birth (21 cohorts, N = 9358) and in children aged 1-11 years (12 cohorts, N = 3610). We conducted meta-analyses to assess the impact of latitude on birth season-specific associations at both time points. RESULTS: We identified associations between birth season and DNAm (False Discovery Rate-adjusted p values < 0.05) at two CpGs at birth (winter-born) and four in the childhood (summer-born) analyses when compared to children born in autumn. Furthermore, we identified twenty-six differentially methylated regions (DMR) at birth (winter-born: 8, spring-born: 15, summer-born: 3) and thirty-two in childhood (winter-born: 12, spring and summer: 10 each) meta-analyses with few overlapping DMRs between the birth seasons or the two time points. The DMRs were associated with genes of known functions in tumorigenesis, psychiatric/neurological disorders, inflammation, or immunity, amongst others. Latitude-stratified meta-analyses [higher (≥ 50°N), lower (< 50°N, northern hemisphere only)] revealed differences in associations between birth season and DNAm by birth latitude. DMR analysis implicated genes with previously reported links to schizophrenia (LAX1), skin disorders (PSORS1C, LTB4R), and airway inflammation including asthma (LTB4R), present only at birth in the higher latitudes (≥ 50°N). CONCLUSIONS: In this large epigenome-wide meta-analysis study, we provide evidence for (i) associations between DNAm and season of birth that are unique for the seasons of the year (temporal effect) and (ii) latitude-dependent variations in the seasonal associations (spatial effect). DNAm could play a role in the molecular mechanisms underlying the effect of birth season on adult health outcomes.

Different protein intake in the first year and its effects on adiposity rebound and obesity throughout childhood: 11 years follow-up of a randomized controlled trial.

BACKGROUND AND OBJECTIVES: Infant feeding affects child growth and later obesity risk. We examined whether protein supply in infancy affects the adiposity rebound, body mass index (BMI) and overweight and obesity up to 11 years of age. METHODS: We enrolled healthy term infants from five European countries in a double blind randomized trial, with anticipated 16 examinations within 11 years follow-up. Formula-fed infants (n = 1090) were randomized to isoenergetic formula with higher or lower protein content within the range stipulated by EU legislation in 2001. A breastfed reference group (n = 588) was included. Adiposity rebound and BMI trajectories were estimated by generalized additive mixed models in 917 children, with 712 participating in the 11 year follow-up. RESULTS: BMI trajectories were elevated in the higher compared to the lower protein group, with significantly different BMI at adiposity rebound (0.24 kg/m2, 0.01-0.47, p = 0.040), and an increased risk for overweight at 11 years (adjusted Odds Ratio 1.70; 1.06-2.73; p = 0.027) but no significant difference for obesity (adjusted Odds Ratio 1.47; 0.66-3.27). The two formula groups did not differ in the timing of adiposity rebound, but all children with obesity at 11 years had an early adiposity rebound before four years. CONCLUSIONS: Compared to conventional high protein formula, feeding lower protein formula in infancy lowers BMI trajectories up to 11 years and achieves similar BMI values at adiposity rebound as observed in breastfed infants.

Agreement between a regional pharmacovigilance centre and an adjudication committee regarding adverse drug reactions on a cohort of hospitalised children.

BACKGROUND AND PURPOSE: The EREMI project was set up to collect data on adverse drug reactions (ADRs) occurring due to off-label and/or unlicensed drugs prescribed to hospitalised children in France. These events were evaluated by a regional pharmacovigilance centre (RPC) and an adjudication committee (AC). The aim of this study was to assess the agreement between these two different entities on their evaluation of ADRs. EXPERIMENTAL APPROACH: The RPC first validated the ADRs and assessed their causality using the Naranjo scale. The AC assessed then ADRs using all available information, including the RPC evaluation. The agreement on severity and nature of ADRs, role of treatment (suspect or concomitant) and drug causality was calculated using Cohen's nonparametric kappa coefficient (k). KEY RESULTS: Three hundred and eighty-six events were reported in 219 children. The RPC excluded 65 events and validated 321 ADRs. Agreement was very good on nature of ADRs (k=0.85) and role of treatment (k=0.81), moderate on severity of ADRs (k=0.60) and very poor on drug causality (k=0.05). CONCLUSION AND IMPLICATIONS: Agreement between the RPC and the AC was not constant throughout this evaluation. They troubled to agree on severe ADRs and on drug causality.

