Dietary intake and nutritional status in patients with newly diagnosed inflammatory bowel disease: insights from the IBSEN III study.

BACKGROUND: Dietary recommendations in inflammatory bowel disease (IBD) are inconclusive, and patients may follow restrictive diets with increased risk of malnutrition. The aim of this study was to compare dietary intakes and nutritional status in men and women with newly diagnosed IBD with a general population sample, and to investigate whether intakes were in line with the Nordic Nutrition Recommendations. METHODS: This was a cross-sectional study including adults≥ 40 years with IBD from the Inflammatory Bowel Disease in South-Eastern Norway (IBSEN) III cohort study. A validated food frequency questionnaire (FFQ) was used in dietary data collection, and a sample from the seventh survey of the Tromsø Study was included as a comparison group. RESULTS: A total of 227 men and women with IBD were included. IBD patients had higher intake of grain products, sweetened beverages, energy, fat and polyunsaturated fat (PUFA), but lower intake of dairy products, alcohol and iodine compared to adults from the comparison sample (p < 0.01). Intakes of saturated fat and carbohydrates in both genders, and vitamin D in women were not within recommended levels. Anemia and hypoalbuminemia were more prevalent in IBD patients than in the comparison sample. CONCLUSIONS: Dietary intakes in newly diagnosed IBD patients were mostly in line with Nordic Nutrition Recommendations. Higher proportion of IBD patients exceeded recommended allowances of fat and added sugar than the comparison sample. Insufficient micronutrient intake, anemia and hypoalbuminemia are present challenges in IBD patients that require monitoring.

Self-prescribed dietary restrictions in patients with inflammatory bowel disease (IBD) due to inconclusive dietary guidance may influence their risk of malnutrition. Comprehensive assessment of both dietary intake and nutritional status as early as time of diagnosis may help identify challenges in this patient group and implement appropriate interventions.

Evaluation of a digital FFQ using 24 h recalls as reference method, for assessment of habitual diet in women with South Asian origin in Norway.

OBJECTIVE: Dietary assessment tools should be designed for the target population. We developed an FFQ designed to assess diet in South Asian women in Norway. The study objective was to evaluate this FFQ using 24-h dietary recalls as reference method. DESIGN: Approximately 3 weeks after the participants (n 40) had filled in the FFQ, the first of three non-consecutive 24-h dietary recalls was completed. The recalls were telephone-based, unannounced and performed by a trained dietitian, with 2-3 weeks between each interview. SETTING: The DIASA 1 study, in Oslo, Norway. PARTICIPANTS: Women of South Asian ethnic origin participating in the DIASA 1 study were invited to participate in the evaluation study. RESULTS: The WebFFQasia significantly overestimated the absolute intake of energy, protein, fat and carbohydrates compared with the 24-h dietary recalls. Absolute intakes of sugar, starch and fibre did not differ significantly between the methods. For energy percentages (E%), there were no significant differences, except for monounsaturated fat. Correlations were strong for E% from sugar and saturated fat and moderate for E% from fibre, carbohydrate, total fat and protein. Fourteen food groups out of twenty three were not significantly different compared with the reference method, and sixteen groups showed strong to moderate correlations. CONCLUSION: The WebFFQasia may be used to assess E% from habitual diet and can adequately estimate intakes and rank participants according to nutrient intake and main food categories at group level.

Placental weight, surface area, shape and thickness - Relations with maternal ethnicity and cardio-metabolic factors during pregnancy.

