Maternal health and birth outcomes in a South African birth cohort study

Subcortical Brain Volumes and Neurocognitive Function in Children With Perinatal HIV Exposure: A Population-Based Cohort Study in South Africa

Background

Children who are HIV-exposed and uninfected (HEU) are at risk for early neurodevelopmental impairment. Smaller basal ganglia nuclei have been reported in neonates who are HEU compared to HIV-unexposed (HU); however, neuroimaging studies outside infancy are scarce. We examined subcortical brain structures and associations with neurocognition in children who are HEU.

Methods

This neuroimaging study was nested within the Drakenstein Child Health Study birth cohort in South Africa. We compared (T1-weighted) magnetic resonance imaging-derived subcortical brain volumes between children who were HEU (n = 70) and HU (n = 92) at age 2-3 years using linear regression. Brain volumes were correlated with neurodevelopmental outcomes measured with the Bayley Scales of Infant and Toddler Development III.

Results

Compared to HU children, on average children who were HEU had 3% lower subcortical grey matter volumes. Analyses of individual structures found smaller volume of the putamen nucleus in the basal ganglia (-5% difference, P = .016) and the hippocampus (-3% difference, P = .044), which held on adjustment for potential confounders (P < .05). Maternal viremia and lower CD4 count in pregnancy were associated with smaller child putamen volumes. Children who were HEU had lower language scores than HU; putamen and hippocampus volumes were positively correlated with language outcomes.

Conclusions

Overall, children who are HEU had a pattern of smaller subcortical volumes in the basal ganglia and hippocampal regions compared to HU children, which correlated with language function. Findings suggest that optimizing maternal perinatal HIV care is important for child brain development. Further studies are needed to investigate underlying mechanisms and long-term outcomes.

Language outcomes of preschool children who are HIV-exposed uninfected: An analysis of a South African cohort

INTRODUCTION

There are approximately 16 million children who are HIV-exposed and uninfected (CHEU) worldwide. Studies suggest that CHEU are at risk for developmental impairment in infancy, particularly in language domains. However, there is limited research examining neurocognitive function in CHEU older than 2 years, including important pre-school years. This study aimed to investigate associations between HIV exposure without infection and neurocognitive outcomes and to determine risk factors for neurodevelopment in CHEU at age 3-4 years.

METHODS

The Drakenstein Child Health Study is a South African population-based birth cohort which enrolled women in pregnancy with ongoing follow up. Neurocognitive outcomes were assessed in children at 3.5 years by trained assessors blinded to HIV status including general cognitive function, language, and memory, measured using the Kaufmann Assessment Battery for Children, Second Edition (KABC-II). Data were compared between CHEU and children who were HIV-unexposed uninfected (CHUU) using multivariable logistic and linear regression, including testing for effect modification; sex-stratified risk factor analyses were performed.

RESULTS

A total of 497 children were included (97 [20%] CHEU; 400 [80%] CHUU; 50% male), with a mean age of 3.5 years (range 3.4-3.6). Groups had similar birth and household characteristics, although mothers of CHEU were older, on average. Overall, CHEU had lower expressive language scores compared to CHUU on unadjusted and adjusted analyses (effect size: -0.23 [95% CI -0.45, -0.01]). There were no group differences in general cognitive or memory function (p>0.05). On sex-stratified analyses, male CHEU were found to have higher odds of suboptimal cognitive development compared to male CHUU (aOR 2.28 [95% CI 1.06, 4.87], p = 0.034). Several other factors including birthweight, maternal education, maternal ART duration and HIV viral load during pregnancy were associated with cognition, memory, or expressive language outcomes in CHEU, dependent on child sex.

INTERPRETATION

The findings suggest that perinatal HIV exposure continues to be associated with impaired language development across the preschool years, highlighting the importance of targeting early interventions to optimise language outcomes. Further, the results suggest the importance of demographic, biological and HIV-related variables influencing developmental outcomes in CHEU. The greater risk of suboptimal cognitive development in male CHEU requires investigation around sex-specific mechanisms.

Association of in utero HIV exposure with child brain structure and language development: a South African birth cohort study

BACKGROUND

There is a growing population of children with in utero HIV exposure who are at risk of poor neurodevelopmental outcomes despite avoiding HIV infection. However, the underlying neurobiological pathways are not understood and neuroimaging studies are lacking. We aimed to investigate the cortical brain structure of children who are HIV-exposed and uninfected (HEU) compared to HIV-unexposed (HU) children and to examine the relationship with neurodevelopment.

METHODS

The Drakenstein Child Health birth cohort study enrolled pregnant women from a high HIV prevalence area in South Africa with longitudinal follow-up of mother-child pairs. High-resolution magnetic resonance imaging scans from 162 children (70 HEU; 92 HU) were acquired at 2-3 years of age. All HEU children were born to mothers taking antiretroviral therapy. Measures of brain structure (cortical thickness and surface area) in the prefrontal cortex regions were extracted from T1-weighted images and compared between groups using multivariate analysis of variance and linear regression. Child development, assessed using the Bayley Scales of Infant and Toddler Development-III, was correlated with cortical structure, and mediation analyses were performed.

RESULTS

Analyses demonstrated an association between HIV exposure and cortical thickness across the prefrontal cortex (p = 0.035). Children who were HEU had thicker cortices in prefrontal regions, with significantly greater cortical thickness in the medial orbitofrontal cortex (mOFC) bilaterally compared to HU children (3.21 mm versus 3.14 mm, p = 0.009, adjusted effect size 0.44 [95% CI 0.12 to 0.75]). Estimates held across multiple sensitivity analyses. There were no group differences in cortical surface area. Language scores, which were lower in HEU versus HU children (81.82 versus 86.25, p = 0.011, effect size - 0.44 [95% CI - 0.78 to - 0.09]), negatively correlated with prefrontal cortical thickness in both groups. Cortical thickness in the mOFC mediated the relationship between HIV exposure and poor language outcomes (Sobel test p = 0.032).

CONCLUSIONS

In this cohort study, exposure to HIV during pregnancy was associated with altered cortical structure in early life. Our findings indicate that differences in cortical thickness development in the prefrontal region in children who are HEU may be a pathway leading to language impairment. Longitudinal studies are needed to determine the lasting impact.

Prevalence of Preterm Birth and Perinatal Outcomes in a Tertiary Hospital in Malaysia

Background Preterm birth (PTB) is defined as neonates that are born alive >22 weeks of gestation and <37 weeks of gestation. Because of the immaturity of different organ systems, 14.84 million newborns worldwide are born prematurely, which is the largest contributing factor to mortality and morbidity. Although studies have been conducted in this field, the magnitude of PTB is a major issue in most developing countries including Malaysia. Objective To assess the prevalence of PTB and the perinatal outcome among women delivered in a tertiary university hospital in Malaysia.  Methods This was a cross-sectional study evaluating all singleton live births weighing>500g and delivered at >22+1 weeks of gestation between January 2015 and December 2019 in Universiti Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia. Data were collected from the hospital's recorded birth registry. The primary outcome was the PTB rate. Data were entered and analysed using Statistical Product and Service Solutions (SPSS) (version 28.0; IBM SPSS Statistics for Windows, Armonk, NY). Results A total of 26,022 singleton live births were reported for the period 2015-2019. PTB rates showed a sharp 6% decrease from 2015 to 2016, after which the trend was inconsistent until 2019. The risk of preterm babies being admitted to the neonatal intensive care unit (NICU) or the ward compared to the risk of neonatal mortality increases for babies of identified sex, delivered via caesarean, and with a birth weight between 2 and 3 kgs. Babies born at a gestational age between 22+1 and 33+6 have a higher risk of neonatal mortality compared to late preterm babies. Conclusions The PTB incidence trend was inconsistent from 2015 to 2019 in a tertiary university hospital in Malaysia, with a far higher prevalence compared to national data. The high NICU admission and mortality rates among preterm infants mean urgent strategies and policies are needed to improve perinatal outcomes.

Risk and rates of hospitalisation in young children: A prospective study of a South African birth cohort

Children in sub-Saharan Africa (SSA) are disproportionately affected by morbidity and mortality. There is also a growing vulnerable population of children who are HIV-exposed uninfected (HEU). Understanding reasons and risk factors for early-life child hospitalisation will help optimise interventions to improve health outcomes. We investigated hospitalisations from birth to two years in a South African birth cohort study. Mother-child pairs in the Drakenstein Child Health Study were followed from birth to two years with active surveillance for hospital admission and investigation of aetiology and outcome. Incidence, duration, cause, and factors associated with child hospitalisation were investigated, and compared between HEU and HIV-unexposed uninfected (HUU) children. Of 1136 children (247 HEU; 889 HUU), 314 (28%) children were hospitalised in 430 episodes despite >98% childhood vaccination coverage. The highest hospitalisation rate was from 0-6 months, decreasing thereafter; 20% (84/430) of hospitalisations occurred in neonates at birth. Amongst hospitalisations subsequent to discharge after birth, 83% (288/346) had an infectious cause; lower respiratory tract infection (LRTI) was the most common cause (49%;169/346) with respiratory syncytial virus (RSV) responsible for 31% of LRTIs; from 0-6 months, RSV-LRTI accounted for 22% (36/164) of all-cause hospitalisations. HIV exposure was associated with increased incidence rates of hospitalisation in infants (IRR 1.63 [95% CI 1.29-2.05]) and longer hospital admission (p = 0.004). Prematurity (HR 2.82 [95% CI 2.28-3.49]), delayed infant vaccinations (HR 1.43 [95% CI 1.12-1.82]), or raised maternal HIV viral load in HEU infants were risk factors for hospitalisation; breastfeeding was protective (HR 0.69 [95% CI 0.53-0.90]). In conclusion, children in SSA experience high rates of hospitalisation in early life. Infectious causes, especially RSV-LRTI, underly most hospital admissions. HEU children are at greater risk of hospitalisation in infancy compared to HUU children. Available strategies such as promoting breastfeeding, timely vaccination, and optimising antenatal maternal HIV care should be strengthened. New interventions to prevent RSV may have additional impact in reducing hospitalisation.