Parental Perception of Body Weight Status of Their 8-year-old Children: Findings from the European CHOP Study.

BACKGROUND: Maternal perception of child weight status in children with overweight or obesity has received a lot of attention but data on paternal perception of children from presumably healthy cohorts are lacking. OBJECTIVE: We aimed to investigate paternal and maternal perception of child weight status at the age of 8 years in a cohort of 591 children from 5 European countries. MATERIAL AND METHODS: Included were 8-year-old children and their parents participating in the European Childhood Obesity Project (EU CHOP). Weight and height of children and parents were measured and Body Mass Index (BMI, kg/m2) was calculated. Both parents were asked to assess their perception of child weight status using Eckstein scales and their concern about child overweight. The agreement between mother and father perceptions was assessed by Cohen kappa coefficient and their relationship was analyzed by linear mixed effects models based on ordinal logistic regression, accounting for country, child gender and BMI, parental BMI, level of education, concern and type of feeding during first year of life. RESULTS: Data from children and both parents were available for 432 girls and boys. Mean BMI was comparable in boys and girls (16.7 ± 2.31 vs. 16.9 ± 2.87 kg/m2, P = 0.55). In total, 172 children (29.3%) were overweight or obese. There was a high degree of agreement between mother and father perceptions of their child's weight status (Cohen kappa 0.77). Multivariate modelling showed that perception levels significantly increased with child BMI but were globally lower than assessed. They differed between countries, gender and types of feeding during first year of life, were influenced by education level of the father but were not related to parental BMI and concern about childhood overweight. CONCLUSIONS: The study showed no overall differences between mothers and fathers in rating their child's weight status but both parents had a propensity to underestimate their child's actual weight, particularly in boys. The EU CHOP trial registered at clinicaltrials.gov as NCT00338689.

DNA methylation and body mass index from birth to adolescence: meta-analyses of epigenome-wide association studies.

BACKGROUND: DNA methylation has been shown to be associated with adiposity in adulthood. However, whether similar DNA methylation patterns are associated with childhood and adolescent body mass index (BMI) is largely unknown. More insight into this relationship at younger ages may have implications for future prevention of obesity and its related traits. METHODS: We examined whether DNA methylation in cord blood and whole blood in childhood and adolescence was associated with BMI in the age range from 2 to 18 years using both cross-sectional and longitudinal models. We performed meta-analyses of epigenome-wide association studies including up to 4133 children from 23 studies. We examined the overlap of findings reported in previous studies in children and adults with those in our analyses and calculated enrichment. RESULTS: DNA methylation at three CpGs (cg05937453, cg25212453, and cg10040131), each in a different age range, was associated with BMI at Bonferroni significance, P < 1.06 × 10-7, with a 0.96 standard deviation score (SDS) (standard error (SE) 0.17), 0.32 SDS (SE 0.06), and 0.32 BMI SDS (SE 0.06) higher BMI per 10% increase in methylation, respectively. DNA methylation at nine additional CpGs in the cross-sectional childhood model was associated with BMI at false discovery rate significance. The strength of the associations of DNA methylation at the 187 CpGs previously identified to be associated with adult BMI, increased with advancing age across childhood and adolescence in our analyses. In addition, correlation coefficients between effect estimates for those CpGs in adults and in children and adolescents also increased. Among the top findings for each age range, we observed increasing enrichment for the CpGs that were previously identified in adults (birth Penrichment = 1; childhood Penrichment = 2.00 × 10-4; adolescence Penrichment = 2.10 × 10-7). CONCLUSIONS: There were only minimal associations of DNA methylation with childhood and adolescent BMI. With the advancing age of the participants across childhood and adolescence, we observed increasing overlap with altered DNA methylation loci reported in association with adult BMI. These findings may be compatible with the hypothesis that DNA methylation differences are mostly a consequence rather than a cause of obesity.

