A longitudinal study of human immunodeficiency virus transmission by heterosexual partners. European Study Group on Heterosexual Transmission of HIV

Mathematical models of disease transmission: a precious tool for the study of sexually transmitted diseases

This paper is an introduction to the mathematical epidemiology of sexually transmitted diseases (STDs) and its application to public health. After a brief introduction to transmission dynamics models, the construction of a deterministic compartmental mathematical model of HIV transmission in a population is described. As a background to STD transmission dynamics, basic reproductive rate, intergroup mixing, rate of partner change, and duration of infectivity are discussed. Use of the models illustrates the effect of sexual mixing (proportionate to highly assortative), of preventive intervention campaigns, and of HIV-chlamydia interaction on HIV prevalence in the different population groups. In particular, planned prevention campaigns can benefit the targeted intervention group but surprisingly can be disadvantageous for the general population. Through examples, mathematical models are shown to be helpful in our understanding of disease transmission, in interpretation of observed trends, in planning of prevention strategies, and in guiding data collection.

Risk factors for HIV-1 transmission from HIV-seropositive male blood donors to their regular female partners in northern Thailand

OBJECTIVE

To describe risks for HIV transmission from male blood donors to their regular female sex partners in Chiang Mai, Thailand.

DESIGN

Cross-sectional study.

METHODS

From March 1992 through September 1995, 405 HIV-seropositive male blood donors (index cases) and their regular female partners were enrolled in the study. Women with risk factors for HIV infection other than sexual contact with the index male were excluded. Couples were interviewed and examined; specimens were collected for laboratory analysis.

RESULTS

Overall, 46% of the 405 women enrolled were HIV-positive. Ninety-eight per cent of male index cases had a history of sex with a female prostitute; 1.5% reported always using condoms with their regular partner. History of sexually transmitted disease (STD) and swollen inguinal lymph nodes in the female partner were associated with an increased risk of HIV infection in the female. History in the female of genital herpes [odds ratio (OR), 3.46; 95% confidence interval (CI), 1.50-8.78], gonorrhea or chlamydia infection (OR, 2.71; 95% CI, 1.39-5.53), and stable relationship of longer than 24 months (OR, 2.28; 95% CI, 1.02-5.09) were associated with an increased risk of HIV infection in the female. Consistent condom use in the past 2 years (OR, 0.10; 95% CI, 0.01-0.79) was associated with a decreased risk of HIV infection in the female.

CONCLUSIONS

Married women in northern Thailand who appear otherwise to be at low risk for HIV infection may be exposed to this virus by their husbands. High rates of sex with commercial sex workers among men and low use of condoms within stable relationships may be important factors promoting the transmission of HIV in married couples. Programs to increase the regular use of condoms among married couples could be an important public health intervention to prevent transmission of HIV and other types of STD in northern Thailand.

The validity of self-reported condom use among adolescents

BACKGROUND

Research and public health interventions designed to reduce the risk of sexually transmitted diseases (STDs) often are based on self-reported condom use. Yet, validation of self-reported condom use, in particular with adolescents, has rarely been described in the literature.

METHODS

Baseline data were obtained from 540 adolescents, 13-21 years of age, enrolled in a 1-year longitudinal study of health beliefs, sexual behaviors, and STD acquisition. Of the 445 participants reporting to be sexually active, 404 (90.8%) agreed to a complete physical examination, including a genital examination, with STD screening after completing the self-administered written questionnaire. Participants' written self-report of condom use was compared to histories obtained by clinicians and laboratory diagnosis of acute STDs to assess validity of written self-report.

RESULTS

Complete data were available for 321 females and 77 males of whom 52 females and 5 males had laboratory evidence of 63 infections. Although three individuals who had STDs reported to be consistent users of condoms, a significant association (P < 0.05) was found between those who reported more frequent condom use with the last two partners and the absence of STDs.

