Serial monogamy and biologic concurrency: measurement of the gaps between sexual partners to inform targeted strategies

An Analysis of Sex Practices and Behaviors Among African Americans in Sexually Concurrent and Sexually Exclusive Relationships

Historically, sexually concurrent relationships have been associated with increased risk for sexually transmitted infections (STIs), including HIV. Due to socio-structural factors, African Americans (AAs) have higher rates of STIs compared to other racial groups and are more likely to engage in sexually concurrent (SC) relationships. Current research has challenged the assumption that SC is the only risky relationship type, suggesting that both SC and sexually exclusive (SE) relationships are at equal risk of STI and HIV acquisition and that both relationship types should engage in safer sex practices. This study aimed to compare sex practices and behaviors among AA men and women in SC and SE relationships (N = 652). Results demonstrate differences in sexual practices and behaviors between SC and SE men and women. Overall, SC and SE women report condom use with male partners less frequently than SC and SE men. SC men were more likely to report substance use during sex compared to SC and SE women. Pre-exposure prophylaxis (PrEP) use did not differ across groups. SE men were less likely to report STI testing and diagnosis compared to SC women. Findings support the need to focus on culturally and gender-specific safer sex interventions among AAs.

Partner notification and treatment outcomes among South African adolescents and young adults diagnosed with a sexually transmitted infection via laboratory-based screening

Partner notification and treatment are essential components of sexually transmitted infection (STI) management, but little is known about such practices among adolescents and young adults. Using data from a prospective cohort study (AYAZAZI) of youth aged 16-24 years in Durban, South Africa, we assessed the STI care cascade across participant diagnosis, STI treatment, partner notification, and partner treatment; index recurrent STI and associated factors; and reasons for not notifying partner of STI. Participants completed laboratory-based STI screening (Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma genitalium, Trichomonas vaginalis) at enrollment and at 12 months. Of the 37/216 participants with STI (17%), 27/37 (73%) were women and 10/37 (27%) were men. Median age was 19 years (IQR: 18-20). Of the participants with STI, 23/37 (62%) completed a Treatment and Partner Tracing Survey within 6 months of diagnosis. All survey participants reported completing STI treatment (100%), 17/23 (74%) notified a partner, and 6/23 (35%) reported partner treatment. Overall, 4/23 (11%) participants had 12-month recurrent C. trachomatis infection, with no association with partner notification or treatment. Stigma and lack of STI knowledge were reasons for not notifying partner of STI. STI partner notification and treatment is a challenge among youth. Novel strategies are needed to overcome barriers along the STI care cascade.

Partner faithfulness and sexual reproductive health practices in Botswana: does perception of partner infidelity influence sexual risk behaviours of people aged 10-34 years?

The main aim of this study was to test whether perception of partner infidelity prompts people to adopt behaviour that is meant to compensate for the increased risk of infection posed by their partner's infidelity; or whether it prompts people to engage in behaviour that magnifies the risk associated with partner infidelity. Data used were derived from the fourth and latest Botswana AIDS Impact Survey (BAIS IV) conducted in 2013. The sample consisted of 6985 people aged 10-34 years. Logistic regression analysis was used to identify factors associated with perception of partner infidelity and sexual risk behaviours. Perception of partner infidelity with the current and most recent partner was 39.6% while perception of partner infidelity with other previous sexual partners was 79.9%. The main socio-demographic factors associated with perception of partner infidelity were being a man, being single and having secondary education, while sexual risk behaviours associated with perception of partner infidelity were having multiple sexual partners and being involved in multiple concurrent sexual partnerships. These relationships were statistically significant at the 5% level. Botswana's HIV prevention strategies should seek to improve partner communication within relationships in order to enhance people's confidence and skills so as to minimize perceptions of infidelity.

Association of Timing of Sexual Partnerships and Perceptions of Partners' Concurrency With Reporting of Sexually Transmitted Infection Diagnosis

IMPORTANCE

The timing of sexual partnerships is important for sexually transmitted infection (STI) transmission potential. Studies often measure timing as whether partnerships overlap in time (concurrency), but this measure does not account for how STI risk from previous partners can be carried forward into future partnerships even when there is a time gap between them (serial monogamy) if the infectious period is greater than this time gap.

