SA-MRC/Wits Agincourt Unit (Research Outputs/Publications)

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Estimates of HIV incidence among drug users in St. Petersburg, Russia: continued growth of a rapidly expanding epidemic
(2010-07-30) Linda M. Niccolai; Sergei V. Verevochkin; Olga V. Toussova; Edward White; Russell Barbour; Andrei P. Kozlov; Robert Heimer
Background: Russia has one of the world’s fastest growing HIV epidemics and it has been largely concentrated among injection drug users (IDU). St Petersburg, Russia’s second largest city, is one of the country’s regions that has been most affected by the HIV epidemic. To monitor the current epidemic situation, we sought to estimate recent HIV incidence among IDU in St Petersburg. Methods: In a cross-sectional study of 691 IDU recruited during 2005–08, HIV incidence was estimated by two methods: a retrospective cohort analysis and BED capture enzyme immunoassay (EIA) results. Socio-demographic and behavioural correlates of incident infections and spatial patterns were examined. Results: In the retrospective cohort analysis, the incidence rate was estimated to be 14.1/100 person-years [95% confidence interval (CI) 10.7–17.6]. Using results of BED EIA and two correction formulas for known misclassification, incidence estimates were 23.9 (95% CI 17.8–30.1) and 25.5 (95% CI 18.9–32.0) per 100 person-years. Independent correlates of being recently infected included current unemployment (P = 0.004) and not having injected drugs in the past 30 days (P = 0.03). HIV incident cases were detected in all but one district in the city, with focal areas of transmission observed to be expanding. Conclusions: High HIV incidence among IDU in St Petersburg attests to continued growth of the epidemic. The need for expansion of HIV prevention interventions targeted to vulnerable populations throughout the city is urgent. These results also suggest that the BED EIA may over-estimate incidence even after correction for low specificity.
CD4+ T-cell count at antiretroviral therapy initiation in the "Treat AII" era in South A: an interrupted time series analysis.
(2012-11-05) Yapa HM; Kim H-y; Post FA; Jiamsakul A; de Neve J-W; Tanser F; Iwuji C; Baisley K; Shamanesh M; Pillay D; Siedner MJ; Barnighausen T; Bot J
Performance of four computer-coded verbal autopsy methods for cause of death assignment compared with physician coding on 24,000 deaths in low- and middle-income countries
(2014) Nikita Desai; Lukasz Aleksandrowicz; Pierre Miasnikof; Ying Lu; Jordana Leitao; Peter Byass; Stephen Tollman; Paul Mee; Dewan Alam; Suresh Kumar Rathi; Abhishek Singh; Rajesh Kumar; Faujdar Ram; Prabhat Jha
Background: Physician-coded verbal autopsy (PCVA) is the most widely used method to determine causes of death (CODs) in countries where medical certification of death is uncommon. Computer-coded verbal autopsy (CCVA) methods have been proposed as a faster and cheaper alternative to PCVA, though they have not been widely compared to PCVA or to each other. Methods: We compared the performance of open-source random forest, open-source tariff method, InterVA-4, and the King-Lu method to PCVA on five datasets comprising over 24,000 verbal autopsies from low- and middle-income countries. Metrics to assess performance were positive predictive value and partial chance-corrected concordance at the individual level, and cause-specific mortality fraction accuracy and cause-specific mortality fraction error at the population level. Results: The positive predictive value for the most probable COD predicted by the four CCVA methods averaged about 43% to 44% across the datasets. The average positive predictive value improved for the top three most probable CODs, with greater improvements for open-source random forest (69%) and open-source tariff method (68%) than for InterVA-4 (62%). The average partial chance-corrected concordance for the most probable COD predicted by the open-source random forest, open-source tariff method and InterVA-4 were 41%, 40% and 41%, respectively, with better results for the top three most probable CODs. Performance generally improved with larger datasets. At the population level, the King-Lu method had the highest average cause-specific mortality fraction accuracy across all five datasets (91%), followed by InterVA-4 (72% across three datasets), open-source random forest (71%) and open-source tariff method (54%). Conclusions: On an individual level, no single method was able to replicate the physician assignment of COD more than about half the time. At the population level, the King-Lu method was the best method to estimate cause-specific mortality fractions, though it does not assign individual CODs. Future testing should focus on combining different computer-coded verbal autopsy tools, paired with PCVA strengths. This includes using open-source tools applied to larger and varied datasets (especially those including a random sample of deaths drawn from the population), so as to establish the performance for age- and sex-specific CODs
