Disrupted prenatal maternal cortisol, maternal obesity, and childhood wheeze. Insights into prenatal programming

Maternal stressful life events during pregnancy and childhood asthma and wheeze

BACKGROUND

Studies have linked prenatal maternal psychosocial stress to childhood wheeze/asthma but have rarely investigated factors that may mitigate risks.

OBJECTIVE

To investigate associations between prenatal stress and childhood wheeze/asthma, evaluating factors that may modify stress effects.

METHODS

Participants included 2056 mother-child dyads from Environmental influences on Child Health Outcomes (ECHO)-PATHWAYS, a consortium of 3 prospective pregnancy cohorts (the Conditions Affecting Neurocognitive Development and Learning in Early Childhood study, The Infant Development and Environment Study, and a subset of the Global Alliance to Prevent Prematurity and Stillbirth study) from 6 cities. Maternal stressful life events experienced during pregnancy (PSLEs) were reported using the Pregnancy Risk Assessment Monitoring System Stressful Life Events questionnaire. Parents reported child wheeze/asthma outcomes at age 4 to 6 years using standardized questionnaires. We defined outcomes as ever asthma, current wheeze, current asthma, and strict asthma. We used modified Poisson regression with robust standard errors (SEs) to estimate risk ratios (RRs) and 95% CI per 1-unit increase in PSLE, adjusting for confounders. We evaluated effect modification by child sex, maternal history of asthma, maternal childhood traumatic life events, neighborhood-level resources, and breastfeeding.

RESULTS

Overall, we observed significantly elevated risk for current wheeze with increasing PSLE (RR, 1.09 [95% CI, 1.03-1.14]), but not for other outcomes. We observed significant effect modification by child sex for strict asthma (P interaction = .03), in which risks were elevated in boys (RR, 1.10 [95% CI, 1.02-1.19]) but not in girls. For all other outcomes, risks were significantly elevated in boys and not in girls, although there was no statistically significant evidence of effect modification. We observed no evidence of effect modification by other factors (P interactions > .05).

CONCLUSION

Risk of adverse childhood respiratory outcomes is higher with increasing maternal PSLEs, particularly in boys.

Obesity in pregnancy-Long-term effects on offspring hypothalamic-pituitary-adrenal axis and associations with placental cortisol metabolism: A systematic review

Obesity, affecting one in three pregnant women worldwide, is not only a major obstetric risk factor. The resulting low-grade inflammation may have a long-term impact on the offspring's HPA axis through dysregulation of maternal, placental and fetal corticosteroid metabolism, and children born of obese mothers have increased risk of diabetes and cardiovascular disease. The long-term effects of maternal obesity on offspring neurodevelopment are, however, undetermined and could depend on the specific effects on placental and fetal cortisol metabolism. This systematic review evaluates how maternal obesity affects placental cortisol metabolism and the offspring's HPA axis. Pubmed, Embase and Scopus were searched for original studies on maternal BMI, obesity, and cortisol metabolism and transfer. Fifteen studies were included after the screening of 4556 identified records. Studies were small with heterogeneous exposures and outcomes. Two studies found that maternal obesity reduced placental HSD11β2 activity. In one study, umbilical cord blood cortisol levels were affected by maternal BMI. In three studies, an altered cortisol response was consistently seen among offspring in childhood (n = 2) or adulthood (n = 1). Maternal BMI was not associated with placental HSD11β1 or HSD11β2 mRNA expression, or placental HSD11β2 methylation. In conclusion, high maternal BMI is associated with reduced placental HSD11β2 activity and a dampened cortisol level among offspring, but the data is sparse. Further investigations are needed to clarify whether the HPA axis is affected by prenatal factors including maternal obesity and investigate if adverse effects can be ameliorated by optimising the intrauterine environment.

Association between psychological factors and molar-incisor hypomineralization: A cross-sectional study

BACKGROUND

Molar-incisor hypomineralization (MIH) is a developmental enamel defect characterized by opacities from white to brownish color. A suspected multifactorial etiology has been suggested, whereas psychological factors during pregnancy have only been limitedly analyzed.

AIM

We assessed the association between stress, depression, and anxiety in pregnancy and the presence of MIH in children at a later age.

DESIGN

Using a cross-sectional Web-based questionnaire, we included 384 mothers who had children aged 6 and 12 years from Pasto, Colombia. Data were collected between October 2021 and March 2022. Sociodemographic variables; maternal and child factors related to prenatal, natal, or postnatal problems; and psychological factors such as stress and symptoms of anxiety and depression in pregnancy were inquired. Utilizing photographs depicting MIH lesions, mothers assessed their child's MIH status. A directed acyclic graph (DAG) analysis was performed to create causal assumptions, and logistic regression models were estimated to evaluate these assumptions. p-value was set at p < .05.

RESULTS

The prevalence of MIH was 33.3%; 12.8% of the participants exhibited hypomineralization in both molars and incisors. DAG analysis and logistic regression models determined that MIH (present or not) was associated with symptoms of maternal depression (ORadj  = 3.26, 95% CI: 1.92-5.52, p < .001), and MIH (both molars and incisors) was associated with symptoms of maternal anxiety (ORadj  = 3.49, 95% CI: 1.80-6.76, p < .001).

CONCLUSION

Psychological factors, among others, were significantly associated with the presence of MIH.

Associations between early-life exposure to PM2.5 and reductions in childhood lung function in two North American longitudinal pregnancy cohort studies

Data integration of epidemiologic studies across different geographic regions can provide enhanced exposure contrast and statistical power to examine adverse respiratory effects of early-life exposure to particulate matter <2.5 microns in diameter (PM2.5). Methodological tools improve our ability to combine data while more fully accounting for study heterogeneity.

Methods

Analyses included children enrolled in two longitudinal birth cohorts in Boston, Massachusetts, and Mexico City. Propensity score matching using the 1:3 nearest neighbor with caliper method was used. Residential PM2.5 exposure was estimated from 2 months before birth to age 6 years using a validated satellite-based spatiotemporal model. Lung function was tested at ages 6-11 years and age, height, race, and sex adjusted z scores were estimated for FEV1, FVC, FEF25-75%, and FEV1/FVC. Using distributed lag nonlinear models, we examined associations between monthly averaged PM2.5 levels and lung function outcomes adjusted for covariates, in unmatched and matched pooled samples.

Results

In the matched pooled sample, PM2.5 exposure between postnatal months 35-44 and 35-52 was associated with lower FEV1 and FVC z scores, respectively. A 5 µg/m3 increase in PM2.5 was associated with a reduction in FEV1 z score of 0.13 (95% CI = -0.26, -0.01) and a reduction in FVC z score of 0.13 (95% CI = -0.25, -0.01). Additionally PM2.5 during postnatal months 23-39 was associated with a reduction in FEF25-75% z score of 0.31 (95% CI = -0.57, -0.05).

Conclusions

Methodological tools enhanced our ability to combine multisite data while accounting for study heterogeneity. Ambient PM2.5 exposure in early childhood was associated with lung function reductions in middle childhood.

Life Course of Asthma

Asthma is a heterogeneous chronic airway disease that can vary over a lifetime. Although broad categories of asthma by severity and type have been constructed, there remains a tremendous opportunity to discover an approach to managing asthma with additional factors in mind. Many in the field have suggested and are pursuing a novel paradigm shift in how asthma might be better managed, considering the life course of exposures, management priorities, and predicted trajectory of lung function growth. This approach will require a more holistic view of prenatal, postnatal, adolescence, hormonal and gender aspects, and the aging process. In addition, the environment, externally and internally, including in one's genetic code and epigenetic changes, are factors that affect how asthma progresses or becomes more stable in individuals. This chapter focuses on the various influences that may, to differing degrees, affect people with asthma, which can develop at any time in their lives. Shifting the paradigm of thought and strategies for care and advocating for public policies and health delivery that focus on this philosophy is paramount to advance asthma care for all.

Prenatal lead exposure and childhood lung function: Influence of maternal cortisol and child sex

INTRODUCTION

Maternal hypothalamic-pituitary-adrenal (HPA) axis disruption in pregnancy may contribute to the programming of childhood respiratory disease and may modify the effect of chemical toxins, like lead (Pb), on lung development. Child sex may further modify these effects. We sought to prospectively examine associations between maternal HPA axis disruption, prenatal Pb and childhood lung function and explore potential effect modification by maternal cortisol and child sex on the association between prenatal Pb and lung function outcomes.

MATERIALS AND METHODS

Analyses included 222 mothers and children enrolled in a longitudinal birth cohort study in Mexico City. Maternal diurnal salivary cortisol was assessed in pregnancy; cortisol awakening response (CAR) and diurnal slope were calculated. Blood Pb was measured during the second trimester of pregnancy. Post-bronchodilator lung function was tested at ages 8-11 years. Associations were modeled using generalized linear models with interaction terms, adjusting for covariates.

RESULTS

A higher (flatter) diurnal slope was associated with lower FEV₁/FVC ratio (β: 0.433, 95%CI [-0.766, -0.101]). We did not find any main effect associations between prenatal Pb and lung function outcomes. We report an interaction between Pb and cortisol in relation to FEV₁/FVC and FEF_25-75% (p_interaction<0.05 for all). Higher prenatal Pb was associated with reduced FEV₁/FVC only in children whose mothers had a high CAR. Higher prenatal Pb was also associated with reduced FEV₁/FVC and FEF_25-75% in mothers with a flatter diurnal slope. A 3-way interaction between prenatal Pb, CAR and sex on FEV₁/FVC, indicated that boys born to women with high CAR and higher prenatal Pb levels had lower FEV₁/FVC ratios (p_interaction = 0.067).

