Maternal haemoglobin levels in pregnancy and child DNA methylation: a study in the pregnancy and childhood epigenetics consortium.

Altered maternal haemoglobin levels during pregnancy are associated with pre-clinical and clinical conditions affecting the fetus. Evidence from animal models suggests that these associations may be partially explained by differential DNA methylation in the newborn with possible long-term consequences. To test this in humans, we meta-analyzed the epigenome-wide associations of maternal haemoglobin levels during pregnancy with offspring DNA methylation in 3,967 newborn cord blood and 1,534 children and 1,962 adolescent whole-blood samples derived from 10 cohorts. DNA methylation was measured using Illumina Infinium Methylation 450K or MethylationEPIC arrays covering 450,000 and 850,000 methylation sites, respectively. There was no statistical support for the association of maternal haemoglobin levels with offspring DNA methylation either at individual methylation sites or clustered in regions. For most participants, maternal haemoglobin levels were within the normal range in the current study, whereas adverse perinatal outcomes often arise at the extremes. Thus, this study does not rule out the possibility that associations with offspring DNA methylation might be seen in studies with more extreme maternal haemoglobin levels.

The experience of life events and body composition in middle childhood: a population-based study.

While studies suggest potential influences of childhood adversities on obesity development in adulthood, less is known about the short-term association in children. We examined the association between a wide range of life events experienced in the first ten years of life (including maltreatment and milder adversities) and body composition in 5333 ten-year old Dutch children. In structured interviews, mothers retrospectively reported on their children's experience of 24 events. BMI was calculated, and fat mass index and fat free mass index were determined by dual-x-ray absorptiometry scanning. Linear regressions showed that, unadjusted, a higher number of life events was associated with higher BMI and body composition. However, associations attenuated to non-significance after adjustment for covariates. Similar findings were observed for maltreatment and milder life events. Thus, the number of experienced life events was not associated with body composition in middle childhood. Rather, other factors, like socioeconomic conditions, accounted for the relationship between life events and weight development in children.

Associations of Hair Cortisol Concentrations With Cardiometabolic Risk Factors in Childhood.

CONTEXT: Biological stress is related to cardiovascular disease in adults. The associations of stress with cardiovascular and metabolic diseases may originate in childhood. OBJECTIVE: This work aims to examine the associations of hair cortisol concentrations at age 6 years with cardiometabolic risk factors at ages 6 and 10 years. METHODS: Cortisol concentrations were measured in hair of 6-year-old children (n = 2598) participating in the Generation R Study, a population-based prospective cohort study in Rotterdam, the Netherlands. Main outcome measures included blood pressure, heart rate, concentrations of insulin, glucose, lipids, and C-reactive protein in blood at ages 6 and 10 years. RESULTS: Higher hair cortisol concentrations at age 6 years were associated with higher systolic blood pressure at age 10 years (difference 0.17 SD score; 95% CI, 0.03-0.31). The association attenuated into nonsignificance after adjustment for childhood body mass index (BMI) at age 6 years. Higher hair cortisol concentrations at age 6 years were associated with an increase in total and low-density lipoprotein cholesterol between ages 6 and 10 years but not with those measurements at age 6 or 10 years. Hair cortisol concentrations were not associated with other cardiometabolic risk factors at age 6 or 10 years. CONCLUSION: Hair cortisol concentrations were not independent of BMI associated with cardiometabolic risk factors at 6 or 10 years. The associations of biological stress with cardiometabolic risk factors may develop at later ages.

Associations of Hair Cortisol Concentrations with General and Organ Fat Measures in Childhood.

CONTEXT: Stress may lead to an adverse body fat distribution from childhood onwards. OBJECTIVE: To examine the associations of hair cortisol concentration (HCC) at 6 years with general and organ fat measures, risk of overweight, and nonalcoholic fatty liver disease (NAFLD) at 10 years and to assess whether these were independent of adiposity measures at 6 years. DESIGN, SETTING AND PARTICIPANTS: HCCs were measured in hair of 6-year-old children (n = 2042) participating in the Generation R Study, a population-based prospective cohort study. MAIN OUTCOME MEASURES: Body mass index (BMI), fat mass index measured by dual-energy X-ray absorptiometry scan, and visceral fat index, pericardial fat index, liver fat fraction measured by magnetic resonance imaging and risk of overweight and NAFLD were obtained at 10 years. RESULTS: The associations of higher HCC at 6 years, with higher BMI, fat mass index, and increased risk of overweight at age 10 years are explained by the relationships observed at 6 years. HCCs at 6 years were associated with a higher liver fat fraction (difference 0.11 liver fat fraction standard deviation score; 95% confidence interval [CI] 0.03, 0.18) and a higher risk of NAFLD at 10 years (odds ratio 1.95; 95% CI 1.06, 3.56), independent of fat mass index at 6 years. HCCs were not associated with pericardial or visceral fat indices. CONCLUSIONS: Higher HCCs at 6 years were associated with higher BMI, fat mass index, liver fat fraction, and higher risks of overweight and NAFLD at 10 years. Only the associations for liver fat fraction and NAFLD were independent of fat mass index at 6 years.

