Differences in birth weight by sex using adjusted quantile distance functions

Recommendations for a Better Understanding of Sex and Gender in the Neuroscience of Mental Health

There are prominent sex/gender differences in the prevalence, expression, and life span course of mental health and neurodiverse conditions. However, the underlying sex- and gender-related mechanisms and their interactions are still not fully understood. This lack of knowledge has harmful consequences for those with mental health problems. Therefore, we set up a cocreation session in a 1-week workshop with a multidisciplinary team of 25 researchers, clinicians, and policy makers to identify the main barriers in sex and gender research in the neuroscience of mental health. Based on this work, here we provide recommendations for methodologies, translational research, and stakeholder involvement. These include guidelines for recording, reporting, analysis beyond binary groups, and open science. Improved understanding of sex- and gender-related mechanisms in neuroscience may benefit public health because this is an important step toward precision medicine and may function as an archetype for studying diversity.

Investigation of maternal polymorphisms in genes related to glucose homeostasis and the influence on birth weight: a cohort study

OBJECTIVES

To contribute to a better understanding of the maternal genetic mechanisms that influence obstetric outcomes and that are involved in maternal and child health, this study aimed to evaluate the association between maternal genetic variants and the offspring birth weight by analyzing single-nucleotide polymorphisms (SNPs) in genes related to glucose homeostasis.

METHODS

Three polymorphisms were analyzed (GCK rs1799884, TCF7L2 rs7903146 and LEPR rs1137101) in 250 pregnant women who participated in a Brazilian prospective cohort study. Genotyping was performed by Real-Time Polymerase Chain Reaction (qPCR) using pre-designed TaqMan® SNP genotyping assays. Vitamin D dosage was performed by chemiluminescence. Variance, Pearson's chi-square test and multiple linear regression were used for the statistical analysis.

RESULTS

It was possible to verify a significant association between birth weight and maternal GCK rs1799884 when obstetric outcomes, clinical and anthropometric characteristics were taken into consideration. The children of homozygous women for the minor allele GCK rs1799884 presented lower birth weight (β = -335.25, 95% CI = -669.39; -1.17, p = 0.04). Furthermore, a direct link between a leptin receptor variant and gestational duration was found (p = 0.037).

CONCLUSION

The variant GCK rs1799884 (mm) was associated with a reduction in newborn weight in the miscegenated Brazilian population.

Health impacts of a randomized biomass cookstove intervention in northern Ghana

BACKGROUND

Household air pollution (HAP) from cooking with solid fuels has adverse health effects. REACCTING (Research on Emissions, Air quality, Climate, and Cooking Technologies in Northern Ghana) was a randomized cookstove intervention study that aimed to determine the effects of two types of "improved" biomass cookstoves on health using self-reported health symptoms and biomarkers of systemic inflammation from dried blood spots for female adult cooks and children, and anthropometric growth measures for children only.

METHODS

Two hundred rural households were randomized into four different cookstove groups. Surveys and health measurements were conducted at four time points over a two-year period. Chi-square tests were conducted to determine differences in self-reported health outcomes. Linear mixed models were used to assess the effect of the stoves on inflammation biomarkers in adults and children, and to assess the z-score deviance for the anthropometric data for children.

RESULTS

We find some evidence that two biomarkers of oxidative stress and inflammation, serum amyloid A and C-reactive protein, decreased among adult primary cooks in the intervention groups relative to the control group. We do not find detectable impacts for any of the anthropometry variables or self-reported health.

CONCLUSIONS

Overall, we conclude that the REACCTING intervention did not substantially improve the health outcomes examined here, likely due to continued use of traditional stoves, lack of evidence of particulate matter emissions reductions from "improved" stoves, and mixed results for HAP exposure reductions.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov (National Institutes of Health); Trial Registration Number: NCT04633135 ; Date of Registration: 11 November 2020 - Retrospectively registered. URL: https://clinicaltrials.gov/ct2/show/NCT04633135?term=NCT04633135&draw=2&rank=1.

Determinants of nutritional status during the first 1000 days of life in Lebanon: Sex of the child matters

BACKGROUND

The first 1000 days of life support child growth and long-term health, but few studies address this period in Lebanon and the Eastern Mediterranean Region.

OBJECTIVE

To examine the determinants of nutritional status among Lebanese children ≤2 years old by child's sex.

METHODS

We analysed data from a nationally representative cross-sectional survey of 466 mother-child dyads. We classified socio-economic, maternal, and child characteristics using a hierarchical conceptual framework into distal, intermediate, and proximal levels, respectively. Sex-stratified weighted multiple linear regression was computed to identify the determinants of length-for-age z-scores (LAZ) and weight-for-length z-scores (WLZ).