INTRODUCTION: A better understanding of the determinants of placental growth is needed. Our primary aim was to explore associations between maternal ethnic origin and cardio-metabolic factors during pregnancy, and placental weight, surface area, shape and thickness. METHODS: A multi-ethnic population-based cohort study of 474 pregnant women examined at mean 15 and 28 weeks' gestation. Placentas were inspected after birth by a placental pathologist. Outcome measures were trimmed placental weight and three uncorrelated placental components; surface area, shape (oval vs round) and thickness, created through a principal components analysis. Multivariate linear regression models were used to explore the associations with maternal factors. RESULTS: Compared with ethnic European women, mothers with South- and East Asian ethnicity had placentas with lower weight (-51 g (95% CI: 75, -27) and -55 g (-95, -14) respectively), primarily due to a smaller surface area. The association between South Asian ethnicity and placental surface area was still significant after adjusting for maternal characteristics and cardio-metabolic factors. Fat mass index in early pregnancy was associated with higher placental weight and thickness. Placental surface area was positively associated with mid-gestational increases in fat mass, fasting glucose and triglycerides and with the 2-h glucose value at the 28 week oral glucose tolerance test, and inversely with a mid-gestational increase in HDL-cholesterol. DISCUSSION: Mid-gestational changes in fat mass, glucose, triglycerides and cholesterol were associated with, but only partly explained ethnic differences in placental surface area, while maternal fat mass in early pregnancy was associated with placental thickness.

DNA methylation risk score for type 2 diabetes is associated with gestational diabetes.

BACKGROUND: Gestational diabetes mellitus (GDM) and type 2 diabetes mellitus (T2DM) share many pathophysiological factors including genetics, but whether epigenetic marks are shared is unknown. We aimed to test whether a DNA methylation risk score (MRS) for T2DM was associated with GDM across ancestry and GDM criteria. METHODS: In two independent pregnancy cohorts, EPIPREG (n = 480) and EPIDG (n = 32), DNA methylation in peripheral blood leukocytes was measured at a gestational age of 28 ± 2. We constructed an MRS in EPIPREG and EPIDG based on CpG hits from a published epigenome-wide association study (EWAS) of T2DM. RESULTS: With mixed models logistic regression of EPIPREG and EPIDG, MRS for T2DM was associated with GDM: odd ratio (OR)[95% CI]: 1.3 [1.1-1.8], P = 0.002 for the unadjusted model, and 1.4 [1.1-1.7], P = 0.00014 for a model adjusted by age, pre-pregnant BMI, family history of diabetes and smoking status. Also, we found 6 CpGs through a meta-analysis (cg14020176, cg22650271, cg14870271, cg27243685, cg06378491, cg25130381) associated with GDM, and some of their methylation quantitative loci (mQTLs) were related to T2DM and GDM. CONCLUSION: For the first time, we show that DNA methylation marks for T2DM are also associated with GDM, suggesting shared epigenetic mechanisms between GDM and T2DM.

Long-term outcomes of foreskin reconstruction in distal hypospadias; a cohort study spanning twenty years.

INTRODUCTION: Surgical correction of hypospadias aims to achieve normal functionality and appearance. This entails foreskin reconstruction (FR) in countries where the uncircumcised penis constitutes the norm. Long-term data are however scarce. OBJECTIVE: To investigate the long-term outcome of FR in cohort of patients operated for distal hypospadias combined with approximately 20 years after surgery. METHODS: The hospital management system was searched for patients operated for distal hypospadias in conjunction with FR between 1997 and 2004. Prospective participants were invited to participate in an online questionnaire. Signed consent allowed for extended medical chart review, with regards to hypospadias grade, surgical procedure and complications. RESULTS: Response rate of 44.6 %. For 113 participants, median age at primary surgery was 5.2 (1.0-15.5) years. Two-thirds had a distal meatus while the remaining, meatus was mid to distal shaft. Urethroplasties performed were mainly glanular approximation procedures and meatal based flap procedures in 85 %. Foreskin fistula developed in 15 % of cases. There was no significant relationship between urethroplasty procedure or meatal position and risk of foreskin complications. Three layer closure of foreskin resulted in significantly less complications than two layer closure. Twenty years on 95 % of the men still had an intact foreskin, of whom 16.8 % had received treatment for phimosis. Foreskin was retractable in 92.5 % and 74.7 % in the flaccid and erect states respectively. Ninety intact men had had their sexual debut and in those 23.3 % reported foreskin related issues with intercourse. Evolution of foreskin retractability can be seen in the figure. DISCUSSION: Current results show that three layer FR in conjunction with hypospadias surgery is feasible and that short-term complication rates were comparable with what has previously been published in the literature. Long-term results indicate that FR is durable with regards to anatomical reconstruction however foreskin function especially in relation to sexual function was compromised in about 25 %. Foreskin retractability after surgery predicted retractability in adulthood for the flaccid but not erect penis. Limitations of this study include the retrospective nature of data collection, and that the questionnaire used was not validated. We however achieved a decent response rate and were able to capture important long-term data. CONCLUSIONS: FR has an acceptable complication rate. Long-term results two decades on are remarkably durable with regards to the anatomical preservation of the prepuce, however functionality was compromised with regards to retractability and sexual function in approximately 25 %.