Associations between socio-demographic characteristics of pregnant women and birth outcome: The Nutritional status of Expectant Mothers and their newborn Infants study

BACKGROUND

Low socio-economic status is associated with poor birth outcomes, however, few studies on this topic have been conducted in South Africa. We determined associations between socio-demographic variables of pregnant women and birth outcome in their offspring.

METHODS

This study was nested in a prospective cohort study conducted at an antenatal clinic at a regional hospital in Bloemfontein, South Africa. Questionnaires on socio-demographic information were completed on 682 pregnant women in a structured interview. Post-delivery, 331 participants provided the Road to Health Booklets for 347 infants, in which birth data were recorded. Associations between socio-demographic variables and birth outcome (defined as premature delivery or low length-for-age or low weight-for-length at birth) were investigated. Logistic regression with backward selection (p < 0.05) was used to select independent factors that were significantly associated with birth outcome. Variables with a p-value of <0.15 on bivariate analysis were considered for inclusion in the model.

RESULTS

Poor birth outcome was observed in 36.3% (116/320) of women. The odds of experiencing poor birth outcome were lower for women who owned a stove versus those who did not (OR 0.11, 95% CI: 0.02-0.67), and higher for women with grade 8-10 (OR 5.84, 95% CI: 1.90-17.91) or grade 10-12 (OR 4.33, 95% CI: 1.50-12.49) as their highest level of education versus tertiary education. The odds of experiencing poor birth outcomes were also higher for those employed part-time (OR 2.55, 95% CI: 1.10-5.93) versus full-time and/or self-employed.

CONCLUSION

Our findings confirm that the presence of basic amenities such as a stove, better education and employment improve the chances of better birth outcomes. Early screening of pregnant women for the identification of socio-demographic risk factors that may impact on birth outcome is recommended.

The impact of antenatal and postnatal indoor air pollution or tobacco smoke exposure on lung function at 3 years in an African birth cohort

BACKGROUND AND OBJECTIVE

Indoor air pollution (IAP) and tobacco smoke exposure (ETS) are global health concerns contributing to the burden of childhood respiratory disease. Studies assessing the effects of IAP and ETS in preschool children are limited. We assessed the impact of antenatal and postnatal IAP and ETS exposure on lung function in a South African birth cohort, the Drakenstein Child Health Study.

METHODS

Antenatally enrolled mother-child pairs were followed from birth. Lung function measurements (oscillometry, multiple breath washout and tidal breathing) were performed at 6 weeks and 3 years. Quantitative antenatal and postnatal IAP (particulate matter [PM10 ], volatile organic compounds [VOC]) and ETS exposures were measured. Linear regression models explored the effects of antenatal and postnatal exposures on lung function at 3 years.

RESULTS

Five hundred eighty-four children had successful lung function testing, mean (SD) age of 37.3 (0.7) months. Exposure to antenatal PM10 was associated with a decreased lung clearance index (p < 0.01) and postnatally an increase in the difference between resistance at end expiration (ReE) and inspiration (p = 0.05) and decrease in tidal volume (p = 0.06). Exposure to antenatal VOC was associated with an increase in functional residual capacity (p = 0.04) and a decrease in time of expiration over total breath time (tE /tTOT ) (p = 0.03) and postnatally an increase in respiratory rate (p = 0.05). High ETS exposure postnatally was associated with an increase in ReE (p = 0.03).

CONCLUSION

Antenatal and postnatal IAP and ETS exposures were associated with impairment in lung function at 3 years. Strengthened efforts to reduce IAP and ETS exposure are needed.

Investigating the association of prenatal psychological adversities with mother and child telomere length and neurodevelopment

BACKGROUND

Exposure to prenatal maternal psychological adversities can negatively affect the offspring's developing brain. Shortened telomere length (TL) has been implicated as a mechanism for the transgenerational effects of maternal psychological adversities on offspring. This study aimed to determine associations between prenatal psychological stressors and distress with maternal and early life TL, and associations between maternal, newborn and child TL with neurodevelopmental outcomes at 2 years of age.

METHODS

Follow-up TL was measured in a subgroup of African mothers (n = 138) and their newborns (n = 142) and children (n = 96) at 2-years in the Drakenstein Child Health Study. Prenatal symptoms of depression, distress, intimate partner violence, posttraumatic stress-disorder and childhood trauma were measured at 27 weeks gestation. Neurodevelopment was assessed at 2 years using the Bayley Scales of Infant and Toddler Development III. TLs were measured in whole bloods from mothers and their children at 2-years, and cord bloods in newborns.

RESULTS

Maternal prenatal stressors and distress were not significantly associated with TL in mothers or their children at birth or at 2-years. Furthermore, maternal psychological measures were not associated with early-life attrition of TL. Longer TL in children at 2-years was associated (p = 0.04) with higher motor functioning.

LIMITATIONS

Limited numbers of participants and single time-point psychological measures.

CONCLUSIONS

This study is the first to provide information on the association of early life TL with prenatal psychological adversities and neurodevelopmental outcomes in a population of low-income African mothers and their children.

Risk and rates of hospitalisation in young children: a prospective study of a South African birth cohort

Introduction

Children in sub-Saharan Africa (SSA) are disproportionately affected by morbidity and mortality; there is also a growing vulnerable population of children who are HIV-exposed uninfected (HEU). Understanding reasons and risk factors for early-life child hospitalisation will help optimise interventions to improve health outcomes. We investigated hospitalisations from birth to two years in a South African birth cohort.

Methods

Mother-child pairs in the Drakenstein Child Health Study were followed from birth to two years with active surveillance for hospital admission and investigation of aetiology and outcome. Incidence, duration, cause, and factors associated with child hospitalisation were investigated, and compared between HEU and HIV-unexposed uninfected (HUU) children.

Results

Of 1136 children (247 HEU; 889 HUU), 314 (28%) children were hospitalised in 430 episodes despite >98% childhood vaccination coverage. The highest hospitalisation rate was from 0-6 months, decreasing thereafter; 20% (84/430) of hospitalisations occurred in neonates at birth. Amongst hospitalisations subsequent to discharge after birth, 83% (288/346) had an infectious cause; lower respiratory tract infection (LRTI) was the most common cause (49%;169/346) with respiratory syncytial virus (RSV) responsible for 31% of LRTIs; from 0-6 months, RSV-LRTI accounted for 22% (36/164) of all-cause hospitalisations. HIV exposure was a risk factor for hospitalisation in infants (IRR 1.63 [95% CI 1.29-2.05]) and longer hospital admission (p=0.004). Prematurity (HR 2.82 [95% CI 2.28-3.49]), delayed infant vaccinations (1.43 [1.12-1.82]), or raised maternal HIV viral load in HEU infants were risk factors; breastfeeding was protective (0.69 [0.53-0.90]).

Conclusion

Children in SSA continue to experience high rates of hospitalisation in early life. Infectious causes, especially RSV-LRTI, underly most hospital admissions. HEU children are at particular risk in infancy. Available strategies such as promoting breastfeeding, timely vaccination, and optimising antenatal maternal HIV care should be strengthened. New interventions to prevent RSV may have a large additional impact in reducing hospitalisation.

Succession and determinants of the early life nasopharyngeal microbiota in a South African birth cohort

BACKGROUND

Bacteria colonizing the nasopharynx play a key role as gatekeepers of respiratory health. Yet, dynamics of early life nasopharyngeal (NP) bacterial profiles remain understudied in low- and middle-income countries (LMICs), where children have a high prevalence of risk factors for lower respiratory tract infection. We investigated longitudinal changes in NP bacterial profiles, and associated exposures, among healthy infants from low-income households in South Africa.

METHODS

We used short fragment (V4 region) 16S rRNA gene amplicon sequencing to characterize NP bacterial profiles from 103 infants in a South African birth cohort, at monthly intervals from birth through the first 12 months of life and six monthly thereafter until 30 months.

RESULTS

Corynebacterium and Staphylococcus were dominant colonizers at 1 month of life; however, these were rapidly replaced by Moraxella- or Haemophilus-dominated profiles by 4 months. This succession was almost universal and largely independent of a broad range of exposures. Warm weather (summer), lower gestational age, maternal smoking, no day-care attendance, antibiotic exposure, or low height-for-age z score at 12 months were associated with higher alpha and beta diversity. Summer was also associated with higher relative abundances of Staphylococcus, Streptococcus, Neisseria, or anaerobic gram-negative bacteria, whilst spring and winter were associated with higher relative abundances of Haemophilus or Corynebacterium, respectively. Maternal smoking was associated with higher relative abundances of Porphyromonas. Antibiotic therapy (or isoniazid prophylaxis for tuberculosis) was associated with higher relative abundance of anerobic taxa (Porphyromonas, Fusobacterium, and Prevotella) and with lower relative abundances of health associated-taxa Corynebacterium and Dolosigranulum. HIV-exposure was associated with higher relative abundances of Klebsiella or Veillonella and lower relative abundances of an unclassified genus within the family Lachnospiraceae.