OBJECTIVE

To examine the association of the timing of partnerships, measured as the time gap or time overlap between partners, and perceptions of partners' concurrency with STI transmission.

DESIGN, SETTING, AND PARTICIPANTS

This survey study that was conducted in 2017 included 8867 participants in Britain aged 16 to 44 years who reported 1 or more sexual partners in the 5 years before the interview. Data were collected from 2010 to 2012 from Britain's third National Survey of Sexual Attitudes and Lifestyles (Natsal-3), a large probability survey (response rate, 57.7%) designed to be broadly representative of the general population.

EXPOSURES

Gaps between participants' 3 or fewer most recent partners in the past 5 years were calculated from dates of the last sexual encounter with former partners and the first sexual encounter with subsequent partners. Negative gaps denote overlapping partnerships (concurrency); positive gaps denote serial monogamy. Participant perception of most recent partner concurrency was proxied by asking participants whether they knew or thought that their partners had had sex with other partners since their first sexual encounter together.

MAIN OUTCOMES AND MEASURES

Reported STI diagnosis in the past 5 years.

RESULTS

Of 8867 participants eligible for this analysis, 3509 (39.6%) were male and 5158 (58.2%) were female, with a mean age of 28 years. Overall, 48.1% of males and 39.5% of females reported 2 or more partners and 1 or more time gaps. The median time gap was 2 months (interquartile range, -3 months to 8 months). Although 67.0% of the time gaps were 1 month or more, many were sufficiently short time gaps for STI transmission. The time gap was independently associated with STI diagnosis, without a significant decrease in likelihood until the time gap was 4 months or more for females (adjusted odds ratio [OR]: 0.39, 95% CI, 0.19-0.81) and 6 months or more for males (adjusted OR: 0.42, 95% CI, 0.20-0.85) compared with time overlaps of 2 years or more. Participant perception of partners' concurrency (reported by half of the participants) was independently associated with STI diagnosis among females (reporting no partner concurrency vs reporting partner concurrency: adjusted OR, 0.32; 95% CI, 0.22-0.49).

CONCLUSIONS AND RELEVANCE

The findings suggest that the gap between partners is often sufficiently small to permit STI transmission and that many people, although themselves monogamous, have partners who are not, which itself is associated with an increase in the risk of STI acquisition. Public health practitioners should communicate these epidemiological facts, and researchers should develop measures that better capture the risk of STI transmission from partners.

Capturing sexual contact patterns in modelling the spread of sexually transmitted infections: Evidence using Natsal-3

BACKGROUND

Understanding the spread of sexually transmitted infections (STIs) in a population is of great importance to the planning and delivery of health services globally. The worldwide rise of HIV since the 1980's, and the recent increase in common STIs (including HPV and Chlamydia) in many countries, means that there is an urgent need to understand transmission dynamics in order to better predict the spread of such infections in the population. Unlike many other infections which can be captured by assumptions of random mixing, STI transmission is intimately linked to the number and pattern of sexual contacts. In fact, it is the huge variation in the number of new sexual partners that gives rise to the extremes of risk within populations which need to be captured in predictive models of STI transmission. Such models are vital in providing the necessary scientific evidence to determine whether a range of controls (from education to screening to vaccination) are cost-effective.

METHOD AND RESULTS

We use probability sample survey data from Britain's third National Survey of Sexual Attitudes and Lifestyles (Natsal-3) to determine robust distributions for the rate of new partnerships that involve condomless sex and can therefore facilitate the spread of STIs. Different distributions are defined depending on four individual-level characteristics: age, sex, sexual orientation, and previous sexual experience. As individual behaviour patterns can change (e.g. by remaining in a monogamous relationship for a long period) we allow risk-percentiles to be randomly redrawn, to capture longer term behaviour as measured by Natsal-3. We demonstrate how this model formulation interacts with the transmission of infection by constructing an individual-based SIS-P (Susceptible-Infected-Susceptible-Protected) transmission model for the spread of a generic STI, and observing overall population demographics when varying the transmission probability within a partnership, recovery rate and the level of population protection (e.g. from vaccination where applicable).

