The Association of Prenatal Vitamin D Status With Pregnancy and Neonatal Outcomes.

Context: Vitamin D inadequacy is globally prevalent among pregnant women; however, its impact on pregnancy remains inconclusive. Objective: This study aims to explore the associations of maternal and umbilical cord serum 25-hydroxyvitamin D (25(OH)D) levels with pregnancy and neonatal outcomes. Method: We used archived serum samples from the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study participants in the Hong Kong center and assayed maternal 25(OH)D levels at midgestation and umbilical cord 25(OH)D at birth using liquid chromatography-tandem mass spectroscopy. Data regarding pregnancy and perinatal outcomes were extracted from the HAPO study dataset and the hospital computerized medical system. Results: Only 247 (16.4%) mothers and 66 (5.0%) neonates met the criteria for vitamin D sufficiency (ie, 25(OH)D ≥ 75 nmol/L). The ratio of umbilical cord to maternal vitamin D levels was positively associated with maternal age and ambient solar radiation at the month of delivery, while negatively associated with maternal serum total 25(OH)D at midgestation (all P < .001). Umbilical cord serum 25(OH)D was independently associated with a lower primary cesarean section rate (OR 0.990, 95% CI 0.982-0.999; P = .032). There were no associations of maternal and umbilical cord 25(OH)D levels with other adverse pregnancy and neonatal outcomes. Conclusion: Placental vitamin D transfer was found to be higher with a lower maternal vitamin D level, older maternal age, and higher ambient solar radiation at the time of the delivery. The protective effect of sufficient vitamin D in a cesarean section will require further studies.

Development of the early-life gut microbiome and associations with eczema in a prospective Chinese cohort.

IMPORTANCE: Eczema is a major allergic disease in children, which is particularly prevalent in Chinese children during their first year of life. In this study, we showed that alterations in the infant gut microbiota precede the development of eczema in a prospective Chinese cohort. In particular, we discovered enrichments of the genera Clostridium sensu stricto 1 and Finegoldia in the cases at 3 and 1 month of age, respectively, which may represent potential targets for intervention to prevent eczema. Besides, we identified a depletion of Bacteroides from 1 to 6 months of age and an enrichment of Clostridium sensu stricto 1 at 3 months in the eczema cases, patterns also observed in C-section-born infants within the same time frames, providing first evidence to support a role of the gut microbiota in previously reported associations between C-section and increased risk of eczema in infancy.

Early emergence of sexual dimorphism in offspring leukocyte telomere length was associated with maternal and children's glucose metabolism-a longitudinal study.

BACKGROUND: Leukocyte telomere length (LTL) is suggested to be a biomarker of biological age and reported to be associated with metabolic diseases such as type 2 diabetes. Glucose metabolic traits including glucose and insulin levels have been reported to be associated with LTL in adulthood. However, there is relatively little research focusing on children's LTL and the association with prenatal exposures. This study investigates the relationship between maternal and offspring glucose metabolism with offspring LTL in early life. METHODS: This study included 882 mother-child pairs from the HAPO Hong Kong Field Centre, with children evaluated at age 7.0 ± 0.4 (mean ± SD) years. Glucose metabolic traits including maternal post-load glucose during pregnancy, children's glucose and insulin levels, and their derived indices at follow-up were measured or calculated. Offspring LTL was assessed using real-time polymerase chain reaction. RESULTS: Sex- and age-adjusted children's LTL was found to be associated with children's HOMA-IR (ß=-0.046 ± 0.016, p=0.005). Interestingly, both children's and maternal post-load glucose levels were positively associated with children's LTL. However, negative associations were observed between children's LTL and children's OGTT insulin levels. In addition, the LTL in females was more strongly associated with pancreatic beta-cell function whilst LTL in males was more strongly associated with OGTT glucose levels. CONCLUSIONS: Our findings suggest a close association between maternal and offspring glucose metabolic traits with early life LTL, with the offspring sex as an important modifier of the disparate relationships in insulin production and response.

The roles of newborn anthropometrics in the association between maternal weight gain and childhood cardiovascular risks.

OBJECTIVE: The aim was to study the association between newborn anthropometrics and childhood cardiovascular risks and whether newborn anthropometrics mediate the effect of maternal gestational weight gain (GWG) on childhood risks. METHODS: Data of 926 mother-child dyads from the Hyperglycemia and Adverse Pregnancy Outcomes study were analyzed. Newborn anthropometrics were treated as predictors and mediators by using a regression model and causal mediation model, respectively. RESULTS: Newborn sum of skinfolds (SSF) was associated with childhood diastolic blood pressure (DBP) and pulse wave velocity (coefficients [95% CI]: 0.13 [0.06 to 0.20]; 0.08 [0.004 to 0.15]), whereas newborn ponderal index (PI) was inversely associated with childhood systolic blood pressure (SBP), DBP, and pulse wave velocity (-0.08 [-0.15 to -0.01]; -0.08 [-0.14 to -0.008]; -0.09 [-0.16 to -0.03]). Newborn SSF mediated the effects of maternal excessive GWG on childhood SSF and DBP (proportion of total effect 9% and 8%, respectively). In contrast, a significant negative mediation through newborn PI was found for the effect of maternal excessive GWG on childhood DBP (-8%) and its effect on childhood SBP through birth weight (-27%). CONCLUSIONS: Childhood cardiovascular risks are positively associated with newborn SSF but inversely associated with newborn PI. Newborn SSF mediates the impact of excessive maternal GWG on childhood BP, but birth weight and newborn PI negatively mediate it.