An individual participant data meta-analysis on metabolomics profiles for obesity and insulin resistance in European children.

Childhood obesity prevalence is rising in countries worldwide. A variety of etiologic factors contribute to childhood obesity but little is known about underlying biochemical mechanisms. We performed an individual participant meta-analysis including 1,020 pre-pubertal children from three European studies and investigated the associations of 285 metabolites measured by LC/MS-MS with BMI z-score, height, weight, HOMA, and lipoprotein concentrations. Seventeen metabolites were significantly associated with BMI z-score. Sphingomyelin (SM) 32:2 showed the strongest association with BMI z-score (P = 4.68 × 10-23) and was also closely related to weight, and less strongly to height and LDL, but not to HOMA. Mass spectrometric analyses identified SM 32:2 as myristic acid containing SM d18:2/14:0. Thirty-five metabolites were significantly associated to HOMA index. Alanine showed the strongest positive association with HOMA (P = 9.77 × 10-16), while acylcarnitines and non-esterified fatty acids were negatively associated with HOMA. SM d18:2/14:0 is a powerful marker for molecular changes in childhood obesity. Tracing back the origin of SM 32:2 to dietary source in combination with genetic predisposition will path the way for early intervention programs. Metabolic profiling might facilitate risk prediction and personalized interventions in overweight children.

Are All Breast-fed Infants Equal? Clustering Metabolomics Data to Identify Predictive Risk Clusters for Childhood Obesity.

OBJECTIVES: Fetal and early life represent a period of developmental plasticity during which metabolic pathways are modified by environmental and nutritional cues. Little is known on the pathways underlying this multifactorial complex. We explored whether 6 months old breast-fed infants could be clustered into metabolically similar groups and that those metabotypes could be used to predict later obesity risk. METHODS: Plasma samples were obtained from 183 breast-fed infants aged 6 months participating in the European multicenter Childhood Obesity Project study. We measured amino acids along with polar lipid concentrations (acylcarnitines, lysophosphatidylcholines, phosphatidylcholines, sphingomyelins). We determined the metabotypes using a Bayesian agglomerative clustering method and investigated the properties of these clusters with respect to clinical, programming, and metabolic factors up to 6 years of age. RESULTS: We identified 20 metabolite clusters comprising 1 to 39 children. Phosphatidylcholines predominantly influenced the clustering process. In the largest clusters (n ≥ 14), large differences existed for birth length (unadjusted P < 0.0001) and length and weight at 6 months (unadjusted P < 0.0001 and P = 0.012, respectively). Infants tended to cluster together by country (unadjusted P < 0.001). The body mass index (BMI) z score at 6 years of age tended to differ (unadjusted P = 0.07). CONCLUSIONS: Our exploratory study provided evidence that breast-fed infants are not metabolically homogeneous and that variation in metabolic profiles among infants may provide insight into later development and health. This work highlights the potential of metabotypes for identifying inter-individual differences that may form the basis for developing personalized early preventive strategies.

End-of-life decisions and practices for very preterm infants in the Wallonia-Brussels Federation of Belgium.