Human respiratory syncytial virus diversity and epidemiology among patients hospitalized with severe respiratory illness in South Africa, 2012–2015
(2015) Ziyaad Valley-Omar; Stefano Tempia; Orienka Hellferscee; Sibongile Walaza; Ebrahim Variava6; Halima Dawood; Kathleen Kahn; Meredith McMorrow; Marthi Pretorius; Senzo Mtshali; Ernest Mamorobela; Nicole Wolter; Marietjie Venter; Anne von Gottberg; Cheryl Cohen; Florette K. Treurnicht
Background: We aimed to describe the prevalence of human respiratory syncytial virus (HRSV) and evaluate associations between HRSV subgroups and/or genotypes and epidemiologic characteristics and clinical outcomes in patients hospitalized with severe respiratory illness (SRI). Methods: Between January 2012 and December 2015, we enrolled patients of all ages admitted to two South African hospitals with SRI in prospective hospital-based syndromic surveillance. We collected respiratory specimens and clinical and epidemiological data. Unconditional random effect multivariable logistic regression was used to assess factors associated with HRSV infection. Results: HRSV was detected in 11.2% (772/6908) of enrolled patients of which 47.0% (363/772) were under the age of 6 months. There were no differences in clinical outcomes of HRSV subgroup A-infected patients compared with HRSV subgroup B-infected patients but among patients aged <5 years, children with HRSV subgroup A were more likely be coinfected with Streptococcus pneumoniae (23/208 11.0% vs. 2/90, 2.0%; adjusted odds ratio 5.7). No significant associations of HRSV A genotypes NA1 and ON1 with specific clinical outcomes were observed. Conclusions: While HRSV subgroup and genotype dominance shifted between seasons, we showed similar genotype diversity as noted worldwide. We found no association between clinical outcomes and HRSV subgroups or genotypes.
Cohort Profile: Health and Ageing in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI).
(2018) F Xavier Go´ mez-Olive´; Livia Montana; Ryan G Wagner; Chodziwadziwa W Kabudula; Julia K Rohr; Kathleen Kahn; Till Ba¨rnighausen; Mark Collinson; David Canning; Thomas Gaziano; Joshua A Salomon; Collin F Payne; Alisha Wad; Stephen M Tollman; Lisa Berkman
‘It’s because I like things… it’s a status and he buys me airtime’: exploring the role of transactional sex in young women’s consumption patterns in rural South Africa (secondary findings from HPTN 068)
(2018) Meghna Ranganathan; Lori Heise; Catherine MacPhail; Heidi Stöckl; Richard J. Silverwood; Kathleen Kahn; Amanda Selin; F. Xavier Gómez-Olivé; Charlotte Watts; Audrey Pettifor
Background ‘Transactional sex’, defined as a non-marital, non-commercial sexual relationship in which money or material goods are exchanged for sex, is associated with young women’s increased vulnerability to HIV infection. Existing research illustrates that the motivations for transactional sex are complex. The fulfilment of psycho-social needs such as the need to belong to a peer group are important factors underlying young women’s desires to obtain certain consumption items and thus engage in transactional sex. Methods We use a mixed-methods approach to explore the relationship between transactional sex and consumption patterns among young women in rural Mpumalanga province, South Africa. In the secondary analysis of 693 sexually active young women, we use factor analysis to group the different consumption items and we use multivariable logistic regression to demonstrate the relationship between transactional sex and consumption patterns. The qualitative study uses five focus group discussions and 19 in-depth interviews to explore further young women’s motivations for acquiring different consumption items. Results The quantitative results show that young women that engage in transactional sex have higher odds of consuming items for entertainment (e.g., movie tickets) than on practical items (e.g., food and groceries). The qualitative findings also revealed that young women’s perceptions of items that were considered a ‘need’ were strongly influenced by peer pressure and a desire for improved status. Further, there was a perception that emerged from the qualitative data that relationships with sugar daddies offered a way to acquire consumer goods associated with a ‘modern lifestyle’, such as items for personal enhancement and entertainment. However, young women seem aware of the risks associated with such relationships. More importantly, they also develop relationship with partners of similar age, albeit with the continued expectation of material exchange, despite engaging in the relationship for love. Conclusion This study shows that young women are willing to take certain risks in order to have a degree of financial independence. Interventions that provide alternative methods of attaining this independence, such as the provision of cash transfers may have potential in preventing them from engaging in transactional relationships. Further, the psycho-social reasons that drive young women’s motivations for consumption items resulting in risky sexual behaviours need to be better understood.