Cohort profile update: the Norwegian STORK Groruddalen (STORK G) pregnancy and birth cohort-the role of ethnicity and causal pathways for obesity, type 2 diabetes, cardiovascular disease and other health issues.

PURPOSE: The STORK Groruddalen cohort was set up in 2008 to explore ethnic differences in: (1) maternal health, primarily gestational diabetes (GDM) and related health issues during pregnancy and post partum, and effects of exposures on risk for type 2 diabetes, cardiovascular disease and other health issues, and (2) offspring's growth and body composition, overweight/obesity and effects of early life exposures. PARTICIPANTS: 823 women (74% of invited) were followed from gestational week (GW) 15. Data were collected from 618 fathers. In total, 59% of women and 53% of fathers had origin from non-Western countries. Maternal mean age was 29.9 years (SD 4.9), and body mass index (BMI) 25.3 kg/m2 (4.9). Data were obtained from 772 women (94%) at GW 28, and 662 women (80%) 14 weeks post partum. Eleven years post partum, 385 women (53% of eligible/47% of original cohort) attended, age was 42.0 years (4.8) and BMI 27.1 kg/m2 (5.1). We have data for 783 children at birth, and for 586 at last time point, mean age 8.6 (0.5) years, weight 30.7 (6.8) kg and length 133.9 (6.3) cm. FINDINGS TO DATE: We collected questionnaire data from parents, clinical measurements and blood samples from mothers, and data on children's growth (mid-pregnancy to 8 years). Our biobank includes maternal blood and urine samples, biopsy material from placentas and umbilical venous cord blood. We found several clinically important differences in maternal health, with higher risk in ethnic minority groups for GDM, insulin resistance, vitamin D and iron deficiency, depressive symptoms and physical inactivity. Contrasting patterns of fetal growth and risk of overweight/thinness at preschool age were observed across ethnic groups. Maternal GDM, obesity and high gestational weight gain were associated with children's BMI trajectories. FUTURE PLANS: We will examine the impact of maternal and fetal health and development during pregnancy on long-term outcomes for mothers and offspring. TRIAL REGISTRATION NUMBER: Project title STORK G-2: Women and Risk of Type 2 Diabetes NCT03870724 (ClinicalTrials.gov).

Epigenetic marks associated with gestational diabetes mellitus across two time points during pregnancy.

An adverse intrauterine or periconceptional environment, such as hyperglycemia during pregnancy, can affect the DNA methylation pattern both in mothers and their offspring. In this study, we explored the epigenetic profile in maternal peripheral blood samples through pregnancy to find potential epigenetic biomarkers for gestational diabetes mellitus (GDM), as well as candidate genes involved in GDM development. We performed an epigenome-wide association study in maternal peripheral blood samples in 32 pregnant women (16 with GDM and 16 non-GDM) at pregnancy week 24-28 and 36-38. Biochemical, anthropometric, and obstetrical variables were collected from all the participants. The main results were validated in an independent cohort with different ethnic origin (European = 307; South Asians = 165). Two hundred and seventy-two CpGs sites remained significantly different between GDM and non-GDM pregnant women across two time points during pregnancy. The significant CpG sites were related to pathways associated with type I diabetes mellitus, insulin resistance and secretion. Cg01459453 (SELP gene) was the most differentiated in the GDM group versus non-GDM (73.6 vs. 60.9, p = 1.06E-11; FDR = 7.87E-06). Three CpG sites (cg01459453, cg15329406, and cg04095097) were able to discriminate between GDM cases and controls (AUC = 1; p = 1.26E-09). Three differentially methylated positions (DMPs) were replicated in an independent cohort. To conclude, epigenetic marks during pregnancy differed between GDM cases and controls suggesting a role for these genes in GDM development. Three CpGs were able to discriminate GDM and non-GDM groups with high specificity and sensitivity, which may be biomarker candidates for diagnosis or prediction of GDM.