BACKGROUND: Very preterm birth (24 to < 32 week's gestation) is a major public health issue due to its prevalence, the clinical and ethical questions it raises and the associated costs. It raises two major clinical and ethical dilemma: (i) during the perinatal period, whether or not to actively manage a baby born very prematurely and (ii) during the postnatal period, whether or not to continue a curative treatment plan initiated at birth. The Wallonia-Brussels Federation in Belgium counts 11 neonatal intensive care units. METHODS: An inventory of key practices was compiled on the basis of an online questionnaire that was sent to the 65 neonatologists working in these units. The questionnaire investigated care-related decisions and practices during the antenatal, perinatal and postnatal periods, as well as personal opinions on the possibility of standardising and/or legislating for end-of-life decisions and practices. The participation rate was 89% (n = 58). RESULTS: The results show a high level of homogeneity pointing to overall agreement on the main principles governing curative practice and the gestational age that can be actively managed given the current state of knowledge. There was, however, greater diversity regarding principles governing the transition to end-of-life care, as well as opinions about the need for a common protocol or law to govern such practices. CONCLUSION: Our results reflect the uncertainty inherent in the complex and diverse situations that are encountered in this extreme area of clinical practice, and call for qualitative research and expert debates to further document and make recommendations for best practices regarding several "gray zones" of end-of-life care in neonatology, so that high quality palliative care may be granted to all neonates concerned with end-of-life decisions.

Effect of Lower Versus Higher Protein Content in Infant Formula Through the First Year on Body Composition from 1 to 6 Years: Follow-Up of a Randomized Clinical Trial.

OBJECTIVE: The objective of this study was to investigate the effect of lower protein (LP) versus higher protein (HP) content in infant formula on body composition from 3 months to 6 years. METHODS: In a multicenter, double-blind European trial, healthy infants (N = 1,090) were randomly assigned to different protein content formulas (upper [HP] and lower [LP] limits of the European Union regulations in 2001) during the first year; breastfed infants (N = 588) were recruited for reference values. Weight, height, and triceps and subscapular skinfold (SF) thickness were measured repeatedly (N = 650 at 6 years), and body composition was estimated (Slaughter). The 99th percentile of fat mass index reference data were used to assess excess body fat at 6 years. RESULTS: At 2 and 6 years, the study observed greater sum of SFs (Δ 2 years: 0.5 mm, P = 0.026, Δ 6 years: 0.6 mm, P = 0.045), fat mass index (Δ 2 years: 0.12 kg/m², P = 0.008, Δ 6 years: 0.15 kg/m², P = 0.011), and fat-free mass index (Δ 2 years: 0.17 kg/m², P = 0.003, Δ 6 years: 0.18 kg/m², P = 0.010) in the HP group compared with the LP group. At 6 years, the HP group had a twofold higher risk than the LP group for excess body fat (adjusted odds ratio: 2.13, P = 0.019). CONCLUSIONS: Infant formula with HP levels induced greater fat mass in children from 2 to 6 years. Lowering the protein content of infant formula may result in a healthier body composition in early childhood.

DNA-Methylation and Body Composition in Preschool Children: Epigenome-Wide-Analysis in the European Childhood Obesity Project (CHOP)-Study.

Adiposity and obesity result from the interaction of genetic variation and environmental factors from very early in life, possibly mediated by epigenetic processes. Few Epigenome-Wide-Association-Studies have identified DNA-methylation (DNAm) signatures associated with BMI and body composition in children. Body composition by Bio-Impedance-Analysis and genome-wide DNAm in whole blood were assessed in 374 pre-school children from four European countries. Associations were tested by linear regression adjusted for sex, age, centre, education, 6 WBC-proportions according to Houseman and 30 principal components derived from control probes. Specific DNAm variants were identified to be associated with BMI (212), fat-mass (230), fat-free-mass (120), fat-mass-index (24) and fat-free-mass-index (15). Probes in genes SNED1(IRE-BP1), KLHL6, WDR51A(POC1A), CYTH4-ELFN2, CFLAR, PRDM14, SOS1, ZNF643(ZFP69B), ST6GAL1, C3orf70, CILP2, MLLT4 and ncRNA LOC101929268 remained significantly associated after Bonferroni-correction of P-values. We provide novel evidence linking DNAm with (i) altered lipid and glucose metabolism, (ii) diabetes and (iii) body size and composition in children. Both common and specific epigenetic signatures among measures were also revealed. The causal direction with phenotypic measures and stability of DNAm variants throughout the life course remains unclear and longitudinal analysis in other populations is required. These findings give support for potential epigenetic programming of body composition and obesity.