Cash transfers for HIV prevention: what do young women spend it on? Mixed methods findings from HPTN 068
(2018) Catherine MacPhail; Nomhle Khoza; Amanda Selin; Aimée Julien; Rhian Twine; Ryan G. Wagner; Xavier Goméz-Olivé; Kathy Kahn; Jing Wang; Audrey Pettifor
Background Social grants have been found to have an impact on health and wellbeing in multiple settings. Who receives the grant, however, has been the subject of discussion with regards to how the money is spent and who benefits from the grant. Methods Using survey data from 1214 young women who were in the intervention arm and completed at least one annual visit in the HPTN 068 trial, and qualitative interview data from a subset of 38 participants, we examined spending of a cash transfer provided to young women conditioned on school attendance. Results We found that spending was largely determined and controlled by young women themselves and that the cash transfer was predominately spent on toiletries, clothing and school supplies. In interview data, young women discussed the significant role of cash transfers for adolescent identity, specifically with regard to independence from family and status within the peer network. There were almost no negative consequences from receiving the cash transfer. Conclusions We established that providing adolescents access to cash was not reported to be associated with social harms or negative consequences. Rather, spending of the cash facilitated appropriate adolescent developmental behaviors. The findings are encouraging at a time in which there is global interest in addressing the structural drivers of HIV risk, such as poverty, for young women.
Men’s perspectives on the impact of femaledirected cash transfers on gender relations: Findings from the HPTN 068 qualitative study
(2018) Makhosazane Nomhle Khoza; Sinead Delany-Moretlwe; Fiona Scorgie; Jennifer Hove; Amanda Selin; John Imrie; Rhian Twine; Kathleen Kahn; Audrey Pettifor; Catherine MacPhail
Background HIV is an inherently gendered disease in eastern and southern Africa, not only because more women than men are infected, but also because socially constructed gender norms work to increase women’s HIV-infection risk. The provision of cash transfers to young women alone in such a context adds another dimension to already existing complex social relations where patriarchal values are entrenched, gender inequality is the norm, and violence against women and girls is pervasive. It raises concerns about complicating young women’s relationships with their male partners or possibly even setting them up for more violence. In our attempt to understand how cash transfers influence social relations in the context of a trial among young women in South Africa, we used qualitative data collected during the trial to explore men’s perceptions of the impact of cash transfers on male-female relationships, both intimate and platonic, peer relationships. Method Between April 2012 and August 2015, we conducted focus group discussions (n = 12) and interviews (n = 20) with the male peers and intimate partners of young women aged 13–20 years, who were participating in a phase III randomised controlled trial of CTs for HIV prevention in Mpumalanga, South Africa. A thematic content analysis approach was used to analyse the data. The codebook was developed on the basis of the topic guides, with additional codes added inductively as they emerged from the data. Results Intimate partners were older (range 20–32 years) and more likely to be working than the male peers. Both intimate partners and male peers were supportive of the CT trial targeting young women; younger peers however expressed some concerns that the money might diminish their power and status in relationships. HIV testing requirements associated with the trial appeared to have improved communication about sex and HIV in intimate relationships, with some women even encouraging their partners to go for an HIV test. Conclusion CTs provide AGYW with a measure of autonomy and power to contribute in their gendered relationships, albeit in limited ways. However, there is potential for CTs to have a negative impact on male-female relationships if the cash received by AGYW is equal to or greater than the income earned by their male counterparts or sexual partners.
