The reliability of sexual partnership histories: implications for the measurement of partnership concurrency during surveys

Predictors of romantic partner nomination reciprocity in adolescent social networks

Network data uniquely allow relationships to be multiply reported, creating varying rates of relationship nomination reciprocation. However, what drives such variation is unclear. Variation in reciprocation may reflect substantive information about relationships (e.g., social salience or desirability) or study design (e.g., question wording or capped nominations). We examine predictors of nomination reciprocity in romantic network data from the PROSPER study to analyze individual and dyadic predictors of nomination reciprocity. Results show higher grades predict higher reciprocity, while same-sex relationships and behaviorally discordant dyads are less likely to be reciprocal.

Estimating contact network properties by integrating multiple data sources associated with infectious diseases

To effectively mitigate the spread of communicable diseases, it is necessary to understand the interactions that enable disease transmission among individuals in a population; we refer to the set of these interactions as a contact network. The structure of the contact network can have profound effects on both the spread of infectious diseases and the effectiveness of control programs. Therefore, understanding the contact network permits more efficient use of resources. Measuring the structure of the network, however, is a challenging problem. We present a Bayesian approach to integrate multiple data sources associated with the transmission of infectious diseases to more precisely and accurately estimate important properties of the contact network. An important aspect of the approach is the use of the congruence class models for networks. We conduct simulation studies modeling pathogens resembling SARS-CoV-2 and HIV to assess the method; subsequently, we apply our approach to HIV data from the University of California San Diego Primary Infection Resource Consortium. Based on simulation studies, we demonstrate that the integration of epidemiological and viral genetic data with risk behavior survey data can lead to large decreases in mean squared error (MSE) in contact network estimates compared to estimates based strictly on risk behavior information. This decrease in MSE is present even in settings where the risk behavior surveys contain measurement error. Through these simulations, we also highlight certain settings where the approach does not improve MSE.

Only Death Will Separate Us: The Role of Extramarital Partnerships among Himba Pastoralists

Extramarital partnerships are highly stigmatized in many societies and are typically excluded from studies of family dynamics and social support. Nevertheless, in many societies such relationships are common and can have important impacts on resource security and health outcomes. However, current studies of these relationships come mainly from ethnographic studies, with quantitative data extremely rare. Here we present data from a 10-year study of romantic partnerships among a community of Himba pastoralists in Namibia, where concurrency is common. The majority of married men (97%) and women (78%) currently reported having more than one partner (n = 122). Using multilevel models comparing marital and nonmarital relationships, we found that, contrary to conventional wisdom surrounding concurrency, Himba form enduring bonds with extramarital partners that often last decades and are very similar to marital ones in terms of length, emotional affect, reliability, and future prospects. Qualitative interview data showed that extramarital relationships were imbued with a set of rights and obligations that, while distinct from those of spouses, provide an important source of support. Greater inclusion of these relationships in studies of marriage and family would provide a clearer picture of social support and resource transfers in these communities and help to explain variation in the practice and acceptance of concurrency around the world.

Spatio-temporal estimates of HIV risk group proportions for adolescent girls and young women across 13 priority countries in sub-Saharan Africa

The Global AIDS Strategy 2021-2026 identifies adolescent girls and young women (AGYW) as a priority population for HIV prevention, and recommends differentiating intervention portfolios geographically based on local HIV incidence and individual risk behaviours. We estimated prevalence of HIV risk behaviours and associated HIV incidence at health district level among AGYW living in 13 countries in sub-Saharan Africa. We analysed 46 geospatially-referenced national household surveys conducted between 1999-2018 across 13 high HIV burden countries in sub-Saharan Africa. Female survey respondents aged 15-29 years were classified into four risk groups (not sexually active, cohabiting, non-regular or multiple partner[s] and female sex workers [FSW]) based on reported sexual behaviour. We used a Bayesian spatio-temporal multinomial regression model to estimate the proportion of AGYW in each risk group stratified by district, year, and five-year age group. Using subnational estimates of HIV prevalence and incidence produced by countries with support from UNAIDS, we estimated new HIV infections in each risk group by district and age group. We then assessed the efficiency of prioritising interventions according to risk group. Data consisted of 274,970 female survey respondents aged 15-29. Among women aged 20-29, cohabiting (63.1%) was more common in eastern Africa than non-regular or multiple partner(s) (21.3%), while in southern countries non-regular or multiple partner(s) (58.9%) were more common than cohabiting (23.4%). Risk group proportions varied substantially across age groups (65.9% of total variation explained), countries (20.9%), and between districts within each country (11.3%), but changed little over time (0.9%). Prioritisation based on behavioural risk, in combination with location- and age-based prioritisation, reduced the proportion of population required to be reached in order to find half of all expected new infections from 19.4% to 10.6%. FSW were 1.3% of the population but 10.6% of all expected new infections. Our risk group estimates provide data for HIV programmes to set targets and implement differentiated prevention strategies outlined in the Global AIDS Strategy. Successfully implementing this approach would result in more efficiently reaching substantially more of those at risk for infections.

Measuring the Impact of Bedroom Privacy on Social Networks in a Long-Term Care Facility for Hong Kong Older Adults: A Spatio-Social Network Analysis Approach

This study aims to measure the impact of bedroom privacy on residents' social networks in a long-term care (LTC) facility for older adults. Little is known about how the architectural design of bedrooms affects residents' social networks in compact LTC facilities. Five design factors affecting privacy were examined: bedroom occupancy, visual privacy, visibility, bedroom adjacency, and transitional space. We present a spatio-social network analysis approach to analyse the social network structures of 48 residents. Results show that residents with the highest bedroom privacy had comparatively smaller yet stronger groups of network partners in their own bedrooms. Further, residents who lived along short corridors interacted frequently with non-roommates in one another's bedrooms. In contrast, residents who had the least privacy had relatively diverse network partners, however, with weak social ties. Clustering analyses also identified five distinct social clusters among residents of different bedrooms, ranging from diverse to restricted. Multiple regressions showed that these architectural factors are significantly associated with residents' network structures. The findings have methodological implications for the study of physical environment and social networks which are useful for LTC service providers. We argue that our findings could inform current policies to develop LTC facilities aimed at improving residents' well-being.