Vitamin D Levels During Pregnancy Are Associated With Offspring Telomere Length: A Longitudinal Mother-Child Study.

CONTEXT: Leukocyte telomere length (LTL) is a biomarker of biological aging and is associated with metabolic diseases such as type 2 diabetes. Insufficient maternal vitamin D was associated with increased risk for many diseases and adverse later life outcomes. OBJECTIVE: This study investigates the relationship between vitamin D levels and offspring LTL at early life. METHODS: This observational, longitudinal, hospital-based cohort study included eligible mother-child pairs from the HAPO Hong Kong Field Centre, with 853 offspring at age 6.96 ±â€…0.44 (mean ±â€…SD) years. LTL was measured using real-time polymerase chain reaction while serum vitamin D metabolites 25(OH)D2, 25(OH)D3, and 3-epi-25(OH)D3 were measured in maternal blood (at gestation 24-32 weeks) and cord blood by liquid chromatography-mass spectrometry. RESULTS: LTL at follow-up was significantly shorter in boys compared with girls (P < 0.001) at age 7. Childhood LTL was negatively associated with childhood BMI (ß ±â€…SE = -0.016 ±â€…0.007)(P = 0.02) and HOMA-IR (ß ±â€…SE = -0.065 ±â€…0.021)(P = 0.002). Multiple linear regression was used to evaluate the relationship between 25(OH)D and LTL, with covariate adjustments. Childhood LTL was positively correlated with total maternal 25(OH)D (0.048 ±â€…0.017) (P = 0.004) and maternal 3-epi-25(OH)D3 (0.05 ±â€…0.017) (P = 0.003), even after adjustment for covariates. A similar association was also noted for cord 3-epi-25(OH)D3 (0.037 ±â€…0.018) (P = 0.035) after adjustment for offspring sex and age. CONCLUSION: Our findings suggest 25(OH)D3 and 3-epi-25(OH)D3 in utero may impact on childhood LTLs, highlighting a potential link between maternal vitamin D and biological aging.

Maternal and Neonatal 3-epi-25-hydroxyvitamin D Concentration and Factors Influencing Their Concentrations.

BACKGROUND: Little is known about the presence of 3-epi-25 hydroxyvitamin D in maternal and neonatal circulation, the extent of its contribution to total 25 hydroxyvitamin D, or factors influencing its levels. METHODS: A total of 1502 and 1321 archived maternal and umbilical cord serum samples from the Hyperglycemia and Adverse Pregnancy Outcome Study cohort from Hong Kong were assayed for 25(OH)D2, 25(OH)D3, and isomeric form of 25(OH)D3 (3-epi-25(OH)D3) by a liquid chromatography-tandem mass spectrometry method. RESULTS: Vitamin D deficiency (total serum 25(OH)D level < 50 nmol/L) and severe vitamin D deficiency (total serum 25(OH)D level < 25 nmol/L) occurred in 590 (39.3%) and 25 (1.7%) mothers, respectively. 3-epi-25(OH)D3 could be detected in 94.5% of maternal and 92.1% of neonatal umbilical sera, with the highest 3-epi-25(OH)D3 levels contributing to 19.9% and 15.3% of the maternal and umbilical cord sera 25(OH)D3 levels, respectively. Pregnancy with a male fetus, ambient solar radiation, and maternal glycemia and 25(OH)D3 levels were independent factors associated with maternal 3-epi-25(OH)D3 level. Advanced maternal age, multiparity, maternal gestational weight gain below the Institute of Medicine recommendation, maternal glycemic status, and earlier gestational age at delivery were significantly associated with higher umbilical cord serum 3-epi-25(OH)D3. CONCLUSIONS: 3-epi-25(OH)D3 accounted for a significant portion of total 25(OH)D in maternal and neonatal circulations. Further study is needed to determine the possible mechanism underlying this observation.

Optimal gestational weight gain for Chinese women - analysis from a longitudinal cohort with childhood follow-up.