Transactional sex and incident HIV infection in a cohort of young women from rural South Africa
(2018) Kelly Kilburn; Meghna Ranganathan; Marie C.D. Stoner; James P. Hughes; Catherine MacPhail; Yaw Agyei; F. Xavier Gomez-Oliv; Kathleen Kahn; Audrey Pettifor
Objective: In sub-Saharan Africa, young women who engage in transactional sex (the exchange of sex for money or gifts) with a male partner show an elevated risk of prevalent HIV infection. We analyse longitudinal data to estimate the association between transactional sex and HIV incidence. Design: We used longitudinal data from a cohort of 2362 HIV-negative young women (aged 13–20 years) enrolled in a randomized controlled trial in rural, South Africa who were followed for up to four visits over 6 years. Methods: The effect of transactional sex on incident HIV was analysed using stratified Cox proportional hazards models and cumulative incidence curves. Risk ratios were estimated using log-binomial models to compare the effects across visits. Results: HIV incidence was higher for young women that reported transactional sex (hazard ratio 1.59, 95% confidence interval 1.02–2.19), particularly when money and/ or gifts were received frequently (at least weekly) (hazard ratio 2.71, 95% confidence interval 1.44–5.12). We also find that effects were much stronger during the main trial and dissipate at the postintervention visit, despite an increase in both transactional sex and HIV. Conclusion: Transactional sex elevates the risk of HIV acquisition among young women, especially when it involves frequent exchanges of money and/or gifts. However, the effect was attenuatedafterthe main trial, possibly due to the changing nature oftransactionalsex and sexual partners as women age. These findings suggest that reducing transactional sex among young women, especially during adolescence, is important for HIV prevention.
Executive function associated with sexual risk in young South African women: Findings from the HPTN 068 cohort
(2018-04-02) Molly Rosenberg; Audrey Pettifor; Mihaela Duta; Nele Demeyere; Ryan G. Wagner; Amanda Selin; Catherine MacPhail; Oliver Laeyendecker; James P. Hughes; Alan Stein; Stephen Tollman; Kathleen Kahn
Purpose Heightened sexual risk in adolescence and young adulthood may be partially explained by deficits in executive functioning, the set of cognitive processes used to make reasoned decisions. However, the association between executive function and sexual risk is understudied among adolescent girls and young women, particularly in low- and middle-income countries. Methods In a cohort of 853 young women age 18–25 in rural Mpumalanga province, South Africa, we evaluated executive function with three non-verbal cognitive tests: I. a rule-finding test, II. a trail-making test, and III. a figure drawing test. Using log-binomial regression models, we estimated the association between lower executive function test scores and indicators of sexual risk (unprotected sex acts, concurrent partnerships, transactional sex, and recent HSV-2 infection). Results In general, young women with lower executive function scores reported higher frequencies of sexual risk outcomes, though associations tended to be small with wide confidence intervals. Testing in the lowest quintile of Test I was associated with more unprotected sex [aPR (95% CI): 1.4 (1.0, 1.8)]. Testing in the lowest quintile of Test II was associated with more concurrent relationships and transactional sex [aPR (95% CI): 1.6 (1.1, 2.5) and 1.7 (1.3, 2.4), respectively], and testing in the lowest four quintiles of Test III was associated with more concurrent relationships [aPR (95% CI): 1.7 (1.0, 2.7)]. Conclusions These results demonstrate an association between low executive function and sexual risk in South African young women. Future work should seek to understand the nature of this association and whether there is promise in developing interventions to enhance executive function to reduce sexual risk.
Hope, the Household Environment, and Sexual Risk Behaviors Among Young Women in Rural South Africa (HPTN 068)
(2018-06) Lauren M Hill; Laurie Abler; Suzanne Maman; Rhian Twine; Kathleen Kahn; Catherine MacPhail; Audrey Pettifor
We assessed the psychological trait of hope as an explanatory mediator in the relationship between the home environment and sexual risk behaviors among 2533 young women in rural South Africa. Hope mediated the relationship between average household age and sexual debut (mediated effect = −0.003, p<.05), and between household consumption and sexual debut (mediated effect = −0.019, p<.05). Both higher average household age (β = 0.01; 95%CI: 0.00, 0.01) and greater household consumption (β = 0.05; 95%CI: 0.02, 0.08) were marginally associated with higher hope. In turn, greater hope was associated with lower odds of sexual debut (aOR= 0.62; 95%CI: 0.52, 0.74). These results provide important preliminary evidence of the role of the home environment in shaping protective psychological assets and healthy sexual behaviors. Continued exploration of the relationship between hope and the home environment may help to explain why young women in this context have a disproportionate risk for HIV.
