Sexually transmitted diseases and risk behaviors among market vendors in China

OBJECTIVES: The rate of sexually transmitted diseases (STDs) in China has soared over the past 20 years. There is a need to study STD prevalence in the general population of the country. GOAL: To report the prevalence and patterns of STDs and the relationships between STD status and demographic and behavioral factors. STUDY DESIGN: A total of 4,510 market vendors in a city in eastern China were interviewed and tested for STDs. RESULTS: The prevalence of any STD among participants was 16.55% (women, 21.04%; men, 11.54%). Among those who tested positive for an STD, chlamydia was most common (8.89%), followed by herpes (6.50%). Participants who had no schooling and participants who had college or higher level of schooling had a similarly high STD prevalence (26.19% vs. 24.00%, respectively). Prevalence of all STDs was significantly higher among women, those with more discretionary income, and those with multiple partners. CONCLUSIONS: Special considerations are needed for low versus high education groups as well as men versus women to maximize the effects of STD prevention programs and messages in China.     

Prevalence and risk factors for hepatitis B virus infections among visitors to an STD clinic.

OBJECTIVE: To determine the prevalence and risk factors for hepatitis B virus (HBV) infections among individuals attending an STD clinic in a low endemic region. STUDY DESIGN: A total of 1228 women and 1648 men attending the STD clinic at the University Hospital Rotterdam, Netherlands, were examined for HBV infection by determination of hepatitis B surface antigen (HBsAg) and antibodies to hepatitis B core antigen (anti-HBc). Demographic characteristics, information on sexual behaviour, and intravenous drug use were recorded. RESULTS: The seroprevalence of HBsAg was 1.4% in women and 2.1% in men (0% in homosexual men). The seroprevalence of anti-HBc was 13% in women and 20% in men (36% in homosexual men). Native country, intravenous drug use, a history of STD, and the number of partners in the past half year (inversely) were independent risk factors for HBsAg positivity in women and heterosexual men. For anti-HBc independent associations were observed for native country, age, intravenous drug use, commercial sex, number of lifetime partners, homosexual contacts, orogenital contact (inverse), and a history of STD. CONCLUSION: The HBV prevalence in the STD clinic attendants was high, exceeding the national estimate, and indicates that the STD clinic population may be considered a high risk group. Our data confirmed an increased risk for HBV infections among established risk groups. Therefore, these risk groups should be routinely screened to identify HBV cases for counselling and contact tracing.     

Hepatitis B infection among Chinese STD patients in Kuala Lumpur, Malaysia

This study documents the prevalence of Hepatitis B serological markers among STD patients who have had multiple sexual partners in Kuala Lumpur, Malaysia, and compares the rates with those of a sample of the population with single or no sexual partners. A total of 336 Chinese STD patients (multiple partners group) and 234 Chinese control subjects (non-multiple partner group) were screened. Those with a history of blood transfusion or parenteral drug abuse had been excluded from the study, and all study subjects were heterosexuals. The overall carrier rate was 9.2% for the multiple partner group (MP group) and 6.8% for the non-multiple partner group (NMP group). Infection rates were 64.3% for the MP-group and 38.9% for the NMP group. After adjustments for age and sex, there was no significant difference in carrier rates between the two groups, but infection rates were significantly different with the MP group, being 3.2 times more likely to acquire infection than the NMP group. The study concludes that in heterosexuals, those with multiple sexual partners have increased chances of acquiring HBV infection.     

Pattern of sexually transmitted diseases and risk factors among women attending an STD referral clinic in Nairobi, Kenya

BACKGROUND: In Kenya, sexually transmitted disease (STD) clinics care for large numbers of patients with STD-related signs and symptoms. Yet, the etiologic fraction of the different STD pathogens remains to be determined, particularly in women. GOAL: The aim of the study was to determine the prevalence of STDs and of cervical dysplasia and their risk markers among women attending the STD clinic in Nairobi. STUDY DESIGN: A cross-section of women were interviewed and examined; samples were taken. RESULTS: The mean age of 520 women was 26 years, 54% had a stable relationship, 38% were pregnant, 47% had ever used condoms (1% as a method of contraception), 11% reported multiple partners in the previous 3 months, and 32% had a history of STDs. The prevalence of STDs was 29% for HIV type 1, 35% for candidiasis, 25% for trichomoniasis, 16% for bacterial vaginosis, 6% for gonorrhea, 4% for chlamydia, 6% for a positive syphilis serology, 6% for genital warts, 12% for genital ulcers, and 13% for cervical dysplasia. Factors related to sexual behavior, especially the number of sex partners, were associated with several STDs. Gonorrhea, bacterial vaginosis, cervical dysplasia, and genital warts or ulcers were independently associated with HIV infection. Partners of circumcised men had less-prevalent HIV infection. CONCLUSION: Most women reported low-risk sexual behavior and were likely to be infected by their regular partner. HIV and STD prevention campaigns will not have a significant impact if the transmission between partners is not addressed.     