Influence of Feeding Types during the First Months of Life on Calciuria Levels in Healthy Infants: A Secondary Analysis from a Randomized Clinical Trial.

BACKGROUND/AIMS: Dietary factors can modify calciuria. We aim to investigate urinary calcium excretion in healthy infants according to their protein. METHODS: Secondary data analysis from a randomized clinical trial where healthy term infants were randomized after birth to a higher (HP) or lower (LP) protein content formula that was consumed until age 1 year. A non-randomized group of breastfed (BF) infants was used for reference. Anthropometry, dietary intakes and calciuria (calcium/creatinine ratios) from spot urine samples were assessed at ages 3 and 6 months. At 6 months, the kidney volumes were assessed using ultrasonography, and the serum urea and creatinine levels were determined. RESULTS: BF infants showed the highest calciuria levels, followed by the HP and the LP groups (p < 0.001 for all comparisons). Either protein intakes or formula types modulated the calciuria in linear regression models adjusted for other influencing dietary factors. The usual cut-off values classified 37.8% (BF), 16.8% (HP) and 4.9% (LP) of the infants as hypercalciuric. CONCLUSIONS: Feeding types during the first months of life affect calciuria, with BF infants presenting the highest levels. We propose new cut-off values, based on feeding types, to prevent the overestimation in hypercalciuria diagnoses among BF infants.

Maternal Smoking during Pregnancy and DNA-Methylation in Children at Age 5.5 Years: Epigenome-Wide-Analysis in the European Childhood Obesity Project (CHOP)-Study.

Mounting evidence links prenatal exposure to maternal tobacco smoking with disruption of DNA methylation (DNAm) profile in the blood of infants. However, data on the postnatal stability of such DNAm signatures in childhood, as assessed by Epigenome Wide Association Studies (EWAS), are scarce. Objectives of this study were to investigate DNAm signatures associated with in utero tobacco smoke exposure beyond the 12th week of gestation in whole blood of children at age 5.5 years, to replicate previous findings in young European and American children and to assess their biological role by exploring databases and enrichment analysis. DNA methylation was measured in blood of 366 children of the multicentre European Childhood Obesity Project Study using the Illumina Infinium HM450 Beadchip (HM450K). An EWAS was conducted using linear regression of methylation values at each CpG site against in utero smoke exposure, adjusted for study characteristics, biological and technical effects. Methylation levels at five HM450K probes in MYO1G (cg12803068, cg22132788, cg19089201), CNTNAP2 (cg25949550), and FRMD4A (cg11813497) showed differential methylation that reached epigenome-wide significance according to the false-discovery-rate (FDR) criteria (q-value<0.05). Whereas cg25949550 showed decreased methylation (-2% DNAm ß-value), increased methylation was observed for the other probes (9%: cg12803068; 5%: cg22132788; 4%: cg19089201 and 4%: cg11813497) in exposed relative to non-exposed subjects. This study thus replicates previous findings in children ages 3 to 5, 7 and 17 and confirms the postnatal stability of MYO1G, CNTNAP2 and FRMD4A differential methylation. The role of this differential methylation in mediating childhood phenotypes, previously associated with maternal smoking, requires further investigation.

Endocrine and Metabolic Biomarkers Predicting Early Childhood Obesity Risk.