HIV-1 diversity among young women in rural South Africa: HPTN 068
(2018-07-05) Mariya V. Sivay; Sarah E. Hudelson; Jing Wang; Yaw Agyei; Erica L. Hamilton; Amanda Selin; Ann Dennis; Kathleen Kahn; F. Xavier Gomez-Olive; Catherine MacPhail; James P. Hughes; Audrey Pettifor; Susan H. Eshleman; Mary Kathryn Grabowski
Background South Africa has one of the highest rates of HIV-1 (HIV) infection world-wide, with the highest rates among young women. We analyzed the molecular epidemiology and evolutionary history of HIV in young women attending high school in rural South Africa. Methods Samples were obtained from the HPTN 068 randomized controlled trial, which evaluated the effect of cash transfers for school attendance on HIV incidence in women aged 13–20 years (Mpumalanga province, 2011–2015). Plasma samples from HIV-infected participants were analyzed using the ViroSeq HIV-1 Genotyping assay. Phylogenetic analysis was performed using 200 pol gene study sequences and 2,294 subtype C reference sequences from South Africa. Transmission clusters were identified using Cluster Picker and HIV-TRACE, and were characterized using demographic and other epidemiological data. Phylodynamic analyses were performed using the BEAST software. Results The study enrolled 2,533 young women who were followed through their expected high school graduation date (main study); some participants had a post-study assessment (follow-up study). Two-hundred-twelve of 2,533 enrolled young women had HIV infection. HIV pol sequences were obtained for 94% (n = 201/212) of the HIV-infected participants. All but one of the sequences were HIV-1 subtype C; the non-C subtype sequence was excluded from further analysis. Median pairwise genetic distance between the subtype C sequences was 6.4% (IQR: 5.6–7.2). Overall, 26% of study sequences fell into 21 phylogenetic clusters with 2–6 women per cluster. Thirteen (62%) clusters included women who were HIV-infected at enrollment. Clustering was not associated with study arm, demographic or other epidemiological factors. The estimated date of origin of HIV subtype C in the study population was 1958 (95% highest posterior density [HPD]: 1931–1980), and the median estimated substitution rate among study pol sequences was 1.98x10-3 (95% HPD: 1.15x10-3–2.81x10-3) per site per year. Conclusions Phylogenetic analysis suggests that multiple HIV subtype C sublineages circulate among school age girls in South Africa. There were no substantive differences in the molecular epidemiology of HIV between control and intervention arms in the HPTN 068 trial.
Genomic and environmental risk factors for cardiometabolic diseases in Africa: methods used for Phase 1 of the AWI-Gen population cross-sectional study
(2018-07-12) Stuart A. Al; Cassandra Soo; Godfred Agongo; Marianne Alberts; Lucas Amenga-Etego; Romuald P. Boua; Ananyo Choudhury; Nigel J. Crowther; Cornelius Depuur; F. Xavier GómezOlivé; Issa Guiraud; Tilahun N. Haregu; Scott Hazelhurst; Kathleen Kahn; Christopher Khayeka-Wandabwa; Catherine Kyobutung; Zané Lombard; Felistas Mashinya; Lisa Micklesfield; Shukri F. Mohamed; Freedom Mukomana; Seydou Nakanabo-Diallo; Hamtandi M. Natama; Nicholas Ngomi; Engelbert A. Nonterah; Shane A. Norris; Abraham R. Oduro; Athanase M. Somé; Hermann Sorgho; Paulina Tindana; Halidou Tinto; Stephen Tollman; Rhian Twine; Alisha Wade; Osman Sankoh; Michèle Ramsay
There is an alarming tide of cardiovascular and metabolic disease (CMD) sweeping across Africa. This may be a result of an increasingly urbanized lifestyle characterized by the growing consumption of processed and calorie-dense food, combined with physical inactivity and more sedentary behaviour. While the link between lifestyle and public health has been extensively studied in Caucasian and African American populations, few studies have been conducted in Africa. This paper describes the detailed methods for Phase 1 of the AWI-Gen study that were used to capture phenotype data and assess the associated risk factors and end points for CMD in persons over the age of 40 years in sub-Saharan Africa (SSA). We developed a population-based cross-sectional study of disease burden and phenotype in Africans, across six centres in SSA. These centres are in West Africa (Nanoro, Burkina Faso, and Navrongo, Ghana), in East Africa (Nairobi, Kenya) and in South Africa (Agincourt, Dikgale and Soweto). A total of 10,702 individuals between the ages of 40 and 60 years were recruited into the study across the six centres, plus an additional 1021 participants over the age of 60 years from the Agincourt centre. We collected socio-demographic, anthropometric, medical history, diet, physical activity, fat distribution and alcohol/tobacco consumption data from participants. Blood samples were collected for disease-related biomarker assays, and genomic DNA extraction for genome-wide association studies. Urine samples were collected to assess kidney function. The study provides base-line data for the development of a series of cohorts with a second wave of data collection in Phase 2 of the study. These data will provide valuable insights into the genetic and environmental influences on CMD on the African continent