CONCLUSION

In this group of adolescents, self-report of condom use with the last two partners was associated with the absence of an acute STD. This finding suggests that self-reported condom use is a valid indicator of risk for STDs, with implication for those working with adolescents clinically and in research contexts.

Dilution assessment of cervicovaginal secretions collected by vaginal washing to evaluate mucosal shedding of free human immunodeficiency virus

A 10 mM concentration of lithium does not interfere with reverse transcription (RT) or PCR. Sampling of cervicovaginal fluid by vaginal washing, with lithium (10 mM) in the washing buffer as a marker of dilution, may be utilized to accurately determine in HIV-infected women, by quantitative RT-PCR, the genital shedding of acellular HIV RNA at the level of the mucosa itself.

Effect of antiviral treatment on the shedding of HIV-1 in semen

OBJECTIVE

The potential role of antiretroviral treatment on the infectiousness of HIV-1-infected men was examined by studying the effect of antiviral treatment on the shedding of HIV-1 in semen.

METHODS

Forty-four patients enrolled in various treatment protocols were asked to donate a semen sample before they began a new antiviral treatment and at a follow-up visit after 6 to 15 weeks of treatment. Since most patients were on blinded protocols, patients were stratified by response of blood viral load. The effect of each patient's treatment was classified as good (n = 24), fair (n = 8) and marginal (n = 13) by measurement of the HIV RNA reduction in blood plasma (> 1.0 log10; 0.5-1.0 log10 and < 0.5 log10 HIV RNA copies/ml reduction, respectively). The effect of treatment on shedding of HIV-1 in semen was documented by the reduction of HIV RNA concentration in seminal plasma and by quantitative HIV-1 seminal cell culture.

RESULTS

Overall, antiviral treatment resulted in a significant fall in the viral load in semen (RNA and culture) that paralleled the reduction of viral load in blood. More pronounced reductions of HIV RNA in semen were observed as the effectiveness of treatment on blood HIV RNA levels increased (median drop from baseline 0, 0.3 log10 and 0.8 log10 RNA copies/ml in patients with marginal, fair and good treatment effect, respectively). Thirteen patients lost detectable HIV RNA in blood on treatment and all of these had undetectable levels of HIV-1 in semen by culture and RNA analysis at follow-up. In 19 of the 31 patients (62%) who still had HIV RNA in their blood during treatment, semen HIV levels were below detection in semen at follow-up.

CONCLUSIONS

Treatment-induced changes of HIV RNA concentration in blood are generally associated with a corresponding change in seminal HIV RNA: If confirmed in larger studies, potent antiretroviral therapy might reduce the spread of HIV-1.

Detection of human immunodeficiency virus type 1 and type 2 in the female genital tract: implications for the understanding of virus transmission

Risk of perinatal or female to male sexual transmission of HIV is likely to be associated with whether, and at what concentration, the virus is present in the cervical and vaginal secretions of the HIV-infected woman. Examining correlates of cervical and vaginal HIV shedding is, therefore, essential for the development of strategies to interrupt HIV transmission. This article presents the rationale for using detection of HIV in the female genital tract as a marker of infectivity, and briefly describes methods for detecting HIV-1 and HIV-2 in cervical or vaginal fluids. Findings from studies incorporating the measurement of HIV in the female genital tract are reviewed, placing particular emphasis on issues relevant to epidemiological studies of HIV transmission.

Effectiveness of condoms in preventing HIV transmission

The consistent use of latex condoms continues to be advocated for primary prevention of HIV infection despite limited quantitative evidence regarding the effectiveness of condoms in blocking the sexual transmission of HIV. Although recent meta-analyses of condom effectiveness suggest that condoms are 60 to 70% effective when used for HIV prophylaxis, these studies do not isolate consistent condom use, and therefore provide only a lower bound on the true effectiveness of correct and consistent condom use. A reexamination of HIV seroconversion studies suggests that condoms are 90 to 95% effective when used consistently, i.e. consistent condom users are 10 to 20 times less likely to become infected when exposed to the virus than are inconsistent or non-users. Similar results are obtained utilizing model-based estimation techniques, which indicate that condoms decrease the per-contact probability of male-to-female transmission of HIV by about 95%. Though imperfect, condoms provide substantial protection against HIV infection. Condom promotion therefore remains an important international priority in the fight against AIDS.