There is growing evidence of long-term effects of early dietary intervention in infancy on later obesity risk. Many studies showed reduced risk of obesity with breastfeeding in infancy, which could be related to the reduced protein intake with human milk compared to infant formula. In a randomized controlled trial (Childhood Obesity Project), we were able to show that infant formula with reduced protein content results in lower BMI both at 2 and 6 years. These effects seem to be mediated mainly by branched-chain amino acids which stimulate the insulin-like growth factor (IGF)-1 axis and insulin release. In this trial, we also showed an influence of high-protein diet on larger kidney size, which seems to be partly explained by a significant effect of free IGF-1 on kidney volume. The IGF-1 axis was shown to regulate early growth, adipose tissue differentiation and early adipogenesis in animals and in humans. Leptin and adiponectin can also be regarded as important endocrine regulators of obesity. These markers were tested in observational studies. Leptin seems to be closely correlated with BMI but changes in adiponectin require further exploration. Still, there is a lack of good data or some results are contradictory to indicate the role of either leptin or adiponectin in infancy for determining later obesity risk.

Rapid growth and childhood obesity are strongly associated with lysoPC(14:0).

BACKGROUND: Despite the growing interest in the early-origins-of-later-disease hypothesis, little is known about the metabolic underpinnings linking infant weight gain and childhood obesity. OBJECTIVE: To discover biomarkers reflective of weight change in the first 6 months and overweight/obesity at age 6 years via a targeted metabolomics approach. DESIGN: This analysis comprised 726 infants from a European multicenter randomized trial (Childhood Obesity Programme, CHOP) for whom plasma blood samples at age 6 months and anthropometric data up to the age of 6 years were available. 'Rapid growth' was defined as a positive difference in weight within the first 6 months of life standardized to WHO growth standards. Weight change was regressed on each of 168 metabolites (acylcarnitines, lysophosphatidylcholines, sphingomyelins, and amino acids). Metabolites significant after Bonferroni's correction were tested as predictors of later overweight/obesity. RESULTS: Among the overall 19 significant metabolites, 4 were associated with rapid growth and 15 were associated with a less-than-ideal weight change. After adjusting for feeding group, only the lysophosphatidylcholine LPCaC14:0 remained significantly associated with rapid weight gain (ß = 0.18). Only LPCaC14:0 at age 6 months was predictive of overweight/obesity at age 6 years (OR 1.33; 95% CI 1.04-1.69). CONCLUSION: LPCa14:0 is strongly related to rapid growth in infancy and childhood overweight/obesity. This suggests that LPCaC14:0 levels may represent a metabolically programmed effect of infant weight gain on the later obesity risk. However, these results require confirmation by independent cohorts.

Lower protein content in infant formula reduces BMI and obesity risk at school age: follow-up of a randomized trial.

BACKGROUND: Early nutrition is recognized as a target for the effective prevention of childhood obesity. Protein intake was associated with more rapid weight gain during infancy-a known risk factor for later obesity. OBJECTIVE: We tested whether the reduction of protein in infant formula reduces body mass index (BMI; in kg/m(2)) and the prevalence of obesity at 6 y of age. DESIGN: The Childhood Obesity Project was conducted as a European multicenter, double-blind, randomized clinical trial that enrolled healthy infants born between October 2002 and July 2004. Formula-fed infants (n = 1090) were randomly assigned to receive higher protein (HP)- or lower protein (LP)-content formula (within recommended amounts) in the first year of life; breastfed infants (n = 588) were enrolled as an observational reference group. We measured the weight and height of 448 (41%) formula-fed children at 6 y of age. BMI was the primary outcome. RESULTS: HP children had a significantly higher BMI (by 0.51; 95% CI: 0.13, 0.90; P = 0.009) at 6 y of age. The risk of becoming obese in the HP group was 2.43 (95% CI: 1.12, 5.27; P = 0.024) times that in the LP group. There was a tendency for a higher weight in HP children (0.67 kg; 95% CI: -0.04, 1.39 kg; P = 0.064) but no difference in height between the intervention groups. Anthropometric measurements were similar in the LP and breastfed groups. CONCLUSIONS: Infant formula with a lower protein content reduces BMI and obesity risk at school age. Avoidance of infant foods that provide excessive protein intakes could contribute to a reduction in childhood obesity. This trial was registered at clinicaltrials.gov as NCT00338689.