The Acceptability and Feasibility of Implementing a Bio-Behavioral Enhanced Surveillance Tool for Sexually Transmitted Infections in England: Mixed-Methods Study

BACKGROUND

Sexually transmitted infection (STI) surveillance is vital for tracking the scale and pattern of epidemics; however, it often lacks data on the underlying drivers of STIs.

OBJECTIVE

This study aimed to assess the acceptability and feasibility of implementing a bio-behavioral enhanced surveillance tool, comprising a self-administered Web-based survey among sexual health clinic attendees, as well as linking this to their electronic health records (EHR) held in England's national STI surveillance system.

METHODS

Staff from 19 purposively selected sexual health clinics across England and men who have sex with men and black Caribbeans, because of high STI burden among these groups, were interviewed to assess the acceptability of the proposed bio-behavioral enhanced surveillance tool. Subsequently, sexual health clinic staff invited all attendees to complete a Web-based survey on drivers of STI risk using a study tablet or participants' own digital device. They recorded the number of attendees invited and participants' clinic numbers, which were used to link survey data to the EHR. Participants' online consent was obtained, separately for survey participation and linkage. In postimplementation phase, sexual health clinic staff were reinterviewed to assess the feasibility of implementing the bio-behavioral enhanced surveillance tool. Acceptability and feasibility of implementing the bio-behavioral enhanced surveillance tool were assessed by analyzing these qualitative and quantitative data.

RESULTS

Prior to implementation of the bio-behavioral enhanced surveillance tool, sexual health clinic staff and attendees emphasized the importance of free internet/Wi-Fi access, confidentiality, and anonymity for increasing the acceptability of the bio-behavioral enhanced surveillance tool among attendees. Implementation of the bio-behavioral enhanced surveillance tool across sexual health clinics varied considerably and was influenced by sexual health clinics' culture of prioritization of research and innovation and availability of resources for implementing the surveys. Of the 7367 attendees invited, 85.28% (6283) agreed to participate. Of these, 72.97% (4585/6283) consented to participate in the survey, and 70.62% (4437/6283) were eligible and completed it. Of these, 91.19% (4046/4437) consented to EHR linkage, which did not differ by age or gender but was higher among gay/bisexual men than heterosexual men (95.50%, 722/756 vs 88.31%, 1073/1215; P<.003) and lower among black Caribbeans than white participants (87.25%, 568/651 vs 93.89%, 2181/2323; P<.002). Linkage was achieved for 88.88% (3596/4046) of consenting participants.

CONCLUSIONS

Implementing a bio-behavioral enhanced surveillance tool in sexual health clinics was feasible and acceptable to staff and groups at STI risk; however, ensuring participants' confidentiality and anonymity and availability of resources is vital. Bio-behavioral enhanced surveillance tools could enable timely collection of detailed behavioral data for effective commissioning of sexual health services.

Sexually Transmitted Infection Prevention With Long-Acting Reversible Contraception: Factors Associated With Dual Use

BACKGROUND

Long-acting reversible contraception (LARC) is extremely effective in preventing pregnancy; however, it does not provide sexually transmitted infection (STI) prevention. Therefore, dual use is recommended for the prevention of STIs, in addition to pregnancy, by using LARC methods with condoms. This study assessed factors associated with LARC only use and dual-LARC and condom use among college women.

METHODS

The National College Health Assessment-II Fall 2012 to 2013 was used for this analysis. The analytic sample was restricted to women who used a LARC method (ie, intrauterine device or implant) (N = 1658). The main outcome was dual method use, LARC and condom, at last sex. An adjusted logistic regression model assessed sociodemographic factors (age, relationship, race), health care utilization (routine gynecological examination), and sexual behavior (number of partners) as factors associated with dual condom-LARC use at the last time of vaginal-sex. Prevalence ratios (PR) and 95% confidence intervals (CI) were estimated.