RESULTS

The mean (standard deviation) of LAZ and WLZ was -0.3 (1.6) and 0.5 (1.5) among boys and -0.1 (1.4) and 0.5 (1.0) among girls, respectively. At the distal level, maternal intermediate or high school education was associated with higher boys' LAZ (β 1.0, 95% confidence interval (CI) 0.2, 1.8), and less crowded households were associated with higher girls' LAZ (β 0.8, 95% CI 0.3, 1.4). At the intermediate level, maternal obesity was associated with lower girls' LAZ (β -0.9, 95% CI -1.4, -0.4). At the proximal level, birth length directly (β 0.1, 95% CI 0.0, 0.2) and breast-feeding duration inversely (β -0.1, 95% CI -0.1, -0.0) associated with girls' LAZ. For WLZ, paternal attainment of university degree or technical diploma was associated with lower boys' WLZ (β -0.9, 95% CI -1.8, -0.1). Among the proximal determinants, birthweight was directly associated with boys' WLZ (β 1.2, 95% CI 0.6, 1.8), while being a third or later child was associated with lower girls' WLZ (β -0.5, 95% CI -0.8, -0.2). Child age was directly associated with WLZ among boys and girls (β 0.1, 95% CI 0.0, 0.1).

CONCLUSIONS

Nutritional status determinants differed by child's sex in Lebanon. These findings may help inform interventions to improve child growth.

Correlations between the Status of the Umbilical Cord and Neonatal Health Status

Purpose: This study aimed to identify correlations between the status of the umbilical cord and neonatal health status.Methods: In total, 172 newborns were enrolled who were admitted to the newborn nursery with a gestational age of 35 weeks or older and a body weight of 2 kg or above. Data were collected on the basic personal information of the newborns, the diameter and soft tissue status of the umbilical cord, and neonatal health status after birth. Analyses were performed using t-test, analysis of variance, <i>x</i>² test, and Fisher exact test.Results: Umbilical cord diameter exhibited a statistically significant difference by sex (t=2.71, <i>p</i>=.007). A thin umbilical cord diameter was associated with a 1-minute Apgar score less than 8 points (t=2.47, <i>p</i>=.015) and with being transferred to the intensive care unit (t=2.45, p=.015). Poor soft tissue status of the umbilical cord was associated with a 1-minute Apgar score of less than 8 points (<i>x</i>²=16.68, <i>p</i><.001) and with oxygen being supplied (<i>x</i>²=4.81, <i>p</i>=.028).Conclusion: Assessing the umbilical cord diameter and status in newborns is an important tool for evaluating neonatal health status after birth, and this point also underscores the importance of professionals' careful observations in the newborn nursery.

Large-for-gestational age is male-gender dependent in artificial frozen embryo transfers cycles: a cohort study of 1295 singleton live births

RESEARCH QUESTION

What is the effect of frozen embryo transfer (FET) on infant birth weight outcomes and which variables predic large-for-gestational age (LGA) infants.

DESIGN

In a large cohort study, the birth weight of 1295 singleton live births from blastocyst freeze-all-IVF treatments carried out between February 2015 and February 2017 at a single IVF centre were analysed. All embryo transfers were vitrified-warmed blastocyst transfers in artificial FET cycles, with patients having one (n = 864) or two (n = 431) blastocysts transferred. All live births were from ultrasound confirmed single fetal heart pregnancies.

RESULTS

The mean gestational age at delivery was 38.2 (±1.7) weeks, with a 1.11 : 1 female to male ratio for infants delivered. The small and large-for-gestational age rates were 5.02 and 13.28%, with 81.7% of infants appropriate for gestational age. In a multiple logistic regression analysis, the independent variables selected in the model to predict having an LGA infant were maternal parity, infant gender and maternal body mass index (BMI). The risk for LGA at term was significantly higher for male infants when adjusting for maternal parity and BMI (2.8 OR 1.805 to 4.450; P < 0.001).

CONCLUSION

The present study showed that fetal growth of artificial cycle FET pregnancies resulted in an 13.28% LGA infant rate that was mostly male gender dependent.

One size does not fit all: Examining ethnicity in gestational weight gain guidelines

Pregnancy-related metrics vary by race/ethnicity, yet most gestational weight gain (GWG) guidelines are ethnicity-blind. We estimated small-for-gestational age (SGA) risk in a Japanese population, examining GWG adequacy categorized by Institute of Medicine (IOM) and Japanese guidelines in male (N  = 192) and female (N = 191) full-term singleton infants. For predicting SGA, IOM guidelines had high sensitivity ( ≥ 0.75), but low specificity ( ≤ 0.25); Japanese guidelines had high specificity ( ≥ 0.80) but low sensitivity ( ≤ 0.50). GWG guidelines' implicit notions of Caucasian-Americans as optimal may lead to 'One Size Fits All' recommendations that can obscure important biocultural factors contributing to maternal child health outcomes.