Psychological and social factors associated with histories of risk for human immunodeficiency virus infection among African-American inner-city women

Minority women constitute the fastest-growing segment of the American epidemic of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS). The present study examined the psychological and social factors related to HIV risk among 153 African-American inner-city women who completed measures of HIV risk history, sexual and substance use behaviors, perceived risk for HIV infection, self-efficacy to reduce risk (belief that one can effectively perform specific behaviors), and perceived social norms supporting risk reduction. Fifty-five percent of the women (n = 84) reported at least one factor that had placed them at known risk for HIV infection. Results of a stepwise regression analysis showed that HIV risk history was associated with self-perceived risk for HIV infection and self-efficacy to perform risk-reducing actions. Social norms for safer sex did not contribute significantly to the explained variance. Women at risk were more likely to have been forced or coerced into unwanted sex and were less likely to have been familiar with their most recent sex partner. These result suggest that HIV risk-reduction interventions targeting inner-city women should focus on skills training approaches to build self-efficacy and empower women to adopt risk-reducing practices.

HIV testing, behaviors, and knowledge among adolescents at high risk

PURPOSE

We examined HIV testing behavior and its predictors among adolescents considered at high risk for HIV.

METHODS

Self-reports of HIV testing, knowledge, attitudes, and high-risk acts were examined among 272 adolescents aged 13-23 years (M = 18.7; SD = 2.3) attending community-based agencies that serve youth at high risk for HIV in Los Angeles, New York City, and San Francisco.

RESULTS

Evidence of adolescents' risk for HIV is reflected in a rate of 4.8% seropositivity, 24% injecting drug use, a mean of 4.3 (SD = 11.6) sexual partners during the previous 3 months, and 71% condom use during vaginal/ anal sex. HIV testing was common (63%) and often repeated (M = 3.6, SD = 4.0). Knowledge of the meaning and consequences of testing was high (84% correct). Contrary to service providers' expectations, youth were likely to return for their test results (90% returned). Youth who were older, labeled themselves gay or bisexual, lived in Los Angeles or San Francisco, and those who injected drugs were significantly more likely, compared to peers, to get tested for HIV.

CONCLUSIONS

These results suggest a need for more detailed observational studies of HIV testing behavior that include evaluation of characteristics of the youth, the testing site, and the attitudes and beliefs of providers offering HIV testing.

Multiple condom use and decreased condom breakage and slippage in Thailand

There is compelling evidence that male condoms effectively prevent transmission of sexual pathogens, including HIV-1. Condom breakage and slippage reduce this effect. We measured rates of condom slippage and breakage during heterosexual commercial sex in northern Thailand. Of 7,594 condoms examined in 4,734 client visits (5,040 sex acts), breakage was noted in 1.8% of single condom use (49.3% of acts), as compared with 0.2% with two condoms (49% of sex acts), and no breaks with more than two condoms (1.2% of sex acts). These breakage rates declined from 5.9% in a similar 1992 study in which 2.8% of sex acts were with more than one condom used at a time. Slippage occurred in only 0.1% of sex acts. Case-control analysis indicated that multiple clients, younger aged clients, sex after midnight, and high intensity (rough) sex were associated with condom breaks. The decline in breakage may be attributable to greater expertise in condom use by sex workers and clients, in response to the successful Thai national "100% Condom Campaign." Use of more than one condom during sex has been initiated by sex workers and their clients, a community response to condom promotion messages and fears of HIV infection. These data demonstrate the potential of condom use for high efficacy in reducing exposure to HIV-1 and other STDs. If condom use in commercial sex remains high, HIV incidence may decline among Thai men.