CONCLUSIONS

In this intensively sampled cohort, there was rapid and predictable replacement of early profiles dominated by health-associated Corynebacterium and Dolosigranulum with those dominated by Moraxella and Haemophilus, independent of exposures. Season and antibiotic exposure were key determinants of NP bacterial profiles. Understudied but highly prevalent exposures prevalent in LMICs, including maternal smoking and HIV-exposure, were associated with NP bacterial profiles. Video Abstract.

Pathways to adverse pregnancy outcomes: exploring the mediating role of intimate partner violence and depression: results from a South African rape cohort study

Adverse pregnancy outcomes (APOs) are common occurrences that contribute to negative maternal and child health outcomes. Our aim was to test the hypothesis that trauma exposure and depression are drivers of the better-recognised risk factors for miscarriage, abortion and stillbirths. Our comparative cohort study based in Durban, South Africa recruited women who reported a recent rape (n = 852) and those who had never experienced rape (n = 853), with follow-up for 36 months. We explored APOs (miscarriage, abortion or stillbirth) among those having a pregnancy during follow-up (n = 453). Potential mediators were baseline depression, post-traumatic stress symptoms, substance abuse, HbA1C, BMI, hypertension and smoking. A structural equation model (SEM) was used to determine direct and indirect paths to APO. Overall, 26.6% of the women had a pregnancy in the follow-up period and 29.4% ended in an APO, with miscarriage (19.9%) the most common outcome, followed by abortion (6.6%) and stillbirths (2.9%). The SEM showed two direct pathways from exposure to childhood trauma, rape and other trauma, to APO which were ultimately mediated by hypertension and/or BMI, but all paths to BMI were mediated by depression and IPV-mediated pathways from childhood and other trauma to hypertension. Food insecurity mediated a pathway from experiences of trauma in childhood to depression. Our study confirms the important role of trauma exposure, including rape, and depression on APOs, through their impact on hypertension and BMI. It is critical that violence against women and mental health are more systematically addressed in antenatal, pregnancy and postnatal care.

Low and differential polygenic score generalizability among African populations due largely to genetic diversity

African populations are vastly underrepresented in genetic studies but have the most genetic variation and face wide-ranging environmental exposures globally. Because systematic evaluations of genetic prediction had not yet been conducted in ancestries that span African diversity, we calculated polygenic risk scores (PRSs) in simulations across Africa and in empirical data from South Africa, Uganda, and the United Kingdom to better understand the generalizability of genetic studies. PRS accuracy improves with ancestry-matched discovery cohorts more than from ancestry-mismatched studies. Within ancestrally and ethnically diverse South African individuals, we find that PRS accuracy is low for all traits but varies across groups. Differences in African ancestries contribute more to variability in PRS accuracy than other large cohort differences considered between individuals in the United Kingdom versus Uganda. We computed PRS in African ancestry populations using existing European-only versus ancestrally diverse genetic studies; the increased diversity produced the largest accuracy gains for hemoglobin concentration and white blood cell count, reflecting large-effect ancestry-enriched variants in genes known to influence sickle cell anemia and the allergic response, respectively. Differences in PRS accuracy across African ancestries originating from diverse regions are as large as across out-of-Africa continental ancestries, requiring commensurate nuance.

Placental histopathology, maternal characteristics and neonatal outcome in cases of preterm birth in a high-risk population in South Africa

Background. Preterm birth remains a global health concern and is one of the most common pregnancy complications associated with perinatal morbidity and mortality.Objective. To investigate placental pathology and its associations with obstetric, maternal and neonatal outcomes in the Eastern Cape region of South Africa (SA) in order to help understand its associations with preterm birth in that region. Methods. In this prospective study, placentas were collected consecutively from patients attending a public tertiary referral hospital in SA, delivering preterm (n=100; 28 - 34 weeks gestational age) and term (n=20; >36 weeks gestational age). Placentas were submitted for histopathology, and comparisons with maternal characteristics and neonatal outcomes in preterm birth were undertaken.Results. Histological analysis revealed pathology in all preterm placentas (100%), with maternal vascular malperfusion (47%) and abruptio placentae (41%) most commonly identified. Acute chorioamnionitis (21%) was associated with term births (p=0.002). Maternal characteristics and neonatal outcomes significantly associated with preterm birth included pre-eclampsia (p=0.006), neonatal respiratory distress syndrome (p=0.004) and neonatal jaundice (p=0.003). Intrauterine demise (p=0.004) and alcohol abuse (p≤0.005) were significantly associated with term delivery. The number of mothers delivering preterm who were HIV-positive was high (41%). Conclusion. The pathology identified in all preterm placentas supports the need to update institutional policies for submission of placentas from all preterm births for histopathology, particularly in countries with a high burden of preterm birth.

Maternal perinatal depression and child brain structure at 2-3 years in a South African birth cohort study

Maternal perinatal depression is associated with risk of adverse child developmental outcomes and differences in offspring brain structure. Evidence from low- and middle-income countries is lacking as is an investigation of antenatal, postnatal, and persistent depression in the same sample. In a South African birth cohort, we investigated the effect of antenatal and postpartum maternal depressive symptoms on offspring brain structure at 2-3 years of age. Magnetic resonance imaging was performed, extracting cortical thickness and surface areas in frontal cortex regions of interest and subcortical volumes using FreeSurfer software. Maternal depressive symptoms were measured using the Edinburgh Postpartum Depression Scale and the Beck Depression Inventory II antenatally and at 6-10 weeks, 6 months, 12 months, and 18 months postpartum and analyzed dichotomously and continuously. Linear regressions were used controlling for child age, sex, intracranial volume, maternal education, age, smoking, alcohol use and HIV. 146 children were included with 38 (37%) exposed to depressive symptoms antenatally and 44 (35%) exposed postnatally. Of these, 16 (13%) were exposed to both. Postpartum, but not antenatal, depressive symptoms were associated with smaller amygdala volumes in children (B = -74.73, p = 0.01). Persistent maternal depressive symptoms across pregnancy and postpartum were also independently associated with smaller amygdala volumes (B = -78.61, p = 0.047). Differences in amygdala volumes among children exposed to postnatal as well as persistent maternal depressive symptomatology underscore the importance of identifying women at-risk for depression during the entire perinatal period.

DNA methylation as a potential mediator of the association between indoor air pollution and neurodevelopmental delay in a South African birth cohort

BACKGROUND

Exposure to indoor air pollution during pregnancy has been linked to neurodevelopmental delay in toddlers. Epigenetic modification, particularly DNA methylation (DNAm), may explain this link. In this study, we employed three high-dimensional mediation analysis methods (HIMA, DACT, and gHMA) followed by causal mediation analysis to identify differentially methylated CpG sites and genes that mediate the association between indoor air pollution and neurodevelopmental delay. Analyses were performed using data from 142 mother to child pairs from a South African birth cohort, the Drakenstein Child Health Study. DNAm from cord blood was measured using the Infinium MethylationEPIC and HumanMethylation450 arrays. Neurodevelopment was assessed at age 2 years using the Bayley Scores of Infant and Toddler Development, 3rd edition across four domains (cognitive development, general adaptive behavior, language, and motor function). Particulate matter with an aerodynamic diameter of 10 μm or less (PM₁₀) was measured inside participants' homes during the second trimester of pregnancy.

RESULTS

A total of 29 CpG sites and 4 genes (GOPC, RP11-74K11.1, DYRK1A, RNMT) were identified as significant mediators of the association between PM₁₀ and cognitive neurodevelopment. The estimated proportion mediated (95%-confidence interval) ranged from 0.29 [0.01, 0.86] for cg00694520 to 0.54 [0.11, 1.56] for cg05023582.

CONCLUSIONS

Our findings suggest that DNAm may mediate the association between prenatal PM₁₀ exposure and cognitive neurodevelopment. DYRK1A and several genes that our CpG sites mapped to, including CNKSR1, IPO13, IFNGR1, LONP2, and CDH1, are associated with biological pathways implicated in cognitive neurodevelopment and three of our identified CpG sites (cg23560546 [DAPL1], cg22572779 [C6orf218], cg15000966 [NT5C]) have been previously associated with fetal brain development. These findings are novel and add to the limited literature investigating the relationship between indoor air pollution, DNAm, and neurodevelopment, particularly in low- and middle-income country settings and non-white populations.

Household Food Insecurity and Demographic Factors, Low Birth Weight and Stunting in Early Childhood: Findings from a Longitudinal Study in South Africa

BACKGROUND

Low birthweight (LBW) as well as early childhood stunting are risk factors for increased childhood morbidity in low-and middle-income countries (LMIC). The Covid 19 pandemic has exacerbated food insecurity and unemployment globally, prompting concerns for maternal and child health.

OBJECTIVES

We used data from the great recession of 2008 to examine the relationship between household food security and other risk factors with LBW and stunting using a longitudinal sample of South African women and their offspring.