Epigenome-wide association study of serum folate in maternal peripheral blood leukocytes.

Aim: To perform an epigenome-wide association study (EWAS) of serum folate in maternal blood. Methods: Cross-ancestry (Europeans = 302, South Asians = 161) and ancestry-specific EWAS in the EPIPREG cohort were performed, followed by methyl quantitative trait loci analysis and association with cardiometabolic phenotypes. Replication was attempted using maternal folate intake and blood methylation data from the MoBa study and verified if the findings were significant in a previous EWAS of maternal serum folate in cord blood. Results & conclusion: cg19888088 (cross-ancestry) in EBF3, cg01952260 (Europeans) and cg07077240 (South Asians) in HERC3 were associated with serum folate. cg19888088 and cg01952260 were associated with diastolic blood pressure. cg07077240 was associated with variants in CASC15. The findings were not replicated and were not significant in cord blood.

Cross-Ancestry DNA Methylation Marks of Insulin Resistance in Pregnancy: An Integrative Epigenome-Wide Association Study.

Although there are some epigenome-wide association studies (EWAS) of insulin resistance, for most of them authors did not replicate their findings, and most are focused on populations of European ancestry, limiting the generalizability. In the Epigenetics in Pregnancy (EPIPREG; n = 294 Europeans and 162 South Asians) study, we conducted an EWAS of insulin resistance in maternal peripheral blood leukocytes, with replication in the Born in Bradford (n = 879; n = 430 Europeans and 449 South Asians), Methyl Epigenome Network Association (MENA) (n = 320), and Botnia (n = 56) cohorts. In EPIPREG, we identified six CpG sites inversely associated with insulin resistance across ancestry, of which five were replicated in independent cohorts (cg02988288, cg19693031, and cg26974062 in TXNIP; cg06690548 in SLC7A11; and cg04861640 in ZSCAN26). From methylation quantitative trait loci analysis in EPIPREG, we identified gene variants related to all five replicated cross-ancestry CpG sites, which were associated with several cardiometabolic phenotypes. Mediation analyses suggested that the gene variants regulate insulin resistance through DNA methylation. To conclude, our cross-ancestry EWAS identified five CpG sites related to lower insulin resistance.

Insulin and Body Mass Index Decrease Serum Soluble Leptin Receptor Levels in Humans.

CONTEXT: Serum soluble leptin receptor (sOb-R) may protect against future type 2 diabetes or serve as a marker for protective features, but how sOb-R is regulated is largely unknown. OBJECTIVE: This work aimed to test how serum sOb-R is influenced by glucose, insulin, body fat, body mass index (BMI), food intake, and physical activity. METHODS: We performed an epidemiological triangulation combining cross-sectional, interventional, and Mendelian randomization study designs. In 5 independent clinical studies (n = 24-823), sOb-R was quantified in serum or plasma by commercial enzyme-linked immunosorbent assay kits using monoclonal antibodies. We performed mixed-model regression and 2-sample Mendelian randomization. RESULTS: In pooled, cross-sectional data, leveling by study, sOb-R was associated inversely with BMI (ß [95% CI] -0.19 [-0.21 to -0.17]), body fat (-0.12 [-0.14 to -0.10), and fasting C-peptide (-2.04 [-2.46 to -1.62]). sOb-R decreased in response to acute hyperinsulinemia during euglycemic glucose clamp in 2 independent clinical studies (-0.5 [-0.7 to -0.4] and -0.5 [-0.6 to -0.3]), and immediately increased in response to intensive exercise (0.18 [0.04 to 0.31]) and food intake (0.20 [0.06 to 0.34]). In 2-sample Mendelian randomization, higher fasting insulin and higher BMI were causally linked to lower sOb-R levels (inverse variance weighted, -1.72 [-2.86 to -0.58], and -0.20 [-0.36 to -0.04], respectively). The relationship between hyperglycemia and sOb-R was inconsistent in cross-sectional studies and nonsignificant in intervention studies, and 2-sample Mendelian randomization suggested no causal effect of fasting glucose on sOb-R. CONCLUSION: BMI and insulin both causally decreased serum sOb-R levels. Conversely, intensive exercise and food intake acutely increased sOb-R. Our results suggest that sOb-R is involved in short-term regulation of leptin signaling, either directly or indirectly, and that hyperinsulinemia may reduce leptin signaling.