Use and effectiveness of condoms during anal intercourse. A review

BACKGROUND AND OBJECTIVES

Anal intercourse has been associated with a high risk of human immunodeficiency virus transmission. Survey data suggest that unprotected anal intercourse is practiced by a substantial proportion of the sexually active population, regardless of sexual orientation.

GOAL

To review the literature related to the use and effectiveness of condoms during anal intercourse, with emphasis on prevention of human immunodeficiency virus transmission.

STUDY DESIGN

Literature review.

RESULTS

Epidemiologic studies have shown that consistent, correct condom use reduces the overall risk of sexual transmission of human immunodeficiency virus. Evidence for the effectiveness of condoms used during anal intercourse is less definitive. Survey and clinical trials data indicate that condom breakage and slippage rates vary during anal intercourse and may be considerably higher than during vaginal intercourse. Although condoms designed for anal intercourse have been studied and marketed in Europe, data on their actual performance are scarce. In addition, no information exists on the effectiveness of polyurethane or other nonlatex condoms for use during anal intercourse.

CONCLUSIONS

Development of newer and more effective condoms for use during anal intercourse requires consideration of the ethical issues involved in testing and marketing devices used during an activity that carries with it the potential for a substantial risk to health.

Women and the heterosexual transmission of HIV: risks and prevention strategies

Heterosexual intercourse has become a significant means of HIV transmission, even in countries where this was previously not the case. Consequently the promotion of safer sexual practices for heterosexual women and men is of major public health importance. We examine the risks to women of contracting HIV through heterosexual sex, and critically discuss the most commonly recommended strategies for safer sex for heterosexuals. We conclude that all safer sex strategies have limitations, and therefore a wide range of options should be promoted.

Incidence of three sexually transmitted diseases during a safer sex promotion program for HIV-infected women

Promotion of safer sex practices typically includes education, skills building, and condom distribution. To evaluate the impact of such promotions and describe risk factors for sexually transmitted disease (STD), a retrospective review of 741 sexually active HIV-infected women was conducted. The cohort was African-American (82%), at least 22 years of age (81%), acquired HIV through sex (36%), had a CD4 count above 200/ mm3 (76%), and had a history of substance (alcohol or drug) use (38%). Those with incident STD (14.7%) were more likely to be under 22 years of age, to have a history of substance use, and to have an STD at entry. Traditional methods of promoting safer sex practices should be enhanced by other options such as regular screening, partner treatment, and the use of microbicides and other female-controlled methods.

Salivary binding antibodies induced by human immunodeficiency virus type 1 recombinant gp120 vaccine. The NIAID AIDS Vaccine Evaluation Group

Salivary binding antibodies induced by candidate human immunodeficiency virus type 1 (HIV-1) vaccines in healthy, HIV-1 uninfected volunteers were assessed in a clinical trial evaluating intramuscularly injected HIV-1MN recombinant gp120 (rgp120) vaccine alone or with HIV-1IIIB rgp120 vaccine. The two rgp120 vaccines induced envelope glycoprotein-specific immunoglobulin G (IgG) and IgA antibodies in whole saliva and serum.

Sexual intercourse during menstruation and self-reported sexually transmitted disease history among women

OBJECTIVES

The purpose of this study was to examine the practice of sexual intercourse during menstruation and the relationship of this practice to the experience of sexually transmitted diseases (STD) among women in the United States.

METHODS

Logistic regression technique was used to conduct an analysis of population-based data from a national sample of 1586 sexually active 20- to 37-year-old women to examine the patterns of sexual intercourse during menstruation and its relationship with STD outcome.

RESULTS

More than one fourth of the women reported that they usually have vaginal intercourse during their menses, and 16% reported that they had had vaginal intercourse during their last menstrual period. Proportions of women engaging in this practice were higher among those who reported greater frequency of intercourse and larger numbers of lifetime sex partners. Almost half the women who had intercourse more than twice a week and more than one third of the women who had more than seven lifetime sex partners reported that they usually have vaginal intercourse during menses. The findings suggest that this practice is relatively more common among the better educated, young, white women and their sex partners. Most interestingly, despite the fact that sex during menses is most common among women in relatively low-risk groups, we were able to observe a strong statistical association between sexual intercourse during menstruation and self-reported STD history.

