Sexually Transmitted Infections

Mills, S; Saidel, T; Magnani, R; Brown, T

doi: 10.1136/sti.2004.011916pmid: 15572641

Background: HIV epidemics in most countries are highly concentrated among population subgroups such as female sex workers, injecting drug users, men who have sex with men, mobile populations, and their sexual partners. The perception that they are important only when they cause epidemic expansion to general populations has obscured a critical lack of coverage of preventive interventions in these groups, as well as appropriate methods for monitoring epidemic and behavioural risk trends. The difficulties in accessing such groups have likewise often cast doubt on the representativeness of observed disease and behavioural risk estimates and their validity and reliability, particularly those related to sampling and the measurement of risk behaviours. Objectives: To review methodological obstacles in conducting surveillance with population subgroups in concentrated HIV epidemics, elaborate on recent advancements that partially overcome these obstacles, and illustrate the importance of modelling integrated HIV, STI, and behavioural surveillance data. Methods: Review of published HIV, STI, and behavioural surveillance data, research on epidemic dynamics, and case studies from selected countries. Conclusions: The population subgroups that merit regular and systematic surveillance in concentrated epidemics are best determined through extensive assessment and careful definition. Adherence to recently refined chain referral and time location sampling methods can help to ensure more representative samples. Finally, because of the inherent limitations of cross sectional surveys in understanding associations between complex sexual behaviours and HIV and STI transmission, mathematical models using multiple year data offer opportunities for integrated analysis of behavioural change and HIV/STI trends.

Slaymaker, E; Buckner, B

doi: 10.1136/sti.2004.012054pmid: 15572647

Objectives: This paper assesses the evidence of changes in sexual behaviour in Zambia, accounting for differences in the composition of survey samples and for evidence of changes in reporting bias. It compares the estimates of sexual behaviour measures obtained using two different survey methodologies. Methods: Data from five nationally representative household surveys carried out between 1996 and 2003 were analysed for change in selected sexual behaviours. Results: There is some evidence for an increase in men’s age at first sex. The proportion of people reporting multiple partnerships and not using a condom at last sex has declined since 1996. Unprotected sex with non-cohabiting partners is reported less frequently in the later surveys. The socioeconomic and demographic composition of the survey samples has changed across the years but the declines in behaviour remain statistically significant after adjustment for these changes. There is evidence of a changing reporting bias over the period of interest, with respondents less likely to report a young age at first sex in later surveys. Conclusions: Between 1996 and 2003, reported sexual behaviour has changed in Zambia among both men and women. Different survey methods produce significantly different estimates of sexual behaviour. This must be taken into account when carrying out trend analyses using data from different sources.

Cleland, J; Boerma, J T; Carael, M; Weir, S S

doi: 10.1136/sti.2004.013151pmid: 15572634

This supplement contains selected papers from a workshop on the measurement of sexual behaviour in the era of HIV/AIDS held at the London School of Hygiene and Tropical Medicine in September 2003. The focus was on low and middle income countries, where the majority of HIV infections occur. The motive for holding such a meeting is easy to discern. As the AIDS pandemic continues to spread and as prevention programmes are scaling up, the need to monitor trends in sexual risk behaviours becomes ever more pressing. Behavioural data are an essential complement to biological evidence of changes in HIV prevalence or incidence. Biological evidence, though indispensable, is by itself insufficient for policy and programme guidance. AIDS control programmes need to be based on monitoring of not only trends in infections but also of trends in those behaviours that underlie epidemic curtailment or further spread.