Antiretroviral Drug Use and HIV Drug Resistance Among Young Women in Rural South Africa: HPTN 068
(2018-11-01) Zhang, Yinfeng PhD; Sivay, Mariya V. PhD; Hudelson, Sarah E. BS; Clarke, William PhD; Breaud, Autumn MS; Wang, Jing MS, MA; Piwowar-Manning, Estelle BS, MT (ASCP); Agyei, Yaw MPH, BS, MT (ASCP); Fogel, Jessica M. PhD; Hamilton, Erica L. MPH; Selin, Amanda MHS; MacPhail, Catherine PhD; Kahn, Kathleen MD, PhD; Gómez-Olivé, Francesc Xavier MD, PhD; Hughes, James P. PhD; Pettifor, Audrey PhD, MPH; Eshleman, Susan H. MD, PhD
Background: Antiretroviral (ARV) drugs are used for HIV treatment and prevention. We analyzed ARV drug use and HIV drug resistance in a cohort of young women in rural South Africa enrolled in the HIV Prevention Trials Network (HPTN) 068 study, which evaluated the use of a cash transfer conditional on school attendance to reduce HIV incidence. Methods: ARV drug testing was performed using plasma samples from 2526 young women. This included 2526 enrollment samples (80 HIV-infected and 2446 HIV-uninfected) and 162 seroconversion samples (first HIV-positive study visit). Testing was performed using a qualitative assay that detects 20 ARV drugs from 5 drug classes. HIV drug resistance testing was performed with the ViroSeq HIV-1 Genotyping System for samples that had HIV viral loads ≥400 copies per milliliter. Results: At enrollment, ARV drugs were detected in 10 (12.5%) of 80 HIV-infected young women. None of 2446 HIV-uninfected young women had ARV drugs detected at enrollment. ARV drugs were also detected in 16 (9.9%) of 162 seroconverters. At enrollment, 9 (13.4%) of 67 young women with genotyping results had HIV drug resistance; resistance was also detected in 9 (6.9%) of 131 seroconverters with genotyping results. Conclusions: Most of the HIV-infected young women in this cohort from rural South Africa were not taking ARV drugs, suggesting they were unaware of their HIV status or were not in care. HIV drug resistance was detected in young women with both prevalent and new HIV infection.
Body composition and physical activity as mediators in the relationship between socioeconomic status and blood pressure in young South African women: a structural equation model analysis
(2018-11-11) Richard J Munthali; Mercy Manyema; Rihlat Said-Mohamed; Juliana Kagura; Stephen Tollman; Kathleen Kahn; F Xavier Gómez-Olivé; Lisa K Micklesfield; David Dunger; Shane A Norris
Objectives Varying hypertension prevalence across different socioeconomic strata within a population has been well reported. However, the causal factors and pathways across different settings are less clear, especially in sub-Saharan Africa. Therefore, this study aimed to compare blood pressure (BP) levels and investigate the extent to which socioeconomic status (SES) is associated with BP, in rural and urban South Africa women. Setting Rural and urban South Africa. Design Cross-sectional. Participants Cross-sectional data on SES, total moderate and vigorous physical activity (MVPA), anthropometric and BP were collected on rural (n=509) and urban (n=510) young black women (18–23 years age). Pregnant and mentally or physically disabled women were excluded from the study. Results The prevalence of combined overweight and obesity (46.5% vs 38.8%) and elevated BP (27.0% vs 9.3%) was higher in urban than rural women, respectively. Results from the structural equation modelling showed significant direct positive effects of body mass index (BMI) on systolic BP (SBP) in rural, urban and pooled datasets. Negative direct effects of SES on SBP and positive total effects of SES on SBP were observed in the rural and pooled datasets, respectively. In rural young women, SES had direct positive effects on BMI and was negatively associated with MVPA in urban and pooled analyses. BMI mediated the positive total effects association between SES and SBP in pooled analyses (ß 0.46; 95% CI 0.15 to 0.76). Conclusions Though South Africa is undergoing nutritional and epidemiological transitions, the prevalence of elevated BP still varies between rural and urban young women. The association between SES and SBP varies considerably in economically diverse populations with BMI being the most significant mediator. There is a need to tailor prevention strategies to take into account optimizing BMI when designing strategies to reduce future risk of hypertension in young women. This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the license is given, and indication of whether changes were made.