CONCLUSIONS

Sexual intercourse during menstruation may emerge more consistently as a risk factor for the heterosexual transmission of HIV or other sexually transmitted pathogens in future studies. If future epidemiologic studies continue to bolster this finding, then public health efforts should promote abstinence during the female menstrual period and target those groups of women among whom this practice is prevalent.

Changes in sexual behavior and a decline in HIV infection among young men in Thailand

BACKGROUND

In Thailand the epidemic of human immunodeficiency virus (HIV) infection is of recent origin. Because of the high seroprevalence of HIV among sex workers, the Ministry of Public Health began a program in 1990 and 1991 to promote the use of condoms during commercial sex. We evaluated the effect of this and other programs to prevent HIV infection in Thailand.

METHODS

Using direct interviews, we studied five cohorts of 21-year-old men from northern Thailand who were conscripted into the army by a lottery in 1991, 1993, and 1995. In all, 4311 men were tested for HIV antibodies by enzyme-linked immunosorbent assay, with confirmation by Western blot assay.

RESULTS

In the 1991 and 1993 cohorts, the prevalence of HIV infection was 10.4 to 12.5 percent. In 1995, it fell to 6.7 percent (P < 0.001). The seroprevalence was only 0.7 percent among men who did not have sexual relations with a sex worker before 1992. Over the study period, the proportion of men who reported having sexual relations with a sex worker fell from 81.4 percent to 63.8 percent (P < 0.001). From 1991 to 1995, the men's reported use of condoms during the most recent sexual contacts with sex workers increased from 61.0 percent to 92.5 percent (P < 0.001); and in 1995, 15.2 percent of men had a history of a sexually transmitted disease, as compared with 42.2 percent in 1991 (P < 0.001).

CONCLUSIONS

Public health programs in Thailand have led to substantial changes in sexual behavior among young men, especially an increased use of condoms, and the rate of new HIV infections has declined.

Reproductive decision-making and determinants of contraceptive use in HIV-infected women

Perinatal transmission and reproductive decisions of HIV-infected women can be categorized in statistical and epidemiological terms. These reports and figures, however, do little to fully explain the complexities of human relationships, life experiences, personal and cultural influences, and situational and environmental variables that impact on the HIV-infected woman regarding reproductive decision-making. It is only with genuine attempts to understand the woman's perspective and the dynamic and unique variables that influence reproductive decision-making, as well as maintaining a non-judgmental and culturally sensitive perspective, can we hope to assist women, and society as a whole, in coming to terms with the complexities of HIV and reproductive decision-making. Further study is needed to identify factors that influence reproductive decision-making in HIV-infected women. The determinants of contraceptive use regarding demographic factors, barriers to contraceptive use, and factors that contribute to successful contraceptive use in this population must be understood if efforts to reduce the number of unplanned pregnancies are to be successful. More conclusive data are needed on the safety and efficacy of oral contraceptives in HIV-infected women as well as data that describe the effects of longer acting hormonal contraceptives such as levonorgestrel implants (Norplant; Wyeth-Ayerst, Philadelphia, PA) and injectable medroxyprogesterone acetate (Depo Provera; Upjohn Company, Kalamazoo, MI). More research is needed to determine the effects of patient education and counseling and closer follow-up on effective long-term contraception in HIV-infected women.

Risk factors for pelvic inflammatory disease. A case control study

BACKGROUND AND OBJECTIVES

Pelvic inflammatory disease (PID) is associated with major medical and economic consequences for women of reproductive age. Identification of the risk factors associated with PID is crucial to efforts for prevention of these consequences.

GOAL

To identify risk factors and markers for symptomatic PID.

STUDY DESIGN

A case-control study of 234 women with PID treated at San Francisco General Hospital between October 1986 and August 1989 and 122 controls attending the Women's Clinic at the same institution. The two groups were comparable in sociodemographic, reproductive, sexual, and medical history.