BACKGROUND: Maternal gestational weight gain (GWG) influences not only on pregnancy outcome but also impacts on mothers' and children's long-term health. However, there is no consensus on recommendations of optimal GWG in Asians or the Chinese population. METHODS: We performed a secondary analysis of the birth outcome of Chinese women who had joined the "Hyperglycemia and Adverse Pregnancy Outcome" study in Hong Kong and their children's cardiometabolic risk at 7-year of age. Optimal ranges of GWG were derived from models based on the probabilities of small for gestational age and large for gestational age (model 1), lean and fat infants (model 2) and the integration of model 1 and 2 (model 3), and were compared with that recommended by the Institute of Medicine (IOM) on children's cardiometabolic risk. FINDINGS: GWG range derived from model 2 is associated with 8 cardiometabolic risk factors, while that from models 1 and 3 are associated with 1 and 7 of them respectively. Mothers whose GWG lie within the recommended range increases from 40.8% according to the IOM recommendation to 50.2% according to that derived from model 2. INTERPRETATION: Optimal GWG derived from model 2 (i.e. 14.0-18.5 kg, 9.0-16.5 kg and 5.0-11.0 kg for underweight, normal weight and overweight Chinese women, respectively) appeared to be associated with the lowest cardiometabolic risk in the offspring. FUNDING: General Research Fund of the Research Grants Council of the Hong Kong SAR, China (grants CUHK 473408 and, in part, CUHK 471713).

Development of Gestational Age-Specific Thyroid Function Test Reference Intervals in Four Analytic Platforms Through Multilevel Modeling.

Background: A population-based reference interval (RI) of thyroid hormones in pregnancy using a standardized methodology is crucial for clinicians to make accurate diagnoses and important for the comparison of test results obtained from different analytic platforms. Methods: We enrolled 600 healthy Chinese women to obtain longitudinal serum samples across gestation, after exclusion of subjects with antibodies to thyroid peroxidase, thyroglobulin or thyrotropin receptor. Gestational age-specific RIs were constructed by using polynomial regression equations with MLwiN. Results: Free thyroxine (fT4) levels rose to a peak at the 7th-8th gestational weeks and then declined gradually till 28th week, while thyrotropin (TSH) level decreased from early pregnancy to a nadir at the 9th week. The data support the recent notion by the American Thyroid Association to raise the TSH upper RI to 4.0 mIU/L. We also demonstrate that thyroid hormone reference ranges are not affected in a mildly iodine-deficient population and by including women with the presence of antibodies against thyroid peroxidase and thyroglobulin who are otherwise healthy. Conclusions: The study highlights a methodology in constructing gestational age-specific thyroid function test RIs on different analytic platforms to provide a better interpretation and comparison of results obtained across different platforms.

Long-term maternal cardiometabolic outcomes 22 years after gestational diabetes mellitus.

AIMS/INTRODUCTION: Women with gestational diabetes mellitus are at increased risk for type 2 diabetes. We characterized the association between maternal glycemia during pregnancy with long-term outcomes. METHODS AND METHODS: In this prospective nested case-cohort study, participants were recalled for follow up with detailed evaluation including oral glucose tolerance test at 8, 15 and 22 years. Logistic regression was used to estimate the risk of developing impaired glucose tolerance/type 2 diabetes and metabolic syndrome at follow up. The association between maternal glycemia at pregnancy and follow up was evaluated by linear regression. We also charted trajectory of ß-cell function during follow up. RESULTS: The analysis included 121 women with a mean follow-up period of 22.5 years, and a mean age of 50.3 years. Gestational diabetes was associated with an adjusted odds ratio of 2.48 (95% confidence interval 1.03-5.99) for combined diabetes/impaired glucose tolerance at follow up (P = 0.04). Women with a pre-pregnancy body mass index ≥23 had an odds ratio of 5.43 (95% confidence interval 1.87-15.72) for metabolic syndrome at follow up, compared with those with body mass index <23 (P = 0.002). Both fasting and 2-h glucose during pregnancy were strongly associated with glycemic indices at follow up (P-value <0.001-0.016). Gestational diabetes was associated with impaired ß-cell function that remained relatively stable after the index pregnancy. CONCLUSIONS: Chinese women with a history of gestational diabetes have a high prevalence of impaired glucose tolerance/type 2 diabetes at 22-year follow up. Glucose levels during mid-pregnancy are strongly associated with those of middle age.

Augmented Velocity Index: A New Doppler Index Associated with Arterial Stiffness.

