Objective: Adolescent girls and young women (AGYW) have a much higher risk of HIV infection than young men of the same age. One hypothesis for this disparity is AGYW are more likely to be in sexual partnerships with older men with HIV; however, evidence has been inconclusive.

Design: We used longitudinal data from a randomized trial in South Africa (HPTN 068) to determined whether partner age difference is associated with incident HIV infection in AGYW.

Methods: Age difference was examined continuously and dichotomously (≥5 years). We examined inverse probability of exposure weighted survival curves and calculated time-specific risk differences and risk ratios over 5.5 years of follow-up. We also used a marginal structural Cox model to estimate hazard ratios over the entire study period.

Results: Risk of HIV was higher in AGYW with an age-disparate partnership versus not and the risk difference was largest at later time points. At 5.5 years, AGYW with an age-disparate partnership had a 12.6% (95% confidence interval 1.9–23.3) higher risk than AGYW with no age-disparate partnerships. The weighted hazard ratio was 1.91 (95% confidence interval 1.33–2.74), an association that remained after weighting for either transactional or condomless sex, and after examining continuous age-differences.

Conclusion: Age-disparate partnerships increased risk of HIV infection, even after accounting for transactional sex and condomless sex. The relationship between age-disparate partnerships and HIV infection may be explained by increased exposure to infection from men in a higher HIV prevalence pool rather than differences in sexual behaviour within these partnerships.

Background: Verbal autopsy is an increasingly important methodology for assigning causes to otherwise uncertified deaths, which amount to around 50% of global mortality and cause much uncertainty for health planning. The World Health Organization sets international standards for the structure of verbal autopsy interviews and for cause categories that can reasonably be derived from verbal autopsy data. In addition, computer models are needed to efficiently process large quantities of verbal autopsy interviews to assign causes of death in a standardised manner. Here, we present the InterVA-5 model, developed to align with the WHO-2016 verbal autopsy standard. This is a harmonising model that can process input data from WHO-2016, as well as earlier WHO-2012 and Tariff-2 formats, to generate standardised cause-specific mortality profiles for diverse contexts.

The software development involved building on the earlier InterVA-4 model, and the expanded knowledge base required for InterVA-5 was informed by analyses from a training dataset drawn from the Population Health Metrics Research Collaboration verbal autopsy reference dataset, as well as expert input.

Results: The new model was evaluated against a test dataset of 6130 cases from the Population Health Metrics Research Collaboration and 4009 cases from the Afghanistan National Mortality Survey dataset. Both of these sources contained around three quarters of the input items from the WHO-2016, WHO-2012 and Tariff-2 formats. Cause-specific mortality fractions across all applicable WHO cause categories were compared between causes assigned in participating tertiary hospitals and InterVA-5 in the test dataset, with concordance correlation coefficients of 0.92 for children and 0.86 for adults.

The InterVA-5 model’s capacity to handle different input formats was evaluated in the Afghanistan dataset, with concordance correlation coefficients of 0.97 and 0.96 between the WHO-2016 and the WHO-2012 format for children and adults respectively, and 0.92 and 0.87 between the WHO-2016 and the Tariff-2 format respectively.

Conclusions: Despite the inherent difficulties of determining “truth” in assigning cause of death, these findings suggest that the InterVA-5 model performs well and succeeds in harmonising across a range of input formats. As more primary data collected under WHO-2016 become available, it is likely that InterVA-5 will undergo minor re-versioning in the light of practical experience. The model is an important resource for measuring and evaluating cause-specific mortality globally.

Despite the large interest in economic interventions to reduce HIV risk, little research has been done to show whether there are economic gains of these interventions for younger women and what intermediary role economic resources play in changing participants' sexual behavior. This paper contributes to this gap by examining the impacts of a conditional cash transfer (CCT) for young women in South Africa on young women's economic resources and the extent to which they play a role in young women's health and behavior. We used data from HIV Prevention Trials Network 068 study, which provided transfers to young women (in addition to their parents) conditional on the young woman attending at least 80% of school days in the previous month. We found that the CCT increased young women's economic wellbeing in terms of having savings, spending money, being unindebted, and food secure. We also investigated heterogeneous effects of the program by household economic status at baseline because the program was not specifically poverty targeted and found that the results were driven by young women from the poorest families. From these results, we examined heterogeneity by baseline poverty for other outcomes related to HIV risk including sexual behavior and psychosocial well-being. We found psychosocial well-being benefits in young women from the poorest families and that economic wellbeing gains explained much these impacts.