CONCLUSIONS

Associations between prenatal Pb and childhood lung function were modified by disrupted maternal cortisol in pregnancy and child sex. These findings underscore the need to consider complex interactions to fully elucidate effects of prenatal Pb exposure on childhood lung function.

Third trimester cortisol is positively associated with gestational weight gain in pregnant women with class one obesity

BACKGROUND/OBJECTIVE

Prevalence of pre-pregnancy obesity and excessive gestational weight gain (GWG) are higher among women of color with low SES. Dysregulation of the Hypothalamic-Pituitary-Adrenal (HPA) axis and its end-product, cortisol, during pregnancy is hypothesized to be associated with excessive GWG. However, past studies have produced inconsistent findings and often did not include health disparities populations. This study examined the association between pre-pregnancy body mass index (BMI), third trimester diurnal cortisol, and GWG in low-income, predominantly Hispanic women.

SUBJECTS/METHODS

The MADRES study is an ongoing prospective cohort study of primarily Hispanic, low-income pregnant women and their children in Los Angeles, California. Data from 176 participants were included in this study. Total cortisol secretion (area under the curve, AUC) was quantified using four salivary cortisol samples (awakening, 30 min after awakening, afternoon, and bedtime) that were collected at home on one day during the third trimester of pregnancy. Moderation of the association between total cortisol and GWG by pre-pregnancy BMI was tested using multiple linear regression with a multiplicative interaction term.

RESULTS

There was no association between total cortisol secretion and GWG overall (p = 0.82), but the association between total cortisol and GWG was stronger for women with class 1 pre-pregnancy obesity compared to women with normal pre-pregnancy BMI (interaction term p = 0.04).

CONCLUSIONS

Results suggest that obesity status before pregnancy may be exacerbating the physiological impact of cortisol on GWG.

Perinatal origins of chronic lung disease: mechanisms-prevention-therapy-sphingolipid metabolism and the genetic and perinatal origins of childhood asthma

Childhood asthma derives from complex host-environment interactions occurring in the perinatal and infant period, a critical time for lung development. Sphingolipids are bioactive molecules consistently implicated in the pathogenesis of childhood asthma. Genome wide association studies (GWAS) initially identified a link between alleles within the 17q21 asthma-susceptibility locus, childhood asthma, and overexpression of the ORMDL sphingolipid biosynthesis regulator 3 (ORMDL3), an inhibitor of de novo sphingolipid synthesis. Subsequent studies of pediatric asthma offer strong evidence that these asthma-risk alleles correlate with early-life aberrancies of sphingolipid homeostasis and asthma. Relationships between sphingolipid metabolism and asthma-related risk factors, including maternal obesity and respiratory viral infections, are currently under investigation. This review will summarize how these perinatal and early life exposures can synergize with 17q21 asthma risk alleles to exacerbate disruptions of sphingolipid homeostasis and drive asthma pathogenesis.

Intergenerational Impacts of Maternal Stress on Early Childhood Atopy in Black Americans

OBJECTIVE

Black children are disproportionately affected by atopic diseases (i.e., atopic dermatitis, allergic rhinitis, asthma, and food allergies), with health disparities present in early life. Studies in White samples suggest that maternal stress confers risk for offspring atopy, yet little is known about these relationships in Black populations. This study seeks to (a) examine the relationship between self-reported and physiological indicators of maternal stress and offspring atopy and (b) explore warm and responsive caregiving as a potential protective factor in Black Americans.

METHODS

A sample of 179 Black mother-child dyads of varying socioeconomic status participated in a prospective longitudinal study. Mothers completed self-reports of childhood trauma, prenatal stress, postnatal stress, and physician diagnosis of offspring atopy; provided blood samples to assess physiological responses to chronic stress exposure; and participated in a behavioral task with their infant.

RESULTS

Maternal self-reports of childhood trauma, prenatal stress, and postnatal stress were not associated with offspring diagnosis of atopy by 2-3 years of age. Mothers who produced a smaller inflammatory response during pregnancy were more likely to have an offspring with atopy by 2-3 years of age. Warm and responsive parenting demonstrated a protective effect; the positive association between maternal stress and offspring atopy was less apparent in cases of mother-child interactions characterized by high levels warm and responsive parenting.

CONCLUSION

Failure to replicate previous findings suggests that the maternal stress-offspring atopy relationship is complex. Future studies must examine the unique stressors in Black Americans, as well as caregiving as a potential protective factor.

Maternal psychiatric status and infant wheezing: The role of maternal hormones and cord blood cytokines

RATIONALE

Maternal psychosocial stress might be associated with development of allergic diseases in the offspring.

OBJECTIVES

To evaluate the association of maternal depression and anxiety with ever wheezing and recurrent wheezing among infants and to assess the role of maternal hypothalamo-pituatary-adrenal axis changes and fetal immune response in this association.

METHODS

This study encompasses two designs; cohort design was developed to evaluate the association of prenatal depression with development of wheezing in infants while nested case-control design was used to assess the role of maternal cortisol and tetranectin and cord blood interleukin 13 and interferon γ.

RESULTS

We enrolled 697 pregnant women. Elementary school graduate mother (odds ratio [OR] = 1.5, p = .06), maternal smoking during pregnancy (OR = 3.4, p = .001), familial history of asthma (OR = 2.7, p < .001) increased the risk of ever wheezing. Elementary school graduate mother (OR = 2.6, p = .002), maternal smoking during pregnancy (OR = 4.8, p < .001) and familial history of asthma (OR = 1.7, p = .01) increased the risk of recurrent wheezing. Maternal previous psychiatric disease, or Edinburgh Postnatal Depression Scale or Spielberger State-Trait Anxiety Inventory scores were not associated with wheezing. Maternal tetranectin levels were significantly higher among never wheezers compared to the ever wheezers (264.3 ± 274.8 vs. 201.6 ± 299.7, p = .04).

CONCLUSIONS

In conclusion, the major risk factors for ever wheezing and recurrent wheezing were maternal smoking, level of education and family history of asthma. However, maternal depression and anxiety were not determined as risk factors for wheezing. Maternal tetranectin carries potential as a biomarker for wheezing in the infant.

Maternal Prenatal Hair Cortisol Is Associated with Child Wheeze among Mothers and Infants with Tobacco Smoke Exposure and Who Face High Socioeconomic Adversity

The association of co-occurring prenatal stress and tobacco exposures on childhood wheezing and asthma are not well established. In this study, we compared maternal prenatal hair cortisol concentration (HCC) to the maternal report of infant wheezing (y/n) in the first year of life among mother-infant dyads exposed to tobacco smoke and socioeconomic adversity. Data were obtained from the Vitamin C to Decrease Effects of Smoking in Pregnancy on Infant Lung Function study. Maternal adversity was defined by the level of education, household income, and health insurance provider. Hair was collected at delivery, representing average circulating third-trimester cortisol levels. HCC was log transformed and dichotomized into high/low cortisol groups that were placed into a multivariate model predicting wheeze. Subjects (n = 132) were primarily White with ≤high school education and receiving government-provided health insurance. Forty-five percent of infants wheezed. Average HCC was 3.39 pg/mg hair. Women with HCC > 3.55 pg/mg were more than twice as likely to report having a child who wheezed (odds ratio 2.56, 95% confidence interval 1.22-5.40; p = 0.01), adjusting for insurance provider and maternal asthma. Among this sample of dyads with prenatal smoke exposure, elevated maternal HCC was associated with child wheeze that was not diminished after consideration of covariates.

Integrated and diurnal indices of maternal pregnancy cortisol in relation to sex-specific parasympathetic responsivity to stress in infants

Maternal hypothalamic-pituitary-adrenal axis activity may prenatally program sex-specific stress-response pathways. We investigated associations between maternal cortisol during pregnancy and infant parasympathetic responsivity to stress among 204 mother-infant pairs. Cortisol indices included 3rd trimester hair cortisol, as well as diurnal slope and area under the curve, derived from saliva samples collected during pregnancy. Mother-infant dyads participated in the Repeated Still-Face Paradigm (SFP-R) at age 6 months. We calculated respiration-adjusted respiratory sinus arrhythmia (RSA_c ), an indicator of parasympathetic activation, from infant respiration and cardiac activity measured during the SFP-R. We used multivariable linear mixed models to examine each cortisol index in relation to infant RSA_c and investigated sex differences using cross-product terms. Diurnal cortisol indices were not associated with RSA_c . There was no association between hair cortisol and baseline RSA_c . However, hair cortisol was associated with sex-specific changes in RSA_c over the SFP-R such that, among girls, parasympathetic withdrawal was reduced with increasing prenatal exposure to cortisol. Consistently higher levels of prenatal cortisol exposure may lead to dampened parasympathetic responsivity to stress during infancy, particularly among girls. Maternal hair cortisol may be particularly valuable for studying the effects of prenatal cortisol exposure on infant autonomic reactivity.