Prevalence of Chlamydia trachomatis and Neisseria gonorrhoeae among at-risk women, young sex workers, and street youth attending community organizations in Quebec City, Canada

BACKGROUND: Despite a relatively recent decline in the global incidence of Chlamydia trachomatis and Neisseria gonorrhoeae it seems that some segments of the population such as street youth, sex workers, and individuals with social problems or delinquent behavior could be part of a core group for STDs. These persons may be reluctant to undergo STD diagnosis in traditional medical settings. GOALS: To determine the prevalence of C trachomatis and N gonorrhoeae infection using polymerase chain reaction on urine samples among subjects attending an anonymous HIV testing clinic and four community organizations in Quebec City, and to identify associated risk factors. STUDY DESIGN: A cross-sectional study of 626 street youth, sex workers, and women with social problems or delinquent behavior was conducted. RESULTS: The prevalences of N gonorrhoeae and C trachomatis were, respectively, 1.1% (95% CI, 0.5%--2.3%) and 5.8% (95% CI, 4.1%--7.9%). No significant difference was found between men and women, but the sexually transmitted disease (STD) prevalence was much higher in subjects younger than 20 years: 11.4% versus 3.6% (P < 0.01). In a logistic regression model, factors independently associated with STD infection were age younger than 20 years (OR, 2.6; P = 0.007), occasional sex partners (OR, 2.9; P = 0.007), and injection of drugs (OR, 2.8; P = 0.002) in the preceding 6 months. CONCLUSIONS: A moderate STD prevalence was found in the study population. The prevalence, however, can be considered high (>10%) among street youth and young sex workers. Providing community-based STD screening and treatment services appear to be an efficient method for reaching these high-risk groups.     

Signs and symptoms of urethritis and cervicitis among women with or without Mycoplasma genitalium or Chlamydia trachomatis infection

OBJECTIVES: To study the prevalence, symptoms, and signs of Mycoplasma genitalium and Chlamydia trachomatis infections in women attending a Swedish STD clinic, accessible for both sexes, and in a group of young women called in the cervical cancer screening programme. METHODS: A cross sectional study among female STD clinic attendees in Orebro and a study among women called for Papanicolaou smear screening. Attendees were examined for urethritis and cervicitis. First void urine and endocervical samples were tested for M genitalium and C trachomatis. RESULTS: The prevalence of C trachomatis and M genitalium in the STD clinic population was 10% (45/465) and 6% (26/461), respectively. Dual infection was diagnosed in four women. In the cancer screening group of women the corresponding prevalence was 2% (1/59) and 0%, respectively. Among the STD clinic attendees there were no significant differences in symptoms (32% v 23%, RR 1.4, 95% CI 0.6 to 3.4) or signs (71% v 50%, RR 1.4, 95% CI 0.9 to 2.3) between C trachomatis and M genitalium infections. Microscopic signs of cervicitis were significantly more common among M genitalium and C trachomatis infected women than in the cancer screening group of women. 56% (15/27) of male partners of M genitalium infected women were infected with M genitalium compared to 59% of male partners of C trachomatis infected women who were infected with C trachomatis (p = 0.80). CONCLUSIONS: M genitalium is a common infection associated with cervicitis and with a high prevalence of infected sexual partners supporting its role as a cause of sexually transmitted infection.     

Efficacy of patient-delivered partner medication in the treatment of sexual partners in Uganda