ß-Cell Function, Hepatic Insulin Clearance, and Insulin Sensitivity in South Asian and Nordic Women After Gestational Diabetes Mellitus.

South Asian women have a higher risk of type 2 diabetes after gestational diabetes mellitus (GDM) than Nordic women; however, the mechanisms behind this difference remain unclear. We investigated insulin sensitivity, ß-cell function, and hepatic insulin clearance in 179 South Asian and 108 Nordic women ∼17 months after GDM (mean age 35.3 years, BMI 29.1 kg/m2) by oral glucose tolerance test using deconvolution of C-peptide kinetics. Thirty-one percent of South Asian and 53% of Nordic participants were normoglycemic at the time of measurement. South Asian women had higher areas under the curve (AUCs) for glucose, prehepatic insulin, and peripheral insulin and lower insulin sensitivity, disposition index, and fasting hepatic insulin clearance than Nordic women. In the group with prediabetes or diabetes, South Asian women had similar AUCs for glucose and prehepatic insulin but a higher AUC for peripheral insulin, lower disposition index, and lower fasting hepatic insulin clearance than Nordic women. The waist-to-height ratio mediated ∼25-40% of the ethnic differences in insulin sensitivity in participants with normoglycemia. Overall, our novel data revealed that South Asian women with normoglycemia after GDM showed lower insulin secretion for a given insulin resistance and lower hepatic insulin clearance than Nordic women. South Asian women are at high risk of developing type 2 diabetes after GDM, and preventive efforts should be prioritized.

High prevalence and significant ethnic differences in actionable HbA1C after gestational diabetes mellitus in women living in Norway.

BACKGROUND: The type 2 diabetes risk after gestational diabetes mellitus (GDM) is twice as high in South Asian compared to European women. Current guidelines differ regarding which test to use as a screening-tool post-GDM. We aimed to identify ethnic differences in the prevalence rates and early predictors for actionable HbA1c (defined as prediabetes and diabetes) short time after GDM. METHODS: This cross-sectional study, enrolling South Asian and Nordic women 1-3 years after a diagnosis of GDM, was undertaken at three hospitals in Norway. We performed a clinical and laboratory evaluation including an oral glucose tolerance test (OGTT). Medical records were used to retrieve data during pregnancy. Prediabetes was classified with HbA1c alone or combined with OGTT glucose measurements according to the WHO, WHO-IEC, and ADA criteria (fasting plasma glucose (FPG) 6.1-6.9 mmol/L, FPG 6.1-6.9 mmol/L and/or HbA1c 42-47 mmol/mol (6.0-6.4%), and FPG 5.6-6.9 mmol/L and/or HbA1c 39-47 mmol/mol (5.7-6.4%)). Ethnic differences in prevalence and predictors of glucose deterioration were assed by χ2 (Pearson) tests and logistic regression models. RESULTS: We included 163 South Asian and 108 Nordic women. Actionable HbA1c levels were highly prevalent and more so among South Asian than Nordic women (WHO-IEC-HbA1c: 25.8% vs. 6.5% (p ≤ 0.001), ADA-HbA1c: 58.3% vs. 22.2% (p ≤ 0.001)). Although adding OGTT-data gave higher combined prevalence rates of prediabetes and diabetes (WHO: 65.6% vs. 47.2% (p ≤ 0.05), WHO-IEC: 70.6% vs. 47.2% (p ≤ 0.001), ADA: 87.8% vs. 65.7% (p ≤ 0.001)), the excess risk in the South Asian women was best captured by the HbA1c. Important predictors for glucose deterioration after GDM were: South Asian ethnicity, GDM before the index pregnancy, use of glucose-lowering drugs in pregnancy, higher age, and higher in-pregnancy fasting glucose levels. CONCLUSIONS: In women with GDM 1-3 year previously, we found high prevalence and significant ethnic differences in actionable ADA-HbA1c levels, with South Asian ethnicity, GDM before the index pregnancy, and the use of glucose-lowering drugs in pregnancy as the most important risk factors. This study reinforces the importance of annual screening-preferably with HbA1c measurements-to facilitate early intervention after GDM.