We combined behavioral survey data from the human immunodeficiency virus (HIV) Prevention Trials Network 068 study with phylogenetic information to determine if cluster membership was associated with characteristics of young women and their partners. Clusters were more likely to involve young women from specific villages and schools, indicating some localized transmission.

Background/Aims: We aimed to estimate the prevalence of cognitive impairment, and the sociodemographic and comorbid predictors of cognitive function among older, rural South African adults.

Methods: Data were from a population-based study of 5,059 adults aged >= 40 years in rural South Africa in 2015. Cognitive impairment was defined as scoring <= 1.5 SDs below the mean composite time orientation and memory score, or requiring a proxy interview with "fair" or "poor" proxy-reported memory. Multiple linear regression estimated the sociodemographic and comorbid predictors of cognitive score, with multiplicative statistical interactions between each of age and sex with education.

Results: Cognitive impairment increased with age, from 2% of those aged 40-44 (11/516) to 24% of those aged >= 75 years (214/899). The independent predictors of lower cognitive score were being older, female, unmarried, not working, having low education, low household wealth, and a history of cardiovascular conditions. Education modified the negative associations between female sex, older age, and cognitive function score. Conclusions: The prevalence of cognitive impairment increased with age and is comparable to rates of dementia reported in other sub-Saharan African countries. Age and sex differences in cognitive function scores were minimized as education increased, potentially reflecting the power of even poor-quality education to improve cognitive reserve.

Background Intimate partner violence (IPV) is a human rights violation and is associated with a variety of adverse physical and mental health outcomes. Collective efficacy, defined as mutual trust among community members and willingness to intervene on the behalf of the common good, has been associated with reduced neighbourhood violence. Limited research has explored whether community collective efficacy is associated with reduced incidence of IPV. This is of particular interest among adolescent girls and young women (AGYW) in sub-Saharan Africa, where the burden of HIV is greatest and IPV is common. Methods We collected longitudinal data among 2533 AGYW (ages 13-20) enrolled in the HPTN 068 cohort in Mpumalanga province, South Africa between 2011 and 2016. We included participants from 26 villages where community surveys were collected during the HPTN 068 study. Collective efficacy was measured at the village level via two population-based cross-sectional surveys in 2012 and 2014. Multivariable Poisson generalised estimating equation regression models estimated the relative risk ratio (RR) between village collective efficacy scores and subsequent physical IPV 12 month incidence, adjusting for village-level clustering and covariates. Results Thirty-eight per cent of the cohort (n=950) reported at least one episode of recent physical IPV during follow-up. For every SD higher level of collective efficacy, there was a 6% lower level of physical IPV incidence (adjusted RR: 0.94; 95% CI 0.89 to 0.98) among AGYW after adjusting for covariates. Conclusions Community-level interventions that foster the development of collective efficacy may reduce IPV among AGYW.

Objective: The study aimed to investigate the relationship between physical activity, gross motor skills and adiposity in South African children of pm-school age.

Design: Cross-sectional study.

Setting: High-income urban, and low-income urban and rural settings in South Africa.

Participants: Children (3-6 years old, n 268) were recruited from urban high-income (n 46), urban low-income (n 91) and rural low-income (n 122) settings. Height and weight were measured to calculate the main outcome variables: BMI and BMI-for-age Z-score (BAZ). Height-for-age and weight-for-age Z-scores were also calculated. Actigraph GT3X+ accelerometers were used to objectively measure physical activity; the Test of Gross Motor Development (Version 2) was used to assess gross motor skills.

Results: More children were overweight/obese and had a higher BAZ from urban low-income settings compared with urban high-income settings and rural low-income settings. Being less physically active was associated with thinness, but not overweight/obesity. Time spent in physical activity at moderate and vigorous intensities was positively associated with BMI and BAZ. Gross motor proficiency was not associated with adiposity in this sample.