Friendships Among Young South African Women, Sexual Behaviours and Connections to Sexual Partners (HPTN 068)
(2019-01-25) Elizabeth Fearon; Richard D. Wiggins; Audrey E. Pettifor; Catherine MacPhail; Kathleen Kahn; Amanda Selin; F. Xavier Gómez-Olivé; James R. Hargreaves
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 crosssectionally surveyed 2326 13–20 year-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 0.37 years per friend at least one year 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
Assessing risk for HIV infection among adolescent girls in SouthAfrica: an evaluation of the VOICE risk score (HPTN 068)
(2019-07) Danielle Giovenco; Audrey Pettifor; Catherine MacPhail; Kathleen Kahn; Ryan Wagner; Estelle Piwowar-Manning; Jing Wang; James P Hughes
AbstractIntroduction:To maximize impact and minimize costs, antiretroviral pre-exposure prophylaxis (PrEP) interventions should beoffered to those at highest risk for HIV infection. The risk score derived from the VOICE trial is one tool currently being uti-lized to determine eligibility in adolescent PrEP trials in sub-Saharan Africa. This study is aimed at evaluating the utility of therisk score in predicting HIV incidence among a cohort of adolescent girls in rural South Africa.Methods:We utilized data from HIV Prevention Trials Network (HPTN) 068, a phase III randomized controlled trial con-ducted in rural Mpumalanga province, South Africa. School-attending young women aged 13 to 20 years were enrolled intothe trial from 2011 to 2012 and followed for up to three years. A risk score based on individual-level risk factors measuredat enrolment was calculated for HPTN 068 participants who completed a one-year follow-up visit and were HIV seronegativeat enrolment. Possible scores ranged from 0 to 10. A proportional hazards model was then used to determine if risk score atenrolment was predictive of incident HIV infection at follow-up and an area under the curve analysis was used to examine thepredictive ability of the score.Results and Discussion:The risk score had limited variability in the HPTN 068 sample. Scores≥5 identified 85% of incidentinfections from 94% of the sample, compared to the VOICE sample in which scores≥5 identified 91% of incident infectionsfrom only 64% of participants. The risk score did not predict HIV incidence after one year of follow-up (hazardratio=1.029; 95% confidence interval (CI): 0.704, 1.503,p=.884) and showed poor predictive ability (area under thecurve=0.55; 95% CI: 0.44, 0.65). Certain individual risk factors that comprise the risk score may be context specific or notrelevant for adolescent populations. Additional factors should be considered when assessing risk for the purposes of deter-mining PrEP eligibility.Conclusions:The VOICE risk score demonstrated low utility to predict HIV incidence in the HPTN 068 sample. Findings high-light the need for an age and developmentally appropriate tool for assessing risk for HIV infection among adolescents. Use ofthe VOICE risk score for determining PrEP eligibility in younger populations should be carefully considered.
Sexual Partner Types and Incident HIV Infection Among Rural South African Adolescent Girls and Young Women Enrolled in HPTN 068: A Latent Class Analysis
(2019-09-01) Nguyen, Nadia PhD; Powers, Kimberly A. PhD; Miller, William C. MD, PhD, MPH; Howard, Annie Green PhD; Halpern, Carolyn T. PhD; Hughes, James P. PhD; Wang, Jing MS, MA; Twine, Rhian MPH; Gomez-Olive, F. Xavier MD, PhD; MacPhail, Catherine PhD; Kahn, Kathleen MD, PhD; Pettifor, Audrey E. PhD
Background: Sexual partners are the primary source of incident HIV infection among adolescent girls and young women (AGYW) in sub-Saharan Africa. Identifying partner types at greatest risk of HIV transmission could guide the design of tailored HIV prevention interventions. Methods: We conducted a secondary analysis of data from AGYW (aged 13–23 years) enrolled in a randomized controlled trial of cash transfers for HIV prevention in South Africa. Annually, AGYW reported behavioral and demographic characteristics of their 3 most recent sexual partners, categorized each partner using prespecified labels, and received HIV testing. We used latent class analysis (LCA) to identify partner types from reported characteristics, and generalized estimating equations to estimate the relationship between both LCA-identified and prespecified partner types and incident HIV infection. Results: Across 2140 AGYW visits, 1034 AGYW made 2968 partner reports and 63 AGYW acquired HIV infection. We identified 5 LCA partner types, which we named monogamous HIV-negative peer partner; one-time protected in-school peer partner; out-of-school older partner; anonymous out-of-school peer partner; and cohabiting with children in-school peer partner. Compared to AGYW with only monogamous HIV-negative peer partners, AGYW with out-of-school older partners had 2.56 times the annual risk of HIV infection (95% confidence interval: 1.23 to 5.33), whereas AGYW with anonymous out-of-school peer partners had 1.72 times the risk (95% confidence interval: 0.82 to 3.59). Prespecified partner types were not associated with incident HIV. Conclusion: By identifying meaningful combinations of partner characteristics and predicting the corresponding risk of HIV acquisition among AGYW, LCA-identified partner types may provide new insights for the design of tailored HIV prevention interventions.