Asthma epidemiology and risk factors

Asthma is a clinical syndrome that affects all age groups. Asthma prevalence worldwide has seen a rapid increase in the latter part of the last century. Recent data has shown that asthma prevalence has plateaued and even decreased in some areas of the world, despite continuing to increase in other areas of the world. Many risk factors have been associated with asthma and the differences in distributions of these risk factors may explain the differences in prevalence. This article will review recent trends in the prevalence of asthma and recent studies that investigate risk factors of asthma.

Pre-pregnancy Maternal Weight and Gestational Weight Gain Increase the Risk for Childhood Asthma and Wheeze: An Updated Meta-Analysis

Background: Mounting evidence suggests that childhood asthma is closely associated with maternal weight before pregnancy and gestational weight gain (GWG), yet the results are not often reproducible. Objectives: We conducted a comprehensive meta-analysis, aiming to evaluate the association of pre-pregnancy maternal obesity or overweight and high GWG with the risk for childhood asthma and wheeze. Methods: Literature search, quality assessment, and data extraction were completed independently and in duplicate. Effect-size estimates are expressed as odds ratio (OR) with 95% confidence interval (CI). Results: Twenty-two observational studies involving 145,574 mother-child pairs were meta-analyzed. In overall analyses, maternal obesity or overweight in pre-pregnancy significantly increased the risk of both childhood asthma and wheeze (adjusted OR: 1.41 and 1.13, 95% CI: 1.26-1.59 and 1.07-1.20, both p < 0.001). Per 1 kg/m² increment in maternal body mass index was associated with a significantly increased risk of childhood asthma and wheeze (adjusted OR: 1.03, 95% CI: 1.02-1.03, p < 0.001). Compared with normal GWG, very high GWG (adjusted OR: 1.24, 95% CI: 1.04-1.47, p: 0.018), moderate high GWG (adjusted OR: 1.12, 95% CI: 1.04-1.21, p: 0.004), and very low GWG (adjusted OR: 1.26, 95% CI: 1.08-1.47, p: 0.004) increased the risk of childhood asthma and wheeze. There was a low probability of publication bias. Conclusions: Our findings indicate that both pre-pregnancy maternal obesity or overweight and very to moderate high or low GWG render their offspring susceptible to a significantly increased risk of having childhood asthma and wheeze.

Steroid Hormones in Cord Blood Mediate the Association Between Maternal Prepregnancy BMI and Birth Weight

OBJECTIVE

Maternal overweight has been associated with increasing offspring birth weight, but epidemiological data on potential biological mechanisms are limited. This study aimed to examine whether steroid hormones mediate the association between maternal prepregnancy BMI (pre-BMI) and birth weight.

METHODS

This study involving 2,039 participants was conducted from an ongoing cohort study in Wuhan, China. Mediation analysis was used to identify the extent to which steroid hormones mediated associations.

RESULTS

Each one-unit increase in pre-BMI was significantly associated with lower log₂ -transformed cord blood levels of cortisol and corticosterone. Levels of cortisol and corticosterone were also negatively associated with birth weight. It was estimated that corticosterone mediated 3.48% of the association between pre-BMI and birth weight, and no significant mediation effect was observed in cortisol. After stratification by maternal gestational weight gain (GWG; within or in excess of the Institute of Medicine [IOM] guidelines), the associations of pre-BMI with cortisol and corticosterone levels were significant in the women with GWG > IOM but not in women with GWG ≤ IOM. When the mediation analysis in the women with GWG > IOM was limited, the mediation effects of cord blood cortisol and corticosterone were both significant (P < 0.05).

CONCLUSIONS

Cord blood cortisol and corticosterone partially mediate the association of increased maternal pre-BMI with higher birth weight.

Maternal childhood and lifetime traumatic life events and infant bronchiolitis

BACKGROUND

Viral bronchiolitis is a common respiratory infection that often affects term, otherwise healthy infants. A small literature suggests maternal stress during pregnancy is associated with bronchiolitis. However, the association between maternal exposure to lifetime traumatic stress, including traumatic events occurring in childhood or throughout the life course, and bronchiolitis has not been studied previously.

OBJECTIVES

To investigate the association between maternal exposure to total lifetime and childhood traumatic stress events and infant bronchiolitis.

METHODS

We studied mother-infant dyads enrolled in a prospective prenatal cohort, recruited 2006-2011, and Tennessee Medicaid. During pregnancy, we assessed maternal lifetime exposure to types of traumatic events by questionnaire. We captured bronchiolitis diagnoses in term, non-low birthweight infants' first 12 months using linked Medicaid data. In separate models, we assessed the association of maternal lifetime traumatic events (0 to 20 types) and a subset of traumatic events that occurred during childhood (0 to 3: family violence, sexual, and physical abuse) and infant bronchiolitis using multivariable log-binomial models.

RESULTS

Of 629 women, 85% were African American. The median count (interquartile range) of lifetime traumatic events was 3 (2, 5); 42% reported ≥1 childhood traumatic event. Among infants, 22% had a bronchiolitis diagnosis (0 to 2 lifetime traumatic events: 24%; 3 events: 20%; 4 to 5 events: 18%; 6 or more events: 24%). Total maternal lifetime traumatic events were not associated with bronchiolitis in multivariable analyses. For maternal childhood traumatic events, the risk of infant bronchiolitis increased with number of event types reported: adjusted Risk ratios were 1.12 (95% confidence interval [CI] 0.80, 1.59), 1.31 (95% CI 0.83, 2.07), and 2.65 (95% CI 1.45, 4.85) for 1, 2, and 3 events, respectively, vs none.

CONCLUSIONS

Infants born to women reporting multiple types of childhood trauma were at higher risk for bronchiolitis. Further research is needed to explore intergenerational effects of traumatic experiences.

Prenatal cortisol modifies the association between maternal trauma history and child cognitive development in a sex-specific manner in an urban pregnancy cohort

Women's experience of trauma may cause lifelong alterations in physiological stress regulation, which can be transmitted to offspring in utero. We investigated, in a prospective pregnancy cohort, associations among maternal lifetime interpersonal trauma (IPT) history, prenatal cortisol dysregulation, and children's memory domains. Sex-specific effects were also explored. Pregnant women were enrolled from Brigham & Women's Hospital and affiliated clinics near Boston, MA, in 2002-2007. IPT was assessed with the Revised Conflict Tactics Scale, short form. Salivary cortisol was measured at five time points on each of three days in one week at 29.0 ± 5.1 weeks gestation, and morning rise and diurnal slope were calculated. The Wide Range Assessment of Memory & Learning, 2nd Edition was administered at 6.5 ± 1.0 years and scores were generated for general memory and three sub-domains: verbal, visual, and attention/concentration. In total, 258 maternal-child dyads provided memory and IPT and/or cortisol data. IPT was positively associated with verbal memory in boys (β ± SE: 4.6 ± 2.6) and inversely associated with visual memory score in girls (-6.5 ± 3.2). IPT did not predict prenatal cortisol, but prenatal cortisol modified the association between IPT history and child memory in varying coefficient models allowing for non-linear effect modification. The strongest evidence of interaction was for visual memory in boys: IPT history was associated with poorer visual memory only in those with flatter prenatal diurnal slope (interaction p = .005). Maternal lifetime IPT that leads to prenatal HPA dysregulation may have consequences for child memory, more so than either trauma or elevated cortisol alone. Boys may be more vulnerable to effects. Sex- and timing-specific effects require further investigation.

Prospective Relations Between Prenatal Maternal Cortisol and Child Health Outcomes

OBJECTIVE

The aim of the study was to investigate prospective, longitudinal associations between maternal prenatal cortisol response to an interpersonal stressor and child health for the subsequent 3 years.

METHODS

One hundred twenty-three women expecting their first child provided salivary cortisol samples between 12 and 32 weeks of gestation (M (SD) = 22.4 (4.9) weeks) before and after a videotaped couple conflict discussion with their partner. Mothers reported on overall child health and several indicators of child illness (sick doctor visits, fevers, ear, and respiratory infections) when children were 6 months (n = 114), 1 (n = 116), and 3 (n = 105) years old. Associations between maternal prenatal cortisol reactivity and recovery and later child health at each of the three time points were analyzed using longitudinal regression models.

RESULTS

Greater cortisol reactivity in response to the couple conflict discussion was associated with maternal self-report of better overall child health (p = .016, 95% CI = 0.06-1.30, Cohen's f = 0.045) across the study period. Greater cortisol reactivity was also associated with lower incidence rate ratios for maternal reports of sick doctor visits (incidence rate ratio 95% CI = 0.25-0.83, p = .006), fevers (95% CI = 0.25-0.73, p = .002), ear infections (95% CI = 0.25-0.58, p < .001), and respiratory infections (95% CI = 0.08-1.11, p = .073). Cortisol recovery was unrelated to study outcomes (all p's > 0.05). Maternal prenatal depressive symptoms moderated the association between cortisol reactivity and overall child health (p = .034, 95% CI = 0.07-1.87 for interaction term) but no other health outcomes (p's > 0.05). Among women with lower depressive symptoms, cortisol reactivity was not associated with overall child health; among women with higher levels of depressive symptoms, greater cortisol reactivity was associated with better overall child health.

CONCLUSIONS

This study provides longitudinal evidence that greater maternal cortisol reactivity to a salient interpersonal stressor during pregnancy is associated with fewer child health problems and better maternal report of overall child health during infancy and into early childhood.

TRIAL REGISTRATION

Clinicaltrials.gov ID NCT01901536.