Multi-ancestry genome-wide association study of gestational diabetes mellitus highlights genetic links with type 2 diabetes.

Gestational diabetes mellitus (GDM) is associated with increased risk of pregnancy complications and adverse perinatal outcomes. GDM often reoccurs and is associated with increased risk of subsequent diagnosis of type 2 diabetes (T2D). To improve our understanding of the aetiological factors and molecular processes driving the occurrence of GDM, including the extent to which these overlap with T2D pathophysiology, the GENetics of Diabetes In Pregnancy Consortium assembled genome-wide association studies of diverse ancestry in a total of 5485 women with GDM and 347 856 without GDM. Through multi-ancestry meta-analysis, we identified five loci with genome-wide significant association (P < 5 × 10-8) with GDM, mapping to/near MTNR1B (P = 4.3 × 10-54), TCF7L2 (P = 4.0 × 10-16), CDKAL1 (P = 1.6 × 10-14), CDKN2A-CDKN2B (P = 4.1 × 10-9) and HKDC1 (P = 2.9 × 10-8). Multiple lines of evidence pointed to the shared pathophysiology of GDM and T2D: (i) four of the five GDM loci (not HKDC1) have been previously reported at genome-wide significance for T2D; (ii) significant enrichment for associations with GDM at previously reported T2D loci; (iii) strong genetic correlation between GDM and T2D and (iv) enrichment of GDM associations mapping to genomic annotations in diabetes-relevant tissues and transcription factor binding sites. Mendelian randomization analyses demonstrated significant causal association (5% false discovery rate) of higher body mass index on increased GDM risk. Our results provide support for the hypothesis that GDM and T2D are part of the same underlying pathology but that, as exemplified by the HKDC1 locus, there are genetic determinants of GDM that are specific to glucose regulation in pregnancy.

Cohort profile: Epigenetics in Pregnancy (EPIPREG) - population-based sample of European and South Asian pregnant women with epigenome-wide DNA methylation (850k) in peripheral blood leukocytes.

Pregnancy is a valuable model to study the association between DNA methylation and several cardiometabolic traits, due to its direct potential to influence mother's and child's health. Epigenetics in Pregnancy (EPIPREG) is a population-based sample with the aim to study associations between DNA-methylation in pregnancy and cardiometabolic traits in South Asian and European pregnant women and their offspring. This cohort profile paper aims to present our sample with genetic and epigenetic data and invite researchers with similar cohorts to collaborative projects, such as replication of ours or their results and meta-analysis. In EPIPREG we have quantified epigenome-wide DNA methylation in maternal peripheral blood leukocytes in gestational week 28±1 in Europeans (n = 312) and South Asians (n = 168) that participated in the population-based cohort STORK Groruddalen, in Norway. DNA methylation was measured with Infinium MethylationEPIC BeadChip (850k sites), with technical validation of four CpG sites using bisulphite pyrosequencing in a subset (n = 30). The sample is well characterized with few missing data on e.g. genotype, universal screening for gestational diabetes, objectively measured physical activity, bioelectrical impedance, anthropometrics, biochemical measurements, and a biobank with maternal serum and plasma, urine, placenta tissue. In the offspring, we have repeated ultrasounds during pregnancy, cord blood, and anthropometrics up to 4 years of age. We have quantified DNA methylation in peripheral blood leukocytes in nearly all eligible women from the STORK Groruddalen study, to minimize the risk of selection bias. Genetic principal components distinctly separated Europeans and South Asian women, which fully corresponded with the self-reported ethnicity. Technical validation of 4 CpG sites from the methylation bead chip showed good agreement with bisulfite pyrosequencing. We plan to study associations between DNA methylation and cardiometabolic traits and outcomes.