RESULTS

Risk factors and markers identified by univariate analysis were < 12 years education, gravidity > 0, parity > 0, spontaneous abortion > 0, lack of a birth control method, > 1 male sexual partner in the previous 30 days, younger than 18 years at age of first sex, history of gonorrhea, sex during the previous menses, douching, exposure to nongonococcal urethritis in the previous 30 days, and history of crack cocaine use. With multivariate analysis to control for confounders the risks still identified were parity > 0, (odds ratio [OR] 4.44; 95% confidence interval [CI] 2.34 to 8.42), > 1 sexual partner in the previous 30 days (OR 11.08; 95% CI 4.31 to 28.5), sex during the previous menses (OR 5.22; 95% CI 1.88 to 14.48), and a lack of contraception (OR 7.6; 95% CI 4.10 to 14.09).

CONCLUSIONS

Findings indicated that certain reproductive behaviors could be targeted for public health attention and risk reduction interventions to reduce the incidence of PID. These include limiting numbers of sexual partners and encouraging the use of barrier methods of contraception for sexually transmitted disease prevention. Another finding was that it is probably best to avoid sexual intercourse during the menses. The question of douching as a risk factor for PID could not be answered by this study.

Probability of heterosexual transmission of HIV: relationship to the number of unprotected sexual contacts. European Study Group in Heterosexual Transmission of HIV

The objective of this study was to investigate the relationship between the number of unprotected heterosexual contacts with an HIV-infected person and the probability of HIV transmission. Data from a European study involving 563 heterosexual partners of HIV-infected subjects were analyzed. The number of unprotected contacts could be estimated for 525 couples (377 with male index case, 148 with female index case) from the reported frequency of unprotected contacts and an estimate of the length of the period during which transmission could have occurred. Nonparametric (isotonic regression) and parametric (Bernoulli model) analyses were performed on data at study entry and on follow-up data (121 couples). The nonparametric analysis resulted in several exposure groups, with the proportion of infected partners increasing with the number of contacts. For example, the percentage of female partners infected ranged from 10%, among those with < 10 unprotected contacts with an infected male, to 23% after 2,000 unprotected contacts. The parametric estimates of (assumed constant) per-contact infectivity were higher for male-to-female than for female-to-male transmission, but not significantly so. However, in comparison with nonparametric estimates, the model assuming constant infectivity appears to seriously underestimate the risk after very few contacts and to seriously overestimate the risk associated with a large number of contacts. Our results suggest that the association between the number of unprotected sexual contacts and the probability of infection is weak and highly inconsistent with constant per-contact infectivity. Probable explanations for these findings include large variability in infectivity between couples and within individuals over time. Estimates based on partner study data under the hypothesis of constant infectivity can, therefore, be highly misleading at a public health level, particularly when extrapolated to multiple casual contacts.

Screening and treatment of sexually transmitted diseases: an important strategy for reducing the risk of HIV transmission

The role of sexually transmitted diseases (STDs) in the spread of human immunodeficiency virus (HIV) infection is reviewed. The rationale for and approach to reducing STD prevalence in high-risk communities are presented. Given the asymptomatic nature of these infections and problems associated with delivering curative therapy, effective interventions will require the use of diagnostic tests for screening and the use of single-dose therapies in appropriate settings: Treatment of individuals with STDs will likely reduce individual risk, while reduction of STD prevalence in high-risk communities may curtail the epidemic spread of HIV.

Orgasm without organisms: science or propaganda?

The worldwide epidemic of sexually transmitted diseases (STDs) presents a major public health challenge to medical practitioners and educators as they seek to implement preventive educational strategies in the adolescent population. The serious consequences of many STDs and the insufficient impact of condom promotion in this high-risk group have led to increasing recognition that sexual intercourse is medically unwise for young adolescents. As a result of this recognition, some educators have proposed that adolescent sexuality education focus on the explicit teaching of noncoital sexual activities, sometimes called outercourse. This paper explores the emergence of this educational strategy, the assertion that noncoital sexual activities will positively impact the rising incidence of STDs and unplanned pregnancy in teenagers, and the hypothetical benefits of adolescent noncoital sex.

