Whitney Barnett

Investigating the early-life determinants of illness in Africa: the Drakenstein Child Health Study

Respiratory disease is the predominant cause of illness in children globally. We describe a unique multidisciplinary South African birth cohort, the Drakenstein Child Health Study (DCHS), to investigate the incidence, risk factors, aetiology and long-term impact of early lower respiratory tract infection (LRTI) on child health. Pregnant women from a poor, peri-urban community with high exposure to infectious diseases and environmental risk factors are enrolled with 1000 mother–child pairs followed for at least 5 years. Biomedical, environmental, psychosocial and demographic risk factors are longitudinally measured. Environmental exposures are measured using monitors placed at home visits. Lung function is measured in children at 6 weeks, annually and during LRTI episodes. Microbiological investigations including microbiome and multiplex PCR measures are done longitudinally and at LRTI episodes. The DCHS is a unique African birth cohort study that uses sophisticated measures to comprehensively investigate the early-life determinants of child health in an impoverished area of the world.

Risk factors for respiratory syncytial virus associated with acute lower respiratory infection in children under five years: Systematic review and meta-analysis

Background Respiratory syncytial virus (RSV) is the most common pathogen identified in young children with acute lower respiratory infection (ALRI) as well as an important cause of hospital admission. The high incidence of RSV infection and its potential severe outcome make it important to identify and prioritise children who are at higher risk of developing RSV–associated ALRI. We aimed to identify risk factors for RSV–associated ALRI in young children. Methods We carried out a systematic literature review across 4 databases and obtained unpublished studies from RSV Global Epidemiology Network (RSV GEN) collaborators. Quality of all eligible studies was assessed according to modified GRADE criteria. We conducted meta–analyses to estimate odds ratios with 95% confidence intervals (CI) for individual risk factors. Results We identified 20 studies (3 were unpublished data) with “good quality” that investigated 18 risk factors for RSV–associated ALRI in children younger than five years old. Among them, 8 risk factors were significantly associated with RSV–associated ALRI. The meta–estimates of their odds ratio (ORs) with corresponding 95% confidence intervals (CI) are prematurity 1.96 (95% CI 1.44–2.67), low birth weight 1.91 (95% CI 1.45–2.53), being male 1.23 (95% CI 1.13–1.33), having siblings 1.60 (95% CI 1.32–1.95), maternal smoking 1.36 (95% CI 1.24–1.50), history of atopy 1.47 (95% CI 1.16–1.87), no breastfeeding 2.24 (95% CI 1.56–3.20) and crowding 1.94 (95% CI 1.29–2.93). Although there were insufficient studies available to generate a meta–estimate for HIV, all articles (irrespective of quality scores) reported significant associations between HIV and RSV–associated ALRI. Conclusions This study presents a comprehensive report of the strength of association between various socio–demographic risk factors and RSV–associated ALRI in young children. Some of these amenable risk factors are similar to those that have been identified for (all cause) ALRI and thus, in addition to the future impact of novel RSV vaccines, national action against ALRI risk factors as part of national control programmes can be expected to reduce burden of disease from RSV. Further research which identifies, accesses and analyses additional unpublished RSV data sets could further improve the precision of these estimates.

Aetiology of childhood pneumonia in a well vaccinated South African birth cohort: a nested case-control study of the Drakenstein Child Health Study

