In utero Head Circumference is Associated with Childhood Allergy

Impact of prenatal maternal psychological distress on fetal biometric parameters in household air pollution-exposed Nigerian women

Rationale

Studies identify prenatal household air pollution (HAP) exposure and maternal psychological distress (PMPD) as independent factors contributing to gestational ill-health and adverse birth outcomes.

Objective

We investigated the impact of PMPD on fetal biometric parameters (FBP) in HAP-exposed pregnant Nigerian women.

Methods

The randomized controlled trial (RCT; ClinicalTrials.gov NCT02394574) investigated effects of HAP exposure in pregnant Nigerian women (n = 324), who customarily cooked with polluting fuels (firewood or kerosene). Half of the women (intervention group) were given CleanCook ethanol stoves to use for 156 days during the study. Once a month, all women were administered an abridged version of the SF-12v2TM health-related quality of life questionnaire to assess psychological distress. Using mixed effects linear regression models, adjusted for relevant covariates, we analyzed associations between the women’s exposure to PM2·5 (particulate matter with an aerodynamic diameter<2·5 microns) from HAP, their PMPD scores, and FBP (ultrasound estimated fetal weight [UEFW], head circumference [HC], abdominal circumference [AC], femur length [FL], biparietal diameter [BPD], estimated gestational age [GA] and intrauterine growth restriction [IUGR]), and birth anthropometric measures (birth weight [BW] and birth length [BL]).

Results

PMPD negatively impacted UEFW, HC, FL, BPD and BL (p<0·05). Controls (kerosene/firewood users) experienced significantly higher PMPD compared with ethanol-stove users (p<0·05). The mediation analysis revealed that the proportion of the outcome (fetal biometrics, birth anthropometrics, IUGR and GA), which can be explained via PMPD by groups (intervention vs. control) after adjusting for confounding variables was 6·2% (0·062). No significant correlation was observed between levels of PM2.5 exposure and PMPD scores.

Conclusions

PMPD was an independent mediator of adverse fetal biometric parameters in pregnant women, who were exposed to HAP from burning of firewood/kerosene. Formulating preventative measures to alleviate maternal distress during pregnancy and reducing exposure to HAP is important from public health perspectives.

Exploring the Genetic Correlation Between Growth and Immunity Based on Summary Statistics of Genome-Wide Association Studies

The relationship between growth and immune phenotypes has been presented in the context of physiology and energy allocation theory, but has rarely been explained genetically in humans. As more summary statistics of genome-wide association studies (GWAS) become available, it is increasingly possible to explore the genetic relationship between traits at the level of genome-wide summary statistics. In this study, publicly available summary statistics of growth and immune related traits were used to evaluate the genetic correlation coefficients between immune and growth traits, as well as the cause and effect relationship between them. In addition, pleiotropic variants and KEGG pathways were identified. As a result, we found negative correlations between birthweight and immune cell count phenotypes, a positive correlation between childhood head circumference and eosinophil counts (EO), and positive or negative correlations between childhood body mass index and immune phenotypes. Statistically significant negative effects of immune cell count phenotypes on human height, and a slight but significant negative influence of human height on allergic disease were also observed. A total of 98 genomic regions were identified as containing variants potentially related to both immunity and growth. Some variants, such as rs3184504 located in SH2B3, rs13107325 in SLC39A8, and rs1260326 located in GCKR, which have been identified to be pleiotropic SNPs among other traits, were found to also be related to growth and immune traits in this study. Meanwhile, the most frequent overlapping KEGG pathways between growth and immune phenotypes were autoimmune related pathways. Pleiotropic pathways such as the adipocytokine signaling pathway and JAK-STAT signaling pathway were also identified to be significant. The results of this study indicate the complex genetic relationship between growth and immune phenotypes, and reveal the genetic background of their correlation in the context of pleiotropy.