Augmented Velocity Index (Avi) is a new Doppler index developed to quantify velocity changes at the late systolic peak. We examined its reliability, association with arterial stiffness and cardiovascular risk factors. The Avi is calculated as (late systolic peak velocity - early systolic peak velocity)/(highest peak systolic velocity - end-diastolic velocity). Fifty volunteers (mean age ± standard deviation: 43.5 ± 14.2 y, men: 52%) without known medical illnesses or drug use were recruited. Carotid Doppler waveforms with measurements of Avi were recorded. Carotid pressure waveforms were obtained by applanation tonometry for measurement of the Augmentation Index (AI). Clinical measurements including body mass index (BMI) and blood pressure (BP) were assessed, and fasting blood was taken for measurement of glycemia and lipid profile. Another 15 volunteers (age range: 22-60 y, men: 33.3%) were recruited to study the reliability of Avi measurement. The results revealed that carotid Avi closely correlated with the index of arterial stiffness, AI (r = 0.76, p < 0.001) on Pearson correlation. On multiple linear regression analysis, Avi remained a significant independent determinant of AI after adjustments for clinical variables. The Avi had significant associations with cardiovascular risk factors (age, BMI, total cholesterol, low-density lipoprotein cholesterol, systolic and diastolic BP). The intra-class correlation coefficients for inter-observer and intra-observer reliability of Avi measurements were 0.93 (95% confidence interval [CI]: 0.8-0.98) and 0.97 (95% CI: 0.92-0.99) respectively. In conclusion, the Avi is a reproducible new Doppler index, independently associated with arterial stiffness in terms of the AI, which initially correlated with cardiovascular risk factors.

The impact of maternal gestational weight gain on cardiometabolic risk factors in children.

AIMS/HYPOTHESIS: Accumulating evidence suggests an impact of gestational weight gain (GWG) on pregnancy outcomes; however, data on cardiometabolic risk factors later in life have not been comprehensively studied. This study aimed to evaluate the relationship between GWG and cardiometabolic risk in offspring aged 7 years. METHODS: We included a total of 905 mother-child pairs who enrolled in the follow-up visit of the multicentre Hyperglycemia and Adverse Pregnancy Outcome study, at the Hong Kong Centre. Women were classified as having gained weight below, within or exceeding the 2009 Institute of Medicine (IOM) guidelines. A standardised GWG according to pre-pregnancy BMI categories was calculated to explore for any quadratic relationship. RESULTS: Independent of pre-pregnancy BMI, gestational hyperglycaemia and other confounders, women who gained more weight than the IOM recommendations had offspring with a larger body size and increased odds of adiposity, hypertension and insulin resistance (range of p values of all the traits: 4.6 × 10-9 < p < 0.0390) than women who were within the recommended range of weight gain during pregnancy. Meanwhile, women who gained less weight than outlined in the recommendations had offspring with increased risks of hypertension and insulin resistance, compared with those who gained weight within the recommended range (7.9 × 10-3 < p < 0.0477). Quadratic relationships for diastolic blood pressure, AUC for insulin, pancreatic beta cell function and insulin sensitivity index were confirmed in the analysis of standardised GWG (1.4 × 10-3 < pquadratic < 0.0282). Further adjustment for current BMI noticeably attenuated the observed associations. CONCLUSIONS/INTERPRETATION: Both excessive and inadequate GWG have independent and significant impacts on childhood adiposity, hypertension and insulin resistance. Our findings support the notion that adverse intrauterine exposures are associated with persistent cardiometabolic risk in the offspring.

In Utero Exposure to Maternal Hyperglycemia Increases Childhood Cardiometabolic Risk in Offspring.

OBJECTIVE: The objective of this study was to evaluate the effect of maternal hyperglycemia during pregnancy on cardiometabolic risk in offspring during early childhood. RESEARCH DESIGN AND METHODS: A total of 970 mothers who had joined the Hyperglycemia and Adverse Pregnancy Outcome study were reevaluated, together with their child born during the study period, 7 years after delivery. RESULTS: Offspring born to mothers diagnosed with gestational diabetes mellitus (GDM), as defined by the World Health Organization 2013 GDM criteria, had higher rates of abnormal glucose tolerance (4.7% vs. 1.7%; P = 0.04), higher rates of overweight or obesity, greater BMI, higher blood pressure (BP), lower oral disposition index, and a trend toward reduced ß-cell function compared with those born to mothers without GDM. For each SD increase in maternal fasting, 1-h, and 2-h glucose levels on oral glucose tolerance tests (OGTTs) between 24 and 32 weeks of the index pregnancy, the risk of abnormal glucose tolerance in the offspring showed a corresponding increase (adjusted odds ratio [OR] 1.85-2.00). The associations were independent of BMI before pregnancy, childhood obesity, or being born large for gestational age. The area under the curve for glucose levels during the five-point OGTT increased to a similar extent in boys and girls with each SD increase in maternal 1-h and 2-h plasma glucose on OGTTs during pregnancy. All three maternal glucose levels were also associated with increased adjusted ORs for childhood overweight or obesity and adiposity among girls, but not boys. CONCLUSIONS: Maternal hyperglycemia in pregnancy is independently associated with offsprings' risk of abnormal glucose tolerance, obesity, and higher BP at 7 years of age. Its effect on childhood adiposity was apparent only in girls, not boys.