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.

Understanding the cumulative risk of maternal prenatal biopsychosocial factors on birth weight: a DynaHEALTH study on two birth cohorts.

BACKGROUND: There are various maternal prenatal biopsychosocial (BPS) predictors of birth weight, making it difficult to quantify their cumulative relationship. METHODS: We studied two birth cohorts: Northern Finland Birth Cohort 1986 (NFBC1986) born in 1985-1986 and the Generation R Study (from the Netherlands) born in 2002-2006. In NFBC1986, we selected variables depicting BPS exposure in association with birth weight and performed factor analysis to derive latent constructs representing the relationship between these variables. In Generation R, the same factors were generated weighted by loadings of NFBC1986. Factor scores from each factor were then allocated into tertiles and added together to calculate a cumulative BPS score. In all cases, we used regression analyses to explore the relationship with birth weight corrected for sex and gestational age and additionally adjusted for other factors. RESULTS: Factor analysis supported a four-factor structure, labelled closely to represent their characteristics as 'Factor1-BMI' (body mass index), 'Factor2-DBP' (diastolic blood pressure), 'Factor3-Socioeconomic-Obstetric-Profile' and 'Factor4-Parental-Lifestyle'. In both cohorts, 'Factor1-BMI' was positively associated with birth weight, whereas other factors showed negative association. 'Factor3-Socioeconomic-Obstetric-Profile' and 'Factor4-Parental-Lifestyle' had the greatest effect size, explaining 30% of the variation in birth weight. Associations of the factors with birth weight were largely driven by 'Factor1-BMI'. Graded decrease in birth weight was observed with increasing cumulative BPS score, jointly evaluating four factors in both cohorts. CONCLUSION: Our study is a proof of concept for maternal prenatal BPS hypothesis, highlighting the components snowball effect on birth weight in two different European birth cohorts.

Epigenome-wide meta-analysis of blood DNA methylation in newborns and children identifies numerous loci related to gestational age.

BACKGROUND: Preterm birth and shorter duration of pregnancy are associated with increased morbidity in neonatal and later life. As the epigenome is known to have an important role during fetal development, we investigated associations between gestational age and blood DNA methylation in children. METHODS: We performed meta-analysis of Illumina's HumanMethylation450-array associations between gestational age and cord blood DNA methylation in 3648 newborns from 17 cohorts without common pregnancy complications, induced delivery or caesarean section. We also explored associations of gestational age with DNA methylation measured at 4-18 years in additional pediatric cohorts. Follow-up analyses of DNA methylation and gene expression correlations were performed in cord blood. DNA methylation profiles were also explored in tissues relevant for gestational age health effects: fetal brain and lung. RESULTS: We identified 8899 CpGs in cord blood that were associated with gestational age (range 27-42 weeks), at Bonferroni significance, P < 1.06 × 10- 7, of which 3343 were novel. These were annotated to 4966 genes. After restricting findings to at least three significant adjacent CpGs, we identified 1276 CpGs annotated to 325 genes. Results were generally consistent when analyses were restricted to term births. Cord blood findings tended not to persist into childhood and adolescence. Pathway analyses identified enrichment for biological processes critical to embryonic development. Follow-up of identified genes showed correlations between gestational age and DNA methylation levels in fetal brain and lung tissue, as well as correlation with expression levels. CONCLUSIONS: We identified numerous CpGs differentially methylated in relation to gestational age at birth that appear to reflect fetal developmental processes across tissues. These findings may contribute to understanding mechanisms linking gestational age to health effects.

Psychological Distress and Weight Gain in Pregnancy: a Population-Based Study.