METHODS

Food security indicators, alcohol use, blood pressure and other characteristics were examined in relation to LBW (≤ 2500 g), stunting (height for age ≤ 2SD) and severe stunting (height for age ≤ 3SD). Regression modelling with clustering at maternal ID level were employed to adjust for maternal characteristics and women who gave birth more than once during the reference period.

RESULTS

Birthweight data were available for 1173 children and height for age 1216 children. The prevalence of LBW was 14.7% while stunting and severe stunting was 17.8% and 14.5%. Child hunger in the household, maternal hypertension and alcohol use were associated with low birthweight. Food expenditure below the Stats SA poverty line and low dietary diversity was associated with stunting and severe stunting respectively. Maternal height and low birthweight were associated with both stunting and severe stunting.

CONCLUSIONS FOR PRACTICE

Interventions that can improve household food security and nutritional status during the periconceptional and antenatal period may reduce the prevalence of low birthweight and subsequent stunting in low- and middle-income countries.

In-utero HIV exposure and cardiometabolic health among children 5-8 years: findings from a prospective birth cohort in South Africa

OBJECTIVE

To evaluate if in-utero HIV exposure is associated with adverse cardiometabolic health outcomes at 5-8 years of age.

DESIGN

Prospective cohort study.

METHODS

We enrolled a random sample of HIV-exposed but uninfected (HEU) and HIV-unexposed children from the Drakenstein Child Health study, a longitudinal birth cohort study in Cape Town, South Africa, in a cardiometabolic health pilot study. Outcomes were assessed by trained study staff and included: anthropometry, body composition and size, blood pressure, fasting plasma glucose, HbA1c, lipids, and insulin resistance using HOMA-IR. We used multivariable linear and log-binomial regression to estimate associations between HIV-exposure and cardiometabolic outcomes, adjusted for child age, sex, height, body size, and maternal factors as appropriate.

RESULTS

We included 260 children (HEU n = 100, HIV-unexposed n = 160). HEU children had older mothers (median age 30 vs. 26 years), with minimal differences in gestational age and size at birth by HIV-exposure status. In multivariable analyses, HEU children had lower weight-for-age (mean difference -0.35, 95% confidence interval -0.66, -0.05), and height-for-age (mean difference -0.29, 95% confidence interval -0.56, -0.03; z-scores). There were no differences in adiposity, impaired glucose metabolism, or lipid levels by HIV-exposure status. Overall, 12% of children had blood pressure more than 90th percentile, with no differences by HIV-exposure status.

CONCLUSION

Overall, there were few differences in cardiometabolic outcomes between HEU and HIV-unexposed children in this South African cohort. Although these findings are reassuring, monitoring of cardiometabolic health is important as HEU and HIV-unexposed children enter adolescence and cardiometabolic risk trajectories become established.

Association of Maternal and Child Anemia With Brain Structure in Early Life in South Africa

Importance

Anemia affects millions of pregnant women and their children worldwide, particularly in low- and middle-income countries. Although anemia in pregnancy is a well-described risk factor for cognitive development, the association with child brain structure is poorly understood.

Objective

To explore the association of anemia during pregnancy and postnatal child anemia with brain structure in early life.

Design, Setting, and Participants

This neuroimaging nested cohort study was embedded within the Drakenstein Child Health Study (DCHS), a population-based birth cohort in South Africa. Pregnant individuals were enrolled into the DCHS between 2012 and 2015 from 2 clinics in a periurban setting. Mother-child pairs were assessed prospectively; follow-up is ongoing. A subgroup of children had brain magnetic resonance imaging (MRI) at age 2 to 3 years from 2015 to 2018. This study focused on the 147 pairs with structural neuroimaging and available hemoglobin data. Data analyses were conducted in 2021 and 2022.

Exposures

Mothers had hemoglobin measurements during pregnancy, and a subgroup of children had hemoglobin measurements during early life. Anemia was classified as hemoglobin levels less than 11 g/dL based on World Health Organization guidelines; children younger than 6 months were classified using local guidelines.

Main Outcomes and Measures

Child brain volumes of global, subcortical, and corpus callosum structures were quantified using T1-weighted MRI. Linear regression models were used to analyze the associations between maternal and child anemia with child brain volumes, accounting for potential confounders.

Results

Of 147 children (mean [SD] age at MRI, 34 [2] months; 83 [56.5%] male) with high-resolution MRI scans, prevalence of maternal anemia in pregnancy was 31.3% (46 of 147; median [IQR] gestation of measurement: 13 [9-20] weeks). Maternal anemia during pregnancy was significantly associated with smaller volumes of the child caudate bilaterally (adjusted percentage difference, -5.30% [95% CI, -7.01 to -3.59]), putamen (left hemisphere: -4.33% [95% CI, -5.74 to -2.92]), and corpus callosum (-7.75% [95% CI, -11.24 to -4.26]). Furthermore, antenatal maternal hemoglobin levels were also associated with brain volumes in the caudate (left hemisphere: standardized β = 0.15 [95% CI, 0.02 to 0.28]; right hemisphere: β = 0.15 [95% CI, 0.02 to 0.27]), putamen left hemisphere (β = 0.21 [95% CI, 0.07 to 0.35]), and corpus callosum (β = 0.24 [95% CI, 0.09 to 0.39]). Prevalence of child anemia was 52.5% (42 of 80; median [IQR] age of measurement: 8.0 [2.7 to 14.8] months). Child anemia was not associated with brain volumes, nor did it mediate the association of maternal anemia during pregnancy with brain volumes.

Conclusions and Relevance

In this cohort study, anemia in pregnancy was associated with altered child brain structural development. Given the high prevalence of antenatal maternal anemia worldwide, these findings suggest that optimizing interventions during pregnancy may improve child brain outcomes.

Effects of Nutritional and Social Factors on Favorable Fetal Growth Conditions Using Structural Equation Modeling

Poor birth outcomes such as low birth weight, low birth length and short gestational age, are public health concern issues in South Africa (SA). This study utilized structural equation modeling (SEM) to explore how nutritional and social factors contribute to favorable fetal growth conditions (FFGC) in pregnant women living with and without human immunodeficiency virus (HIV), in the Free State Province of SA. Sociodemographic characteristics, stress, health and nutrition-related information, and birth outcomes data were collected and analyzed from a subsample of 305 women enrolled in a cohort study from 2018−2020. Descriptive statistics were analyzed in R version 4.1.2 and SEM was conducted in Lavaan version 0.6−5. Higher gestational body mass index (GBMI) and income levels were associated with higher FFGC (p < 0.05). Household incomes were positively associated with dietary micronutrient quality (p = 0.002), GBMI (p = 0.012) and food security (p = 0.001). Low incomes (p = 0.004) and food insecurity (p < 0.001) were associated with higher stress, while social support was positively associated with food security status (p = 0.008). These findings highlight the complex interconnections between the social and nutritional factors that are associated with fetal growth conditions. Multisectoral community-based programs may be a useful strategy to address these challenges.

Antenatal maternal depression, early life inflammation and neurodevelopment in a South African birth cohort

BACKGROUND

Antenatal exposure to maternal psychological adversity, including depression, increases the risk of impaired neurodevelopment in children. The underlying biological mechanisms remain unclear, especially in early life during critical windows of development and maturation. This study investigated the association of antenatal maternal depression, maternal and early life inflammatory markers and neurodevelopmental outcomes in children at 2 years of age.

METHODS

A subgroup of mothers and their children (n = 255) that were enrolled in a South African birth cohort study, the Drakenstein Child Health Study, were followed from the antenatal period through to 2 years of child age. Maternal depressive symptoms were measured by the Beck Depression Inventory (BDI-II) at 26 weeks gestation. Serum inflammatory markers [granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon-γ (IFN-γ), interleukin IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12p70, IL-13, tumour necrosis factor-α (TNF-α), neutrophil gelatinase-associated lipocalin (NGAL) and metalloproteinase-9 (MMP-9)] were measured in mothers at enrolment and in their children at 6-10 weeks and at 2 years. Neurodevelopment was assessed at 2 years using the Bayley Scales of Infant and Toddler Development III.

RESULTS

Antenatal depressive symptoms (present in 25% of the mothers) were significantly associated with higher levels of IL-7 (p = 0.008), IL-8 (p = 0.019) and TNF-α (p = 0.031) in the mothers after correcting for sociodemographic and lifestyle factors. Serum IL-1β and NGAL levels were significantly elevated over time in children born to mothers with depressive symptoms compared to those without depression, after controlling for maternal and child health and sociodemographic factors. Elevated infant IL-1β at 6-10 weeks of age partially mediated the association of maternal depressive symptoms with poorer language scores at 2 years.

CONCLUSION

Alterations in early life immunity, as reflected by elevated IL-1β, is a potential pathway through which antenatal maternal depressive symptoms may impact language development in young children.

Subcortical brain volumes in young infants exposed to antenatal maternal depression: Findings from a South African birth cohort

BACKGROUND

Several studies have reported enlarged amygdala and smaller hippocampus volumes in children and adolescents exposed to maternal depression. It is unclear whether similar volumetric differences are detectable in the infants' first weeks of life, following exposure in utero. We investigated subcortical volumes in 2-to-6 week old infants exposed to antenatal maternal depression (AMD) from a South African birth cohort.

METHODS

AMD was measured with the Beck Depression Inventory 2nd edition (BDI-II) at 28-32 weeks gestation. T2-weighted structural images were acquired during natural sleep on a 3T Siemens Allegra scanner. Subcortical regions were segmented based on the University of North Carolina neonatal brain atlas. Volumetric estimates were compared between AMD-exposed (BDI-II ⩾ 20) and unexposed (BDI-II < 14) infants, adjusted for age, sex and total intracranial volume using analysis of covariance.