Incidence and laboratory diagnosis of sexually-transmitted infections among university students in a high-prevalence community

Objective: The purpose of this study was to determine the incidence of four sexually-transmitted infection (STI) agents among university students. Participants: A total of 1744 Milwaukee, Wisconsin metropolitan area student encounters at two university health clinics. Methods: Following consent, participants completed an eight-item demographic and behavioral questionnaire and provided a specimen for Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and Mycoplasma genitalium RNA testing. Results: C. trachomatis (7.2%) and M. genitalium (6.7%) detection rates were highest, with C. trachomatis more likely to result in symptomatic infection in males and females. Female M. genitalium detection rates did not differ as a function of symptomatic status. Students identifying as African American were more likely to test positive for M. genitalium than other races/ethnicities. M. genitalium detection in both genders was a function of reported condom usage. Conclusions: Students would benefit from familiarity with emerging STI agents, as well as behaviors associated with increased risk of STI.

Inter-partner Agreement of Condom Use and Sexual Positioning in Male Couples

Accurate, reliable self-reports of sexual behavior are a crucial component of valid HIV risk-estimation and behavioral intervention evaluation, yet this data's reliability remains understudied. The goal of this study was to describe interpartner agreement on recent receptive anal intercourse (AI) and condomless receptive AI frequencies, among a sample of male couples. We quantified interpartner agreement on self-reported receptive AI and condomless receptive AI (absolute and relative to AI frequency), and position and condom use during a couple's most recent AI, using cross-sectional data from male partners (US, 2016-2017; N = 718 individuals). Proportional and statistical agreement (intraclass correlation coefficients (ICC), kappa (k)) were assessed. Observed agreement for receptive AI frequency was 49.44% (ICC (95% CI): 0.82(0.79, 0.84)) and for relative receptive frequency, 59.05% (ICC: 0.96 (0.85, 0.96). Agreement on condomless receptive AI was 90.21% (ICC: 0.78 (0.75, 0.82), and for relative condomless receptive AI, 91.15% (ICC: 0.80 (0.77, 0.83). Most recent AI position agreement was 89.42% (k (95% CI): 0.84 (0.80, 0.88)), and condom use, 98.89% (k: 0.82 (0.87, 0.98)). Observed agreement was higher among those who reported consistent positioning and condom use. Further research on self-reported sexual behavior data is needed to improve research validity and intervention effectiveness.

Assessing the Reliability of Self-Reported Sexual Behavior Among Male Couples

Coupled gay, bisexual, and other men who have sex with men (GBMSM) are at particularly high risk for HIV, and a clear understanding of behavioral risk is key to effective interventions. Accurate behavioral self-reports are a crucial component of valid sexual health research, yet reliability of these data remains understudied. This study aimed to quantify and identify predictors of dyadic discordance in reported 3-month anal intercourse (AI) occurrence and frequency. Using cross-sectional data from 407 male couples in the U.S. (2016-2017), we calculated proportional dyadic concordance and used dyad-level logistic and linear regression to identify demographic, behavioral, and relationship traits associated with the odds of discordant frequency reports and the relative difference between discordant partner reports. Couples had high levels of concordant reports of 3-month anal AI occurrence (97%) but low interpartner agreement in reported frequency (37%). After adjustment, the odds of discordance were significantly associated with dyadic employment and differences on the Communal Coping to Reduce HIV Threat Scale (CCS) (p < .05). Among frequency-discordant couples, the mean relative difference between partner reports was 52.80% ± 35.91% (M ± SD). After adjustment, relative differences between partners' reported AI frequencies were positively associated with interpartner differences in CCS (p < .05). These results indicate that among GBMSM couples in committed partnerships, self-reported sexual behavior data may be impacted by granularity, recall, and relationship characteristics. Further research in this area is warranted to better understand measurement error in self-reported sexual activity data.

The Prevalence, Frequency and Social Ecology of Sexual Concurrency Among Young Adult Women

CONTEXT

Sexual concurrency among women is associated with increased risks of STD transmission, unintended pregnancy and sexual health disparities. Understanding the prevalence of concurrency-overlapping sexual partnerships-is imperative to reducing these disparities.

METHODS

Weekly, population-representative panel data from 757 women aged 18-22, collected from 2008 to 2012 in Michigan, were drawn from the Relationship Dynamics and Social Life study. Univariate analyses assessed the prevalence of two forms of sexual concurrency. Multivariate logistic regression models investigated associations between women's social-ecological characteristics and concurrency.

RESULTS

Twenty percent of women had vaginal intercourse with two partners in one week; 14% had intercourse with a second partner during an ongoing relationship. In both cases, the majority of individuals had intercourse with the second partner in one to three weeks in total. The likelihood of both types of concurrency was elevated among women who believed they should have sex with men after seeing them for a while (log-odds, 0.27 and 0.23, respectively) and among those who were Black (0.58 and 1.02, respectively); the likelihood was reduced among women who were more willing to refuse unwanted sex (-0.10 and -0.13, respectively) and who were in exclusive, cohabiting, or married or engaged relationships (-1.82 to -2.64). Having intercourse with multiple partners in one week was also associated with receiving sex education from parents, the degree that parents and friends approved of sex, and having had early intercourse without contraception.

CONCLUSIONS

Sexual concurrency among young women is prevalent but intermittent, and interventions that address individuals' social-ecological contexts are needed to reduce negative health outcomes.

Evaluating Sampling Biases from Third-party Reporting as a Method for Improving Survey Measures of Sensitive Behaviors

Survey participants often misreport their sensitive behaviors (e.g., smoking, drinking, having sex) during interviews. Several studies have suggested that asking respondents to report the sensitive behaviors of their friends or confidants, rather than their own, might help address this problem. This is so because the "third-party reporting" (TPR) approach creates a surrogate sample of alters that may be less subject to social desirability biases. However, estimates of the prevalence of sensitive behaviors based on TPR assume that the surrogate sample of friends is representative of the population of interest. We used sociometric data on social networks in Likoma, Malawi to examine this assumption. Specifically, we use friendship network data to investigate whether friends have similar socio-economic characteristics as index respondents, and to measure possible correlations between the likelihood of inclusion in the surrogate sample and sensitive behaviors. From these results, we suggest approaches to strengthen estimates of the prevalence of sensitive behaviors obtained from TPR.

Sexual Concurrency and Contraceptive Use Among Young Adult Women

Leveraging 2.5 years of weekly data from the Relationship Dynamics and Social Life Study, we investigate the relationship between young women's sexual concurrency and their contraceptive behavior. Specifically, we (1) examine whether young women changed their contraceptive use when switching from one to multiple concurrent sexual partners in the same week; (2) explore the uniformity of contraceptive responses to concurrency across relationship context; and (3) compare the contraceptive behaviors of never-concurrent women with those of ever-concurrent women in weeks when they were not concurrent. Nearly one in five sexually active young women had sex with two or more people in the same week. When they were concurrent, these women's odds of using any contraception increased threefold, and their odds of using condoms increased fourfold. This pattern of contraceptive adjustments was the same across relationship characteristics, such as duration and exclusivity. Yet when they were not concurrent, ever-concurrent women were less likely to use any contraception and used condoms less consistently than women who were never concurrent. We discuss these findings in the context of ongoing debates about the role of sexual concurrency in STI transmission dynamics.