Conclusions: The findings of this research highlight the need for obesity prevention particularly in urban low-income settings, as well as the need to take into consideration the complexity of the relationship between adiposity, physical activity and gross motor skills in South African pre-school children.

Background: Understanding how depression is associated with chronic conditions and sociodemographic characteristics can inform the design and effective targeting of depression screening and care interventions. In this study, we present some of the first evidence from sub-Saharan Africa on the association between depressive symptoms and a range of chronic conditions (diabetes, HIV, hypertension, and obesity) as well as sociodemographic characteristics. Methods: A questionnaire was administered to a population-based simple random sample of 5,059 adults aged 40 years and older in Agincourt, South Africa. Depressive symptoms were measured using a modified version of the eight-item Center for Epidemiological Studies-Depression screening tool. Diabetes was assessed using a capillary blood glucose measurement and HIV using a dried blood spot. Results: 17.0% (95% confidence interval: 15.9%-18.1%) of participants had at least three depressive symptoms. None of the chronic conditions were significantly associated with depressive symptoms in multivariable regressions. Older age was the strongest correlate of depressive symptoms with those aged 80 years and older having on average 0.63 (95% confidence interval: 0.40-0.86; p<.001) more depressive symptoms than those aged 40-49 years. Household wealth quintile and education were not significant correlates. Conclusions: This study provides some evidence that the positive associations of depression with diabetes, HIV, hypertension, and obesity that are commonly reported in high-income settings might not exist in rural South Africa. Our finding that increasing age is strongly associated with depressive symptoms suggests that there is a particularly high need for depression screening and treatment among the elderly adults in rural South Africa.

We aimed to estimate the relationship between height (a measure of early-life cumulative net nutrition) and later-life cognitive function among older rural South African adults, and whether education modified this relationship. Data were from baseline in-person interviews with 5059 adults40years in the population-based Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI) study in Agincourt sub-district, South Africa, in 2015. Linear regression was used to estimate the relationship between height quintile and latent cognitive function z-score (representing episodic memory, time orientation, and numeracy), with adjustment for life course covariates and a height-by-education interaction. Mean (SD) height was 162.7 (8.9) cm. Nearly half the sample had no formal education (46%; 2307/5059). Mean age- and sex-adjusted cognitive z-scores increased from -0.68 (95% CI: -0.76 to -0.61) in those with no education in the shortest height quintile to 0.62 (95% CI: 0.52-0.71) in those with at least 8years of education in the tallest height quintile. There was a linear height disparity in cognitive z-scores for those with no formal education (adjusted =0.10; 95% CI: 0.08-0.13 per height quintile), but no height disparity in cognitive z-scores in those with any level of education. Short stature is associated with poor cognitive function and may be a risk factor for cognitive impairment among older adults living in rural South Africa. The height disparity in cognitive function was negated for older adults who had any level of education.

Friends could be influential on young women's sexual health via influences on sexual behaviours and as connections to sexual partners, but are understudied in sub-Saharan Africa. We cross-sectionally surveyed 2326 13-20year-old young women eligible for grades 8-11 in rural South Africa about their sexual behaviour and up to three sexual partners. Participants each described five specific but unidentified friends and the relationships between them in an egocentric' network analysis design. We used logistic regression to investigate associations between friendship characteristics and participants' reports of ever having had sex (n=2326) and recent condom use (n=457). We used linear regression with random effects by participant to investigate friendship characteristics and age differences with sexual partners (n=633 participants, 1051 partners). We found that it was common for friends to introduce young women to those who later became sexual partners, and having older friends was associated with having older sexual partners, (increase of 0.37years per friend at least 1year older, 95% CI 0.21-0.52, adjusted). Young women were more likely to report ever having had sex when more friends were perceived to be sexually active (adjusted OR 1.85, 95% CI 1.72-2.01 per friend) and when they discussed sex, condoms and HIV with friends. Perception of friends' condom use was not associated with participants' reported condom use. While this study is preliminary and unique in this population and further research should be conducted, social connections between friends and sexual partners and perceptions of friend sexual behaviours could be considered in the design of sexual health interventions for young women in South Africa.