BACKGROUND: Patient-based partner referral (PBPR), which is the main method for treating sexual partners of patients with sexually transmitted diseases (STDs), has limited effectiveness. GOAL: The authors compared the efficacy of PBPR with patient-delivered partner medication (PDPM) among patients attending the Mulago STD clinic in Kampala, Uganda. STUDY DESIGN: A total of 383 patients (187 women, 196 men) with STDs were randomized to the PBPR or PDPM group. The proportion of sexual partners treated in either group was compared using the chi-square statistic by intention to treat for partners whose follow-up status was unknown. RESULTS: The two groups had similar background characteristics. Of the 237 partners elicited, 176 (74%) were reported treated in the PDPM group. In the PBPR group, in which 234 partners were elicited, 79 (34%) were referred to the treatment clinic. This difference was statistically significant (risk ratio [RR], 2.44; 95% CI, 1.95-3.07; P < 0.001). Furthermore, PDPM was more effective than PBPR for women and for casual partners for whom PBPR is considered difficult. For women, 86 of 103 partners in the PDPM group were reported treated, compared with 23 of 104 partners in the PBPR group (RR, 4.55; 95% CI, 2.92-7.08; P < 0.001). For casual partners, 18 of 51 (34%) were reported treated in the PDPM group, compared with only three of 45 partners (7%) who were referred in the PBPR group (RR, 1.43; 95% CI, 1.40-2.65; P < 0.01). CONCLUSION: Patient-delivered partner medication is more effective than patient-based partner referral in the treatment of sexual partners.     

Does measured behavior reflect STD risk? An analysis of data from a randomized controlled behavioral intervention study. Project RESPECT Study Group

BACKGROUND: Many studies measure sex behavior to determine the efficacy of sexually transmitted disease (STD)/HIV prevention interventions. GOAL: To determine how well measured behavior reflects STD incidence. STUDY DESIGN: Data from a trial (Project RESPECT) were analyzed to compare behavior and incidence of STD (gonorrhea, chlamydia, syphilis, HIV) during two 6-month intervals. RESULTS: A total of 2879 persons had 5062 six-monthly STD exams and interviews; 8.9% had a new STD in 6 months. Incidence was associated with demographic factors but only slightly associated with number of partners and number of unprotected sex acts with occasional partners. Many behaviors had paradoxical associations with STD incidence. After combining behavior variables to compare persons with highest and lowest risk behaviors, the STD incidence ratio was only 1.7. CONCLUSION: Behavioral interventions have prevented STD. We found people tend to have safe sex with risky partners and risky sex with safe partners. Therefore, it is difficult to extrapolate the disease prevention efficacy of an intervention from a measured effect on behavior alone.     

A population-based serosurveillance of syphilis in Costa Rica

As part of a case-control study to investigate the high incidence of cervical cancer in Costa Rican women, the seroprevalence of the treponematoses, in particular, syphilis was determined. In each age group, women with a history of two or more sex partners were two to four times more likely to be seroreactive in tests for syphilis than women with zero or one sex partner. The highest percentage of reactive results in the microhemagglutination assay for antibodies to Treponema pallidum (MHA-TP) was seen in samples from women aged 50-59 who had had two or more lifetime partners (23.8%). Three observations from our study support reactivity due to syphilis rather than yaws or pinta: (1) a similar percent of reactive rapid plasma reagin (RPR) card test results among MHA-TP reactors in the two age groups of women who were surveyed (42 vs. 49%) was observed; (2) women who were seroreactive in the MHA-TP had multiple risk factors for STD [low socioeconomic status (9.4%), urban residence (22.8%), first intercourse under 16 years of age (14.1%), and multiple sex partners (26.3%)], and (3) only sexually experienced women had reactive results in the MHA-TP test.     

Who goes to sexually transmitted disease clinics? Results from a national population survey.

OBJECTIVES: To examine the pattern of attendance at sexually transmitted disease (STD) clinics in Britain. To compare the demographic characteristics, behaviours and attitudes of STD clinic attenders with those of non-attenders, and to assess the extent to which STD clinics are used by those with high-risk sexual lifestyles. DESIGN: Random sample general population survey of sexual attitudes and lifestyle. SUBJECTS: 18,876 randomly selected men and women resident in Britain aged 16-59 years. MAIN OUTCOME MEASURES: Demographic characteristics, pattern of homosexual partnerships, heterosexual partnerships, payment for sex, abortion, drug injection in the last five years, and attitudes to sexual behaviours amongst 512 respondents who had attended STD clinic in the last five years compared with those who had not. RESULTS: 8.3% of men and 5.6% of women had attended a clinic in their lifetime and 3.4% and 2.6% respectively in the last five years. Attendance rates varied substantially with area of residence. 11% of Inner London residents had attended in the last five years. In multivariate analysis, STD clinic attendance for men was most strongly associated with increased numbers of heterosexual partners, (OR = 6.01 (4.44-8.15) and homosexual partnerships (OR = 9.59 (5.83-15.8)) and more weakly associated with payment for sex, non-manual social class, age 25-44, unmarried status and smoking. Clinic attendance for women was most strongly associated with numbers of heterosexual partners (OR = 3.74 (2.76-5.08) and injecting drug use (OR = 4.39 (1.73-11.1)). A weaker independent association was found with a history of abortion, anal sex, non-manual social class, non-married status and age 16-24. From the total population, 1 in 6 men and 1 in 7 women in the top 5% of the distribution for numbers of heterosexual partners and 1 in 5 men paying for sex and 1 in 4 of those with a homosexual partner had attended a clinic in the last five years. The probability of attendance increased with multiple risk behaviours. Of women 64.2% and of men 69.7% attending clinics reported major risk markers for STD transmission. CONCLUSIONS: STD clinics in Britain are used by a wide demographic spectrum of the population. The behaviours, but not the attitudes, of attenders differed markedly from those of non-attenders. Clinics are relatively efficient in attracting only those with high-risk lifestyles, but, at a population level, the minority of those reporting risk-markers for STD transmission attend clinics. These findings suggest that STD clinics are an important focus for sexual health promotion, but that community programmes are also important for reaching non-attenders.     