Summary Background Pneumonia is a leading cause of mortality and morbidity in children globally. The cause of pneumonia after introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) has not been well studied in low-income and middle-income countries, and most data are from cross-sectional studies of children admitted to hospital. We aimed to longitudinally investigate the incidence and causes of childhood pneumonia in a South African birth cohort. Methods We did a nested case-control study of children in the Drakenstein Child Health Study who developed pneumonia from May 29, 2012, to Dec 1, 2014. Children received immunisations including acellular pertussis vaccine and PCV13. A nested subgroup had nasopharyngeal swabs collected every 2 weeks throughout infancy. We identified pneumonia episodes and collected blood, nasopharyngeal swabs, and induced sputum specimens. We used multiplex real-time PCR to detect pathogens in nasopharyngeal swabs and induced sputum of pneumonia cases and in nasopharyngeal swabs of age-matched and site-matched controls. To show associations between organisms and pneumonia we used conditional logistic regression; results are presented as odds ratios (ORs) with 95% CIs. Findings 314 pneumonia cases occurred (incidence of 0·27 episodes per child-year, 95% CI 0·24–0·31; median age 5 months [IQR 3–9]) in 967 children during 1145 child-years of follow-up. 60 (21%) cases of pneumonia were severe (incidence 0·05 episodes per child-year [95% CI 0·04–0·07]) with a case fatality ratio of 1% (three deaths). A median of five organisms (IQR 4–6) were detected in cases and controls with nasopharyngeal swabs, and a median of six organisms (4–7) recorded in induced sputum (p=0·48 compared with nasopharyngeal swabs). Bordetella pertussis (OR 11·08, 95% CI 1·33–92·54), respiratory syncytial virus (8·05, 4·21–15·38), or influenza virus (4·13, 2·06–8·26) were most strongly associated with pneumonia; bocavirus, adenovirus, parainfluenza virus, Haemophilus influenzae, and cytomegalovirus were also associated with pneumonia. In cases, testing of induced sputum in addition to nasopharyngeal swabs provided incremental yield for detection of B pertussis and several viruses. Interpretation Pneumonia remains common in this highly vaccinated population. Respiratory syncytial virus was the most frequently detected pathogen associated with pneumonia; influenza virus and B pertussis were also strongly associated with pneumonia. Testing of induced sputum increases the yield for detection of several organisms. New vaccines and strategies are needed to address the burden of childhood pneumonia. Funding Bill & Melinda Gates Foundation, Medical Research Council South Africa, National Research Foundation South Africa, National Institute of Health, and H3Africa.

Investigating the psychosocial determinants of child health in Africa: the Drakenstein Child Health Study

BACKGROUND Early life psychobiological and psychosocial factors play a key role in influencing child health outcomes. Longitudinal studies may help elucidate the relevant risk and resilience profiles, and the underlying mechanisms that impact on child health, but there is a paucity of birth cohort data from low and middle-income countries (LMIC). We describe the rationale for and present baseline findings from the psychosocial component of the Drakenstein Child Health Study (DCHS). METHODS We review the psychosocial measures used in the DCHS, a multidisciplinary birth cohort study in a peri-urban area in South Africa, and provide initial data on psychological distress, depression, substance use, and exposure to traumatic stressors and intimate partner violence (IPV). These and other measures will be assessed longitudinally in mothers in order to investigate associations with child neurodevelopmental and health outcomes. RESULTS Baseline psychosocial data is presented for mothers (n=634) and fathers (n=75) who have completed antenatal assessments to date. The sample of pregnant mothers is characterized by multiple psychosocial risk factors, including a high prevalence of psychological distress and depression, high levels of substance use, and high exposure to traumatic stressors and IPV. DISCUSSION These data are consistent with prior South African studies which have documented a high prevalence of a multitude of risk factors during pregnancy. Further longitudinal assessment of mothers and children may clarify the underlying psychobiological and psychosocial mechanisms which impact on child health, and so inform clinical and public health interventions appropriate to the South African and other LMIC contexts.

Risk Factors for Antenatal Depression and Associations with Infant Birth Outcomes: Results From a South African Birth Cohort Study

BACKGROUND Maternal antenatal depression may be particularly prevalent in low- and middle-income countries, but there is a paucity of data on its effect on birth outcomes in such settings. We investigated risk factors for antenatal depression and the associations between depression and infant birth outcomes in the Drakenstein Child Health Study (DCHS), a birth cohort study in the Western Cape, South Africa. METHODS The prevalence of depression in pregnant women enrolled in the DCHS from primary care antenatal clinics was measured using the Beck Depression Inventory (BDI-II). Predictors of antenatal depression were investigated using logistic regression, and the associations between depression and infant birth outcomes were examined in linear regression models. RESULTS Among 726 pregnant women (median age: 26 years), 156 (21%) had BDI-II scores suggesting depression. Independent predictors of depression included single marital status, low socioeconomic status (SES), recent stressful life events, unplanned pregnancy, childhood trauma, and past-year intimate partner violence. No association was observed between antenatal depression and preterm birth. Strong associations were observed between antenatal depression and decreased infant weight-for-age (WAZ) and head circumference-for-age (HCAZ) z-scores at birth. In multivariable analysis, the association between depression and decreased HCAZ remained significant, when adjusted for clinic, SES, and recent stressful life events. CONCLUSIONS Antenatal depression and associated risk factors are highly prevalent in this setting and are associated with adverse fetal growth. Maternal mental health may be an important predictor of infant growth in utero.