BACKGROUND: Psychological distress and inappropriate or excessive weight gain are common in pregnancy and are associated with adverse maternal and offspring outcomes. Psychological well-being and weight status of women during pregnancy might be interrelated. We aimed to examine whether psychological distress during pregnancy is associated with gestational weight gain. METHOD: In a population-based cohort of 3393 pregnant women, information about psychological distress, depressive and anxiety symptoms was assessed at 20 weeks of gestation using the Brief Symptom Inventory questionnaire. Weight was repeatedly measured during pregnancy and obtained by questionnaire before and after pregnancy. Linear regression and multinomial logistic regression models were used. Weight gain in the second half of pregnancy, total weight gain, and the risks of inadequate and excessive total weight gain were the main outcome measures. RESULTS: In total, 7.0% of all women experienced psychological distress. Overall psychological distress and anxiety were associated with lower weight gain in the second half of pregnancy (differences - 1.00 kg (95% confidence interval (CI) - 1.62, - 0.37) and - 0.68 kg (95% CI - 1.24, -0.11), respectively). These associations fully attenuated into non-significance after taking account for socio-demographic variables. Similar results were observed for total weight gain. Only women with anxiety symptoms had, independently of potential confounders, a lower risk of excessive weight gain (odds ratio (OR) 0.61 (95% CI 0.48, 0.91)). CONCLUSIONS: In this large prospective cohort study, the observed associations of psychological distress with weight gain during pregnancy seem to be largely explained by common socio-demographic factors.

Outpatient initiation of the ketogenic diet in children with pharmacoresistant epilepsy: An effectiveness, safety and economic perspective.

BACKGROUND: Children with pharmacoresistant epilepsy usually receive ketogenic diet (KD) as an inpatient, which makes it an expensive treatment. OBJECTIVE: To compare the effectiveness, safety, and costs of outpatient versus inpatient initiated KD. DESIGN: Retrospective observational non-inferiority study. PATIENTS/SETTING: Patients (1-18 years of age) who started KD either inpatient or outpatient. MAIN OUTCOME MEASURES: Effectiveness was defined as ≥50% seizure reduction. Safety was measured by the numbers of emergency visits and complications. Economic impact was analyzed by calculating total costs of treatment. STATISTICAL ANALYSES: Non-inferiority of outpatient initiation was tested using 95% confidence intervals of the differences in effectiveness and safety endpoints between groups with non-inferiority margins of 10%. Nonparametric bootstrap techniques were used to derive a 95% confidence interval for the mean difference in total costs between the groups. RESULTS: Hundred and five patients started KD in the period 2001 to 2017: 43 inpatient and 62 outpatient. At three months, the KD was effective in 61% of outpatients versus 63% of inpatients. The KD was considered safe in 36% of the outpatients, as compared to 29% in the inpatients. Outpatient initiation was shown to be non-inferior to inpatient initiation in terms of safety. Total health care costs of outpatient initiation were € 2901, as compared to € 8195 of inpatient initiation per patient (mean difference € 5294, 95% CI; -€ 7653 to -€ 2935). CONCLUSIONS: Our study suggests that outpatient KD initiation is no worse than inpatient initiation in terms of effectiveness and safety, while carrying lower health care costs.

Hypertensive Disorders of Pregnancy and DNA Methylation in Newborns.

Hypertensive disorders of pregnancy (HDP) are associated with low birth weight, shorter gestational age, and increased risk of maternal and offspring cardiovascular diseases later in life. The mechanisms involved are poorly understood, but epigenetic regulation of gene expression may play a part. We performed meta-analyses in the Pregnancy and Childhood Epigenetics Consortium to test the association between either maternal HDP (10 cohorts; n=5242 [cases=476]) or preeclampsia (3 cohorts; n=2219 [cases=135]) and epigenome-wide DNA methylation in cord blood using the Illumina HumanMethylation450 BeadChip. In models adjusted for confounders, and with Bonferroni correction, HDP and preeclampsia were associated with DNA methylation at 43 and 26 CpG sites, respectively. HDP was associated with higher methylation at 27 (63%) of the 43 sites, and across all 43 sites, the mean absolute difference in methylation was between 0.6% and 2.6%. Epigenome-wide associations of HDP with offspring DNA methylation were modestly consistent with the equivalent epigenome-wide associations of preeclampsia with offspring DNA methylation (R2=0.26). In longitudinal analyses conducted in 1 study (n=108 HDP cases; 550 controls), there were similar changes in DNA methylation in offspring of those with and without HDP up to adolescence. Pathway analysis suggested that genes located at/near HDP-associated sites may be involved in developmental, embryogenesis, or neurological pathways. HDP is associated with offspring DNA methylation with potential relevance to development.