Application of Core Processes for Understanding Multiple Concurrent Sexual Partnerships Among Adolescents in Uganda

Introduction: Adolescents in Uganda, as in other sub-Saharan countries, engage in sex with multiple concurrent partners, thus placing them at risk for HIV and unplanned pregnancies, but it is not clear why. This study explored why adolescents in Uganda engage in multiple concurrent sexual partnerships (MCSP). Methods: This study used a Core Processes methodology. We used the processes of brainstorming, and identification of evidence and theoretical support, in various phases/steps of intervention planning, to provide possible explanations for adolescent MCSP. Results: Adolescents were found to have limited knowledge of the risks associated with MCSP and perceived a low risk for HIV. Peer influence to engage in MCSP exacerbated the problem among adolescents. Poor communication with sexual partners and parents and societal indifference to multiple sexual partnerships increased permissive attitudes toward infidelity. The unclear adolescent sexual and reproductive health policies hampered access to services, and transactional sexual relationships with older (polygamous) sexual partners increased the HIV risk. Adolescents were found to be more concerned about unplanned pregnancies than HIV risk. Discussion: From the empirical evidence, adolescent health programs in Uganda should incorporate comprehensive sexual health education on HIV and teenage pregnancy risk-reduction strategies. Programs should strengthen parental and community support through enhanced collaborative training on communication with and for adolescents. Forming strategic partnerships with various stakeholders for concerted efforts to address the MCSP problem among adolescents is critical.

A Sexual Partnership Duration: Characterizing Sampling Conditions That Permit unbiased Estimation of Survivorship and Effect on It of Covariates

Partnership duration data are commonly obtained through surveys that collect information on relationships that are ongoing during a fixed time window. This sampling mechanism leads to duration data that are left truncated and right censored; such data have been analysed using the standard truncation product limit estimator (TPLE). In this paper, we describe a common sampling scheme for collecting sexual partnership data, discuss a key assumption required for the TPLE to be unbiased, and provide the conditions under which the nonparametric maximum likelihood estimator of the relationship duration distribution is unique and consistent. We also investigate the conditions required for the consistency of the regression coefcient from a Cox proportional hazards model that apply even when the distribution of duration is not completely identifiable due to restrictions on the support of the truncation distribution. Lastly, we will provide some illustrative examples on estimating distribution of most recent partnerships and present spline regression results based on partnership data collected from sexual behavior survey in Mochudi, Botswana.

Implicit attitudes to sexual partner concurrency vary by sexual orientation but not by gender-A cross sectional study of Belgian students

High rates of sexual partner concurrency have been shown to facilitate the spread of various sexually transmitted infections. Assessments of explicit attitudes to concurrency have however found little difference between populations. Implicit attitudes to concurrency may vary between populations and play a role in generating differences in the prevalence of concurrency. We developed a concurrency implicit associations test (C-IAT) to assess if implicit attitudes towards concurrency may vary between individuals and populations and what the correlates of these variations are. A sample of 869 Belgian students (mean age 23, SD 5.1) completed an online version of the C-IAT together with a questionnaire concerning sexual behavior and explicit attitudes to concurrency. The study participants C-IATs demonstrated a strong preference for monogamy (-0.78, SD = 0.41). 93.2% of participants had a pro-monogamy C-IAT. There was no difference in this implicit preference for monogamy between heterosexual men and women. Men who have sex with men and women who have sex with women were more likely to exhibit implicit but not explicit preferences for concurrency compared to heterosexual men and women. Correlates of the C-IAT varied between men and women.

Can Young Adults Accurately Report Sexual Partnership Dates? Factors Associated With Interpartner and Dyad Agreement

BACKGROUND

Sexual partnership dates are critical to sexually transmitted infection/HIV research and control programs, although validity is limited by inaccurate recall and reporting.

METHODS

We examined data from 302 heterosexual adults (151 index-partner dyads) to assess reliability of reporting. Dates of first sex and last sex were collected through individual interviews and joint dyad questionnaires, which were completed together with their partners. We compared index- and partner-reported dates to estimate interpartner agreement. We used log-linear regression to model associations between interpartner differences and partnership characteristics. To assess validity, we compared individually reported dates with those from joint dyad questionnaires.

RESULTS

Most partnerships (66.2%) were 2 years or less in duration, and many (36.2%) were nonmonogamous. Interpartner agreement to within 1, 30, and 365 days was, respectively, 5.6%, 43.1%, and 81.3% for first sex, and 32.9%, 94.5%, and 100.0% for last sex. In adjusted models, longer relationship duration was associated with disagreement on first sex dates; partnership nonmonogamy was associated with disagreement on dates of first sex and last sex. Within dyads, several participant characteristics were associated with reporting dates closer to joint dyad responses (e.g., for first sex date, female sex [54.7%], having fewer sex partners [58.5%], and greater relationship commitment [57.3%]). However, percent agreement to within 30, 60, and 90 days was similar for all groups for both first and last sex dates.

CONCLUSIONS

Agreement was high on date of last sex but only moderate on date of first sex. Methods to increase accuracy of reporting of dates of sex may improve STI research.

Inference on network statistics by restricting to the network space: applications to sexual history data

Analysis of sexual history data intended to describe sexual networks presents many challenges arising from the fact that most surveys collect information on only a very small fraction of the population of interest. In addition, partners are rarely identified and responses are subject to reporting biases. Typically, each network statistic of interest, such as mean number of sexual partners for men or women, is estimated independently of other network statistics. There is, however, a complex relationship among networks statistics; and knowledge of these relationships can aid in addressing concerns mentioned earlier. We develop a novel method that constrains a posterior predictive distribution of a collection of network statistics in order to leverage the relationships among network statistics in making inference about network properties of interest. The method ensures that inference on network properties is compatible with an actual network. Through extensive simulation studies, we also demonstrate that use of this method can improve estimates in settings where there is uncertainty that arises both from sampling and from systematic reporting bias compared with currently available approaches to estimation. To illustrate the method, we apply it to estimate network statistics using data from the Chicago Health and Social Life Survey. Copyright © 2017 John Wiley & Sons, Ltd.