Slaymaker, E

doi: 10.1136/sti.2004.011635pmid: 15572635

Objectives: To investigate whether the indicators of sexual risk behaviour, defined by UNAIDS for use among members of general populations, have been found as risk factors, to examine how information on sexual behaviour is collected and summarised in order to calculate the indicators, and to look for possible sources of error in the data and in interpretation of those indicators. Methods: The literature on risk factors for HIV infection was reviewed. Indicators were calculated for countries where data were available for two or more points in time. Results: Indicators of sexual behaviour describe behaviours that are relevant to HIV risk and that are amenable to change. These behaviours do not correspond closely to the individual risk factors for HIV infection that have been identified in observational studies. Conclusions: Although potential errors of both measurement and interpretation exist, most of the indicators currently defined can fulfil their purpose, providing they are used with caution. Many of the indicators should not be interpreted in isolation but need supporting information to make sense of trends or differences between groups. Much of this information is provided by other indicators. The source of the data used to calculate the indicator is potentially important and should always be provided with indicator estimates. Some estimate of the accuracy of the estimate, either by means of confidence intervals or the number of respondents, should be given.

Zaba, B; Pisani, E; Slaymaker, E; Boerma, J Ties

doi: 10.1136/sti.2004.012674pmid: 15572637

Objectives: To describe recent trends in age at first sex in African countries, identifying and making due allowances for a variety of common reporting errors. Methods: Demographic and Health Surveys (DHS) data from six African countries conducting three or more surveys since 1985 were analysed using survival analysis techniques, combining information on virginity status and retrospective reporting of age at first sex. Hazard analysis was used to separate the effects of reporting error and compositional change and to estimate true changes in sexual debut over time. A multistate life table analysis incorporating transition to first marriage allowed cohorts to be classified according to person years spent as virgins, as sexually active unmarried, and married. Results: Intersurvey comparisons generally suggested a slow secular rise in age at first sex. However, tracing birth cohorts between surveys revealed inconsistencies—median ages reported by female members of a birth cohort in their teens were generally higher than those reported when they reached their twenties, even when allowing for residence and education changes—probably a result of young, sexually active women denying they had ever had sex. Male birth cohorts tend to display the opposite kind of bias. Conclusions: Uganda, Kenya, and Ghana have experienced a more pronounced and unambiguous decline in premarital sexual activity than Tanzania, Zambia, and Zimbabwe, with statistically significant increases in age at first sex. In addition, Uganda has maintained a very short interval between onset of sexual activity and marriage for both sexes.

Biddlecom, A E

doi: 10.1136/sti.2004.011676pmid: 15572644

Objectives: To describe trends over time in sexual behaviour, condom use, and sexually transmitted infections among female and male adolescents in the United States. Methods: A review was carried out of published studies using data from six surveys since the 1970s on sexual behaviour and surveillance data on sexually transmitted infections. Results: The proportion of adolescents who have ever had sexual intercourse increased for females and males through the 1980s and then declined for males through the 1990s. Some survey data showed that the level remained unchanged in the 1990s for adolescent females and other sources showed a decline by 2001. Condom use at first sexual intercourse and current condom use have increased over the past two decades for both male and female adolescents. Incidence rates for gonorrhoea and syphilis among adolescents declined over the 1990s and up through 2002, though new diagnoses of HIV/AIDS among adolescents remained relatively constant throughout the 1990s and into the new century. Conclusion: Although data sources are difficult to compare over time, trends in sexual behaviour, condom use, and sexually transmitted infections among adolescents from different data sources display generally similar directions towards declines in risk behaviours and outcomes, and increases in protective behaviours.