A Key Characteristic of Sex Differences in the Developing Brain: Greater Variability in Brain Structure of Boys than Girls

In many domains, including cognition and personality, greater variability is observed in males than in females in humans. However, little is known about how variability differences between sexes are represented in the brain. The present study tested whether there is a sex difference in variance in brain structure using a cohort of 643 males and 591 females aged between 3 and 21 years. The broad age-range of the sample allowed us to test if variance differences in the brain differ across age. We observed significantly greater male than female variance for several key brain structures, including cerebral white matter and cortex, hippocampus, pallidum, putamen, and cerebellar cortex volumes. The differences were observed at both upper and lower extremities of the distributions and appeared stable across development. These findings move beyond mean levels by showing that sex differences were pronounced for variability, thereby providing a novel perspective on sex differences in the developing brain.

Metabolomic signatures of low birthweight: Pathways to insulin resistance and oxidative stress

Several studies suggest that low birthweight resulting from restricted intrauterine growth can leave a metabolic footprint which may persist into adulthood. To investigate this, we performed metabolomic profiling on 5036 female twins, aged 18-80, with weight at birth information available from the TwinsUK cohort and performed independent replication in two additional cohorts. Out of 422 compounds tested, 25 metabolites associated with birthweight in these twins, replicated in 1951 men and women from the Hertfordshire Cohort Study (HCS, aged 66) and in 2391 men and women from the North Finland Birth 1986 cohort (NFBC, aged 16). We found distinct heterogeneity between sexes and, after adjusting for multiple tests and heterogeneity, two metabolites were reproducible overall (propionylcarnitine and 3-4-hydroxyphenyllactate). Testing women only, we found other metabolites associated with lower birthweight from the meta-analysis of the three cohorts (2-hydroxy-butyric acid and γ-glutamylleucine). Higher levels of all these metabolites can be linked to insulin resistance, oxidative stress or a dysfunction of energy metabolism, suggesting that low birthweight in both twins and singletons are having an impact on these pathways in adulthood.

The impact of altitude on birth weight depends on further mother- and infant-related factors: a population-based study in an altitude range up to 1600 m in Austria between 1984 and 2013

OBJECTIVE

A negative impact of altitude on birth weight has been demonstrated for medium to high-altitude countries.

STUDY DESIGN

The present study aims to show a similar effect for a lower altitude range up to 1600 m in the country of Austria and to adjust for several further risk factors related to mother and infant. In addition, we analyzed whether the effect of altitude influenced birth weight independently or interacted with other factors. For the purpose of this study, almost 1.9 million individual birth certificates of Austrian newborns born between 1984 and 2013 were analyzed. In a multivariate linear regression model, birth weight was associated with altitude of living address and following variables: sex, birth length, gestational age, level of education, maternal age, year of birth, parity, time to previous birth and marital status.

RESULT

Birth weight decreased by 150 g/1000 m altitude, demonstrating a clear effect of altitude on birth weight also in a low to medium altitude level. Additionally, we could show that this effect also depends on other factors, namely gestational age, education of the mother, sex, birth length, year of birth and time to previous delivery. All variables interacted significantly (p<0.0001) with altitude.

CONCLUSION

We observed a negative effect of altitude in an altitude range up to 1600 m. Furthermore, this effect also depends on other risk factors. Therefore, unadjusted estimates as described in many studies may be biased. This population-based study describes the effect of low-to-medium altitude on birth weight in central Europe over a period of 30 years.

Variants Close to NTRK2 Gene Are Associated With Birth Weight in Female Twins

Low weight at birth has previously been shown to be associated with a number of adult diseases such as type 2 diabetes, cardiovascular disease, high blood pressure, and obesity later in life. Genome-wide association studies (GWAS) have been published for singleton-born individuals, but the role of genetic variation in birth weight (BW) in twins has not yet been fully investigated. A GWAS was performed in 4,593 female study participants with BW data available from the TwinsUK cohort. A genome-wide significant signal was found in chromosome 9, close to the NTRK2 gene (OMIM: 600456). QIMR, an Australian twin cohort (n = 3,003), and UK-based singleton-birth individuals from the Hertfordshire cohort (n = 2,997) were used as replication for the top two single nucleotide polymorphism (SNPs) underpinning this signal, rs12340987 and rs7849941. The top SNP, rs12340987, was found to be in the same direction in the Australian twins and in the singleton-born females (fixed effects meta-analysis beta = -0.13, SE = 0.02, and p = 1.48 × 10−8) but not in the singleton-born males tested. These findings provide an important insight into the genetic component of BW in twins who are normally excluded due to their lower BW when compared with singleton births, as well as the difference in BW between twins. The NTRK2 gene identified in this study has previously been associated with obesity.