Using Qualitative Methods to Validate and Contextualize Quantitative Findings: A Case Study of Research on Sexual Behavior and Gender-Based Violence Among Young Swazi Women

Nesting qualitative data collection methods within quantitative studies improves results by assessing validity and providing depth and context. Using data from 3 sources from Swaziland, we triangulate qualitative and quantitative findings to highlight how different methodologies produce discrepant data regarding risky sexual behaviors among young women. We found that women reported similar numbers of lifetime sex partners in all sources, but the proportion reporting multiple and concurrent partnerships was several times higher in qualitative interviews. In addition, qualitative data can provide deeper understanding of how participants, such as those experiencing gender-based violence, understood the experiences behind the quantitative statistics.

Connecting the dots: network data and models in HIV epidemiology

Effective HIV prevention requires knowledge of the structure and dynamics of the social networks across which infections are transmitted. These networks most commonly comprise chains of sexual relationships, but in some populations, sharing of contaminated needles is also an important, or even the main mechanism that connects people in the network. Whereas network data have long been collected during survey interviews, new data sources have become increasingly common in recent years, because of advances in molecular biology and the use of partner notification services in HIV prevention and treatment programmes. We review current and emerging methods for collecting HIV-related network data, as well as modelling frameworks commonly used to infer network parameters and map potential HIV transmission pathways within the network. We discuss the relative strengths and weaknesses of existing methods and models, and we propose a research agenda for advancing network analysis in HIV epidemiology. We make the case for a combination approach that integrates multiple data sources into a coherent statistical framework.

The Impact of Married Individuals Learning HIV Status in Malawi: Divorce, Number of Sexual Partners, and Condom Use With Spouses

This article assesses how married individuals' knowledge of HIV status gained through HIV testing and counseling (HTC) affects divorce, the number of sexual partners, and the use of condoms within marriage. This study improves upon previous studies on this topic because the randomized incentives affecting the propensity to be tested for HIV permit control for selective testing. Instrumental variable probit and linear models are estimated, using a randomized experiment administered as part of the Malawi Longitudinal Study of Families and Health (MLSFH). The results indicate that knowledge of HIV status (1) does not affect chances of divorce for either HIV-negative or HIV-positive respondents; (2) reduces the number of reported sexual partners among HIV-positive respondents; and (3) increases reported condom use with spouses for both HIV-negative and HIV-positive respondents. These results imply that individuals actively respond to information about their HIV status that they learn during HTC, invoking protective behavior against future risk of HIV/AIDS for themselves and their actual and potential sexual partners. Some limitations of this study are a small sample size for those who are HIV-positive and dependence on self-reported sexual behaviors.

Modeling workplace contact networks: The effects of organizational structure, architecture, and reporting errors on epidemic predictions

Face-to-face social contacts are potentially important transmission routes for acute respiratory infections, and understanding the contact network can improve our ability to predict, contain, and control epidemics. Although workplaces are important settings for infectious disease transmission, few studies have collected workplace contact data and estimated workplace contact networks. We use contact diaries, architectural distance measures, and institutional structures to estimate social contact networks within a Swiss research institute. Some contact reports were inconsistent, indicating reporting errors. We adjust for this with a latent variable model, jointly estimating the true (unobserved) network of contacts and duration-specific reporting probabilities. We find that contact probability decreases with distance, and that research group membership, role, and shared projects are strongly predictive of contact patterns. Estimated reporting probabilities were low only for 0-5 min contacts. Adjusting for reporting error changed the estimate of the duration distribution, but did not change the estimates of covariate effects and had little effect on epidemic predictions. Our epidemic simulation study indicates that inclusion of network structure based on architectural and organizational structure data can improve the accuracy of epidemic forecasting models.

Migration, Multiple Sexual Partnerships, and Sexual Concurrency in the Garífuna Population of Honduras

The Garífuna, an ethnic minority group in Honduras, have been disproportionately affected by HIV. Previous research suggests that migration and high rates of multiple sexual partnerships are major drivers of the epidemic. Using data from a 2012 population-based survey, we assessed whether temporary migration was associated with (1) multiple sexual partnerships and (2) sexual concurrency among Garífuna men and women in Honduras. Among both men and women, temporary migration in the last year was associated with an increased likelihood of multiple sexual partnerships and with concurrency, though only the association between migration and multiple sexual partnerships among men was statistically significant (Adjusted Prevalence Ratio 1.7, 95 % CI 1.2-2.4). Migration may contribute to HIV/STI vulnerability among Garífuna men and women via increases in these sexual risk behaviors. Research conducted among men and women at elevated risk of HIV should continue to incorporate measures of mobility, including history of internal migration.

Self-reported sex partner dates for use in measuring concurrent sexual partnerships: correspondence between two assessment methods

Although prevalence of concurrent sexual partnerships is increasingly investigated as a driver of HIV epidemics, its measurement varies and its role in transmission dynamics remains contested. Relying on different methods of obtaining self-reported partnership histories may lead to significant differences in prevalence. This study examined the reliability of two methods for assessing dates of sex and the implications for measuring concurrent sexual partnerships. We conducted a cross-sectional reliability study using self-reported survey data from 650 women ages 18-65 years, recruited online nationwide for human papillomavirus natural history studies from 2007 to 2012. Intermethod reliability of first and last sex with the most recent partner was assessed using weighted kappa. Intraclass correlation coefficient was estimated for intramethod reliability across two consecutive questionnaires administered 4 months apart. Point prevalence of concurrent sexual partnerships at 6 months prior to the questionnaire date was similar between the two question formats (10.5 % for categorical and 10.9 % for continuous). The range between the minimum and maximum cumulative prevalence for 12 months was larger when using the categorical questions (17.0-29.6 % compared to 27.6-28.6 % using the continuous questions). Agreement between the two question formats was moderate for the date of first sex with the most recent partner (κ = 0.56, 95 % CI 0.48-0.64) and almost perfect for the date of last sex (κ = 0.93, 95 % CI 0.91-0.94). Longitudinal agreement for date of first sex was high for the continuous date question (ICC = 0.89, 95 % CI 0.86-0.92). Results of this reliability study can be used to inform the design of future studies of concurrent sexual partnerships and their association with HIV.

Concurrent partnerships in Cape Town, South Africa: race and sex differences in prevalence and duration of overlap

Introduction

Concurrent partnerships (CPs) have been suggested as a risk factor for transmitting HIV, but their impact on the epidemic depends upon how prevalent they are in populations, the average number of CPs an individual has and the length of time they overlap. However, estimates of prevalence of CPs in Southern Africa vary widely, and the duration of overlap in these relationships is poorly documented. We aim to characterize concurrency in a more accurate and complete manner, using data from three disadvantaged communities of Cape Town, South Africa.