RESULTS

Larger volumes were observed in AMD-exposed (N = 49) compared to unexposed infants (N = 75) for the right amygdala (1.93% difference, p = 0.039) and bilateral caudate nucleus (left: 5.79% difference, p = 0.001; right: 6.09% difference, p < 0.001). A significant AMD-by-sex interaction was found for the hippocampus (left: F(1,118) = 4.80, p = 0.030; right: F(1,118) = 5.16, p = 0.025), reflecting greater volume in AMD-exposed females (left: 5.09% difference, p = 0.001, right: 3.54% difference, p = 0.010), but not males.

CONCLUSIONS

Volumetric differences in subcortical regions can be detected in AMD-exposed infants soon after birth, suggesting structural changes may occur in utero. Female infants might exhibit volumetric changes that are not observed in male infants. The potential mechanisms underlying these early volumetric differences, and their significance for long-term child mental health, require further investigation.

A Scoping Review of Preterm Births in Sub-Saharan Africa: Burden, Risk Factors and Outcomes

Preterm births (PTB) are the leading cause of neonatal deaths, the majority of which occur in low- and middle-income countries, particularly those in Sub-Saharan Africa (SSA). Understanding the epidemiology of prematurity is an essential step towards tackling the challenge of PTB in the sub-continent. We performed a scoping review of the burden, predictors and outcomes of PTB in SSA. We searched PubMed, Embase, and three other databases for articles published from the database inception to 10 July 2021. Studies reporting the prevalence of PTB, the associated risk factors, and/or its outcomes were eligible for inclusion in this review. Our literature search identified 4441 publications, but only 181 met the inclusion criteria. Last menstrual period (LMP) was the most commonly used method of estimating gestational age. The prevalence of PTB in SSA ranged from 3.4% to 49.4%. Several risk factors of PTB were identified in this review. The most frequently reported risk factors (i.e., reported in ≥10 studies) were previous history of PTB, underutilization of antenatal care (<4 visits), premature rupture of membrane, maternal age (≤20 or ≥35 years), inter-pregnancy interval, malaria, HIV and hypertension in pregnancy. Premature babies had high rates of hospital admissions, were at risk of poor growth and development, and were also at a high risk of morbidity and mortality. There is a high burden of PTB in SSA. The true burden of PTB is underestimated due to the widespread use of LMP, an unreliable and often inaccurate method for estimating gestational age. The associated risk factors for PTB are mostly modifiable and require an all-inclusive intervention to reduce the burden and improve outcomes in SSA.

Klebsiella pneumoniae Lower Respiratory Tract Infection in a South African Birth Cohort: a Longitudinal Study

OBJECTIVES

The role of Klebsiella pneumoniae (KP) in lower respiratory tract infection (LRTI) is not well studied. We longitudinally investigated KP colonization and its association with LRTI in a South African birth cohort.

METHODS

We conducted a case-control study of infants who developed LRTI and age-matched controls, followed twice weekly through infancy. Nasopharyngeal swabs taken fortnightly and at LRTI for 33-multipex Quantitative multiplex real-time polymerase chain reaction were tested at LRTI and twice weekly from 90 days preceding LRTI. Controls were tested over the equivalent period. Multivariate models investigated the factors associated with LRTI or with KP-associated LRTI (KP-LRTI).

RESULTS

Among 885 infants, there were 439 LRTI episodes, of which 68 (15.5%) were KP-LRTI (OR 1.93; 95% CI 1.25-3.03). Infants with KP-LRTI were younger than those without KP-LRTI (median [IQR] 3.7 [2.1-5.9] vs 4.7 [2.8-7.9] months, P-value=0.009). Clinical features of KP and non-KP-LRTI were similar with 114 (26%) infants hospitalized. Prematurity (adjusted odds ratio [aOR] 11.86; 95% CI 5.22-26.93), HIV exposure (aOR 3.32; 95% CI 1.69-6.53), lower birthweight (aOR 0.68; 95% CI 0.51-0.91), and shorter breastfeeding time (aOR 0.79; 95% CI 0.65-0.96) were associated with KP-LRTI versus non-LRTI. These factors and younger age were associated with KP-LRTI versus non-KP-LRTI.

CONCLUSION

KP was associated with a substantial proportion of LRTI, particularly in premature or HIV-exposed infants in whom strategies for treatment and prevention should be strengthened.

Gestational weight gain during the second and third trimesters and adverse pregnancy outcomes, results from a prospective pregnancy cohort in urban Tanzania

Background

Appropriate gestational weight gain (GWG) is important for optimal pregnancy outcomes. This study prospectively evaluated the associations between GWG during the second and third trimesters of pregnancy and adverse pregnancy outcomes in an urban Tanzanian pregnancy cohort.

Methods

We used data from a randomized clinical trial conducted among pregnant women recruited by 27 weeks of gestation in Dar es Salaam, Tanzania (N = 1230). Women’s gestational weight was measured at baseline and at monthly antenatal visits. Weekly GWG rate during the second and third trimesters was calculated and characterized as inadequate, adequate, or excessive, in conjunction with measured or imputed early-pregnancy BMI status according to the 2009 Institute of Medicine (IOM) GWG guidelines. We used multivariable Poisson regression with a sandwich variance estimator to calculate risk ratios (RR) for associations of GWG with low birth weight, preterm birth, small for gestational age (SGA), and large for gestational age (LGA). Degree of appropriate GWG defined using additional metrics (i.e., percentage of adequacy, z-score) and potential effect modification by maternal BMI were additionally evaluated.

Results

According to the IOM guidelines, 517 (42.0%), 270 (22.0%), and 443 (36.0%) women were characterized as having inadequate, adequate, and excessive GWG, respectively. Overall, compared to women with adequate GWG, women with inadequate GWG had a lower risk of LGA births (RR = 0.54, 95% CI: 0.36–0.80) and a higher risk of SGA births (RR = 1.32, 95% CI: 0.95–1.81). Women with inadequate GWG as defined by percentage of GWG adequacy had a higher risk of LBW (OR = 1.93, 95% CI: 1.03–3.63). In stratified analyses by early-pregnancy BMI, excessive GWG among women with normal BMI was associated with a higher risk of preterm birth (RR = 1.59, 95% CI: 1.03–2.44).

Conclusions

A comparatively high percentage of excessive GWG was observed among healthy pregnant women in Tanzania. Both inadequate and excessive GWGs were associated with elevated risks of poor pregnancy outcomes. Future studies among diverse SSA populations are warranted to confirm our findings, and clinical recommendations on optimal GWG should be developed to promote healthy GWG in SSA settings.

Trial registration: This trial was registered as “Prenatal Iron Supplements: Safety and Efficacy in Tanzania” (NCT01119612; http://clinicaltrials.gov/show/NCT01119612).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12978-022-01441-7.

Pregnancy is a critical lifetime event for both mother and the offspring, with implications in short-term and long-term health consequences. Gestational weight gain (GWG) is an important modifiable factor for pregnancy outcomes related to infant body size and weight and prematurity. Countries in sub-Saharan Africa (SSA) have long had poor rates of insufficient GWG and pregnancy complications associated with insufficient GWG. Nevertheless, some SSA countries are experiencing economic transitions accompanied with changes in lifestyle and nutrition, which might impact pregnancy experiences, including GWG and pregnancy outcomes. This study aimed to characterize recent GWG patterns and the associations of both inadequate and excessive GWG with adverse pregnancy outcomes, using an urban pregnancy cohort in Tanzania. This study found that 42.0%. 22.0%, and 36.0% of women had insufficient, adequate, and excessive GWG, respectively. Insufficient GWG was associated with higher risks of small infant size and low infant body weight, and excessive GWG was associated with higher risk of preterm birth, particularly among women with body mass index 18.5–25.0 kg/m². Results from the present study highlight that both insufficient and excessive GWG are of potential public health concerns in urban centers of SSA, concerning upward trends in obesity and possibly obesity-related pregnancy consequences. Local public health practitioners should continue to advocate longitudinal GWG monitoring and care among African pregnant women, and optimal GWG with feasible and effective clinical guidelines should be developed to prevent both over- and under-gaining of maternal weight during pregnancy.

Food insecurity, depressive symptoms, and the salience of gendered family roles during the COVID-19 pandemic in South Africa

Extensive research has indicated food insecurity to be associated with depressive symptoms, both of which have been indicated to increase globally during the COVID-19 pandemic. Few studies, however, have made use of nationally representative and longitudinal data to investigate this relationship, making causal claims difficult. In South Africa (SA), as with other low- and middle-income contexts, population-based studies have generally focused on mothers during the perinatal period and other vulnerable groups. This study made use of Cross-Lagged Dynamic Panel Models to examine the relationship between household food insecurity and the depressive symptoms of adults across three waves of the National Income Dynamics Survey–Coronavirus Rapid Mobile Survey (NIDS-CRAM) study collected in 2020 and 2021, a dataset nationally representative of all adults in SA in 2017. Stratification of the sample by gender, parenthood and marital statuses allowed for the assessment of gender differences in family roles that might account for differential impacts of food insecurity on mental health outcomes. The findings of this study indicated a significant impact of food insecurity on the depressive symptoms of adults. Controlling for stable trait-like individual differences eliminated much of this relationship, indicating partial or full mediation by unobserved factors. Gender differences in food security's association with depressive symptoms amongst cohabitating parents following the inclusion of individual effects provided support for a gendered role response. These findings provide further evidence of the complex interactions between sex, gender and health.