Home environment and indoor air pollution exposure in an African birth cohort study

BACKGROUND Household indoor air pollution (IAP) is a global health problem and a risk factor for childhood respiratory disease; the leading cause of mortality in African children. This study aimed to describe the home environment and measure IAP in the Drakenstein Child Health Study (DCHS), an African birth cohort. METHODS An antenatal home visit to assess the home environment and measure IAP (particulate matter, sulphur dioxide, nitrogen dioxide, carbon monoxide and volatile organic compounds (VOCs)) was done on pregnant women enrolled to the DCHS, in a low-socioeconomic, peri-urban South African community. Urine cotinine measured maternal tobacco smoking and exposure. Dwellings were categorised according to 6 household dimensions. Univariate and multivariate analysis explored associations between home environment, seasons and IAP levels measured. RESULTS 633 home visits were completed, with IAP measured in 90% of homes. Almost a third of participants were of the lowest socio-economic status and the majority of homes (65%) lacked 2 or more of the dwelling category dimensions. Most households had electricity (92%), however, fossil fuels were still used for cooking (19%) and heating (15%) in homes. Antenatal maternal smoking prevalence was 31%; 44% had passive smoke exposure. Of IAP measured, benzene (VOC) was significantly above ambient standards with median 5.6 μg/m3 (IQR 2.6-17.1). There were significant associations between the use of fossil fuels for cooking and increased benzene [OR 3.4 (95% CI 2.1-5.4)], carbon monoxide [OR 2.9 (95% CI 1.7-5.0)] and nitrogen dioxide [OR 18.6 (95% CI 3.9-88.9)] levels. A significant seasonal association was found with higher IAP levels in winter. CONCLUSION In this low-socioeconomic African community, multiple environmental factors and pollutants, with the potential to affect child health, were identified. Measurement of IAP in a resource-limited setting is feasible. Recognising and quantifying these risk factors is important in effecting public health policy changes.

Antenatal and early life tobacco smoke exposure in an African birth cohort study.

BACKGROUND Exposure to tobacco smoke in African infants has not been well studied, despite the high burden of childhood respiratory disease in these communities. OBJECTIVE To investigate the prevalence of antenatal and early life tobacco smoke exposure and associations with infant birth outcomes in an African birth cohort, the Drakenstein Child Health Study. METHODS Self-report questionnaires assessing maternal and household smoking were administered. Maternal and infant urine cotinine testing was conducted antenatally, at birth and at 6-10 weeks of life to measure tobacco smoke exposure. Multivariate regression models explored the associations between exposure to smoke and infant birth outcomes. RESULTS Of 789 pregnant women included, 250 (32%) were active smokers on cotinine testing. At birth and at 6-10 weeks of life, respectively 135/241 (56%) and 154/291 (53%) infants had urine cotinine levels indicating tobacco smoke exposure. Household smoking was prevalent and was associated with positive infant cotinine test results. Antenatal maternal smoking was associated with decreased infant birthweight-for-age Z-score (0.3, 95%CI 0.1-0.5). CONCLUSION Antenatal and early life tobacco smoke exposure is highly prevalent in this community, and may impact on birth outcomes and subsequent child health. Smoking cessation interventions are urgently needed to reduce tobacco smoke exposure in African communities.

Psychological Trauma and Posttraumatic Stress Disorder: Risk Factors and Associations with Birth Outcomes in the Drakenstein Child Health Study