Curtis, S L; Sutherland, E G

doi: 10.1136/sti.2004.011650pmid: 15572636

Objectives: To review the sexual behaviour data collected in the Demographic and Health Surveys (DHS) and other similar national surveys from the perspective of data quality. Methods: Two indicators of premarital and higher risk sexual behaviour were analysed for 31 surveys in 10 countries in sub-Saharan Africa and Latin America and the Caribbean. The analysis focused on the internal consistency of trends and gender differences in the reported indicators. Results: The authors found fluctuating trends in premarital sex in sub-Saharan Africa but consistent increases in Latin America and the Caribbean. Changes in questionnaire design do not seem to contribute to these trends and there is evidence that the increase in premarital sex is genuine in Latin America. Trends in sex with non-spousal, non-cohabiting partners show large fluctuations and inconsistencies between surveys in some countries but not others. Men are consistently more likely to report non-marital sexual partners than women and unmarried women are less likely than unmarried men to report casual partners. Conclusions: Surveys are potentially a valuable source of information on sexual behaviour but there are sufficient grounds for concern to warrant considerable caution in the use of survey data to monitor trends in sexual behaviour. Survey findings must be evaluated carefully and interpreted in the context of other available information. These results caution against placing heavy emphasis on short term changes in sexual behaviour between individual surveys and highlight the need for attention to quality in data collection.

Plummer, M L; Ross, D A; Wight, D; Changalucha, J; Mshana, G; Wamoyi, J; Todd, J; Anemona, A; Mosha, F F; Obasi, A I N; Hayes, R J

doi: 10.1136/sti.2004.011924pmid: 15572640

Hoffmann, O; Zaba, B; Wolff, B; Sanga, E; Maboko, L; Mmbando, D; von Sonnenburg, F; Hoelscher, M

doi: 10.1136/sti.2004.011908pmid: 15572643

Objectives: To describe the development, characteristics, and follow up of a high risk cohort of women in Tanzania. Differences in social background and sexual behaviour of women working in traditional and modern alcohol selling workplaces are shown. Methods: Data from questionnaires four months before the enrolment of the cohort, at enrolment, and at 32 months were compared. Key informant interviews, social mapping exercises, and focus group discussions were held before the start of the cohort. Results: In the absence of organised prostitution, two different groups of women with high risk exposure were identified during the baseline survey: female workers in modern alcohol selling places such as bars, guesthouses, and restaurants (barmaids) and in traditional places (local brew sellers). Overall, the population had a mean age of 27.7 years with barmaids tending to be younger (24.3 years) than local brew sellers (34.2 years). The main duration of stay in the current workplace was 2.1 years (barmaids 0.9 years; local brew sellers 4.1 years). Barmaids were more likely to have paying casual sex partners than local brew sellers and used condoms more regularly. Local brew sellers tend to be more stable with only 10% lost to follow up after 32 months compared with 24.4% of the bar workers. Conclusions: Preliminary work revealed major differences in characteristics and behaviour between women working in modern and traditional alcohol selling outlets. Thorough preparation of the study, close monitoring of the cohort, and provision of selected benefits resulted in high retention rates over a 32 month project in a highly mobile population.

Hewett, P C; Mensch, B S; Erulkar, A S

doi: 10.1136/sti.2004.013250pmid: 15572639

Objectives: To investigate in a district in Kenya the level and consistency of reporting of sexual behaviour among adolescent girls randomly assigned to two modes of survey interview: face to face interview and audio computer assisted self-interview (ACASI). Methods: The analysis is based on a subsample of over 700 never married girls aged 15–21 years in Kisumu, Kenya, drawn from a population based survey of over 2100 respondents. A questionnaire with 69 questions was used, two thirds of which were considered sensitive, including questions about risky sexual behaviour, alcohol and drug use, contraceptive practice, pregnancy, induced abortions, and births. Results: ACASI produced significantly higher reporting of sex with a relative, stranger, or older man, and higher reporting of coerced sex. However, differences by mode for ever had sex and sex with a boyfriend were not significant. Relative to ACASI, the interviewer administered mode produced highly consistent reporting of sexual activity, both within the main interview and between the main and exit interviews. Conclusions: Both the mode of survey administration and the probing for various behaviours significantly affect the observed prevalence of sexual activity. The ACASI results suggest that adolescent girls in Kenya have more complex and perilous sex lives than traditional face to face surveys of sexual activity indicate. The level of consistency in the interviewer mode is argued to be suspect, particularly given the much lower levels of reporting, relative to ACASI, for types of sexual partners and coerced sexual activity.