Risk factors for HIV and other sexually transmitted diseases and prevention practices among US heterosexual adults: changes from 1990 to 1992

OBJECTIVES

The National AIDS Behavioral Survey (1990-1992) of heterosexual adults (18-49 years) measured human immunodeficiency virus (HIV) risk factors, condom use, and HIV antibody testing, with a focus on major "high-risk" cities.

METHODS

A longitudinal survey was conducted.

RESULTS

There was little reduction in the overall prevalence of HIV risk factors in the national or high-risk cities cohorts over time. Despite this picture of stability, approximately 39% of the population at risk for HIV because of multiple sexual partners turns over annually. There was little change in HIV test-seeking or in consistent condom use with primary sexual partners. Although the majority of at-risk respondents used condoms sporadically or not at all (65%), a significant increase in condom use was found among those reporting multiple sexual partners in both waves, particularly among Black heterosexuals. Data from other surveys and condom sales nationally support the findings.

CONCLUSIONS

There is a need for a series of surveys in this area to assess the reliability of the present findings and to monitor the general US population's response to prevention programs.

Women, contraception and STDs including HIV

It is estimated that eight million women are infected with the human immunodeficiency virus (HIV) worldwide. Heterosexual transmission is the predominant mode of HIV transmission on a global basis and is becoming increasingly important in the Western world. Women have long used contraceptives as a means of protection against an unwanted pregnancy, some of which may also protect against sexually transmitted disease (STD) including HIV. We review the relationship between contraceptive methods and STD acquisition and transmission; HIV acquisition and transmission; and the implications of contraceptive use, particularly regarding disease progression, in those women who are already infected with the virus. It is important for all women that protection against both unwanted pregnancy and HIV acquisition and transmission are considered together and not in isolation as nowhere is the argument for a broad based multi-disciplinary approach more cogent.

Trends in female sexual behaviour and sexually transmitted diseases in London, 1982-1992

OBJECTIVE

To measure changes in female sexual behaviour, including condom use, and their relationship with the incidence of sexually transmitted and other genital diseases in women during the decade 1982-92.

DESIGN

A prospective series of cross-sectional surveys of sexual behaviour reported by a standardised self-administered questionnaire in new patients who presented for screening and diagnosis.

SETTING

A genitourinary medicine clinic in West London.

SUBJECTS

4089 consecutive newly attending patients who completed sexual behaviour questionnaires during 1982, 1987, 1989 and 1992.

MAIN OUTCOME MEASURES

Trends in socio-demographic status, sexual behaviour, condom-use, sexually transmitted diseases and other genital infections diagnosed by routine clinical and laboratory methods.

RESULTS

Women reported significantly increasing condom use (from 3.6% to 20.7%) and decreasing oral contraception (from 51.2% to 40.1%), but the proportion who used no contraception (23.6% to 24.7%) and the proportion who had never been pregnant (58.3% to 59.9%) remained similar. Numbers of sexual partners in the preceding year decreased (p < 0.001) and an increasing proportion of women practised oral intercourse (p < 0.001). During the same period, there was a progressive decline (p < 0.001) in the incidence of gonorrhoea, chlamydial infection and trichomoniasis by approximately two-thirds. However, the incidence of vaginal candidosis (p < 0.001), bacterial vaginosis (p < 0.001) and genital warts (p < 0.01) increased.

CONCLUSIONS

Increasing use of condoms for vaginal intercourse with both regular and non-regular partners has been associated with a decrease in the incidence of gonorrhoea, chlamydial infection and trichomoniasis. There was also an increase in the practice of fellatio and a change in the spectrum of STD and other genital infections with little net reduction in morbidity. HIV infection showed no evidence of heterosexual spread.