RESULTS

Among women reporting LARC use, 24% used a condom. Dual users were less likely to have only 1 sexual partner (adjusted PR [aPR], 0.66; 95% CI, 0.54-0.81) and be in a relationship. Dual users were more likely than LARC-only users to be Hispanic (aPR, 1.34; 95% CI, 1.01-1.78), black (aPR, 1.40; 95% CI, 1.07-1.83), and biracial/multiracial (aPR, 1.38; 95% CI, 1.10-1.73).

CONCLUSIONS

These findings illustrate differences between dual-condom LARC and LARC-only college users. It is likely that relationship status and number of partners influences perceived risk for STIs and decision making for dual use among this population.

Evaluation of vaccination herd immunity effects for anogenital warts in a low coverage setting with human papillomavirus vaccine-an interrupted time series analysis from 2005 to 2010 using health insurance data

Background

Shortly after the human papillomavirus (HPV) vaccine recommendation and hence the reimbursement of vaccination costs for the respective age groups in Germany in 2007, changes in the incidence of anogenital warts (AGWs) were observed, but it was not clear at what level the incidence would stabilize and to what extent herd immunity would be present. Given the relatively low HPV vaccination coverage in Germany, we aimed to assess potential vaccination herd immunity effects in the German setting.

Methods

A retrospective open cohort study with data from more than nine million statutory health insurance members from 2005 to 2010 was conducted. AGW cases were identified using ICD-10-codes. The incidence of AGWs was estimated by age, sex, and calendar quarter. Age and sex specific incidence rate ratios were estimated comparing the years 2009–2010 (post-vaccination period) with 2005–2007 (pre-vaccination period).

Results

Incidence rate ratio of AGWs for the post-vaccination period compared to the pre-vaccination period showed a u-shaped decrease among the 14- to 24-year-old females and males which corresponds well with the reported HPV vaccination uptake in 2008. A maximum reduction of up to 60% was observed for the 16- to 20-year-old females and slightly less pronounced (up to 50%) for the 16- and 18-year-old males. Age groups outside of the range 14–24 years demonstrated no decrease. The decrease of incidence occurred in both sexes early after the vaccine recommendation and stabilized at lower levels in 2009–2010.

Conclusions

A relative reduction of up to 50% among males of approximately similar age groups as that of females receiving the HPV vaccination suggests herd protection resulting from assortative mixing by age. The early decrease among males can be reduced over time due to partner change.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2663-7) contains supplementary material, which is available to authorized users.

Structural and Behavioral Correlates of HIV Infection among Pregnant Women in a Country with a Highly Generalized HIV Epidemic: A Cross-Sectional Study with a Probability Sample of Antenatal Care Facilities in Swaziland

INTRODUCTION

HIV disproportionately affects women in Sub-Saharan Africa. Swaziland bears the highest HIV prevalence of 41% among pregnant women in this region. This heightened HIV-epidemic reflects the importance of context-specific interventions. Apart from routine HIV surveillance, studies that examine structural and behavioral factors associated with HIV infection among women may facilitate the revitalization of existing programs and provide insights to inform context-specific HIV prevention interventions.

METHODS AND FINDINGS

This cross-sectional study employed a two-stage random cluster sampling in ten antenatal health care facilities in the Hhohho region of Swaziland in August and September 2015. Participants were eligible for the study if they were 18 years or older and had tested for HIV. Self-administered tablet-based questionnaires were used to assess HIV risk factors. Of all eligible pregnant women, 827 (92.4%) participated, out of which 297 (35.9%) were self-reportedly HIV positive. Among structural factors, family function was not significantly associated with self-reported HIV positive status, while lower than high school educational attainment (AOR, 1.65; CI, 1.14-3.38; P = 0.008), and income below minimum wage (AOR, 1.81; CI, 1.09-3.01; P = 0.021) were significantly associated with self-reported HIV positive status. Behavioral factors significantly associated with reporting a positive HIV status included; ≥2 lifetime sexual partners (AOR, 3.16; CI, 2.00-5.00; P<0.001), and ever cohabited (AOR, 2.39; CI, 1.66-3.43; P = 0.00). The most cited reason for having multiple sexual partners was financial gain. HIV/AIDS-related knowledge level was high but not associated to self-reported HIV status (P = 0.319).