Methods

We conducted a sexual behaviour survey (n=878) from June 2011 to February 2012 in Cape Town, using Audio Computer-Assisted Self-Interviewing to collect sexual relationship histories on partners in the past year. Using the beginning and end dates for the partnerships, we calculated the point prevalence, the cumulative prevalence and the incidence rate of CPs, as well as the duration of overlap for relationships begun in the previous year. Linear and binomial regression models were used to quantify race (black vs. coloured) and sex differences in the duration of overlap and relative risk of having CPs in the past year.

Results

The overall point prevalence of CPs six months before the survey was 8.4%: 13.4% for black men, 1.9% for coloured men, 7.8% black women and 5.6% for coloured women. The median duration of overlap in CPs was 7.5 weeks. Women had less risk of CPs in the previous year than men (RR 0.43; 95% CI: 0.32–0.57) and black participants were more at risk than coloured participants (RR 1.86; 95% CI: 1.17–2.97).

Conclusions

Our results indicate that in this population the prevalence of CPs is relatively high and is characterized by overlaps of long duration, implying there may be opportunities for HIV to be transmitted to concurrent partners.

Partner age differences and concurrency in South Africa: Implications for HIV-infection risk among young women

Partner-age difference is an HIV-risk factor among young women in Africa, but the underlying mechanisms are poorly understood. We used nationally representative data among black South Africans (men: 3,530; women: 3,946) to examine the proportion of women in partnerships involving male partner concurrency by age of female partners and by age-disparate (≥5 years) partnerships. Of all partners reported by men, 35 % of young (16-24) women were in partnerships involving male partner concurrency of 4 weeks or longer during the past 12 months. Young women in age-disparate partnerships were more likely to be in partnerships with men who had other concurrent partners (9 %; OR 1.88 p < 0.01) and more likely to be connected to an older sexual network. Our results suggest that the relationship between male concurrency and age-disparate relationships may increase HIV risk for young women by connecting them to larger and older sexual networks.

A new approach to measuring partnership concurrency and its association with HIV risk in couples

Empirical estimates of the association between concurrent partnerships (CP) and HIV risk are affected by non-sampling errors in survey data on CPs, e.g., because respondents misreport the extent of their CPs. We propose a new approach to measuring CPs in couples, which permits assessing how respondent errors affect estimates of the association between CPs and HIV risk. Each couple member is asked (1) to report whether s/he has engaged in CPs and (2) to assess whether his/her partner has engaged in CPs, since their couple started. Cross-tabulating these data yields multiple classifications (with varying combinations of sensitivity/specificity) of the CPs of each couple member. We then measure the association between CPs and HIV outcomes according to each classification. The resulting range of estimates is an indicator of the uncertainty associated with respondent errors. We tested this approach using data on 520 matched couples drawn from the Likoma Network Study. Results suggest that existing tests of the concurrency hypothesis are affected by significant uncertainty.

Assessment of a new web-based sexual concurrency measurement tool for men who have sex with men

BACKGROUND

Men who have sex with men (MSM) are the most affected risk group in the United States' human immunodeficiency virus (HIV) epidemic. Sexual concurrency, the overlapping of partnerships in time, accelerates HIV transmission in populations and has been documented at high levels among MSM. However, concurrency is challenging to measure empirically and variations in assessment techniques used (primarily the date overlap and direct question approaches) and the outcomes derived from them have led to heterogeneity and questionable validity of estimates among MSM and other populations.

OBJECTIVE

The aim was to evaluate a novel Web-based and interactive partnership-timing module designed for measuring concurrency among MSM, and to compare outcomes measured by the partnership-timing module to those of typical approaches in an online study of MSM.

METHODS

In an online study of MSM aged ≥18 years, we assessed concurrency by using the direct question method and by gathering the dates of first and last sex, with enhanced programming logic, for each reported partner in the previous 6 months. From these methods, we computed multiple concurrency cumulative prevalence outcomes: direct question, day resolution / date overlap, and month resolution / date overlap including both 1-month ties and excluding ties. We additionally computed variants of the UNAIDS point prevalence outcome. The partnership-timing module was also administered. It uses an interactive month resolution calendar to improve recall and follow-up questions to resolve temporal ambiguities, combines elements of the direct question and date overlap approaches. The agreement between the partnership-timing module and other concurrency outcomes was assessed with percent agreement, kappa statistic (κ), and matched odds ratios at the individual, dyad, and triad levels of analysis.

RESULTS

Among 2737 MSM who completed the partnership section of the partnership-timing module, 41.07% (1124/2737) of individuals had concurrent partners in the previous 6 months. The partnership-timing module had the highest degree of agreement with the direct question. Agreement was lower with date overlap outcomes (agreement range 79%-81%, κ range .55-.59) and lowest with the UNAIDS outcome at 5 months before interview (65% agreement, κ=.14, 95% CI .12-.16). All agreements declined after excluding individuals with 1 sex partner (always classified as not engaging in concurrency), although the highest agreement was still observed with the direct question technique (81% agreement, κ=.59, 95% CI .55-.63). Similar patterns in agreement were observed with dyad- and triad-level outcomes.

CONCLUSIONS

The partnership-timing module showed strong concurrency detection ability and agreement with previous measures. These levels of agreement were greater than others have reported among previous measures. The partnership-timing module may be well suited to quantifying concurrency among MSM at multiple levels of analysis.

Concordance of risk behavior reporting within HCV serodiscordant injecting partnerships of young injection drug users in San Francisco, CA

INTRODUCTION

Young injection drug users (IDU, under age 30) often inject with other IDU, creating an environment for risk of blood-borne disease transmission through sharing of needles and drug preparation equipment. Epidemiologic studies rely on self reported injection behavior data for measures of transmission risk, therefore we sought to quantify the degree of concordance of reported injecting risk behaviors between injecting dyads.

METHODS

From May, 2006 through 2013 we enrolled 72 injecting dyads in San Francisco, California, who were hepatitis C virus (HCV) RNA discordant. Each partnership was followed prospectively for up to six months. Monthly interviews from each partner were date-matched and responses to relationship characteristics and risk behavior questions were compared. Concordance of reporting was estimated with the concordance correlation coefficient for longitudinal data (CCC) and the prevalence adjusted bias adjusted kappa (PABAK).

RESULTS

Participants had a median age of 26 (IQR: 23, 28) years and median years injecting of 7.0 (IQR: 3.0, 10.6). Thirty-eight percent of the injecting dyads were also sexual partners. Concordance levels were highest for partnership characteristics, such as length of acquaintance, number of days cohabitating, and sexual intercourse in the past month (CCC=0.95; 0.82, and 0.90, respectively). Shared injection risk behaviors such as injecting with the HCV+ partner's previously used syringe and using contaminated injection preparation equipment had slight to fair agreement (CCC=0.22; 0.23; PABAK=0.43, 0.36, respectively).