The correlation between food insecurity and infant mortality in North Carolina

OBJECTIVE

Food insecurity (FI) affects approximately 11·1 % of US households and is related to worsened infant outcomes. Evidence in lower income countries links FI and infant mortality rates (IMR), but there are limited data in the USA. This study examines the relationship between FI and IMR in North Carolina (NC).

DESIGN

NC county-level health data were used from the 2019 Robert Woods Johnson Foundation County Health Rankings. The dependent variable was county-level IMR. Eighteen county-level independent variables were selected and a multivariable linear regression was performed. The independent variable, FI, was based on the United States Department of Agriculture's Food Security Supplement to the Current Population Survey.

SETTING

NC counties.

PARTICIPANTS

Residents of NC, county-level data.

RESULTS

The mean NC county-level IMR was 7·9 per 1000 live births compared with 5·8 nationally. The average percentage of county population reporting FI was 15·4 % in the state v. 11·8 % nationally. Three variables statistically significantly predicted county IMR: percent of county population reporting FI; county population and percent population with diabetes (P values, respectively, < 0·04; < 0·05; < 0·03). These variables explained 42·4 % of the variance of county-level IMR. With the largest standardised coefficient (0·247), FI was the strongest predictor of IMR.

CONCLUSIONS

FI, low birth weight and diabetes are positively correlated with infant mortality. While correlation is not causation, addressing FI as part of multifaceted social determinants of health might improve county-level IMR in NC.

Externalizing behavior in preschool children in a South African birth cohort: Predictive pathways in a high-risk context

Mental health problems often begin in early childhood. However, the associations of various individual and contextual risk factors with mental health in the preschool period are incompletely understood, particularly in low- to middle-income countries (LMICs) where multiple risk factors co-exist. To address this gap, we prospectively followed 981 children in a South African birth cohort, the Drakenstein Child Health Study, assessing pre-and postnatal exposures and risk factors. The predictive value of these factors for child mental health (assessed by the Child Behavior Checklist) was modeled using structural equation modeling. We identified two key pathways to greater externalizing behavior: (1) prenatal exposure to substances (alcohol and smoking) directly predicted increased externalizing behavior (β = 0.24, p < 0.001); this relationship was partially mediated by an aspect of infant temperament (negative emotionality; β = 0.05, p = 0.016); (2) lower socioeconomic status and associated maternal prenatal depression predicted more coercive parenting, which in turn predicted increased externalizing behavior (β = 0.18, p = 0.001). Findings in this high-risk LMIC cohort cohere with research from higher income contexts, and indicate the need to introduce integrated screening and intervention strategies for maternal prenatal substance use and depression, and promoting positive parenting across the preschool period.

Early structural brain development in infants exposed to HIV and antiretroviral therapy in utero in a South African birth cohort

Introduction

There is a growing population of children who are HIV‐exposed and uninfected (HEU) with the successful expansion of antiretroviral therapy (ART) use in pregnancy. Children who are HEU are at risk of delayed neurodevelopment; however, there is limited research on early brain growth and maturation. We aimed to investigate the effects of in utero exposure to HIV/ART on brain structure of infants who are HEU compared to HIV‐unexposed (HU).

Methods

Magnetic resonance imaging using a T2‐weighted sequence was undertaken in a subgroup of infants aged 2–6 weeks enrolled in the Drakenstein Child Health Study birth cohort, South Africa, between 2012 and 2015. Mother–child pairs received antenatal and postnatal HIV testing and ART per local guidelines. We compared subcortical and total grey matter volumes between HEU and HU groups using multivariable linear regression adjusting for infant age, sex, intracranial volume and socio‐economic variables. We further assessed associations between brain volumes with maternal CD4 cell count and ART exposure.

Results

One hundred forty‐six infants (40 HEU; 106 HU) with high‐resolution images were included in this analysis (mean age 3 weeks; 50.7% male). All infants who were HEU were exposed to ART (88% maternal triple ART). Infants who were HEU had smaller caudate volumes bilaterally (5.4% reduction, p < 0.05) compared to HU infants. There were no group differences in other subcortical volumes (all p > 0.2). Total grey matter volume was also reduced in infants who were HEU (2.1% reduction, p < 0.05). Exploratory analyses showed that low maternal CD4 cell count (<350 cells/mm³) was associated with decreased infant grey matter volumes. There was no relationship between timing of ART exposure and grey matter volumes.

Conclusions

Lower caudate and total grey matter volumes were found in infants who were HEU compared to HU in the first weeks of life, and maternal immunosuppression was associated with reduced volumes. These findings suggest that antenatal HIV exposure may impact early structural brain development and improved antenatal HIV management may have the potential to optimize neurodevelopmental outcomes of children who are HEU.

Cytomegalovirus acquisition in infancy and the risk of tuberculosis disease in childhood: a longitudinal birth cohort study in Cape Town, South Africa

BACKGROUND

The risk of tuberculosis disease after recent exposure is greatest before age 5 years; however, the mechanisms explaining this increased risk are not well elucidated. Acquisition of viral infections, such as cytomegalovirus, in early life might modulate the immune system. We aimed to evaluate the acquisition of cytomegalovirus infection in infancy and the development of tuberculosis disease in children.

METHODS

In this prospective, birth cohort study we enrolled pregnant women who were between 20 and 28 weeks of gestation attending antenatal care in Paarl, a periurban setting outside of Cape Town, South Africa. Participants were recruited from two clinics (TC Newman and Mbekweni). Infants were given Bacillus Calmette-Guérin vaccination at birth as per national policy. Nasopharyngeal swabs for cytomegalovirus detection using qPCR were done for infants at birth, age 3 and 6 weeks, and age 3, 6, 12, and 24 months. Children were prospectively followed up for tuberculosis disease until age 9 years using tuberculin skin testing, radiographic examinations, GeneXpert, and sputum testing. Tuberculin skin tests were done at the 6-month visit and then at age 12, 24, 36, 48, and 60 months, and at the time of lower respiratory tract infection. We compared tuberculosis disease incidence after age 1 year or after age 6 months in children with and without cytomegalovirus infection using Cox regression and hazard ratios (HRs) with 95% CIs.

FINDINGS

Between March 5, 2012, and March 31, 2015, 1225 pregnant women were recruited and enrolled in the birth cohort. 88 (7%) women were excluded because of loss to antenatal follow-up or pregnancy losses. Of 1143 livebirths, 68 (6%) mother-infant pairs were excluded. In total, 963 children were serially tested for cytomegalovirus (7186 cytomegalovirus measurements taken; median six tests per child, IQR 2-11). The prevalence of congenital cytomegalovirus at age younger than 3 weeks was 2% (18 of 816). Cytomegalovirus positivity increased continuously with age from 3% (27 of 825) by age 6 weeks to 21% (183 of 882) by 3 months, 35% (315 of 909) by 6 months, and 42% (390 of 933) by 12 months. Mother-infant pairs were followed up for a median of 6·9 years (IQR 6·0-7·8). The risk of tuberculosis disease in children after age 1 year was higher in those with cytomegalovirus infection by age 6 weeks (adjusted HR 4·1, 95% CI 1·2-13·8; p=0·022), 3 months (2·8, 1·4-5·8; p=0·0040), 6 months (3·6, 1·7-7·3; p<0·0001), 12 months (3·2, 1·6-6·4; p=0·0010), and 24 months (4·2, 2·0-8·8; p<0·0001). The risk of microbiologically confirmed tuberculosis disease was also higher among children acquiring cytomegalovirus infection before age 3 months (adjusted HR 3·2, 95% CI 1·0-10·6; p=0·048), 6 months (3·9, 1·2-13·0; p=0·027), 12 months (4·4, 1·2-16·3; p=0·027), and 24 months (6·1, 1·3-27·9; p=0·020). In children older than 1 year, the risk of tuberculosis disease was consistently greater in those with high cytomegalovirus loads than in those with low cytomegalovirus loads that were acquired before age 3 months (adjusted HR 2·0 vs 3·7; ptrend=0·0020; both groups compared with cytomegalovirus negative reference) and before age 12 months (2·7 vs 3·7; ptrend=0·0009).

INTERPRETATION

Infants that acquire cytomegalovirus in the first year of life are at high risk of subsequently developing tuberculosis disease. Efforts to prevent tuberculosis in early childhood in high-burden countries might need to deter or delay acquisition of cytomegalovirus perinatally or in the first months of life.

FUNDING

Bill & Melinda Gates Foundation, MRC South Africa, National Research Foundation South Africa, and Wellcome Trust.

Vitamin D concentrations in infancy and the risk of tuberculosis in childhood: A prospective birth cohort in Cape Town, South Africa

INTRODUCTION

Low vitamin D may increase the risk of tuberculosis; however, previous observational cohort studies have had variable results. We investigated the relationship between vitamin D levels in infancy and subsequent development of tuberculosis throughout childhood.