CONCLUSIONS

Structural and behavioral factors showed significant association with self-reported HIV infection among pregnant women in Swaziland while HIV/AIDS-related knowledge and family function did not. This suggests that HIV interventions should be reinforced taking into consideration these findings. The findings also suggest the importance of future research sensitive to the Swazi and African sociocultural contexts, especially research for family function.

Time-Site Survey of Substance Use, Sexual Behaviours, and HIV-Testing Practices among Women Attending Social Venues in Prague

AIM

The rates of HIV acquired through heterosexual contact are increasing in the Czech Republic. This study explored potential HIV risk associa-tions with alcohol, illicit drugs and sexual behaviours among adults from a community-based sample attending gay- and non-gay venues in Prague.

METHODS

Women attending bars, cafes and beer gardens in central Prague responded to the self-administered, time-site survey. Alcohol use was measured by the AUDIT-C and CAGE questionnaires. Sexual network structuring identified number, gender and coital frequency with current and recent sexual partners. Statistical analysis included central tendency, chi-square and logistic regression. Female participants (n=124) ranged from 18 to 67 years of age (mean 29 years); 25% self-identified as non-heterosexual.

RESULTS

We found alcohol to be the preferred drug of choice. Younger heterosexual women with new and casual sexual partners were more likely to use alcohol excessively. Women with children reported the least alcohol use. Sixty percent of the sample had never used condoms; condom-use was associated with longer relationship duration and discussions about HIV status with a sexual partner; non-use tended to occur among unmarried women with multiple male partners in short, serial sexual relationships. Women who sought HIV testing tended to be younger and more self-identified as non-heterosexual. Protective practices were rarely reported even when HIV transmission increases via heterosexual sexual partnering.

CONCLUSION

Further research is recommended regarding cultural and contextual influences on HIV risk behaviours among Czech women.

Measuring concurrency using a joint multistate and point process model for retrospective sexual history data

Understanding the impact of concurrency, defined as overlapping sexual partnerships, on the spread of HIV within various communities has been complicated by difficulties in measuring concurrency. Retrospective sexual history data consisting of first and last dates of sexual intercourse for each previous and ongoing partnership is often obtained through use of cross-sectional surveys. Previous attempts to empirically estimate the magnitude and extent of concurrency among these surveyed populations have inadequately accounted for the dependence between partnerships and used only a snapshot of the available data. We introduce a joint multistate and point process model in which states are defined as the number of ongoing partnerships an individual is engaged in at a given time. Sexual partnerships starting and ending on the same date are referred to as one-offs and modeled as discrete events. The proposed method treats each individual's continuation in and transition through various numbers of ongoing partnerships as a separate stochastic process and allows the occurrence of one-offs to impact subsequent rates of partnership formation and dissolution. Estimators for the concurrent partnership distribution and mean sojourn times during which a person has k ongoing partnerships are presented. We demonstrate this modeling approach using epidemiological data collected from a sample of men having sex with men and seeking HIV testing at a Los Angeles clinic. Among this sample, the estimated point prevalence of concurrency was higher among men later diagnosed HIV positive. One-offs were associated with increased rates of subsequent partnership dissolution. Copyright © 2016 John Wiley & Sons, Ltd.

Characteristics of African American Women and Their Partners With Perceived Concurrent Partnerships in 4 Rural Counties in the Southeastern U.S

BACKGROUND

To the individual with concurrent partners, it is thought that having concurrent partnerships confers no greater risk of acquiring HIV than having multiple consecutive partnerships. However, an individual whose partner has concurrent partnerships (partner's concurrency) is at increased risk for incident HIV infection. We sought to better understand relationships characterized by partner's concurrency among African American women.

METHODS

A total of 1013 African American women participated in a cross-sectional survey from 4 rural Southeastern counties.