Maternal Glucose and LDL-Cholesterol Levels Are Related to Placental Leptin Gene Methylation, and, Together With Nutritional Factors, Largely Explain a Higher Methylation Level Among Ethnic South Asians.

Background: Leptin, mainly secreted by fat cells, plays a core role in the regulation of appetite and body weight, and has been proposed as a mediator of metabolic programming. During pregnancy leptin is also secreted by the placenta, as well as being a key regulatory cytokine for the development, homeostatic regulation and nutrient transport within the placenta. South Asians have a high burden of type 2 diabetes, partly attributed to a "thin-fat-phenotype". Objective: Our aim was to investigate how maternal ethnicity, adiposity and glucose- and lipid/cholesterol levels in pregnancy are related to placental leptin gene (LEP) DNA methylation. Methods: We performed DNA methylation analyses of 13 placental LEP CpG sites in 40 ethnic Europeans and 40 ethnic South Asians participating in the STORK-Groruddalen cohort. Results: South Asian ethnicity and gestational diabetes (GDM) were associated with higher placental LEP methylation. The largest ethnic difference was found for CpG11 [5.8% (95% CI: 2.4, 9.2), p<0.001], and the strongest associations with GDM was seen for CpG5 [5.2% (1.4, 9.0), p=0.008]. Higher maternal LDL-cholesterol was associated with lower placental LEP methylation, in particular for CpG11 [-3.6% (-5.5, -1.4) per one mmol/L increase in LDL, p<0.001]. After adjustments, including for nutritional factors involved in the one-carbon-metabolism cycle (vitamin D, B12 and folate levels), ethnic differences in placental LEP methylation were strongly attenuated, while associations with glucose and LDL-cholesterol persisted. Conclusions: Maternal glucose and lipid metabolism is related to placental LEP methylation, whilst metabolic and nutritional factors largely explain a higher methylation level among ethnic South Asians.

Epigenetic signatures associated with maternal body mass index or gestational weight gain: a systematic review.

Maternal body mass index (BMI) and gestational weight gain (GWG) impacts both the mother's and the child's health, and epigenetic modifications have been suggested to mediate some of these effects in offspring. This systematic review aimed to summarize the current literature on associations between maternal BMI and GWG and epigenetic marks. We performed systematic searches in PubMed and EMBASE and manual searches of reference lists. We included 49 studies exploring the association between maternal BMI and/or GWG and DNA methylation or miRNA; 7 performed in maternal tissues, 13 in placental tissue and 38 in different offspring tissues. The most consistent findings were reported for the relationship between maternal BMI, in particular pre-pregnant BMI, and expression of miRNA Let-7d in both maternal blood and placental tissue, methylation of the gene HIF3A in umbilical cord blood and umbilical tissue, and with expression in the miR-210 target gene, BDNF in placental tissue and cord blood. Correspondingly, methylation of BDNF was also found in placental tissue and cord blood. The current evidence suggests that maternal BMI is associated with some epigenetic signatures in the mother, the placenta and her offspring, which could indicate that some of the effects proposed by the Developmental Origins of Health and Disease-hypothesis may be mediated by epigenetic marks. In conclusion, there is a need for large, well-designed studies and meta-analyses that can clarify the relationship between BMI, GWG and epigenetic changes.

Investigating the causal effect of maternal vitamin B12 and folate levels on offspring birthweight.

BACKGROUND: Lower maternal serum vitamin B12 (B12) and folate levels have been associated with lower offspring birthweight, in observational studies. The aim of this study was to investigate whether this relationship is causal. METHODS: We performed two-sample Mendelian randomization (MR) using summary data on associations between genotype-B12 (10 genetic variants) or genotype-folate (four genetic variants) levels from: a genome-wide association study of 45 576 individuals (sample 1); and both maternal- and fetal-specific genetic effects on offspring birthweight from the latest Early Growth Genetics consortium meta-analysis with 297 356 individuals reporting their own birthweight and 210 248 women reporting their offspring's birthweight (sample 2). We used the inverse variance weighted method, and sensitivity analyses to account for pleiotropy, in addition to excluding a potentially pleiotropic variant in the FUT2 gene for B12 levels. RESULTS: We did not find evidence for a causal effect of maternal or fetal B12 levels on offspring birthweight. The results were consistent across the different methods. We found a positive causal effect of maternal folate levels on offspring birthweight [0.146 (0.065, 0.227), which corresponds to an increase in birthweight of 71 g per 1 standard deviation higher folate]. We found some evidence for a small inverse effect of fetal folate levels on their own birthweight [-0.051 (-0.100, -0.003)]. CONCLUSIONS: Our results are consistent with evidence from randomized controlled trials that higher maternal folate levels increase offspring birthweight. We did not find evidence for a causal effect of B12 levels on offspring birthweight, suggesting previous observational studies may have been confounded.