Mycoplasma genitalium: prevalence, clinical significance, and transmission

OBJECTIVES: To study the prevalence, symptoms and signs of Mycoplasma genitalium and Chlamydia trachomatis infections in STD clinic attendees and in partners of M genitalium infected patients. METHODS: M genitalium and C trachomatis were detected by polymerase chain reaction from urethral and endocervical swab specimens in a cross sectional study among 445 female and 501 male STD clinic attendees. Partners of 26 female and 26 male M genitalium positive index patients were examined. RESULTS: The prevalence of C trachomatis and M genitalium was 4% and 6.3%, respectively, among the women and 5.4% and 6%, respectively, among the men. Dual infections were uncommon. M genitalium was strongly associated with urethritis in both men and women and with cervicitis in women. Among M genitalium infected men, symptomatic urethritis was more common than asymptomatic urethritis. M genitalium and C trachomatis were not associated with symptoms of urethritis or cervicitis in women. Of 26 male partners of M genitalium positive female index patients, 38% were positive, and 77% of the negative partners had symptoms of urethritis. The concordance rate for 22 female partners of male index patients was 45%. For both men and women the M genitalium prevalence was significantly higher in partners of M genitalium positive index patients than in M genitalium negative index patients with urethritis and/or cervicitis. CONCLUSIONS: M genitalium is associated with urethritis in both men and women and with cervicitis in women. A high concordance rate was found among sexual partners of M genitalium infected patients, indicating that the infection is sexually transmitted.     

深圳地区男男性接触者性病艾滋病知识及相关高危性行为调查

目的:了解深圳地区男男性接触者性病艾滋病高危行为状况,为高危人群行为干预提供科学依据。方法:知情同意原则下填写调查问卷,收集整理资料后进行分析。结果:203例男男性接触者中,年龄最小15岁,最大57岁,平均年龄26岁。学历以高中/中专为主(38.9%),婚姻状况以未婚为主(86.7%),主要居住在罗湖(47.78%)、福田(23.65%)。首次性行为年龄最小12岁,最大30岁,52.2%的男男性接触者第一个性伴为男性,平均性伴数31个;双性恋占47.3%,同性恋占43.8%,异性恋占2.0%;过去6个月与男性肛交每次都用安全套仅41.4%;14.3%回答曾经与外国人发生性接触;12.3%回答曾有医生护士或保健人员告之得了某种性病;54.2%做过HIV检测。结论:男男性接触者普遍多性伴,安全套使用率相对较低,加强对MSM的性病艾滋病防治已刻不容缓。     

HIV risk behavior patterns, predictors, and sexually transmitted disease prevalence in the social networks of young Roma (Gypsy) men in Sofia, Bulgaria

OBJECTIVES AND GOAL: This research studied predictors of high-risk sexual practices and sexually transmitted disease (STD) prevalence among Roma (Gypsy) men's social networks in Sofia, Bulgaria. STUDY DESIGN: Fifty-four socially active individuals, approached in Roma neighborhood venues, recruited members (n = 296) of their own networks into the study. Participants completed sociometric and risk behavior interviews and were tested for chlamydia, gonorrhea, syphilis, and trichomonas. RESULTS: Men had a mean of 7 partners in the past year. Fifty-nine percent had multiple partners in the past 3 months. Seventy-three percent reported recent unprotected vaginal and 51% unprotected anal intercourse. Fifty-nine percent of men had sex with other men in the past year. Twenty-two percent had one of the STDs. The social network to which an individual belonged accounted for 23% to 27% of variance in predicting sexual risk behavior. CONCLUSIONS: One's social network was the most powerful predictor of HIV risk behavior. HIV/STD prevention interventions directed toward entire social networks are especially promising.     