Maternal Lifetime Trauma and Birthweight: Effect Modification by In Utero Cortisol and Child Sex

OBJECTIVES

To evaluate associations between maternal lifetime traumatic stress and offspring birthweight and examine modifying effects of third trimester cortisol and fetal sex.

STUDY DESIGN

Analyses included 314 mother-infant dyads from an ethnically mixed pregnancy cohort. Maternal lifetime trauma was reported via the Life Stressor Checklist-Revised. Fenton birthweight for gestational age z-scores (BWGA-z) were calculated. A 3-cm scalp-nearest maternal hair segment collected at birth was assayed to reflect cumulative third trimester cortisol secretion. Multivariable regression was used to investigate associations between maternal lifetime trauma and BWGA-z and examine 2- and 3-way interactions with cortisol and fetal sex. Because subjects with low or high cortisol levels could represent susceptible populations, varying coefficient models that relax the linearity assumption on cortisol level were used to assess the modification of maternal lifetime trauma associations with BWGA-z as a function of cortisol.

RESULTS

Women were primarily minorities (41% Hispanic, 26% black) with ≤12 years education (63%); 63% reported ≥1 traumatic event. Prenatal cortisol modified the association between maternal lifetime trauma and birthweight. Women with higher lifetime trauma and increased cortisol had significantly lower birthweight infants in males; among males exposed to the 90th percentile of cortisol, a 1-unit increase in trauma score was associated with a 0.19-unit decrease in BWGA-z (95% CI, -0.34 to -0.04). Associations among females were nonsignificant, regardless of cortisol level.

CONCLUSIONS

These findings underscore the need to consider complex interactions among maternal trauma, disrupted in utero cortisol production, and fetal sex to fully elucidate intergenerational effects of maternal lifetime trauma.

Sex differences in effects of maternal risk and protective factors in childhood and pregnancy on newborn telomere length

Little research has examined determinants of newborn telomere length, a potential biomarker of lifetime disease risk impacted by prenatal exposures. No study has examined whether maternal exposures in childhood influence newborn telomere length or whether there are sex differences in the maternal factors that influence newborn telomere length. We tested whether a range of maternal risk and protective factors in childhood and pregnancy were associated with newborn telomere length among 151 sociodemographically diverse mother-infant dyads. We further examined whether the pattern of associations differed by infant sex. Newborn telomere length was assessed from cord blood collected at birth. Risk/protective factors included maternal health (smoking, body mass index), socioeconomic status (education, income), stress exposures, and mental health (depressive and posttraumatic stress disorder symptoms) in pregnancy as well as maternal experiences of abuse (physical, emotional, sexual) and familial emotional support in childhood. When examined within the whole sample, only maternal smoking in pregnancy and familial emotional support in childhood emerged as significant predictors of newborn telomere length. Male and female newborns differed in their pattern of associations between the predictors and telomere length. Among males, maternal smoking, higher body mass index, and elevated depressive symptoms in pregnancy and maternal sexual abuse in childhood were associated with shorter newborn telomere length; higher maternal educational attainment and household income in pregnancy and greater maternal familial emotional support in childhood were associated with longer newborn telomere length. Together, these factors accounted for 34% of the variance in male newborn telomere length. None of the risk/protective factors were associated with female newborn telomere length. The results suggest that male fetuses are particularly susceptible to maternal exposure effects on newborn telomere length. These findings have implications for elucidating mechanisms contributing to sex disparities in health.

Prenatal fine particulate exposure and early childhood asthma: Effect of maternal stress and fetal sex

BACKGROUND

The impact of prenatal ambient air pollution on child asthma may be modified by maternal stress, child sex, and exposure dose and timing.

OBJECTIVE

We prospectively examined associations between coexposure to prenatal particulate matter with an aerodynamic diameter of less than 2.5 microns (PM2.5) and maternal stress and childhood asthma (n = 736).

METHODS

Daily PM2.5 exposure during pregnancy was estimated using a validated satellite-based spatiotemporally resolved prediction model. Prenatal maternal negative life events (NLEs) were dichotomized around the median (high: NLE ≥ 3; low: NLE < 3). We used Bayesian distributed lag interaction models to identify sensitive windows for prenatal PM2.5 exposure on children's asthma by age 6 years, and determine effect modification by maternal stress and child sex.

RESULTS

Bayesian distributed lag interaction models identified a critical window of exposure (19-23 weeks' gestation, cumulative odds ratio, 1.15; 95% CI, 1.03-1.26; per interquartile range [1.7 μg/m3] increase in prenatal PM2.5 level) during which children concomitantly exposed to prenatal PM2.5 and maternal stress had increased risk of asthma. No significant association was seen in children born to women reporting low prenatal stress. When examining modifying effects of prenatal stress and fetal sex, we found that boys born to mothers with higher prenatal stress were most vulnerable (19-21 weeks' gestation; cumulative odds ratio, 1.28; 95% CI, 1.15-1.41; per interquartile range increase in PM2.5).

CONCLUSIONS

Prenatal PM2.5 exposure during sensitive windows is associated with increased risk of child asthma, especially in boys concurrently exposed to elevated maternal stress.

Evidence establishing a link between prenatal and early-life stress and asthma development

PURPOSE OF REVIEW

The objective of this review is to provide an update on our evolving understanding of the effects of stress in pregnancy and during early development on the onset of asthma-related phenotypes across childhood, adolescence, and into early adulthood.

RECENT FINDINGS

Accumulating evidence over the past 2 decades has established that prenatal and early-life psychological stress and stress correlates (e.g., maternal anxiety or depression) increase the risk for childhood respiratory disorders. Recent systematic reviews and meta-analyses including numerous prospective epidemiological and case-control studies substantiate a significant effect of prenatal stress and stress in early childhood on the development of wheeze, asthma, and other atopic-related disorders (eczema and allergic rhinitis), with many studies showing an exposure-response relationship. Offspring of both sexes are susceptible to perinatal stress, but effects differ. The impact of stress on child wheeze/asthma can also be modified by exposure timing. Moreover, coexposure to prenatal stress can enhance the effect of chemical stressors, such as prenatal traffic-related air pollution, on childhood respiratory disease risk. Understanding complex interactions among exposure dose, timing, child sex, and concurrent environmental exposures promises to more fully characterize stress effects and identify susceptible subgroups. Although the link between perinatal stress and childhood asthma-related phenotypes is now well established, pathways by which stress predisposes children to chronic respiratory disorders are not as well delineated. Mechanisms central to the pathophysiology of wheeze/asthma and lung growth and development overlap and involve a cascade of events that include disrupted immune, neuroendocrine, and autonomic function as well as oxidative stress. Altered homeostatic functioning of these integrated systems during development can enhance vulnerability to asthma and altered lung development.

SUMMARY

Mechanistic studies that more comprehensively assess biomarkers reflecting alterations across interrelated stress response systems and associated regulatory processes, in both pregnant women and young children, could be highly informative. Leveraging high-throughput systems-wide technologies to include epigenomics (e.g., DNA methylation, microRNAs), transcriptomics, and microbiomics as well as integrated multiomics are needed to advance this field of science. Understanding stress-induced physiological changes occurring during vulnerable life periods that contribute to chronic respiratory disease risk could lead to the development of preventive strategies and novel therapeutic interventions.

The child health exposure analysis resource as a vehicle to measure environment in the environmental influences on child health outcomes program

PURPOSE OF REVIEW

Demonstrate the role of environment as a predictor of child health.

RECENT FINDINGS

The children's health exposure analysis resource (CHEAR) assists the Environmental influences on child health outcomes (ECHO) program in understanding the time sensitive and dynamic nature of perinatal and childhood environment on developmental trajectories by providing a central infrastructure for the analysis of biological samples from the ECHO cohort awards. CHEAR will assist ECHO cohorts in defining the critical or sensitive period for effects associated with environmental exposures. Effective incorporation of these principles into multiple existing cohorts requires extensive multidisciplinary expertise, creativity, and flexibility. The pursuit of life course - informed research within the CHEAR/ECHO structure represents a shift in focus from single exposure inquiries to one that addresses multiple environmental risk factors linked through shared vulnerabilities. CHEAR provides ECHO both targeted analyses of inorganic and organic toxicants, nutrients, and social-stress markers and untargeted analyses to assess the exposome and discovery of exposure-outcome relationships.

SUMMARY

Utilization of CHEAR as a single site for characterization of environmental exposures within the ECHO cohorts will not only support the investigation of the influence of environment on children's health but also support the harmonization of data across the disparate cohorts that comprise ECHO.

Prenatal Nitrate Exposure and Childhood Asthma. Influence of Maternal Prenatal Stress and Fetal Sex

RATIONALE

Impact of ambient pollution upon children's asthma may differ by sex, and exposure dose and timing. Psychosocial stress can also modify pollutant effects. These associations have not been examined for in utero ambient nitrate exposure.

OBJECTIVES

We implemented Bayesian-distributed lag interaction models to identify sensitive prenatal windows for the influence of nitrate (NO3-) on child asthma, accounting for effect modification by sex and stress.

METHODS

Analyses included 752 mother-child dyads. Daily ambient NO3- exposure during pregnancy was derived using a hybrid chemical transport (Geos-Chem)/land-use regression model and natural log transformed. Prenatal maternal stress was indexed by a negative life events score (high [>2] vs. low [≤2]). The outcome was clinician-diagnosed asthma by age 6 years.