Dimensions of internal migration and their relationship to blood pressure in South Africa
(2019-11) Chantel F. Pheiffer; Stephen T. McGarvey; Carren Ginsburg; Mark Collinson; F. Xavier Gómez-Olivé; Stephen Tollman; Michael J. White
Hypertension prevalence is on the rise in low and middle income countries like South Africa, and migration and concomitant urbanization are often considered to be associated with this rise. However, relatively little is known about the relationship between blood pressure (BP) and internal migration - a highly prevalent population process in LMICs. This study employs data for a group of 194 adult men and women from an original pilot dataset drawn from the Agincourt Health and Demographic Surveillance System in northeast South Africa. Migrants in the sample are identified, tracked, and interviewed. The relationship between BP and migration distance and the number of months an individual spends away from his/her home village is estimated using robust OLS regression, controlling for a series of socioeconomic, health, and behavioral characteristics. This study finds migrants who move further distances and for longer durations to have significantly higher systolic and diastolic BP compared with shorter-term migrants and those who remain nearby or in their home village. These associations remain robust and statistically significant when adjusting for measures of socioeconomic conditions, as well as body mass index (BMI), and the number of meals consumed per day. Migration, both in terms of distance and time away, explains significant variation in BP among migrants in a typical South African context. This finding suggests the need for further studies of nutritional and psychosocial factors associated with geographic mobility that may be important factors for understanding rising hypertension in LMICs.
The Mediating Role of Partner Selection in the Association Between Transactional Sex and HIV Incidence Among Young Women
(2019-11-06) Meghna Ranganathan, PhD; Kelly Kilburn, PhD; Marie C.D. Stoner, PhD; James P. Hughes, PhD; Catherine MacPhail, PhD; Francesc Xavier Gomez-Olive, MD, PhD; Ryan G. Wagner, PhD; Kathleen Kahn, PhD; Yaw Agyei, MPH; Audrey Pettifor, PhD
Objective: In sub-Saharan Africa, transactional sex is associated with an increased risk of HIV infection in adolescent girls and young women, but the mechanisms for this relationship remain unclear. We hypothesize that young women who report transactional sex may have multiple partners and older partners, thereby increasing their HIV risk. Setting: We used longitudinal data from the HPTN 068 trial in rural South Africa where young women aged 13–20 who were HIV-negative at enrolment (n = 2362) were followed approximately annually for up to 6 years. Methods: We used the parametric g-formula to estimate the total effect of time-varying, frequent transactional sex (receipt of gifts/money at least weekly versus monthly or less) on HIV incidence and the controlled direct effect for mediation in a simulated cohort using 20,000 bootstrapped observations. We calculated rates and hazard ratios (HRs) over the entire study period. Results: The HR for the total effect of frequent transactional sex on HIV incidence was 1.56 (95% confidence interval: 1.28 to 1.85). However, this effect was mediated by partner age (>5+) and number of partners (>1) and the HR was attenuated to 1.09 (95% confidence interval: 0.90 to 1.28) when setting both partner age and partner number constant. Conclusion: Both partner age difference and partner number mediate the relationship between transactional sex and incident HIV infection. Through this mediation analysis, we provide important longitudinal evidence to suggest that young women who engage in frequent transactional sex select multiple partners, often older male partners that may be part of higher risk sexual networks.