Associations of Maternal Psychological Distress during Pregnancy with Childhood General and Organ Fat Measures.

Background: Psychological distress during pregnancy may influence offspring adiposity. No studies assessed the associations with organ fat measures. We examined the associations of maternal psychological distress, depression, and anxiety during pregnancy with child general and organ fat measures. Methods: In 4161 mother-offspring pairs, psychological distress was self-reported in pregnancy. We obtained general fat measures, including BMI and fat mass index by dual-energy X-ray absorptiometry, and organ fat measures (in a subsample of 2447 children), including subcutaneous, visceral, and pericardial fat indices and liver fat fraction by magnetic resonance imaging at 10 years. Linear and logistic regression models were used. Results: Children of mothers with psychological distress had higher fat mass index [difference 0.14 (95% confidence interval {CI} 0.04-0.24) standard deviation scores (SDS)] and higher risk of obesity [odds ratio (OR) 1.73 (95% CI 1.09-2.74)]. Maternal anxiety was associated with higher BMI [difference 0.16 (95% CI 0.05-0.26) SDS], fat mass index [difference 0.19 (95% CI 0.10-0.28) SDS], and higher risks of overweight and obesity [OR 1.36 (95% CI 1.03-1.81), 1.78 (95% CI 1.13-2.81)]. Maternal anxiety was associated with higher subcutaneous and visceral fat indices and liver fat fraction [differences 0.16 (95% CI 0.03-0.29), 0.15 (95% CI 0.01-0.29), and 0.16 (95% CI 0.02-0.29) SDS]. No associations were observed for maternal depression. Conclusions: Psychological distress and anxiety, but not depression, during pregnancy were associated with higher child general and organ fat measures. A healthy mental state during pregnancy may be important for preventing child adiposity.

Concomitant lamotrigine use is associated with decreased efficacy of the ketogenic diet in childhood refractory epilepsy.

PURPOSE: Anti-epileptic drugs (AEDs) and the ketogenic diet (KD) are often used concomitantly in children with refractory epilepsy. It has been hypothesised that certain AEDs may interfere with KD. The purpose of this study was to elucidate relationships between efficacy of KD and use of specific AEDs. METHODS: A retrospective study was performed in 71 children with refractory epilepsy starting the KD between 2008 and 2014 in Erasmus University Hospital Sophia Children's Hospital. Efficacy of the KD (defined as 50% seizure reduction) was evaluated after three months of treatment and related to the AEDs used. RESULTS: The KD was successful after three months in 61% of the children (N=71). Efficacy was significantly reduced if children (n=16) used lamotrigine (31%) at diet initiation or in the course of the diet, compared to other antiepileptic drugs (69%) (p=0.006). In comparison to children using other antiepileptic drugs, the percentage of children that had adequate ketosis was significantly reduced in case of lamotrigine use (p=0.049). CONCLUSION: Lamotrigine treatment during KD is associated with a decreased efficacy of the KD.

Can we predict efficacy of the ketogenic diet in children with refractory epilepsy?

BACKGROUND: The ketogenic diet (KD) can be effective in reducing seizures in children. Predictors of success have not been identified yet. AIMS: To evaluate efficacy of KD treatment and to search for child- or diet-related factors that can predict its efficacy at 12 months follow-up. In addition we wish to determine the usefulness of a 3-month KD trial period. METHODS: Single center retrospective study in a university paediatric hospital of children with refractory epilepsy in which the KD had been initiated. Patient and diet characteristics as well as seizure reduction data were obtained from medical records and parental review. Efficacy of the KD was defined as ≥ 50% seizure reduction. Variables were evaluated in their relation to a successful treatment at three and 12 months after diet initiation. RESULTS: During a 9.5-year period, the KD was initiated in 59 children with refractory epilepsy. Twenty-four children were still on the KD after 12 months, and 21 experienced ≥50% seizure reduction. Success of the KD at three months was significantly related to a successful response to KD treatment at 12 months (p < 0.001). CONCLUSIONS: The KD can be an effective treatment in reducing seizures in children with refractory epilepsy. No significant relationships between variables and efficacy at 12 months were revealed. Children with a successful response at 3 months were significantly more likely to achieve success at 12 months of KD treatment.