Background Prenatal and peripartum trauma may be associated with poor maternal–fetal outcomes. However, relatively few data on these associations exist from low-middle income countries, and populations in transition. Objective We investigated the prevalence and risk factors for maternal trauma and posttraumatic stress disorder (PTSD), and their association with adverse birth outcomes in the Drakenstein Child Health Study, a South African birth cohort study. Methods Pregnant women were recruited from two clinics in a peri-urban community outside Cape Town. Trauma exposure and PTSD were assessed using diagnostic interviews; validated self-report questionnaires measured other psychosocial characteristics. Gestational age at delivery was calculated and birth outcomes were assessed by trained staff. Multiple logistic regression explored risk factors for trauma and PTSD; associations with birth outcomes were investigated using linear regression. Potential confounders included study site, socioeconomic status (SES), and depression. Results A total of 544 mother–infant dyads were included. Lifetime trauma was reported in approximately two-thirds of mothers, with about a third exposed to past-year intimate partner violence (IPV). The prevalence of current/lifetime PTSD was 19%. In multiple logistic regression, recent life stressors were significantly associated with lifetime trauma, when controlling for SES, study site, and recent IPV. Childhood trauma and recent stressors were significantly associated with PTSD, controlling for SES and study site. While no association was observed between maternal PTSD and birth outcomes, maternal trauma was significantly associated with a 0.3 unit reduction (95% CI: 0.1; 0.5) in infant head-circumference-for-age z-scores (HCAZ scores) at birth in crude analysis, which remained significant when adjusted for study site and recent stressors in a multivariate regression model. Conclusions In this exploratory study, maternal trauma and PTSD were found to be highly prevalent, and preliminary evidence suggested that trauma may adversely affect fetal growth, as measured by birth head circumference. However, these findings are limited by a number of methodological weaknesses, and further studies are required to extend findings and delineate causal links and mechanisms of association.

Acceptability and use of a virtual support group for HIV-positive youth in Khayelitsha, Cape Town using the MXit social networking platform

ABSTRACT Introduction: Médecins Sans Frontières supports human immunodeficiency virus (HIV)-infected youth, aged 12–25 years, at a clinic in Khayelitsha, South Africa. Patients are enrolled in youth clubs, and provided with a virtual chat room, using the cell-phone-based social networking platform, MXit, to support members between monthly/bimonthly club meetings. The acceptability and uptake of MXit was assessed. Methods: MXit was facilitated by lay counsellors, was password protected, and participants could enter and leave at will. Club members were asked to complete self-administered questionnaires and participate in two focus-group discussions. Results and discussion: In total, 60 club members completed the questionnaire, and 12 participated in the focus groups. Fifty-eight percentage were aged 23–25 years, 63% were female and 83% had a cell phone. Sixty percentage had used MXit before, with 38% having used it in the past month. Sixty-five percentage were aware of the chat-room and 39% knew how to access it. Thirty-four percentage used the chat-room at least once, 20% had visited the chat-room in the past month, and 29% had used MXit to have private conversations with other club members. Fifty-seven percentage used the chat-room to get advice, and 84% of all respondents felt that offering a service outside the youth club meetings was important and would like to see one to continue. The cost of using social media platforms was an issue with some, as well as the need for anonymity. Preference for other platforms, logistical obstacles, or loss of interest contributed to non-use. Conclusions: Reported usage of the MXit chat-room was low, but participants indicated acceptance of the programme and their desire to interact with their peers through social media. Suggestions to improve the platform included accessible chat histories, using more popular platforms such as Facebook or WhatsApp, and to have topical discussions where pertinent information for youth is provided.

Investigating tangible and mental resources as predictors of perceived household food insecurity during pregnancy among women in a South African birth cohort study

RATIONALE Food insecurity during pregnancy is concerning given the increased nutritional needs of the mother for proper fetal development. However, research is lacking within the South African context to investigate the association of economic and psychosocial factors and food insecurity among pregnant women, using comprehensive, conceptually driven models. OBJECTIVE This study applies the Network-Individual-Resource (NIR) Model to investigate individual, intimate dyadic, and family level predictors of perceived household food insecurity for pregnant women. METHODS 826 pregnant women enrolled in the Drakenstein Child Health Study (DCHS), a birth cohort in two communities in a peri-urban area of South Africa. Hierarchical logistic regressions were used to investigate the impact of household/family, intimate dyads, and individual tangible and mental resources on perceived household food insecurity during the critical period of pregnancy. Perceived household food insecurity was assessed through an adapted version of the USDA Household Food Security Scale - Short Form. RESULTS Among 826 pregnant women in South Africa, individual-level tangible resources (e.g. income, social assistance, HIV status) and mental resources (e. g. depression, childhood trauma) predicted perceived household food insecurity and these predictors differed by community. Intimate dyadic and family level resources did not predict household food insecurity. CONCLUSIONS Our findings of the economic and psychosocial predictors of perceived household food insecurity among pregnant women in South Africa, mirror findings in general populations. This study provides support for the extension of the NIR model to perceived household food insecurity, particularly regarding individual-level mental and tangible resources, as well as the impact of community-level factors. Future research should investigate the extent to which resource sharing occurs within networks.