METHODS

We enrolled pregnant women between 20-28 weeks' gestation attending antenatal care in a peri-urban South African setting in the Drakenstein Child Health Study. Serum 25(OH)D concentrations were measured in newborn infants between 6-10 weeks of age. Children were followed prospectively for tuberculosis infection and disease using annual tuberculin skin testing, radiographic examinations, and microbiological diagnosis with GeneXpert, culture, and smear testing. Univariable and multivariable Cox regression was performed and hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated.

RESULTS

Children were followed for tuberculosis for a median of 7.2 years (IQR, 6.2-7.9). Among 744 children (< 1% living with HIV, 21% HIV-exposed living without HIV), those who were vitamin D deficient in early infancy were not at increased risk of developing tuberculosis (AHR, 0.8; 95% CI, 0.4-1.6). Infants in the lowest vitamin D concentration tertile were at similar risk of tuberculosis compared to the highest tertile (AHR, 0.7; 95% CI, 0.4-1.4). Vitamin D deficiency was associated with tuberculin conversion ≤2 years of age at a <30nmol/l (AOR, 1.9; 95% CI, 1.2-3.2), but not <50nmol/l (AOR, 1.5; 95% CI, 0.8-2.9), cutoff.

CONCLUSION

In a setting with hyperendemic tuberculosis, vitamin D levels in infancy did not predict tuberculosis at any point in childhood. However, very low vitamin D levels were associated with tuberculin conversion in young children.

Maternal psychosocial risk factors and child gestational epigenetic age in a South African birth cohort study

Accelerated epigenetic aging relative to chronological age has been found to be associated with higher risk of mortality in adults. However, little is known about whether and how in utero exposures might shape child gestational epigenetic age (EA) at birth. We aimed to explore associations between maternal psychosocial risk factors and deviation in child gestational EA at birth (i.e., greater or lower EA relative to chronological age) in a South African birth cohort study-the Drakenstein Child Health Study. Maternal psychosocial risk factors included trauma/stressor exposure; posttraumatic stress disorder (PTSD); depression; psychological distress; and alcohol/tobacco use. Child gestational EA at birth was calculated using an epigenetic clock previously devised for neonates; and gestational EA deviation was calculated as the residuals of the linear model between EA and chronological gestational age. Bivariate linear regression was then used to explore unadjusted associations between maternal/child risk factors and child gestational EA residuals at birth. Thereafter, a multivariable regression method was used to determine adjusted associations. Data from 271 maternal-child dyads were included in the current analysis. In the multivariable regression model, maternal PTSD was significantly and negatively associated with child gestational EA residuals at birth (β = -1.95; p = 0.018), controlling for study site, sex of the child, head circumference at birth, birthweight, mode of delivery, maternal estimated household income, body mass index (BMI) at enrolment, HIV status, anaemia, psychological distress, and prenatal tobacco or alcohol use. Given the novelty of this preliminary finding, and its potential translational relevance, further studies to delineate underlying biological pathways and to explore clinical implications of EA deviation are warranted.

Cleft Lip and/or Palate and Associated Risks in Lower-Middle-Income Countries: A Systematic Review

OBJECTIVE

To identify and review published data on the risks associated with cleft lip and/or palate (CL/P) in lower-middle-income countries (LMICs).

DESIGN

A systematic review of literature was performed on electronic databases using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols. Literature on risks associated with CL/P in LMICs, from 2010 to 2020, were included.

RESULTS

Seventeen studies met the inclusion criteria. All studies adopted an observational study design. Biological and environmental risks were identified. Maternal and paternal age (n = 7) and low socioeconomic status (n = 5) were the most prominently associated environmental risk factors. A strong association was identified between family history of cleft (n = 7) and CL/P occurrence.

CONCLUSION

Environmental risk factors are now being investigated more than biological risk factors in LMICs, aiding health care workers in the early identification of possible cumulative effects of risks in CL/P. Contextually relevant tools are recommended to promote early identification of at-risk infants.

Prevalence and Correlates of Vitamin D Deficiency among Young South African Infants: A Birth Cohort Study

Early-life vitamin D deficiency is associated with adverse child health outcomes, but the prevalence of vitamin D deficiency and its correlates in infants remains underexplored, particularly in sub-Saharan Africa. We aimed to investigate the prevalence of vitamin D deficiency and its correlates among young infants in South Africa. This study included 744 infants, aged 6–10 weeks from the Drakenstein Child Health Study, a population-based birth cohort. Infants were categorized into distinct categories based on serum 25(OH)D concentration level including deficient (<50 nmol/L), insufficient (50–74 nmol/L), and sufficient (≥75 nmol/L). Using multivariable Tobit and logistic regression models, we examined the correlates of serum 25(OH)D₃ levels. The overall prevalence of vitamin D deficiency was 81% (95% confidence intervals (CI]) 78–83). Multivariable regression analysis showed that serum 25(OH)D₃ concentration was independently associated with study site, socioeconomic status, and sex. Birth in winter and breastfeeding were the strongest predictors of lower serum 25(OH)D₃ concentration levels. Compared to non-breastfed children, children breastfed were at higher risk of vitamin D deficiency (AOR, 1.96; 95% CI, 1.04–3.67) and breastfeeding for more than one month was associated with greater likelihood of vitamin D deficiency (AOR, 5.40; 95% CI, 2.37–12.32) and lower vitamin D concentrations (−16.22 nmol/L; 95% CI, −21.06, −11.39). Vitamin D deficiency in infants is ubiquitous, under-recognised, and strongly associated with season of birth and breastfeeding in this setting. Nutritional interventions with vitamin D supplementation in national health programs in low- and middle-income countries are urgently needed to improve early-life vitamin D status in infants.

Associations Between Prenatal Food Insecurity and Prematurity, Pediatric Health Care Utilization, and Postnatal Social Needs

OBJECTIVE

Childhood food insecurity endangers child development and health outcomes. Food insecurity will grow increasingly common in the economic wake of the coronavirus pandemic and prenatal care represents an early, clinical opportunity to identify families at risk. However, longitudinal relationships between clinically-identified prenatal food insecurity and prematurity, pediatric health care utilization, and postnatal social needs have not been described.

METHODS

We examined longitudinal data from mother-child dyads who received prenatal and pediatric care and social needs screening at a large academically-affiliated safety net medical center between October 2018 and July 2019. Associations among household food insecurity and premature birth, pediatric inpatient and outpatient utilization, missed immunizations, and postnatal social needs were estimated using adjusted regression.

RESULTS

Among the 268 mothers, those who experienced prenatal household food insecurity had 3 times higher odds of having a child born prematurely (95% confidence interval [CI] 1.0-8.9, P = .05) and had children with higher inpatient hospitalizations (incidence rate ratio [IRR] 2.4, 95% CI 1.0-5.6, P = .04) and missed immunizations (IRR 3.4, 95% CI 1.1-10.3, P = .03) in the first 6 months of the child's life. These mothers also had higher odds of having any social needs in the pediatric setting (odds ratio 3.4; 95% CI 1.5-8.0, P = .004).

CONCLUSIONS

Prenatal household food insecurity was linked to future adverse perinatal and pediatric outcomes in low-income mother-child dyads. Food insecurity identifies children at social and medical risk, providing an early clinical opportunity to intervene.

The relationship between childhood trauma, socioeconomic status, and maternal depression among pregnant women in a South African birth cohort study

Background

Maternal depression is an important cause of morbidity and mortality. Experiences of childhood trauma contribute to maternal depression, potentially causing adult socio-economic disparities in mental health. We investigate whether adult socioeconomic status (SES) mediates the relationship between childhood trauma and antenatal depression.

Methods

We analyzed data from two sociodemographically distinct peri-urban sites in the Western Cape, South Africa in a birth cohort study, the Drakenstein Child Health Study: Mbekweni (N = 510) and TC Newman (N = 413). Data were collected from pregnant women between 28 and 32 weeks’ gestation.

Results

Associations between trauma and depressive symptoms differed by site (χ2=2163.6, df = 1419, p < 0.01); direct effects of trauma on depression were 0.24 mean increased symptoms in Mbekweni (p < 0.01) and 0.47 in TC Newman (p < 0.01). Trauma was differentially associated with SES (Mbekweni: −0.10, p = 0.07; TC Newman: −0.05, p = 0.37) and SES with depression (Mbekweni: −0.18, p < 0.01; TC Newman: −0.02, p = 0.62) across both sites. Indirect effects of trauma on depression through SES were 0.018 (95% C.I. −0.002-0.039) in Mbekweni and 0.001 (95% C.I. −0.004-0.006) in TC Newman, suggesting mediation was not supported. SES was a stronger indicator of depression risk in relatively poorer Mbekweni.

Conclusion

Neighborhood-level effects and poverty are potentially important modifiers, and points of intervention, for maternal mental health outcomes.

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Childhood trauma and low socioeconomic status (SES) independently predict antenatal depression among a cohort of expecting women.

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The relationship between childhood trauma, SES, and antenatal depression differed by clinical site.

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These differential relationships may have been due to neighborhood effects on social determinants of mental health.

What differs former, light and heavy smokers? Evidence from a post-conflict setting

BACKGROUND

Evidence suggests that people who live in regions affected by the armed conflict are more likely to smoke.

OBJECTIVE

The purpose of this study was to assess factors associated with smoking status in a sample of students in the northern Kosovo province.