CONCLUSIONS

Concordance levels ranged from low to high. Potential sources of measurement error for low agreement items include recall and social-desirability biases and question interpretation.

Measurement of breastfeeding initiation: Ethiopian mothers' perception about survey questions assessing early initiation of breastfeeding

BACKGROUND

Although breastfeeding is almost universal in Ethiopia, only 52% newborns benefited from early initiation in 2011. Early initiation is one of the recommended interventions for saving newborn lives but its potential seems not yet realized for Ethiopian newborns and there is a need for continued efforts to increase coverage. To do so, it is also relevant to focus on consistent and accurate reporting of coverage in early initiation. WHO recommends the question "how long after birth did you first put [name] to the breast?" in order to assess coverage in early initiation. It is designed to measure the time after birth when the mother attempted to initiate breastfeeding regardless of whether breast milk had arrived or not. However, it is unclear how mothers perceive this question and what their responses of time refer to. In this study, we assessed Ethiopian mothers' perception about the question assessing early initiation.

METHODS

Cognitive interviews were conducted between April and May 2013 with eligible mothers in Basona and Debrebirhan woredas (districts), 120 km away from Addis Ababa, Ethiopia.

RESULTS

A total of 49 mothers, most from Basona (n = 36) and the rest from Debrebirhan woredas (n = 13) were interviewed. No probes or follow on questions were required for mothers to understand what the WHO recommended question was about. However, further probing was needed to ascertain what maternal responses of time refer to. Accordingly, mothers' response about the timing of early initiation was related to the first time the newborn received breast milk rather than their first attempt to initiate breastfeeding. In addition, considerable probing was required to approximate and code responses of time based on the WHO coding format because some mothers were unable to assess time in minutes or hours.

CONCLUSION

The existing question is not adequate to identify intended attempts of mothers to initiate breastfeeding. We recommend revising the question as "how long after birth did you first put [name] to the breast even if your breast milk did not arrive yet?" Standard probes or follow on questions are required to avoid subjective interpretation of the indicator.

A digital network approach to infer sex behavior in emerging HIV epidemics

Purpose

Improve the ability to infer sex behaviors more accurately using network data.

Methods

A hybrid network analytic approach was utilized to integrate: (1) the plurality of reports from others tied to individual(s) of interest; and (2) structural features of the network generated from those ties. Network data was generated from digitally extracted cell-phone contact lists of a purposeful sample of 241 high-risk men in India. These data were integrated with interview responses to describe the corresponding individuals in the contact lists and the ties between them. HIV serostatus was collected for each respondent and served as an internal validation of the model’s predictions of sex behavior.

Results

We found that network-based model predictions of sex behavior and self-reported sex behavior had limited correlation (54% agreement). Additionally, when respondent sex behaviors were re-classified to network model predictions from self-reported data, there was a 30.7% decrease in HIV seroprevalence among groups of men with lower risk behavior, which is consistent with HIV transmission biology.

Conclusion

Combining the relative completeness and objectivity of digital network data with the substantive details of classical interview and HIV biomarker data permitted new analyses and insights into the accuracy of self-reported sex behavior.

Characteristics of multiple and concurrent partnerships among women at high risk for HIV infection

OBJECTIVES

We examined parameters of sexual partnerships, including respondents' participation in concurrency, belief that their partner had concurrent partnerships (partners' concurrency), and partnership intervals, among the 2099 women in HIV Prevention Trials Network 064, a study of women at high risk for HIV infection, in 10 U.S. communities.

METHODS

We analyzed baseline survey responses about partnership dates to determine prevalence of participants' and partners' concurrency, intervals between partnerships, knowledge of whether recent partners had undergone HIV testing, and intercourse frequency during the preceding 6 months.

RESULTS

Prevalence of participants' and partners' concurrency was 40% and 36%, respectively; 24% respondents had both concurrent partnerships and nonmonogamous partners. Among women with >1 partner and no concurrent partnerships themselves, the median gap between partners was 1 month. Multiple episodes of unprotected vaginal intercourse with ≥2 of their most recent partners was reported by 60% of women who had both concurrent partnerships and nonmonogamous partners, 50% with only concurrent partners and no partners' concurrency, and 33% with only partners' concurrency versus 14% of women with neither type of concurrency (P < 0.0001). Women who had any involvement with concurrency were also more likely than women with no concurrency involvement to report lack of awareness of whether recent partners had undergone HIV testing (participants' concurrency 41%, partners' concurrency 40%, both participants' and partners' concurrency 48%, neither 17%; P < 0.0001).

CONCLUSIONS

These network patterns and short gaps between partnerships may create substantial opportunities for HIV transmission in this sample of women at high risk for HIV infection.

Measuring prevalence and correlates of concurrent sexual partnerships among young sexually active men in Kisumu, Kenya

Our objectives were to: (1) compare multiple measures of partnership concurrency, including the UNAIDS-recommended definition and (2) describe the prevalence and correlates of concurrent sexual partnerships among young Kenyan men. We analyzed 10,907 lifetime partnerships of 1,368 men ages 18-24 years enrolled in a randomized trial of male circumcision to reduce HIV-1 incidence in Kisumu. Partnership concurrency was determined by overlapping dates and examined over varying recall periods and assumptions. The lifetime prevalence of concurrency was 77 %. Sixty-one percent of all partnerships were concurrent and factors associated with concurrency differed by partner type. Point prevalence of concurrency at the time of the interview was consistently the highest and UNAIDS-recommended definition was the most conservative (25 vs. 18 % at baseline, respectively). Estimates of concurrency were influenced by methods for definition and measurement. Regardless of definition, concurrent partnerships are frequent in this population of young, sexually active men in high HIV prevalence Kisumu, Kenya.