MEASUREMENTS AND MAIN RESULTS

Most mothers were Hispanic (54%) or black (29%), had a high school education or less (66%), never smoked (80%), and reported low prenatal stress (58%); 15% of children developed asthma. BDILMs adjusted for maternal age, race, education, prepregnancy obesity, atopy, and smoking status identified two sensitive windows (7-19 and 33-40 wk gestation), during which increased NO3- was associated with greater odds of asthma, specifically among boys born to mothers reporting high prenatal stress. Cumulative effects of NO3- across pregnancy were also significant in this subgroup (odds ratio = 2.64, 95% confidence interval = 1.27-5.39; per interquartile range increase in ln NO3-).

CONCLUSIONS

Prenatal NO3- exposure during distinct sensitive windows was associated with incident asthma in boys concurrently exposed to high prenatal stress.

Prenatal particulate air pollution exposure and body composition in urban preschool children: Examining sensitive windows and sex-specific associations

BACKGROUND

Evolving animal studies and limited epidemiological data show that prenatal air pollution exposure is associated with childhood obesity. Timing of exposure and child sex may play an important role in these associations. We applied an innovative method to examine sex-specific sensitive prenatal windows of exposure to PM_2.5 on anthropometric measures in preschool-aged children.

METHODS

Analyses included 239 children born ≥ 37 weeks gestation in an ethnically-mixed lower-income urban birth cohort. Prenatal daily PM_2.5 exposure was estimated using a validated satellite-based spatio-temporal model. Body mass index z-score (BMI-z), fat mass, % body fat, subscapular and triceps skinfold thickness, waist and hip circumferences and waist-to-hip ratio (WHR) were assessed at age 4.0 ± 0.7 years. Using Bayesian distributed lag interaction models (BDLIMs), we examined sex differences in sensitive windows of weekly averaged PM_2.5 levels on these measures, adjusting for child age, maternal age, education, race/ethnicity, and pre-pregnancy BMI.

RESULTS

Mothers were primarily Hispanic (55%) or Black (26%), had ≤ 12 years of education (66%) and never smoked (80%). Increased PM_2.5 exposure 8-17 and 15-22 weeks gestation was significantly associated with increased BMI z-scores and fat mass in boys, but not in girls. Higher PM_2.5 exposure 10-29 weeks gestation was significantly associated with increased WHR in girls, but not in boys. Prenatal PM_2.5 was not significantly associated with other measures of body composition. Estimated cumulative effects across pregnancy, accounting for sensitive windows and within-window effects, were 0.21 (95%CI = 0.01-0.37) for BMI-z and 0.36 (95%CI = 0.12-0.68) for fat mass (kg) in boys, and 0.02 (95%CI = 0.01-0.03) for WHR in girls, all per µg/m³ increase in PM_2.5.

CONCLUSIONS

Increased prenatal PM_2.5 exposure was more strongly associated with indices of increased whole body size in boys and with an indicator of body shape in girls. Methods to better characterize vulnerable windows may provide insight into underlying mechanisms contributing to sex-specific associations.

Association of prenatal and early childhood stress with reduced lung function in 7-year-olds

BACKGROUND

No prior study has examined associations between prenatal and early-life stress on childhood lung function or identified critical windows of exposure.

OBJECTIVE

To prospectively examine associations between prenatal and early-life stress and childhood lung function.

METHODS

Stress was indexed by a maternal negative life events (NLEs) score ascertained during pregnancy and between 1 and 2 years post partum. Spirometry was performed when children were a mean (SD) of 6.99 (0.89) years old. Associations of prenatal and early postnatal stress with spirometry z scores were examined in 199 children using linear regression. Effect modification by child sex was explored.

RESULTS

Most mothers were minorities (65% Hispanic, 21% African American), had 12 years or less of education (67%), and did not smoke prenatally (78%). The highest level of prenatal stress (≥5 NLEs) was associated with lower levels of forced expiratory volume in 1 second (FEV₁) (z score = -0.53, P = .03), forced vital capacity (FVC) (z score = -0.49, P = .04), and forced expiratory flow between 25% and 75% (FEF_25%-75%) (z score = -0.68, P = .01) after covariate adjustment; effects were similar for postnatal stress considered separately. In sex-stratified analyses, high postnatal stress (≥5 NLEs) was associated with lower FEV₁ (z score = -0.76, P = .01), FVC (z score = -0.77, P = .01), and FEF_25%-75% (z score = -0.67, P = .02) in boys but not girls, although the interaction term was not significant (P for interaction >.10).

CONCLUSION

These are the first prospective data that link perinatal stress with reduced child lung function. High levels of stress in the prenatal and postnatal periods were associated with symmetric reductions in FEV₁ and FVC consistent with impaired lung growth. Given that lung function growth patterns are established by 7 years of age, these findings have lifelong implications.

Maternal obesity and childhood wheezing and asthma

Obesity represents one of the major public health problems worldwide, with an increased prevalence also among women of reproductive age. Maternal pre-pregnancy overweight and obesity are important risk factors for a number of maternal and foetal/neonatal complications. The objective of this review is to provide an overview of the most recent evidence regarding the associations between pre-pregnancy overweight/obesity and wheezing and asthma in childhood. Potential mechanisms, mediators and confounding factors involved in these associations are also discussed. Despite the relatively large body of studies examining these associations and taking into account main confounders and potential mediators, the causal relationship between maternal obesity and wheezing and asthma in childhood is still uncertain. This uncertainty is not trivial, as any prevention strategy aimed at reducing the burden of these conditions would necessarily imply better understanding of the factors that are in the causal chain.

The accuracy of self-reported pregnancy-related weight: a systematic review

Self-reported maternal weight is error-prone, and the context of pregnancy may impact error distributions. This systematic review summarizes error in self-reported weight across pregnancy and assesses implications for bias in associations between pregnancy-related weight and birth outcomes. We searched PubMed and Google Scholar through November 2015 for peer-reviewed articles reporting accuracy of self-reported, pregnancy-related weight at four time points: prepregnancy, delivery, over gestation and postpartum. Included studies compared maternal self-report to anthropometric measurement or medical report of weights. Sixty-two studies met inclusion criteria. We extracted data on magnitude of error and misclassification. We assessed impact of reporting error on bias in associations between pregnancy-related weight and birth outcomes. Women underreported prepregnancy (PPW: -2.94 to -0.29 kg) and delivery weight (DW: -1.28 to 0.07 kg), and over-reported gestational weight gain (GWG: 0.33 to 3 kg). Magnitude of error was small, ranged widely, and varied by prepregnancy weight class and race/ethnicity. Misclassification was moderate (PPW: 0-48.3%; DW: 39.0-49.0%; GWG: 16.7-59.1%), and overestimated some estimates of population prevalence. However, reporting error did not largely bias associations between pregnancy-related weight and birth outcomes. Although measured weight is preferable, self-report is a cost-effective and practical measurement approach. Future researchers should develop bias correction techniques for self-reported pregnancy-related weight.

Maternal Lifetime Trauma Exposure, Prenatal Cortisol, and Infant Negative Affectivity

Little research has examined the impact of maternal lifetime trauma exposure on infant temperament. We examined associations between maternal trauma history and infant negative affectivity and modification by prenatal cortisol exposure in a sociodemographically diverse sample of mother-infant dyads. During pregnancy, mothers completed measures of lifetime trauma exposure and current stressors. Third-trimester cortisol output was assessed from maternal hair. When infants were 6 months old, mothers completed the Infant Behavior Questionnaire-Revised. In analyses that controlled for infant sex and maternal age, education, race/ethnicity, and stress during pregnancy, greater maternal trauma exposure was associated with increased infant distress to limitations and sadness. Higher and lower prenatal cortisol exposure modified the magnitude and direction of association between maternal trauma history and infant rate of recovery from arousal. The association between maternal trauma history and infant distress to limitations was somewhat stronger among infants exposed to higher levels of prenatal cortisol. The analyses suggested that maternal lifetime trauma exposure is associated with several domains of infant negative affectivity independently of maternal stress exposures during pregnancy and that some of these associations may be modified by prenatal cortisol exposure. The findings have implications for understanding the intergenerational impact of trauma exposure on child developmental outcomes.

Impact of Maternal Lifetime Interpersonal Trauma on Children's Asthma: Mediation Through Maternal Active Asthma During Pregnancy

OBJECTIVE

Traumatic stressors, including child abuse and/or interpersonal violence over a woman's lifecourse, can affect the health of her children. This study examines the associations between maternal lifetime interpersonal trauma (IPT) and children's asthma by age 6 years (n = 857).

METHODS

Pregnant women completed the Revised Conflict Tactics Scale; IPT exposure was categorized as unexposed (55%), early (childhood and/or teen years only, 25%), late (adulthood and/or index pregnancy, 7%), and chronic (early and late, 13%). Clinician-diagnosed asthma in children was reported by mothers at each follow-up visit until the child reached age 6 years. We examined the effects of maternal IPT categories and child's asthma using logistic regression. Using structural equation models, we also examined indirect relationships between maternal chronic IPT and child asthma operating through active asthma in pregnancy, prepregnancy BMI, prenatal smoking, and/or increased exposure to other adverse life events or environmental toxins prenatally. Effect modification by the child's sex was examined.