RESULTS

Older age at first sex was associated with lower prevalence of partner's concurrency (prevalence ratio, 0.70; 95% confidence interval, 0.57-0.87), but the participant's age was not associated with partner's concurrency. After adjusting for covariates, ever having experienced intimate partner violence (IPV) and forced sex were most strongly associated with partner's concurrency (prevalence ratios, 1.61 [95% confidence intervals, 1.23-2.11] and 1.65 [1.20-2.26], respectively). Women in mutually monogamous partnerships were the most likely to receive economic support from their partners; women whose partners had concurrent partnerships did not report more economic benefit than did those whose partners were monogamous.

CONCLUSIONS

Associations between history of IPV and forced sex with partner's concurrency suggest that women with these experiences may particularly benefit from interventions to reduce partner's concurrency in addition to support for reducing IPV and other sexual risks. To inform these interventions, further research to understand partnerships characterized by partner's concurrency is warranted.

Sexual Partnership Patterns Among South African Adolescent Girls Enrolled in HPTN [corrected] 068: Measurement Challenges and Implications for HIV/STI Transmission

BACKGROUND

Estimates of sexual partnership durations, gaps between partnerships, and overlaps across partnerships are important for understanding sexual partnership patterns and developing interventions to prevent transmission of HIV/sexually transmitted infections (STIs). However, a validated, optimal approach for estimating these parameters, particularly when partnerships are ongoing, has not been established.

METHODS

We assessed 4 approaches for estimating partnership parameters using cross-sectional reports on dates of first and most recent sex and partnership status (ongoing or not) from 654 adolescent girls in rural South Africa. The first, commonly used, approach assumes all partnerships have ended, resulting in underestimated durations for ongoing partnerships. The second approach treats reportedly ongoing partnerships as right-censored, resulting in bias if partnership status is reported with error. We propose 2 "hybrid" approaches, which assign partnership status to reportedly ongoing partnerships based on how recently girls last had sex with their partner. We estimate partnership duration, gap length, and overlap length under each approach using Kaplan-Meier methods with a robust variance estimator.

RESULTS

Median partnership duration and overlap length varied considerably across approaches (from 368 to 1024 days and 168 to 409 days, respectively), but gap length was stable. Lifetime prevalence of concurrency ranged from 28% to 33%, and at least half of gap lengths were shorter than 6 months, suggesting considerable potential for HIV/STI transmission.

CONCLUSIONS

Estimates of partnership duration and overlap lengths are highly dependent on measurement approach. Understanding the effect of different approaches on estimates is critical for interpreting partnership data and using estimates to predict HIV/STI transmission rates.

It is complicated: sexual partner characteristic profiles and sexually transmitted infection rates within a predominantly African American population in Mississippi

BACKGROUND

Mississippi has among the highest prevalence of sexually transmitted infections (STIs) in the United States. Understanding sexual networks can provide insight into risk factors for transmission and guide prevention interventions.

METHODS

Participants included 1437 primarily African American (95%) adults presenting for care at an STI clinic in Jackson, Mississippi. Latent class analysis identified underlying population subgroups with unique patterns of response on a comprehensive set of 14 sexual partner variables, such as living with or having a child with a partner, partner dependence and trust, 1-time sexual encounters, multiple main partners, substance use, sexual concurrency, and incarceration. Classes were compared on participant age, sex, sexual orientation, public assistance, lifetime partners, relationship status, and self-reported past-year STI.

RESULTS

Three classes emerged. Class 1 (n = 746) participants were less dependent on partners and less likely to live with or have a child with a partner. Class 2 participants (n = 427) endorsed multiple STI risk factors, including partner incarceration, 6 or more lifetime partners, sexual concurrency, 1-time sexual encounters, and substance use at last sex. Class 3 participants (n = 226) were more likely to be in dependent, committed relationships with children. Class 2 had a higher proportion of self-report past-year STIs (36.7%) compared with classes 1 (26.6%) and 3 (26.1%).

CONCLUSIONS

Certain partner factors such as incarceration, substance use, and concurrency may contribute to increased STI risk. Partner factors may be useful proxies for STI risks and could be useful questions to include in screening questionnaires in clinical settings.