Reciprocal sex partner concurrency and STDs among heterosexuals at high-risk of HIV infection

Inconsistent findings on the relationship of sex partner concurrency to infection with HIV and other sexually transmitted diseases (STDs) may result from differences in how sex partner concurrency is conceptualized. We examine the relationship of reciprocal sex partner concurrency (RSPC) to diagnosed STDs among heterosexuals. Heterosexually active adults (N = 717) were recruited for a cross-sectional study using respondent-driven sampling (RDS) from high-HIV-risk areas in New York City (NYC, 2006-2007) and interviewed about their sexual risk behaviors, number of sex partners, last sex partners, and STD diagnoses (prior 12 months). RSPC was when both the participant and her/his last sex partner had sex with other people during their sexual relationship. Odds ratios (OR), adjusted odds ratios (aOR), and 95 % confidence intervals (95%CI) were estimated by logistic regression. The sample was 52.4 % female, 74.3 % Black; median age was 40 years. RSPC was reported by 40.7 % and any STD diagnoses by 23.4 %. Any STDs was reported by 31.5 % of those reporting RSPC vs. 17.9 % of those who did not (OR = 2.11, 95%CI = 1.49-3.0). Any STDs was independently associated with RSPC (aOR = 1.54, 95%CI = 1.02-2.32), female gender (aOR = 2.15, 95%CI = 1.43-3.23), having more than three sex partners (aOR = 1.72, 95%CI = 1.13-2.63), and unprotected anal sex (aOR = 1.65, 95%CI = 1.12-2.42). Heterosexuals in high-HIV-risk neighborhoods in sexual partnerships that involve RSPC are at greater risk of STDs and, potentially, HIV. RSPC, in addition to sexual risk behaviors and the number of sex partners, may facilitate the heterosexual spread of HIV through STD cofactors and linkage into larger STD/HIV sexual transmission networks.

Partnership concurrency and coital frequency

National HIV prevalence estimates across sub-Saharan Africa range from less than 1 percent to over 25 percent. Recent research proposes several explanations for the observed variation, including prevalence of male circumcision, levels of condom use, presence of other sexually transmitted infections, and practice of multiple concurrent partnerships. However, the importance of partnership concurrency for HIV transmission may depend on how it affects coital frequency with each partner. The coital dilution hypothesis suggests that coital frequency within a partnership declines with the addition of concurrent partners. Using sexual behavior data from rural Malawi and urban Kenya, we investigate the relationship between partnership concurrency and coital frequency, and find partial support for the coital dilution hypothesis. We conclude the paper with a discussion of our findings in light of the current literature on concurrency.

Behavioral, biological, and demographic risk and protective factors for new HIV infections among youth in Rakai, Uganda

BACKGROUND

Prevalence of HIV infection is considerable among youth, although data on risk factors for new (incident) infections are limited. We examined incidence of HIV infection and risk and protective factors among youth in rural Uganda, including the role of gender and social transitions.

METHODS

Participants were sexually experienced youth (15-24 years old) enrolled in the Rakai Community Cohort Study, 1999-2008 (n = 6741). Poisson regression with robust standard errors was used to estimate incident rate ratios (IRR) and 95% confidence intervals (CI) of incident HIV infection.

RESULTS

HIV incidence was greater among young women than young men (14.1 vs. 8.3 per 1000 person-years, respectively); this gender disparity was greater among teenagers (14.9 vs. 3.6). Beyond behavioral (multiple partners and concurrency) and biological factors (sexually transmitted infection symptoms), social transitions such as marriage and staying in school influenced HIV risk. In multivariate analyses among women, HIV incidence was associated with living in a trading village (adjusted IRR (aIRR) = 1.48; 95% CI: 1.04 to 2.11), being a student (aIRR = 0.22; 95% CI: 0.07 to 0.72), current marriage (aIRR = 0.55; 95% CI: 0.37 to 0.81), former marriage (aIRR = 1.73; 95% CI: 1.01 to 2.96), having multiple partners, and sexually transmitted infection symptoms. Among men, new infections were associated with former marriage (aIRR = 5.57; 95% CI: 2.51 to 12.36), genital ulceration (aIRR = 3.56; 95% CI: 1.97 to 6.41), and alcohol use (aIRR = 2.08; 95% CI: 1.15 to 3.77).

CONCLUSIONS

During the third decade of the HIV epidemic in Uganda, HIV incidence remains considerable among youth, with young women particularly at risk. The risk for new infections was strongly shaped by social transitions such as leaving school, entrance into marriage, and marital dissolution; the impact of marriage was different for young men than women.

HIV prevalence by race co-varies closely with concurrency and number of sex partners in South Africa

BACKGROUND

HIV prevalence differs by more than an order of magnitude between South Africa's racial groups. Comparing the sexual behaviors and other risk factors for HIV transmission between the different races may shed light on the determinants of South Africa's generalized HIV epidemic.

METHODS

Five nationally representative and one city-representative population-based surveys of sexual behavior were used to assess the extent to which various risk factors co-varied with HIV prevalence by race in South Africa.

RESULTS

In 2004, the prevalence of HIV was 0.5%, 1%, 3.2% and 19.9% in 15-49 year old whites, Indians, coloureds and blacks respectively. The risk factors which co-varied with HIV prevalence by race in the six surveys were age of sexual debut (in five out of five surveys for men and three out of six surveys for women), age gap (zero surveys in men and three in women), mean number of sex partners in the previous year (five surveys in men and three in women) and concurrent partnerships (five surveys in men and one in women). Condom usage and circumcision were both more prevalent in the high HIV prevalence groups. The reported prevalence of concurrency was 6 to 17 times higher in the black as opposed to the white men in the five surveys.

CONCLUSIONS

The differences in sexual behavior in general, and the prevalence of concurrency and the number of sexual partners in particular, offer a plausible and parsimonious cause to explain a part of the differing prevalences of HIV between South Africa's racial groups.

Cohort Profile: The Likoma Network Study (LNS)

The Likoma network study (LNS) investigates the sexual networks connecting the inhabitants of Likoma, a small island of Lake Malawi with high HIV prevalence. Whereas previous studies of sexual networks and HIV/AIDS in sub-Saharan countries have focused solely on the personal networks of a small number of respondents, the LNS attempts to document the sexual networks of the entire adult population of Likoma. To do so, it uses a unique sociocentric study design, in which all members of the local population are contacted for a survey interview and are asked to nominate their five most recent sexual partners. Using these data, quasi-complete 'maps' of the sexual networks connecting inhabitants of the island can be constructed. These maps allow investigation of the impact of networks on HIV epidemiology and can inform mathematical models of HIV prevention. In addition to data on sexual networks, the LNS data include information on the social networks (e.g. friendship), socioeconomic characteristics and HIV status of Likoma's residents. Baseline data were collected in 2005-06. A first follow-up was conducted in 2007-08 and a second follow-up is planned for early 2013. Access to the LNS data is contingent upon review of a short concept paper and forming collaborations with LNS investigators.

Measuring and modelling concurrency

This article explores three critical topics discussed in the recent debate over concurrency (overlapping sexual partnerships): measurement of the prevalence of concurrency, mathematical modelling of concurrency and HIV epidemic dynamics, and measuring the correlation between HIV and concurrency. The focus of the article is the concurrency hypothesis - the proposition that presumed high prevalence of concurrency explains sub-Saharan Africa's exceptionally high HIV prevalence. Recent surveys using improved questionnaire design show reported concurrency ranging from 0.8% to 7.6% in the region. Even after adjusting for plausible levels of reporting errors, appropriately parameterized sexual network models of HIV epidemics do not generate sustainable epidemic trajectories (avoid epidemic extinction) at levels of concurrency found in recent surveys in sub-Saharan Africa. Efforts to support the concurrency hypothesis with a statistical correlation between HIV incidence and concurrency prevalence are not yet successful. Two decades of efforts to find evidence in support of the concurrency hypothesis have failed to build a convincing case.