RESULTS

Mothers were primarily Hispanic (55%) or black (30%) with less than high school education (62%). In logistic regression models, chronic maternal IPT (compared with unexposed) was associated with asthma in boys (odds ratio = 2.87, 95% confidence interval = 1.48-5.57) but not girls (odds ratio = 0.69, 95% confidence interval = 0.23-2.12; pinteraction = .042). In structural equation models, chronic IPT was associated with maternal active asthma in pregnancy (β = 0.59, p < .001), maternal active asthma was associated with children's asthma (β = 0.20, p = .009), and the total indirect effect for this path was significant (β = 0.12, p = .031). Associations were most evident among boys.

CONCLUSIONS

Mothers' history of chronic IPT was associated with asthma in boys. This association was mediated through active maternal asthma in pregnancy.

Prenatal Stress, Prematurity, and Asthma

Asthma is the most common chronic disease of childhood, affecting millions of children in the United States and worldwide. Prematurity is a risk factor for asthma, and certain ethnic or racial minorities such as Puerto Ricans and non-Hispanic blacks are disproportionately affected by both prematurity and asthma. In this review, we examine current evidence to support maternal psychosocial stress as a putative link between prematurity and asthma, while also focusing on disruption of the hypothalamic-pituitary-adrenal (HPA) axis and immune responses as potential underlying mechanisms for stress-induced "premature asthma." Prenatal stress may cause not only abnormalities in the HPA axis but also epigenetic changes in the fetal glucocorticoid receptor gene (NR3C1), leading to impaired glucocorticoid metabolism. Moreover, maternal stress can alter fetal cytokine balance, favoring TH2 (allergic) immune responses characteristic of atopic asthma: interleukin 6 (IL-6), which has been associated with premature labor, can promote TH2 responses by stimulating production of IL-4 and IL-13. Given a link among stress, prematurity, and asthma, future research should include birth cohorts aimed at confirming and better characterizing "premature asthma." If confirmed, clinical trials of prenatal maternal stress reduction would be warranted to reduce the burden of these common comorbidities. While awaiting the results of such studies, sound policies to prevent domestic and community violence (eg, from firearms) are justified, not only by public safety but also by growing evidence of detrimental effects of violence-induced stress on psychiatric and somatic health.

Toddler temperament and prenatal exposure to lead and maternal depression

BACKGROUND

Temperament is a psychological construct that reflects both personality and an infant's reaction to social stimuli. It can be assessed early in life and is stable over time Temperament predicts many later life behaviors and illnesses, including impulsivity, emotional regulation and obesity. Early life exposure to neurotoxicants often results in developmental deficits in attention, social function, and IQ, but environmental predictors of infant temperament are largely unknown. We propose that prenatal exposure to both chemical and non-chemical environmental toxicants impacts the development of temperament, which can itself be used as a marker of risk for maladaptive neurobehavior in later life. In this study, we assessed associations among prenatal and early life exposure to lead, mercury, poverty, maternal depression and toddler temperament.

METHODS

A prospective cohort of women living in the Mexico City area were followed longitudinally beginning in the second trimester of pregnancy. Prenatal exposure to lead (blood, bone), mercury, and maternal depression were assessed repeatedly and the Toddler Temperament Scale (TTS) was completed when the child was 24 months old. The association between each measure of prenatal exposure and performance on individual TTS subscales was evaluated by multivariable linear regression. Latent profile analysis was used to classify subjects by TTS performance. Multinomial regression models were used to estimate the prospective association between prenatal exposures and TTS performance.

RESULTS

500 mother-child pairs completed the TTS and had complete data on exposures and covariates. Three latent profiles were identified and categorized as predominantly difficult, intermediate, or easy temperament. Prenatal exposure to maternal depression predicted increasing probability of difficult toddler temperament. Maternal bone lead, a marker of cumulative exposure, also predicted difficult temperament. Prenatal lead exposure modified this association, suggesting that joint exposure in pregnancy to both was most toxic.

CONCLUSIONS

Maternal depression predicts difficult temperament and concurrent prenatal exposure to maternal depression and lead predicts a more difficult temperament phenotype in 2 year olds. The role of temperament as an intermediate variable in the path from prenatal exposures to neurobehavioral deficits and other health effects deserves further study.

Spatial clusters of child lower respiratory illnesses associated with community-level risk factors

Identifying geographic areas with increased incidence of disease may elucidate community-level risk factors for intervention development. Lower respiratory illnesses (LRIs) are the leading cause of death in children and are associated with other morbidities. We assessed geographic clustering of LRIs and evaluated if these spatial patterns and associated risk factors differed by phenotype. Participants enrolled at birth in the Tucson Children's Respiratory Study were followed through age three for physician diagnosed LRIs. Spatial clustering analysis, based upon each participant's birth address, was performed for four LRI phenotypes. We conducted principal component analysis at the census tract level to generate indices for lower socioeconomic status (SES), poorer housing conditions, and increased air pollution. Enrollment addresses were mapped for 812 subjects, of whom 58.4%, 33.5%, 34.2%, and 23.4% had any LRI, a wheezing LRI, a viral LRI, and a respiratory syncytial virus (RSV) LRI, respectively. Patterns of spatial clustering and associated risk factors differed by LRI phenotype. Multivariable regression analyses showed that wheezing LRI clusters were associated with increased air pollution (OR = 1.18, P = 0.01). Being in a viral cluster was associated with poorer housing conditions (OR = 1.28, P = 0.01), while being in a RSV cluster was associated with increased air pollution (OR = 1.14, P = 0.006), poorer housing conditions (OR = 1.54, P = 0.003), and higher SES (OR = 0.77, P = 0.001). Our use of social and environmental indices allowed us to identify broad contextual factors that may contribute to increased incidence of LRIs in specific geographic regions. To reduce LRI incidence, multifaceted interventions should be developed at the community level. Pediatr Pulmonol. 2016;51:633-642. © 2015 Wiley Periodicals, Inc.

Prenatal and postnatal stress and asthma in children: Temporal- and sex-specific associations

BACKGROUND

Temporal- and sex-specific effects of perinatal stress have not been examined for childhood asthma.

OBJECTIVES

We examined associations between prenatal and/or postnatal stress and children's asthma (n = 765) and effect modification by sex in a prospective cohort study.

METHODS

Maternal negative life events were ascertained prenatally and postpartum. Negative life event scores were categorized as 0, 1 to 2, 3 to 4, or 5 or greater to assess exposure-response relationships. We examined effects of prenatal and postnatal stress on children's asthma by age 6 years, modeling each as independent predictors, mutually adjusting for prenatal and postnatal stress, and finally considering interactions between prenatal and postnatal stress. Effect modification by sex was examined in stratified analyses and by fitting interaction terms.

RESULTS

When considering stress in each period independently, among boys, a dose-response relationship was evident for each level increase on the ordinal scale prenatally (odds ratio [OR], 1.38; 95% CI, 1.06-1.79; P value for trend = .03) and postnatally (OR, 1.53; 95% CI, 1.16-2.01; P value for trend = .001); among girls, only the postnatal trend was significant (OR, 1.60; 95% CI, 1.14-2.22; P value for trend = .005). Higher stress in both the prenatal and postnatal periods was associated with increased odds of receiving a diagnosis of asthma in girls (OR, 1.37; 95% CI, 0.98-1.91; Pinteraction = .07) but not boys (OR, 1.08; 95% CI, 0.82-1.42; Pinteraction = .61).

CONCLUSIONS

Although boys were more vulnerable to stress during the prenatal period, girls were more affected by postnatal stress and cumulative stress across both periods in relation to asthma. Understanding sex and temporal differences in response to early-life stress might provide unique insight into the cause and natural history of asthma.

The Influence of Antenatal Partner Support on Pregnancy Outcomes

BACKGROUND

While there has been considerable attention given to the multitude of maternal factors that contribute to perinatal conditions and poor birth outcomes, few studies have aimed to understand the impact of fathers or partners. We examined associations of antenatal partner support with psychological variables, smoking behavior, and pregnancy outcomes in two socioeconomically distinct prebirth cohorts.

MATERIALS AND METHODS

Data were from 1764 women recruited from an urban-suburban group practice (Project Viva) and 877 women from urban community health centers (Project ACCESS), both in the Boston area. Antenatal partner support was assessed by the Turner Support Scale. Multivariable linear and logistic regression analyses determined the impact of low antenatal partner support on the outcomes of interest.

RESULTS

In early pregnancy, 6.4% of Viva and 23.0% of ACCESS participants reported low partner support. After adjustment, low partner support was cross-sectionally associated with high pregnancy-related anxiety in both cohorts (Viva AOR 1.8; 95% CI: 1.0-3.4 and ACCESS AOR 1.9; 95% CI: 1.1-3.3) and with depression in ACCESS (AOR 1.9; 95% CI: 1.1-3.3). In Viva, low partner support was also related to depression mid-pregnancy (AOR 3.1; 95% CI: 1.7-5.7) and to smoking (AOR 2.2; 95% CI: 1.3-3.8). Birth weight, gestational age, and fetal growth were not associated with partner support.

CONCLUSIONS

This study of two economically and ethnically distinct cohorts in the Boston area highlights higher levels of antenatal anxiety, depression, and smoking among pregnant women who report low partner support. Partner support may be an important and potentially modifiable target for interventions to improve pregnancy outcomes.