Associations of IGF-1 gene variants and milk protein intake with IGF-I concentrations in infants at age 6 months - results from a randomized clinical trial.

OBJECTIVE: The interplay of genetic and nutritional regulation of the insulin-like growth factor-I axis in children is unclear. Therefore, potential gene-nutrient effects on serum levels of the IGF-I axis in a formula feeding trial were studied. DESIGN: European multicenter randomized clinical trial of 1090 term, formula-fed infants assigned to receive cow's milk-based infant and follow-on formulae with lower (LP: 1.25 and 1.6 g/100 mL) or higher (HP: 2.05 and 3.2 g/100 mL) protein contents for the first 12 months of life; a comparison group of 588 breastfed infants (BF) was included. Eight single nucleotide polymorphisms (SNPs) of the IGF-1-(rs6214, rs1520220, rs978458, rs7136446, rs10735380, rs2195239, rs35767, and rs35766) and two of the IGFBP-3-(rs1496495, rs6670) gene were analyzed. Serum levels of total and free IGF-I, IGFBP-3 and the molar ratio IGF-1/IGFBP-3 at age 6 months were regressed on determined SNPs and feeding groups in 501 infants. RESULTS: IGF-1-SNPs rs1520220, rs978458, and rs2195239 significantly increased total-IGF-I and molar-ratio IGF-I/IGFBP-3 by ~1.3 ng/mL and ~1.3 per allele, respectively; compared to LP infants concentration and molar-ratio were increased in HP by ~1.3 ng/mL and ~1.3 and decreased in BF infants by ~0.6 ng/mL and ~0.6, respectively. IGFBP-3 was only affected by the BF group with ~450 ng/mL lower levels than the LP group. No gene-feeding-group interaction was detected for any SNP, even without correction for multiple testing. CONCLUSIONS: Variants of the IGF-1-gene play an important role in regulating serum levels of the IGF-I axis but there is no gene-protein-interaction. The predominant nutritional regulation of IGF-I and IGFBP-3 gives further evidence that higher protein intake contributes to metabolic programming of growth.

Does insulin-like growth factor-1 mediate protein-induced kidney growth in infants? A secondary analysis from a randomized controlled trial.

BACKGROUND: Animal models have shown that insulin-like growth factor I (IGF-I) may mediate protein-induced kidney growth. Our aim was to analyze the effect of IGF-I on protein-induced kidney growth in healthy infants. METHODS: This is a secondary analysis of a randomized trial that compared growth of infants fed with a higher-protein (HP) (n = 169) vs. lower-protein (LP) (n = 182) formula (in the first year of life). Outcome measures were anthropometric parameters, kidney volume (cm(3)), and total and free IGF-I (ng/ml). RESULTS: The highest levels of total and free IGF-I were found in the HP group. Both parameters correlated significantly with BMI z-score (r = 0.229, P < 0.001 and r = 0.223, P < 0.001, respectively), kidney volume (r = 0.115, P = 0.006 and r = 0.208, P < 0.001, respectively), and kidney volume/body length (r = 0.109, P = 0.010 and r = 0.194, P < 0.001, respectively) at 6 mo. Linear regression analyses showed a significant effect of free IGF-I on kidney volume in models, including significant effects of HP formula and anthropometry. The structural equation model revealed a significant direct effect of the HP formula on kidney volume and an indirect effect mediated by free IGF-I. CONCLUSION: This study suggests that IGF-I partly mediates protein-induced kidney growth in healthy infants. IGF-I could be involved in a pathway for the programming of the renal system.

Randomized controlled trials of antibiotics for neonatal infections: a systematic review.