The effect of interview method on self-reported sexual behavior and perceptions of community norms in Botswana

Since self-reports of sensitive behaviors play an important role in HIV/AIDS research, the accuracy of these measures has often been examined. In this paper we (1) examine the effect of three survey interview methods on self-reported sexual behavior and perceptions of community sexual norms in Botswana, and (2) introduce an interview method to research on self-reported sexual behavior in sub-Saharan Africa. Comparing across these three survey methods (face-to-face, ballot box, and randomized response), we find that ballot box and randomized response surveys both provide higher reports of sensitive behaviors; the results for randomized response are particularly strong. Within these overall patterns, however, there is variation by question type; additionally the effect of interview method differs by sex. We also examine interviewer effects to gain insight into the effectiveness of these interview methods, and our results suggest that caution be used when interpreting the differences between survey methods.

Exploring the use of social network analysis to measure social integration among older adults in assisted living

Social integration is measured by a variety of social network indicators each with limitations in its ability to produce a complete picture of the variety and scope of interactions of older adults receiving long-term services and supports. The purpose of this study was to develop and evaluate the feasibility of collecting sociocentric (whole network) data among older adults in one assisted living neighborhood. The sociocentric approach is required to conduct social network analysis. Applying social network analysis is an innovative way to measure different facets of social integration among residents. Sociocentric data are presented for 12 residents. Network visualization or sociograms are used to illustrate the level of social integration among residents and between residents and staff. Measures of network centrality are reported to illustrate the number of personal connections and cohesion. The use of resident photographs helped residents with cognitive impairment to nominate individuals with whom they interacted. The sociocentric approach to data collection is feasible and allows researchers to measure levels and different aspects of social integration in assisted living environments. Residents with mild to moderate cognitive impairment were able to participate with the aid of resident and staff photographs. This approach is sensitive to capturing routine day-to-day interactions between residents and assisted living staff members that are often not reported in person-centered networks. This study contributes to the foundation for larger more representative studies of entire assisted living organizations that could in the future inform interventions aimed at improving social integration and cohesion among recipients of long-term services and supports.

Unpacking the recommended indicator for concurrent sexual partnerships

Using sexual behaviour survey data, we examine the methodological choice for the time period underlying the UNAIDS Reference Group on Estimates, Modelling, and Projections recommended 'point prevalence' indicator for concurrency. The results confirm that 6 months before the interview is a good time point for calculating the recommended indicator, but this retrospective estimate is substantially lower than the estimate of concurrency based on the number of current partnerships. The discrepancy is only partially explained by disproportionate missing data in those with more sexual partners.

Measuring concurrency: an empirical study of different methods in a large population-based survey and evaluation of the UNAIDS guidelines

BACKGROUND

Recent UNAIDS guidelines recommend measuring concurrency 6 months before the interview date, based on overlapping partnership dates. This has theoretical advantages, but little is known about how well it can be measured in practice.

METHODS

The assumptions underlying the UNAIDS measure were tested using data from a sexual behaviour survey conducted in rural northern Malawi. All resident adults aged 15-59 were eligible. Questions included self-reported concurrency and dates for all marital and nonmarital partnerships in the past 12 months.

RESULTS

A total of 6796 women and 5253 men were interviewed, 83 and 72% of those eligible, respectively. Since few women reported multiple partners, detailed analysis was restricted to men. Overall 19.2% [95% confidence interval (CI) 18.1-20.2] of men self-reported concurrent relationships in the past year (almost all of those with more than one partner). Using overlapping dates the estimate was 16.7% (15.7-17.7). Excluding partnerships which tied on dates (making overlap uncertain) or restricting the analysis to the three most recent partners gave similar results. The UNAIDS 6-month measure was 12.0% (11.1-12.9), and current concurrency was 11.5% (10.6-12.4). The difference between dates-based and self-reported 12-month measures was much larger for unmarried men: 11.1% (9.7-12.4) self-reported; 7.1% (6.9-8.2) on dates. Polygyny (15% of married men) and the longer duration of relationships stabilized the estimates for married men. Nonmarital partnerships were under-reported, particularly those starting longer ago.

CONCLUSIONS

The difficulties of recall of dates for relationships, and under-reporting of partners lead to underestimation of concurrency using date-based measures. Self-reported concurrency is much easier to measure and appears more complete.

Women underestimate the age of their partners during survey interviews: implications for HIV risk associated with age mixing in northern Malawi

BACKGROUND

Age mixing may explain differences in HIV prevalence across populations in sub-Saharan countries, but the validity of survey data on age mixing is unknown.

METHODS

Age differences between partners are frequently estimated indirectly by asking respondents to report their partner's age. Partner's age can also be assessed directly by tracing partners and asking them to report their own age. We use data from 519 relationships, collected in Likoma (Malawi), in which both the partners were interviewed and tested for HIV. In these relationships, age differences were assessed both indirectly and directly, and estimates could thus be compared. We calculate the specificity and sensitivity of the indirect method in identifying age-homogenous/age-disparate relationships in which the male partner is less/more than 5 or 10 years older than the respondent.

RESULTS

Women were accurate in identifying age-homogenous relationships, but not in identifying age-disparate relationships (specificity ≈90%, sensitivity = 24.3%). The sensitivity of the indirect method was even lower in detecting partners older than the respondent by 10+ years (9.6%). Among 43 relationships with an HIV-infected partner included in this study, there were about 3 times more age-disparate relationships according to direct measures of partner's age than according to women's reports of their partner's age (17% vs. 46%).

CONCLUSIONS

Women's survey reports of their partner's age significantly underestimate the extent of and the HIV risk associated with age mixing in this population. Future studies of the effect of sexual mixing patterns on HIV risk in sub-Saharan countries should take reporting biases into account.

Measuring concurrent partnerships: potential for underestimation in UNAIDS recommended method

Research on concurrent sexual partnerships has been constrained by inconsistent and inaccurate measurements of these partnerships. Recently, a UNAIDS working group recommended a method based on sexual partner histories to improve the measurement of concurrency. Using recent survey data for young adults living in Cape Town, South Africa, we found that this method could result in underestimates of concurrency due to respondents' failure to report additional sexual partners.