Fetal growth and incidence of atopic dermatitis in early childhood: Results of the Ulm SPATZ Health Study

Fetal growth may be a precursory factor in observed association between birthweight and atopic dermatitis (AD), however, recent studies utilizing fetal ultrasound-based data have reported contradictory results. This study aims to clarify previous findings through comprehensive investigation of association between several trimester-specific ultrasound-based anthropometric measures with AD diagnosis by age 3 years. Measurements of 386 newborns in the Ulm SPATZ Health Study were converted into adjusted z-scores categorized as "low" (≤1 SD below mean), "normal," or "high" (≥1 SD above mean). AD cases were defined using parent- or pediatrician-report of physician-diagnosis or clinical diagnosis. Adjusted risk ratios (RR) with 95% confidence intervals (95% CI) were calculated using modified Poisson regression. Compared to normal, both low and high 2^nd trimester abdominal circumference [RR 1.51, (95% CI 1.01; 2.24) and 1.83 (1.21; 2.76)], high 2^nd trimester head- abdominal circumference ratio [1.69 (1.16; 2.48)], and faltering 2^nd to 3^rd trimester [1.59 (1.04; 2.43)] head circumference were associated with greater AD risk. High 3^rd trimester femur length [0.54 (0.31; 0.94)] was associated with lower risk. Using more inclusive exposure cut-points (0.8 SD), lower 1^st trimester crown-rump length was also associated with greater AD risk. Our data suggest several different patterns of fetal growth may be differentially associated with AD.

Microglia M2A Polarization as Potential Link between Food Allergy and Autism Spectrum Disorders

Atopic diseases are frequently co-morbid with autism spectrum disorders (ASD). Allergic responses are associated with an activation of mast cells, innate lymphoid cells, and Th2 cells. These cells produce type-2 cytokines (IL4 and IL13), which stimulate microglia and macrophages to adopt a phenotype referred to as ‘alternative activation’ or ‘M2A’. M2A-polarized macrophages and microglia play a physiological role in tissue repair by secreting growth factors such as brain-derived neurotrophic factor (BDNF) and insulin-like growth factor-1. In ASD there is evidence for increased type-2 cytokines, microglia activation, M2A polarization, and increased levels of growth factors. In neurons, these growth factors drive a signal transduction pathway that leads to activation of the enzyme mammalian Target of Rapamycin (mTOR), and thereby to the inhibition of autophagy. Activation of mTOR is an effect that is also common to several of the genetic forms of autism. In the central nervous system, redundant synapses are removed via an autophagic process. Activation of mTOR would diminish the pruning of redundant synapses, which in the context of ASD is likely to be undesired. Based on this line of reasoning, atopic diseases like food allergy, eczema or asthma would represent risk factors for autism spectrum disorders.

Association Between Secretoglobin Family 3A Member 2 (SCGB3A2) Gene Polymorphisms and Asthma in a Korean Population

Background

Secretoglobin family 3A member 2 (SCGB3A2) plays an important role in secreting lung surfactant protein, which is a downstream target of thyroid transcription factor.

Material/Methods

We investigated whether single-nucleotide polymorphisms (SNPs) of SCGB3A2 gene contribute to susceptibility to asthma. To explore this possible association, 2 promoter SNPs (rs6882292, 659 G/A and rs1368408, −112 G/A) and missense SNP (rs151333009, stop codon) were tested in SCGB3A2 gene in 101 asthma patients and 377 healthy control subjects. SNPStats was used to obtain odds ratio (OR), 95% confidence intervals (CI), and P value adjusted for age and sex as covariables. Logistic regression method in each model (dominant, recessive, and log-additive) was applied to analyze genetic data.

Results

rs151333009 SNP showed a monomorphic genotype. Two promoter SNPs (rs6882292, −659 G/A and rs1368408, −112 G/A) showed significant association with asthma (rs6882292, OR=2.66, 95% CI=1.42–5.01, p=0.0033 in dominant model, OR=2.45, 95% CI=1.33–4.54, p=0.0055 in log-additive model; rs1368408, OR=1.59, 95% CI=1.02–2.49, p=0.041 in dominant model, OR=3.02, 95% CI=1.15–7.90, p=0.03 in recessive model, OR=1.63, 95% CI=1.63, 95% CI=1.12–2.37, p=0.012 in log-additive model).

Conclusions

These results suggest that the promoter SNPs (rs6882292 and rs1368408) of SCGB3A2 gene may contribute to susceptibility to asthma in a Korean population.