Prenatal and postnatal stress and wheeze in Mexican children: Sex-specific differences

BACKGROUND

Increasing evidence links early-life exposure to psychosocial stress with adverse childhood respiratory outcomes. The influence of exposure timing has not been completely elucidated.

OBJECTIVE

To examine the association between prenatal and postnatal maternal stress and wheeze in 417 children enrolled in a prospective birth cohort in Mexico City.

METHODS

Maternal negative life event (NLE) scores were ascertained in the second or third trimester of pregnancy and at the 48-month postnatal visit. Children's respiratory outcomes, caregiver report of ever wheeze, and wheeze in the past 12 months were obtained from the International Study of Asthma and Allergies in Childhood survey administered at 48 months. Associations between prenatal and postnatal NLE scores and wheeze were analyzed using a modified Poisson regression approach adjusting for covariates.

RESULTS

In separate models, higher maternal psychosocial stress during pregnancy (relative risk [RR], 1.12; 95% CI, 1.00-1.26) and postnatally (RR, 1.21; 95% CI, 1.08-1.35) were associated with increased risk of wheeze in the past 12 months with an evident exposure-response relationship. There was a significant interaction between postnatal stress and sex in relation to current wheeze. In a sex-stratified model, the association between postnatal stress and risk of wheeze in the past 12 months was stronger in girls (RR, 1.35; 95% CI, 1.13-1.61) than in boys (RR, 1.11; 95% CI, 0.97-1.27) (P for interaction = .04).

CONCLUSION

Prenatal and postnatal stress in mothers was associated with wheeze in preschool-aged children, and the effect of postnatal stress was stronger in girls. Understanding the temporal- and sex-specific effects of stress may better inform prevention strategies.

Lifetime exposure to traumatic and other stressful life events and hair cortisol in a multi-racial/ethnic sample of pregnant women

We examined whether lifetime exposure to stressful and traumatic events alters hypothalamic-pituitary-adrenal (HPA) axis functioning, as indexed by hair cortisol, regardless of associated psychopathology, among pregnant women of different racial/ethnic backgrounds. 180 women provided hair samples for measurement of integrated cortisol levels throughout pregnancy and information regarding their lifetime exposure to stressful and traumatic life events. Results indicate that increased lifetime exposure to traumatic events was associated with significantly greater hair cortisol over the course of pregnancy. Similarly, greater lifetime exposure to stressful and traumatic events weighted by reported negative impact (over the previous 12 months) was associated with significantly greater hair cortisol during pregnancy. All analyses controlled for maternal age, education, body mass index (BMI), use of inhaled corticosteroids, race/ethnicity, and post-traumatic stress disorder (PTSD) and depressive symptoms. Following stratification by race/ethnicity, associations between stressful and traumatic life events and hair cortisol were found among Black women only. This is the first study to consider associations between lifetime stress exposures and hair cortisol in a sociodemographically diverse sample of pregnant women. Increased exposure to stressful and traumatic events, independent of PTSD and depressive symptoms, was associated with higher cortisol production, particularly in Black women. Future research should investigate the influence of such increased cortisol exposure on developmental outcomes among offspring.

The Natural History of Bronchopulmonary Dysplasia: The Case for Primary Prevention

Brochopulmonary dysplasia (BPD) is the most common form of chronic lung disease in infancy. At present, BPD primarily occurs in extremely premature infants (23-28 weeks of gestation) born during the late canalicular/early saccular stage of lung development. This article summarizes the current knowledge of the life course of BPD by emphasizing recent or key articles notating its natural history from the newborn period through adulthood and building the case for a continued focus on its primary prevention.

Prenatal Particulate Air Pollution and Asthma Onset in Urban Children. Identifying Sensitive Windows and Sex Differences

RATIONALE

The influence of particulate air pollution on respiratory health starts in utero. Fetal lung growth and structural development occurs in stages; thus, effects on postnatal respiratory disorders may differ based on timing of exposure.

OBJECTIVES

We implemented an innovative method to identify sensitive windows for effects of prenatal exposure to particulate matter with a diameter less than or equal to 2.5 μm (PM2.5) on children's asthma development in an urban pregnancy cohort.

METHODS

Analyses included 736 full-term (≥37 wk) children. Each mother's daily PM2.5 exposure was estimated over gestation using a validated satellite-based spatiotemporal resolved model. Using distributed lag models, we examined associations between weekly averaged PM2.5 levels over pregnancy and physician-diagnosed asthma in children by age 6 years. Effect modification by sex was also examined.

MEASUREMENTS AND MAIN RESULTS

Most mothers were ethnic minorities (54% Hispanic, 30% black), had 12 or fewer years of education (66%), and did not smoke in pregnancy (80%). In the sample as a whole, distributed lag models adjusting for child age, sex, and maternal factors (education, race and ethnicity, smoking, stress, atopy, prepregnancy obesity) showed that increased PM2.5 exposure levels at 16-25 weeks gestation were significantly associated with early childhood asthma development. An interaction between PM2.5 and sex was significant (P = 0.01) with sex-stratified analyses showing that the association exists only for boys.

CONCLUSIONS

Higher prenatal PM2.5 exposure at midgestation was associated with asthma development by age 6 years in boys. Methods to better characterize vulnerable windows may provide insight into underlying mechanisms.

A Study on Mediation by Offspring BMI in the Association between Maternal Obesity and Child Respiratory Outcomes in the Amsterdam Born and Their Development Study Cohort

BACKGROUND

A causal relationship between maternal obesity and offspring asthma is hypothesized to begin during early development, but no underlying mechanism for the found association is identified. We quantitatively examined mediation by offspring body mass index (BMI) in the association of maternal pre-pregnancy BMI on risk of asthma and wheezing during the first 7-8 years of life in a large Amsterdam born birth cohort.

METHODS

For 3185 mother-child pairs, mothers reported maternal pre-pregnancy BMI and offspring outcomes "ever being diagnosed with asthma" and "wheezing in the past 12 months" on questionnaires. We measured offspring height and weight at age 5-6 years. We performed a multivariate log linear regression comparing outcomes in offspring of mothers with different BMI categories. For each category we quantified and tested mediation by offspring BMI and also investigated interaction by parental asthma.

RESULTS

At the age of 7-8 years, 8% of the offspring ever had asthma and 7% had current wheezing. Maternal pre-pregnancy obesity was associated with higher risks of asthma (adjusted RR 2.32 (95% CI: 1.49-3.61) and wheezing (adjusted RR 2.16 (95% CI: 1.28-3.64). Offspring BMI was a mediator in the association between maternal BMI and offspring wheezing, but not for asthma. There was no interaction by parental asthma.

CONCLUSIONS

Maternal pre-pregnancy obesity was associated with higher risks of offspring asthma and wheezing. The association between maternal obesity and offspring wheezing was both direct and indirect (mediated) through the child's own BMI.

Maternal body mass index in early pregnancy and offspring asthma, rhinitis and eczema up to 16 years of age

Background

Maternal obesity has been linked to offspring asthma; however, other allergy-related diseases, as well as the association beyond early school age, are largely unstudied.

Objective

To examine the associations between maternal body mass index (BMI) in pregnancy and offspring asthma, rhinitis, eczema and sensitization up to 16 years of age.

Methods

A total of 3294 children from the Swedish birth cohort BAMSE were included in the analyses. Maternal BMI was assessed around week 10 in pregnancy. Information on asthma, rhinitis, eczema, lifestyle factors and environmental exposures was obtained by parental questionnaires at 1, 2, 4, 8, 12 and 16 years. Sensitization was defined from IgE levels of inhalant allergens at 4, 8 and 16 years in a subsample of 2850 children. Generalized estimated equation models were used to analyse the associations between maternal BMI and the outcomes at 1–16 years.

Results

Maternal BMI was positively associated with overall risk of asthma up to age of 16 years (adj OR per 5 kg/m² increase: 1.23; 95% CI 1.07–1.40 for prevalent asthma) excluding underweight mothers. In contrast, no significant associations were found for rhinitis, eczema or sensitization. The association with asthma was restricted to obese, rather than overweight mothers, but was attenuated when adjusting for overweight in the offspring. A causal inference test at 16 years further indicated that the child’s own overweight is a mediator in the suggested association between maternal BMI and offspring asthma at 16 years.

Conclusions and Clinical Relevance

Maternal BMI is associated with an increased risk of asthma, but not rhinitis, eczema or sensitization; however, overweight in the offspring seems to have a mediating role. Prevention strategies of maternal pre-pregnancy and childhood obesity might be important to reduce the prevalence of childhood asthma.

Integrating mitochondriomics in children's environmental health

The amount of scientific research linking environmental exposures and childhood health outcomes continues to grow; yet few studies have teased out the mechanisms involved in environmentally-induced diseases. Cells can respond to environmental stressors in many ways: inducing oxidative stress/inflammation, changes in energy production and epigenetic alterations. Mitochondria, tiny organelles that each retains their own DNA, are exquisitely sensitive to environmental insults and are thought to be central players in these pathways. While it is intuitive that mitochondria play an important role in disease processes, given that every cell of our body is dependent on energy metabolism, it is less clear how environmental exposures impact mitochondrial mechanisms that may lead to enhanced risk of disease. Many of the effects of the environment are initiated in utero and integrating mitochondriomics into children's environmental health studies is a critical priority. This review will highlight (i) the importance of exploring environmental mitochondriomics in children's environmental health, (ii) why environmental mitochondriomics is well suited to biomarker development in this context, and (iii) how molecular and epigenetic changes in mitochondria and mitochondrial DNA (mtDNA) may reflect exposures linked to childhood health outcomes.