AIMS: Antibiotics are a key resource for the management of infectious diseases in neonatology and their evaluation is particularly challenging. We reviewed medical literature to assess the characteristics and quality of randomized controlled trials on antibiotics in neonatal infections. METHODS: We performed a systematic search of PubMed, Embase and the Cochrane Library from January 1995 to March 2010. Bibliographies of relevant articles were also hand-searched. We included all randomized controlled trials that involved neonates and evaluated the use of an antibiotic agent in the context of a neonatal infectious disease. Methodological quality was evaluated using the Jadad scale and the Cochrane Risk of Bias Tool. Two reviewers independently assessed studies for inclusion and evaluated methodological quality. RESULTS: A total of 35 randomized controlled trials were evaluated. The majority were conducted in a single hospital institution, without funding. Median sample size was 63 (34-103) participants. The most frequently evaluated antibiotic was gentamicin. Respectively, 18 (51%) and 17 (49%) trials evaluated the therapeutic or prophylactic use of antibiotics in various neonatal infections. Overall, the methodological quality was poor and did not improve over the years. Risk of bias was high in 66% of the trials. CONCLUSIONS: Design and reporting of randomized controlled trials of antibacterial agents in neonates should be improved. Nevertheless, the necessity of implementing such trials when antibacterial efficacy has already been established in other age groups may be questioned and different methods of evaluation should be further developed.

Educational paper: do we need neonatal clinical pharmacologists?

Effective and safe drug administration in young infants should be based on integrated knowledge concerning the evolving physiological characteristics of the infant who will receive the drug and the pharmacokinetic and pharmacodynamic characteristics of a given drug. Consequently, clinical pharmacology in neonates is as dynamic and diverse as the neonates we are entitled to take care of. Even more than median estimates, covariates of variability within the population are of clinical relevance. We aim to illustrate the complexity and the need for neonatal clinical pharmacology based on the gap between current and likely best clinical practice for two commonly administered compounds (aminoglycosides for infection and ibuprofen for patent ductus arteriosus) and one new compound (bevacizumab, to treat threshold retinopathy of prematurity). Progression has been made to render pharmacokinetic studies child size, e.g., low volume samples, optimal study design, and population pharmacokinetics. Challenges to further improve clinical pharmacology in neonates include, when appropriate, the validation of off-patent drug dosing regimens and of infant-tailored formulations. Knowledge integration, i.e., the use of available data to improve current drug use and to predict pharmacokinetics/pharmacodynamics for similar compounds is needed. Development of clinical research networks is helpful to achieve these goals.

The introduction of solid food and growth in the first 2 y of life in formula-fed children: analysis of data from a European cohort study.

BACKGROUND: Early introduction of solid food has been suspected to induce excessive infant energy intake and weight gain. OBJECTIVE: The objective of this study was to test whether introduction of solid foods influences energy intake or growth. DESIGN: Healthy, formula-fed infants who were recruited in 5 European countries were eligible for study participation. Anthropometric measurements were taken at recruitment and at 3, 6, 12, and 24 mo. Time of introduction of solid foods and energy intake were determined by questionnaires and 3-d weighed food records at monthly intervals. Age at introduction of solid food was categorized into 4 groups: ≤ 13 wk, 14-17 wk, 18-21 wk, and ≥ 22 wk. RESULTS: Of 1090 recruited infants, 830 (76%) had data available for age at first introduction of solid food, and 671 (61%) completed the study until 24 mo of age. The median age at introduction of solid food was 19 wk. The time of introduction of solid foods was associated with country, sex, birth weight, parental education and marital status, and maternal smoking. Energy intake was higher in the first 8 mo of life in children with solid-food intake. Solid-food introduction did not predict anthropometric measures at 24 mo. Growth trajectories differed significantly: children with solid-food introduction in the first 12 wk experienced early catch-up growth, whereas those introduced to solid food at >22 wk of age grew more slowly and stayed on lower trajectories. CONCLUSIONS: Solid foods do not simply replace infant formula but increase energy intake. Time of introduction of solid food has little influence on infant growth. This trial was registered at clinicaltrials.gov as NCT00338689.