Completed research activities
Principal Investigators Norris & Kahn
The aim of this study was to conduct multiple projects aimed at providing implementation and assessing feasibility and acceptability of an intervention aimed at improving the health and nutrition of adolescents to reduce the intergenerational risk of metabolic disease. The results from this study have been incorporated into a RCT grant application to examine the effectiveness of this intervention in both rural and urban South Africa.
Birth to Twenty Plus cohort adolescent longitudinal growth study
Principal investigators: Nyati, Norris & Pettifor
Low- and middle-income countries (LMICs) are experiencing a double-burden of malnutrition characterised by high prevalence of both under- and over-nutrition. We set out, using data from the longitudinal Birth to Twenty Plus (Bt20+) birth cohort, to evaluate the patterns of malnutrition and growth in urban Soweto-Johannesburg by: (i) assessing the prevalence of overweight and obesity from ages 2 to 21 years in male and female children, and (ii) determining percentiles for height, weight, BMI, waist and hip circumferences and comparing the centiles to American and Dutch references. In addition, we have been examining specialised areas of adolescent growth (for example, skeletal maturity, metacarpal indices and body composition) in a dense phenotypically detailed sub-cohort (the Bone Health Cohort) that had annual assessments from 9 to 20 years of age.
Prevalence of overweight and obesity for black boys (red solid), white boys (red dashed), black girls (black solid), and white girls (black lines)
The Siyakhula Cohort: The effect of an exclusive breastfeeding support intervention on subsequent development of children in the context of HIV
Principal Investigator Bland and Co-Investigators Rochat, Newell, Stein & Desmond
The Siyakhula Cohort is based at the Africa Health Research Institute's collaborating field site in rural South Africa and includes 1536 HIV-negative children born to HIV-infected (HIV-exposed) and HIV-uninfected (unexposed) mothers enrolled in the Vertical Transmission Study (2000-2006). Follow up from pregnancy through to 12 years includes data on HIV exposure in foetal and early life, and other early life factors (including breastfeeding) known to impact on later health outcomes. This cohort predated the antiretroviral treatment (ART) roll-out which allows for examination of outcomes associated with HIV exposure without ART exposure in utero and during breastfeeding. Data in the preadolescent data collection round included data on growth, health, cognition (including executive function), education and emotional-behavioural outcomes. Ongoing projects within DPHRU focus on analysis of this cohort.
Newton Advanced Fellowship: Investigating the relationship between executive function and mental health problems in early adolescence
Principal Investigator Rochat and Co-Investigator Pearson
This project followed up 160/354 children in the Siyakhula Cohort who met the Child Behaviour Checklist (CBCL) cut off (>65) for any mental disorder at ages 7-11 years and assessed whether this was associated with mental disorders at ages 13-15 years using a clinical interview method (the Developmental and Wellbeing Assessment). We also measured risk-taking using a computerised task, measured executive function and repeated the cognitive measurements from the previous Siyakhula assessment round. Data analysis is currently underway.
Linking longitudinal demographic, health and environmental data in a rural South African cohort (Siyakhula)
Principal Investigator Rochat and Co-investigators Bland, Houle, Tanser & Stein
This study augmented the existing work of the Siyakhula cohort with a primary aim of investigating the life course variables (including HIV and other cumulative adverse exposures) involved in children’s cognitive development and mental health in rural South Africa. A secondary aim was to examine whether environmental factors (for example, access to water and sanitation, access to health services, urban versus rural geographical location, green spaces) mitigate the effects of adversity on development for rural pre-adolescent children. The project extended the data available in the Siyakhula Cohort by linking the existing index child with all the longitudinal data available on the child’s family from the Africa Health Research Institute’s Demographic Surveillance System and Geographical Information System and supplemented this with existing satellite data to create temporal environmental data. Data linkage and the creation of GIS satellite tags were completed.
Amagugu Clinical Trial Early Adolescent Follow Up Study
Principal Investigators Rochat & Bland and Co-Investigators Stein, Houle & Cortina-Borja
This longitudinal follow-up of the Amagugu clinical trial mothers and children took place when the mean age of the children was 12 years (2016-2017). The Amagugu conceptual model hypothesised that, in the longer term, exposure to the intervention would increase health promotion and lead to parent-led health education (including parent-led sex education) to HIV-exposed children, in turn protecting them from early adolescent reproductive health risks. At 18-24 months post intervention we traced and assessed n=374 (81%) of the trial participants. We found that Amagugu intervention mothers were still significantly more likely to have disclosed their HIV status to their child than standard-of-care mothers, and that the vast majority had gone on to disclose to other adults and children in the household. We also found significantly higher rates of health promotion (including taking children on educational clinic visits, teaching them about nutrition and hygiene) among the intervention’s mothers. Importantly, Amagugu intervention mothers were twice as likely as standard-of-care mothers to have talked to the child about sexual education by age 12 years (AOR 2.02 95%CI 1.30,3.15) further validating the hypothesised conceptual model. A further follow-up is planned at age 16 (2020-2021) to establish whether this translates into better reproductive health outcomes (i.e. sexual debut, pregnancies, HIV infection) among the Amagugu children.