Maternal distress associates with placental genes regulating fetal glucocorticoid exposure and IGF2: Role of obesity and sex

Maternal emotional distress symptoms, including life satisfaction, anxiety and depressed mood, are worse in Severely Obese (SO) than lean pregnancy and may alter placental genes regulating fetal glucocorticoid exposure and placental growth. We hypothesised that the associations between increased maternal distress symptoms and changes in placental gene expression including IGF2 and genes regulating fetal glucocorticoid exposure are more pronounced in SO pregnancy. We also considered whether there were sex-specific effects. Placental mRNA levels of 11β-HSDs, NR3C1-α, NR3C2, ABC transporters, mTOR and the IGF2 family were measured in term placental samples from 43 lean (BMI≤25kg/m(2)) and 50 SO (BMI≥40kg/m(2)) women, in whom distress symptoms were prospectively evaluated during pregnancy. The mRNA levels of genes with a similar role in regulating fetal glucocorticoid exposure were strongly inter-correlated. Increased maternal distress symptoms associated with increased NR3C2 and IGF2 isoform 1(IGF2-1) in both lean and SO group (p≤0.05). Increased distress was associated with higher ABCB1 and ABCG2 mRNA levels in SO but lower ABCB1 and higher 11β-HSD1 mRNA levels in lean (p≤0.05) suggesting a protective adaptive response in SO placentas. Increased maternal distress associated with reduced mRNA levels of ABCB1, ABCG2, 11β-HSD2, NR3C1-α and IGF2-1 in placentas of female but not male offspring. The observed sex differences in placental responses suggest greater vulnerability of female fetuses to maternal distress with potentially greater fetal glucocorticoid exposure and excess IGF2. Further studies are needed to replicate these findings and to test whether this translates to potentially greater negative outcomes of maternal distress in female offspring in early childhood.

Childhood abuse is associated with increased hair cortisol levels among urban pregnant women

BACKGROUND

Hypothalamic-pituitary-adrenal (HPA) axis activity is known to be altered following events such as childhood abuse. However, despite potential adverse consequences for the offspring of women who have experienced abuse, very little is known about altered HPA axis activity during pregnancy.

METHODS

During pregnancy, 180 women from diverse racial/ethnic backgrounds reported on their exposure to emotional, physical and/or sexual abuse before the age of 11, and general post-traumatic stress symptoms (ie, not limited to childhood years or abuse experiences). Around delivery, they provided hair samples for the assessment of cortisol levels during pregnancy. Hair cortisol was assessed for each pregnancy trimester. The effect of childhood abuse on hair cortisol was assessed using mixed-effects analyses of covariance models allowing for within-subject correlated observations, and were first performed in the entire sample and subsequently stratified by race/ethnicity.

RESULTS

Controlling for post-traumatic stress symptoms, hair cortisol levels varied by history of child abuse, F(2,166)=3.66, p=0.028. Childhood physical and/or sexual abuse was associated with greater hair cortisol levels, t(166)=2.65, p=0.009, compared with no history of abuse. Because childhood rates of abuse and hair cortisol levels varied by race/ethnicity, analyses were stratified by race/ethnicity. The associations between history of abuse and cortisol levels were only significant among black women, F(2,23)=5.37, p=0.012.

CONCLUSIONS

Childhood abuse, especially physical and/or sexual abuse, is associated with differences in cortisol production during pregnancy, particularly among black women. Future research should investigate how these differences impact physical and mental health outcomes among offspring of affected women.

Mercury and psychosocial stress exposure interact to predict maternal diurnal cortisol during pregnancy

BACKGROUND

Disrupted maternal prenatal cortisol production influences offspring development. Factors influencing the hypothalamic-pituitary-adrenal axis include social (e.g., stressful life events) and physical/chemical (e.g., toxic metals) pollutants. Mercury (Hg) is a common contaminant of fish and exposure is widespread in the US. No prior study has examined the joint associations of stress and mercury with maternal cortisol profiles in pregnancy.

OBJECTIVES

To investigate potential synergistic influences of prenatal stress and Hg exposures on diurnal cortisol in pregnant women.

METHODS

Analyses included 732 women (aged 27.4 ± 5.6 years) from a Mexico City pregnancy cohort. Participants collected saliva samples on two consecutive days (mean 19.52 ± 3.00 weeks gestation) and reported life stressors over the past 6 months. Hg was assessed in toe nail clippings collected during pregnancy.

RESULTS

There were no main effects of Hg or psychosocial stress exposure on diurnal cortisol (ps > .20) but strong evidence of interaction effects on cortisol slope (interaction B = .006, SE = .003, p = .034) and cortisol at times 1 and 2 (interaction B = -.071, SE = .028, p = .013; B = -.078, SE = .032, p = .014). Women above the median for Hg and psychosocial stress exposure experienced a blunted morning cortisol response compared to women exposed to higher stress but lower Hg levels.

CONCLUSIONS

Social and physical environmental factors interact to alter aspects of maternal diurnal cortisol during pregnancy. Research focusing solely on either domain may miss synergistic influences with potentially important consequences to the offspring.

Associations between prenatal traffic-related air pollution exposure and birth weight: Modification by sex and maternal pre-pregnancy body mass index

BACKGROUND

Prenatal traffic-related air pollution exposure is linked to adverse birth outcomes. However, modifying effects of maternal body mass index (BMI) and infant sex remain virtually unexplored.

OBJECTIVES

We examined whether associations between prenatal air pollution and birth weight differed by sex and maternal BMI in 670 urban ethnically mixed mother-child pairs.

METHODS

Black carbon (BC) levels were estimated using a validated spatio-temporal land-use regression (LUR) model; fine particulate matter (PM2.5) was estimated using a hybrid LUR model incorporating satellite-derived Aerosol Optical Depth measures. Using stratified multivariable-adjusted regression analyses, we examined whether associations between prenatal air pollution and calculated birth weight for gestational age (BWGA) z-scores varied by sex and maternal pre-pregnancy BMI.

RESULTS

Median birth weight was 3.3±0.6kg; 33% of mothers were obese (BMI ≥30kg/m(3)). In stratified analyses, the association between higher PM2.5 and lower birth weight was significant in males of obese mothers (-0.42 unit of BWGA z-score change per IQR increase in PM2.5, 95%CI: -0.79 to -0.06) ( PM2.5×sex×obesity Pinteraction=0.02). Results were similar for BC models (Pinteraction=0.002).

CONCLUSIONS

Associations of prenatal exposure to traffic-related air pollution and reduced birth weight were most evident in males born to obese mothers.

Bronchopulmonary dysplasia: NHLBI Workshop on the Primary Prevention of Chronic Lung Diseases

Bronchopulmonary dysplasia (BPD) is the most common complication of extreme preterm birth. Infants who develop BPD manifest aberrant or arrested pulmonary development and can experience lifelong alterations in cardiopulmonary function. Despite decades of promising research, primary prevention of BPD has proven elusive. This workshop report identifies current barriers to the conduct of primary prevention studies for BPD and causal pathways implicated in BPD pathogenesis. Throughout, we highlight promising areas for research to improve understanding of normal and aberrant lung development, distinguish BPD endotypes, and ascertain biomarkers for more targeted therapeutic approaches to prevention. We conclude with research recommendations and priorities to accelerate discovery and promote lung health in infants born preterm.

Racial/ethnic and sociodemographic factors associated with micronutrient intakes and inadequacies among pregnant women in an urban US population

OBJECTIVE

To assess sociodemographic correlates of micronutrient intakes from food and dietary supplements in an urban, ethnically diverse sample of pregnant women in the USA.

DESIGN

Cross-sectional analyses of data collected using a validated semi-quantitative FFQ. Associations between racial, ethnic and sociodemographic factors and micronutrient intakes were examined using logistic regression controlling for pre-pregnancy BMI, maternal age and smoking status.

SETTING

Prenatal clinics, Boston, MA, USA.

SUBJECTS

Analyses included pregnant women (n 274) in the PRogramming of Intergenerational Stress Mechanisms (PRISM) study, an urban longitudinal cohort designed to examine how stress influences respiratory health in children when controlling for other environmental exposures (chemical stressors, nutrition).

RESULTS

High frequencies of vitamin E (52 %), Mg (38 %), Fe (57 %) and vitamin D (77 %) inadequacies as well as suboptimal intakes of choline (95 %) and K (99 %) were observed. Factors associated with multiple antioxidant inadequacies included being Hispanic or African American, lower education and self-reported economic-related food insecurity. Hispanics had a higher prevalence of multiple methyl-nutrient inadequacies compared with African Americans; both had suboptimal betaine intakes and higher odds for vitamin B₆ and Fe inadequacies compared with Caucasians. Nearly all women (98 %) reported Na intakes above the tolerable upper limit; excessive intakes of Mg (35 %), folate (37 %) and niacin (38 %) were also observed. Women reporting excessive intakes of these nutrients were more likely Caucasian or Hispanic, more highly educated, US-born and did not report food insecurity.

CONCLUSIONS

Racial/ethnic and other sociodemographic factors should be considered when tailoring periconceptional dietary interventions for urban ethnic women in the USA.