Core group evolution over time: high-risk sexual behavior in a birth cohort between sexual debut and age 26

BACKGROUND AND OBJECTIVE: Among the limitations of the concept of a sexually transmitted disease core is uncertainty about the stability of sexual behavior over time. The objective was to shed light on characteristics and stability of the core group by assessing sexual behavior longitudinally in a birth cohort. GOALS: The goals were to describe group size and characteristics of people who report 5 or more heterosexual partners per year (a surrogate for the core group) at ages 18, 21, and 26 years. STUDY DESIGN: We used a prospective cohort study with a computer-presented questionnaire on sexual behavior. RESULTS: Of the original cohort members, 991 (97.3% of those believed to be alive) responded at at least one age. A total of 14.7% of women and 26.0% of men were in the core group at either age 18 or 21 or 26, but only 0.5% and 0.9% of women and men, respectively, were in the core group at all ages. Those in the core group were significantly more likely to report concurrent partnerships and higher sexually transmitted disease (STD) rates. Early age at first sex was consistently associated with being in the core group, whereas those with less education were more likely to be in the core group at age 18 but not at later ages. CONCLUSION: The high degree of variability in sexual behavior over time of individuals adds another degree of complexity to the identification of a core group for STD transmission.     

The relationship between knowledge about sexually transmitted diseases and actual sexual behaviour in a group of teenage girls.

PURPOSE: To assess longitudinally the relationship between knowledge about sexually transmitted diseases (STDs) and sexual behaviour, contraceptive use, STD protection and social class in a group of Swedish teenage girls. METHODS: Girls starting their upper secondary school education were invited to attend a teenage clinic during a period of 2 years (5 visits). Questions were asked about family situation, sexual activity, contraceptives, STD protection and knowledge about STD. Gynaecological examinations were performed on entry and completion, and when necessary during the observation period. RESULTS: Eighty-eight girls completed all visits during the observation period. At 16 years of age there were no significant differences in knowledge about various STD and STD protection between girls from different social classes or with respect to coital experience, age of coitarche and the subsequent number of sexual partners at 18 years of age. At 18 years of age there was a better knowledge about STDs and the need for STD protection (p < 0.01) among girls with coital experience compared with those who had no coital experience. Girls reporting many lifetime partners were best informed, but in spite of solid knowledge they did not protect themselves from infection. Even though 34% of the girls with coital experience were found to harbour a STD during the course of this study, almost all girls denied the possibility of having acquired or transmitted an infection. CONCLUSIONS: Although girls were well-informed about sexually transmitted diseases and knew how to avoid infections this knowledge had little influence on behaviour.     

Mechanical failure of the latex condom in a cohort of women at high STD risk.

BACKGROUND AND OBJECTIVES: Mechanical failure may reduce the efficacy of condoms. Little is known about frequency and determinants of condom failure in groups at high risk of sexually transmitted diseases (STD). GOAL: To measure condom breakage and slippage rates and evaluate potential determinants of failure among women attending a public STD clinic. STUDY DESIGN: Women attending an STD clinic participated in a 6-month prospective study of barrier contraception for the prevention of STD. They completed sexual diaries that were reviewed at monthly follow-up visits. No data were collected from the male partners. Baseline characteristics of the participants and time-dependent behaviors were evaluated as potential determinants of condom failure. RESULTS: Of 21,852 condoms used by 892 women, 500 broke during intercourse (2.3%) and 290 slipped (1.3%). Breakage was more common among young, black, single nulliparae who engaged in high-risk behavior. Slippage was more common among married women with children. Failure rates decreased with condom use, with coital frequency, and with use of spermicides. CONCLUSION: User characteristics and experience are determinants of breakage and slippage, which are often regarded only as the effect of product design flaws. Attention to modifiable determinants of failure may improve user counseling and product labeling.     