MATERIALS AND METHODS

A total of 514 students enrolled in University in Kosovska Mitrovica, Kosovo, were recruited between April to June 2015 at Student Public Health Center during mandatory health checks. Participants filled in socio-demographic and behavioral questionnaire and Beck Depression Inventory (BDI). Based on responses about smoking, students were categorized in non-smokers, former smokers, light smokers (1-13 cigarettes/day) and heavy smokers (> 13 cigarettes/day).

RESULTS

Of 514 students, 116 (22.6%) classified themselves as smokers. Higher education level of fathers (Odds ratio [OR]=2.89, 95% confidence interval [CI] 1.30-6.44, p=0.009), not living with smokers (OR=0.42, 95%CI 0.15-0.97, p=0.017) and longer exposure to second hand smoke (OR=1.07, 95%CI 1.01-1.13, p=0.036) was associated with former smoking. Studying medical and natural sciences (OR=2.07, 95%CI 1.05-4.18, p=0.040), consuming alcohol (OR=2.98, 95%CI 1.19-10.03, p=0.020), living with smokers (OR=2.88, 95%CI 1.49-5.56, p=0.002), longer exposure to second hand smoke (OR=1.06, 95%CI 1.01-1.11, p=0.019) and having a more intense depressive symptoms (OR=1.08, 95%CI 1.03-1.13, p=0.002) was associated with light smoking. Being male (OR=0.22, 95%CI 0.07-0.41, p=0.001), older (OR=1.47, 95%CI 1.21-1.78, p=0.001), living with smokers (OR=3.78, 95%CI 1.69-8.07, p=0.001), longer daily exposure to second-hand smoke (OR=1.10, 95%CI 1.04-1.16, p=0.001), and having more severe depressive symptoms (OR=1.12, 95%CI 1.07-1.18, p=0.001) were associated with heavy smoking.

CONCLUSION

Smoking prevention and cessation programs should include the entire community, because exposure to environmental second hand smoke may facilitate initiation and more intense smoking. Screening of student smokers for depression should be prioritized in the process of rebuilding the framework for primary and secondary prevention in the post-conflict period.

Flexible modelling of risk factors on the incidence of pneumonia in young children in South Africa using piece-wise exponential additive mixed modelling

Introduction

Recurrent episodes of pneumonia are frequently modeled using extensions of the Cox proportional hazards model with the underlying assumption of time-constant relative risks measured by the hazard ratio. We aim to relax this assumption in a study on the effect of factors on the evolution of pneumonia incidence over time based on data from a South African birth cohort study, the Drakenstein child health study.

Methods

We describe and apply two models: a time-constant and a time-varying relative effects model in a piece-wise exponential additive mixed model’s framework for recurrent events. A more complex model that fits in the same framework is applied to study the continuously measured seasonal effects.

Results

We find that several risk factors (male sex, preterm birth, low birthweight, lower socioeconomic status, lower maternal education and maternal cigarette smoking) have strong relative effects that are persistent across time. When time-varying effects are allowed in the model, HIV exposure status (HIV exposed & uninfected versus HIV unexposed) shows a strong relative effect for younger children, but this effect weakens as children grow older, with a null effect reached from about 15 months. Weight-for-length at birth shows a time increasing relative effect. We also find that children born in the summer have a much higher risk of pneumonia in the 3-to-8-month age period compared with children born in winter.

Conclusion

This work highlights the usefulness of flexible modelling tools in recurrent events models. It avoids stringent assumptions and allows estimation and visualization of absolute and relative risks over time of key factors associated with incidence of pneumonia in young children, providing new perspectives on the role of risk factors such HIV exposure.

Supplementary Information

The online version contains supplementary material available at (10.1186/s12874-020-01194-6).

Does Universal Screening for Gestational Diabetes Mellitus Improve Neonatal Outcomes in a Socially Vulnerable Population: A Prospective Study in French Guiana

AIMS/INTRODUCTION

French Guiana has a high prevalence of metabolic diseases, which are risk factors for gestational diabetes mellitus. Despite routine screening for gestational diabetes, treatment is still challenging because of health inequalities and different cultural representations of disease and pregnancy. This study was conducted to assess the role of early and universal GDM screening on obstetrical and neonatal complications in a socially deprived population.

MATERIALS AND METHODS

A prospective study was conducted, in the level III maternity in French Guiana. Of 2136 deliveries, 223 had gestational diabetes mellitus, 110 of whom were followed-up for 6 month to detail their social and laboratory parameters.

RESULTS

The prevalence of gestational diabetes in French Guiana (Cayenne Hospital) was estimated at 10.3%. The study population was very precarious with 70% of patients on welfare (universal health coverage or state medical assistance). The following obstetrical complications were observed: cesarean delivery (32%), history of miscarriage (26%) and preeclampsia (7.4%). Nevertheless, neonatal complications were rarely present and included hypoglycemia (2.8%) and macrosomia (2.8%).

CONCLUSION

In French Guiana, gestational diabetes mellitus is very common. However, in a context of widespread poverty and diverse cultural representations, universal screening and monitoring limited the risk of macrosomia.

Exposure to electronic screen before nocturnal sleep increases the risk of hypertensive disorders of pregnancy: A case-control study

AIM

Previous studies indicated that excessive screen time was associated with hypertension in children and adolescents. In our hospital, pregnant women tended to spend a lot of time on electronic devices like smartphones. We aimed to explore the relationship between the screen time and hypertensive disorders of pregnancy (HDP).

METHODS

A case-control study was conducted from November 2019 to May 2020. A total of 160 women with HDP and 197 healthy controls who gave birth to children in the same hospital were recruited and information was recorded by questionnaires. Multivariate analysis was conducted to assess the effect of screen time on HDP.

RESULTS

The results showed that, exposure to electronic screen before nocturnal sleep in cases was significantly longer than that in controls (P = 0.011, odds ratio = 1.50). Smartphones (and/or tablet computers) used only for entertainment also significantly increased the susceptibility to HDP (P < 0.001, odds ratio = 2.84). Other related factors were following: work experience during pregnancy (P = 0.034, odds ratio = 0.53), history of diabetes mellitus (P = 0.013, odds ratio = 2.55), history of family hypertension (P < 0.001, odds ratio = 3.81), body mass index of pre-pregnancy (>25 kg/m² ) (P < 0.001, odds ratio = 6.16).

CONCLUSION

In conclusion, long exposure to electronic screen before nocturnal sleep and the smartphones usage for only entertainment may be associated with the susceptibility to HDP.

Intimate Partner Violence: A Risk Factor for Gestational Diabetes

The early detection and management of gestational diabetes mellitus (GDM) is an important public health goal. GDM, which is defined as a glucose intolerance that develops during pregnancy, affects about 14% of pregnancies globally, and without effective treatment, it is associated with adverse short- and long-term maternal and neonatal outcomes. Risk-factor screening is an acceptable and affordable strategy to enable risk stratification and intervention. However, common biological risk factors such as overweight or obesity, excessive gestational weight gain, and family history of diabetes often have poor predictive ability, failing to identify a large proportion of women at risk of developing GDM. Accumulating evidence implicate psychosocial factors in contributing to GDM risk. As such, intimate partner violence (IPV), through its contributing effects on maternal stress and depression, presents a plausible risk factor for GDM. Experiencing IPV during pregnancy may dysregulate the hypothalamus-pituitary-adrenal (HPA) axis, leading to increased cortisol secretion and insulin resistance. These effects may exacerbate the insulin-resistant environment characteristic of pregnancy, thus increasing GDM risk. This review explores the relationship between IPV and GDM. We highlight studies that have linked IPV with GDM and propose a biological mechanism that connects IPV and GDM. Recommendations for IPV screening strategies to prevent GDM are discussed.

Food insecurity as a risk factor for preterm birth: a prospective facility-based cohort study in rural Haiti

INTRODUCTION

Haiti has an estimated neonatal mortality rate of 32/1000 live births, the highest in the Western Hemisphere. Preterm birth and being born small for gestational age (SGA) are major causes of adverse neonatal outcomes worldwide. To reduce preterm birth and infants born SGA, it is important to understand which women are most at risk and how risk varies within countries. There are few studies estimating the prevalence and risk factors for these conditions in Haiti, particularly in rural regions.

METHODS

We conducted a prospective cohort study of pregnant women at a rural tertiary care centre in Haiti from May to December 2017. We collected data during interviews and from the medical record. We built multivariable models to identify risk factors for preterm birth and being born SGA among women who had a facility-based delivery.

RESULTS

1089 pregnant women delivered at the hospital and were included in this analysis. Median gestational age at delivery was 38 weeks (IQR 36-40). In multivariable analyses, risk factors for preterm birth included maternal age <20 years (adjusted OR (AOR) 1.76, 95% CI 1.14 to 2.72) and >34 years (AOR 1.46, 95% CI 1.01 to 2.11) and severe hunger in the household (AOR 1.57, 95% CI 1.09 to 2.26). Risk factors for SGA were age >34 years (AOR 1.76, 95% CI 1.18 to 2.59), twin pregnancy (AOR 3.28, 95% CI 1.20 to 8.95) and first pregnancy (AOR 1.57, 95% CI 1.12 to 2.23). Number of prior abortions was associated with reduced risk for SGA (AOR 0.41, 95% CI 0.17 to 0.97).

CONCLUSIONS

Food insecurity as a risk factor for preterm birth stands out as an important addition to the understanding of the risk of neonatal morbidity and mortality. This association highlights a potentially important intervention target to improve birth outcomes and suggests that food support has an important role to play for pregnant women who are food insecure in low-income settings.