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.

Chlamydia trachomatis infection in young adults - association with concurrent partnerships and short gap length between partners

BACKGROUND

Sexually transmitted infections (STIs) continue to be highly prevalent in young people. New understanding of sexual risk behaviour is essential for future preventive initiatives. Studies based on self-reported STI history indicate that gap length between sexual partnerships is an important determinant in STI transmission, but little is known about the impact of concurrent partnerships and short gap length. This study aimed to examine the significance of concurrent partnerships and short gap length between serially monogamous partnerships in Chlamydia trachomatis-infected individuals compared to the general population.

METHODS

A Danish cross-sectional study was conducted among individuals aged 15-29 years with a verified C. trachomatis infection and a sample of the background population. Participants answered a web-based questionnaire on sexual behaviour. Associations were identified in multivariate analyses.

RESULTS

In total, 36% of the included young adults reported that they had two or more partners within the last year. Concurrent partnerships were frequent (46%), and the gap length between serially monogamous partnerships tended to be short (median gap length, 64 days, interquartile interval (IQI) = 31, 122). A strong association was found between concurrent partnerships (odds ratio (OR) = 12.5, 95% confidence interval (CI) = 7.7-20.4), short gap length between serially monogamous partnerships (OR = 10.0, 95% CI = 5.7-17.4) and having a verified C. trachomatis infection.

CONCLUSIONS

C. trachomatis infection was strongly associated with concurrent partnerships or short gap length between serially monogamous partnerships. These findings have considerable implications for public health policy. Both types of risk factors should be considered in future preventive interventions aiming to reduce the spread of C. trachomatis infections.

Age at first intercourse and subsequent sexual partnering among adult women in the United States, a cross-sectional study

BACKGROUND

Concurrency and serial monogamy may increase risk for STIs when gaps fall within the infectious period. This study examined the association between early sexual debut and concurrent or serial sexual partnering among heterosexual adult women.

METHODS

We identified 6,791 heterosexually active women, ages 21-44, from the 2006-2010 National Survey of Family Growth, a multi-stage probability sample of women in the United States. Self-reported age at first intercourse was categorized as <15, 15-17 and ≥18 years (referent). Sexual partnering was defined as concurrency (within the same month), serial monogamy with either a 1-3 month, or ≥4 month gap between partners, or monogamy (referent) in the year prior to interview. Polytomous logistic models provided adjusted odds ratios (aOR) and 95% confidence intervals (CI).

RESULTS

Concurrent partnerships in the year prior to interview were reported by 5.2% of women. Serial monogamy with a 1-3 month gap was reported by 2.5% of women. Compared with women whose sexual debut was ≥18 years, those <15 years at sexual initiation had 3.7 times the odds of reporting concurrent partnerships (aOR: 3.72; 95% CI: 2.46-5.62). Women <15 years of age at sexual debut had twice the odds of serial monogamy with gap lengths of 1-3 months between partners (aOR1-3 months: 2.13; 95% CI 1.15-3.94) as compared to women ≥18 years at sexual debut.

CONCLUSIONS

Sexual debut at <15 years is associated with both concurrency and serial monogamy with 1-3 month gaps between partners in U.S. women aged 21-44.

Age at Sexual Debut and Subsequent Sexual Partnering in Adulthood Among American Men

This study examined the association of sexual debut and sexual partnering among men in the United States aged 21 to 44 years who participated in the 2006-2010 National Survey of Family Growth. Age at debut was categorized as <15 years, 15 to 17 years, and ≥18 years to permit comparison with previous research. Sexual partnering was defined as being concurrent, serial monogamist, or monogamist in prior year. Eleven percent reported concurrent partnerships and 6% serial monogamy. Sexual debut <15 and 15 to 17 years was associated with concurrency (adjusted odds ratio [aOR] < 15 = 2.22; 95% confidence interval [CI] = 1.37-3.61; aOR 15-17 = 1.69; 95% CI = 1.05-2.74). Irrespective of age at sexual debut, interventions to reduce risky lifetime number of partners may prevent risky sexual behavior in early adulthood and later in life.