Blood-based epigenetic estimators of chronological age in human adults using DNA methylation data from the Illumina MethylationEPIC array.

BACKGROUND: Epigenetic clocks have been recognized for their precise prediction of chronological age, age-related diseases, and all-cause mortality. Existing epigenetic clocks are based on CpGs from the Illumina HumanMethylation450 BeadChip (450 K) which has now been replaced by the latest platform, Illumina MethylationEPIC BeadChip (EPIC). Thus, it remains unclear to what extent EPIC contributes to increased precision and accuracy in the prediction of chronological age. RESULTS: We developed three blood-based epigenetic clocks for human adults using EPIC-based DNA methylation (DNAm) data from the Norwegian Mother, Father and Child Cohort Study (MoBa) and the Gene Expression Omnibus (GEO) public repository: 1) an Adult Blood-based EPIC Clock (ABEC) trained on DNAm data from MoBa (n = 1592, age-span: 19 to 59 years), 2) an extended ABEC (eABEC) trained on DNAm data from MoBa and GEO (n = 2227, age-span: 18 to 88 years), and 3) a common ABEC (cABEC) trained on the same training set as eABEC but restricted to CpGs common to 450 K and EPIC. Our clocks showed high precision (Pearson correlation between chronological and epigenetic age (r) > 0.94) in independent cohorts, including GSE111165 (n = 15), GSE115278 (n = 108), GSE132203 (n = 795), and the Epigenetics in Pregnancy (EPIPREG) study of the STORK Groruddalen Cohort (n = 470). This high precision is unlikely due to the use of EPIC, but rather due to the large sample size of the training set. CONCLUSIONS: Our ABECs predicted adults' chronological age precisely in independent cohorts. As EPIC is now the dominant platform for measuring DNAm, these clocks will be useful in further predictions of chronological age, age-related diseases, and mortality.

Auto regulatory capacity of the thyroid gland after numerous iodinated contrast media investigations.

Excess of iodine may interfere with thyroid function. It is unclear to what extent the thyroid function is disturbed by repeated infusion of iodide contrast agent (IC) used during X-ray examinations. Thyroid function tests free T4 (FT4), free FT3 (FT3), thyroid-stimulating hormone (TSH), TSH receptor antibodies (TRAb) and thyroid peroxidase antibodies (TPO-Ab) were measured in a group of Norwegian patients with an assumed normal iodine balance before, 1 and 6 weeks after IC infusion. Forty patients (19 females and 21 men) referred for routine CT were included. Thirty two out of 40 patients had previously undertaken IC investigations. The mean TSH concentration was 2.1 mIU/l ± 1.7 at the baseline, increased to 2.9 ± 2.5 after 1 week (p < .001), and reverted to nearly initial values 1.4 ± 0.8 after 6 weeks. Initially the mean FT4 was 14.1 pmol/l ± 1.9 FT4, reduced to 13.3 pmol/l ± 2.5 (p = .009) after 1 week, and returned to 14.0 pmol/l ± 2.5 after 6 weeks, comparable to the initial values (p > .05). FT3 levels did not change during the period. There was no relationship between FT4, or TSH and age, gender, cancer/not cancer, number or frequency of earlier IC investigations. In conclusion, IC induces changes in thyroid function tests, however, they return to normal levels after 6 weeks. Our results suggest adequate auto regulatory capacity of the thyroid gland even in those with repeated contrast investigations (up to 40). Routine testing of thyroid function should therefore not be undertaken in this patient group.