Prevalence and correlates of herpes simplex virus type 2 infection in a population-based survey of young women in low-income neighborhoods of Northern California. The Young Women's Survey Team

BACKGROUND: Herpes simplex virus type 2 (HSV-2) is one of the most common sexually transmitted infections and may enhance transmission of HIV. However, population-based estimates of HSV-2 prevalence and correlates of infection are rare. GOALS: To obtain population-based estimates of HSV-2 prevalence and to identify demographic and sexual behavioral correlates of infection among women in low-income communities of Northern California. STUDY DESIGN: A randomized, single-stage, cluster sample, cross-sectional survey of women age 18 to 29 years who reside in 1990 US Census block groups at the lowest tenth percentile for household income. RESULTS: The survey-weighted prevalence of HSV-2 infection was 34.8% (95% CI, 30.4-39.2). Factors independently associated with HSV-2 seropositivity were black race, older age, lower income, parity, greater number of lifetime male sexual partners, earlier onset of sexual intercourse, sex work, history of sexually transmitted disease (STD), and cocaine use. CONCLUSION: The high prevalence of HSV-2 and the strong correlation with sexual risk underscores the potential for further spread of STD, including HIV, in this young population.     

Providing low-cost sexually transmitted diseases services in two semi-urban health centers in Central African Republic (CAR): characteristics of patients and patterns of health care-seeking behavior.

BACKGROUND: While treatment of symptomatic sexually transmitted diseases (STDs) has been shown to reduce the incidence of HIV infection, there are few published reports describing the delivery of high quality STD care in Africa. GOAL: To test the feasibility of providing comprehensive, affordable STD services through the existing primary care infrastructure. DESIGN: STD treatment services using a syndromic' approach were established in two semi-urban hospital outpatient departments (OPD) in Central African Republic (CAR). A dedicated paramedical provider took a clinical history, performed an examination, explained the diagnosis and the importance of referring partners, dispensed drugs, and offered partner referral vouchers. A fee-for-service system was used to resupply drugs initially purchased with project funds. RESULTS: Of 9,552 visits by index patients and partners over a 28-month period starting in October 1993, 60% were made by women; of these women, 90% were symptomatic, 77% had "vaginal discharge," 70% "lower abdominal pain," and 7% "genital ulcer." Among men, 64 % were symptomatic, 38 % had "urethral discharge," and 14% "genital ulcer." Half of all symptomatic patients presented within 1 week of the onset of symptoms; 44% of men compared to 18% of women had sought care elsewhere before the clinic visit. The average cost per STD treated with recommended drugs was $3.90. Etiologic data from subpopulations in both sites suggest that a high proportion of patients was infected with an STD. CONCLUSIONS: Comprehensive yet affordable care for STDs in persons (and their partners) who recognize symptoms is feasible and should be widely implemented in primary care systems to prevent the spread and complications of STDs and HIV in Africa.     

Patterns of carriage of group B streptococci in genitourinary medicine clinic patients.

Anogenital carriage of group B streptococci was found in 46% (57/125) of men and 38% (68/179) of women attending a genitourinary medicine clinic. Colonisation with group B streptococci was more common in patients who had a history of more than one sexual partner in the preceding three months, but was not related to any previous sexually transmitted infection. Group B streptococci were isolated from either one or both partners of 28 couples, in 12 of which both partners yielded isolates that were indistinguishable by serotyping and phage typing. Colonisation with matching isolates of group B streptococci was more common in couples who had relatively stable relationships.     

The importance of ethnicity as a risk factor for STDs and sexual behaviour among heterosexuals.

OBJECTIVES--To study risk factors for sexually transmitted diseases (STDs) and sexual behaviour. Especially to assess whether there is a higher risk of being infected with STDs among ethnic minorities, and if so for what reasons. SETTING--STD-clinic of the Municipal Health Service of Amsterdam, the Netherlands. SUBJECTS--Cross-sectional study of heterosexuals (255 men and 343 women) with multiple sexual partners, who participated between October 1987 and January 1990. RESULTS--Besides STD-related complaints, ethnicity was an important independent predictor of one or more diagnosed genital STDs. STD-prevalence was higher among men born in Turkey (47%, OR = 3.4) and men born in Surinam (36%, OR = 2.1), compared with Dutch men (21%). While Turkish men had mainly riskful sexual behaviour with prostitutes, Surinam men had more often riskful sexual contact with private partners. Among women, STD prevalence was higher among West-European (38%, OR = 2.3) and Latin-American women (30%, OR = 1.6), compared with Dutch women (21%). Latin American women had more often riskful sexual contact with clients; sexual behaviour of West-European women was riskful with both clients and private partners. CONCLUSIONS--Prevention activities should be directed at specific sexual and ethnic groups, sources of information should be carefully selected, and some groups should be addressed differently with regard to language but to content as well.