Prevalence and risk factors for hepatitis C virus infection among young Thai men

Epidemiologic studies of hepatitis C virus (HCV) infection are unusual in developing countries, especially Thailand. We evaluated the prevalence and risk factors for HCV among military conscripts, including a sample of 5,246 men (1:30 sample), and human immunodeficiency virus (HIV)-1 positive men (N = 500) between 2005 and 2008. The HCV prevalence was 2.2% in the sampled group and 8.4% in HIV-1 sero-positives. Among the sampled group, HIV-1 infection, injection drug use (IDU) history, and unsafe injections were associated with HCV infection; adjusted prevalence rate ratios [RRs; 95% confidence intervals (CIs)] were 3.7 (1.04-12.77), 1.9 (1.04-3.54), and 1.8 (1.02-3.11), respectively. Among HIV-1 sero-positives, an IDU history and residence in southern Thailand were associated with HCV prevalence; adjusted RRs (95% CIs) were 3.5 (1.71-7.24) and 2.6 (1.18-5.61), respectively. Public health measures to prevent HCV in Thailand should focus on reducing injection drug use and other exposures to unsafe injections among young Thai men.

Prevention of acute acoustic trauma by earmuffs during military training

BACKGROUND

Impulse noise produced from firearms can potentially damage hearing organs resulting in sensorineural hearing loss (SNHL). In Chiang Mai during 1997, Detphithak et al reported a prevalence of acute acoustic trauma (AAT) in 22% of new military privates using an H.K.33 for shooting practice without hearing protection. The H.K.33 renders an average sound pressure level of 128 dBA. Earmuffs are claimed by their manufacturing company to attenuate noise 27 dB, and they have been recently introduced in Chiang Mai to prevent AAT.

OBJECTIVE

To study the outcomes of hearing protection against AAT using earmuffs during shooting training (H.K.33) in the Military Reserve Officer Training Corps (MROTC).

MATERIAL AND METHOD

A quasi - experiment study was conducted among 267 normal hearing MROTCs in the Reserve Officers Student Training Center (ROSTC) of the 33rd Military Circle, Chiang Mai, Thailand. Their condition of hearing was examined by an otolaryngologist and an audiologist using pure tone audiometry (PTA) before shooting practice, within 2 hours after the practice, 3 days after the practice at the ROSTC; and 1 month later at Fort Kawila Hospital, Chiang Mai, Thailand.

RESULTS

All 267 MROTCs used earmuffs during shooting practice. Their mean age was 17.95 years. Average sound pressure level of an HK.33 was 127 dBA (range; 126.5-130 dBA). AAT was found in 4 persons (1.5%) within two hours after shooting. Repeat testing 3 days later revealed that only one person (0.37%) still had SNHL. Fortunately, this case reached complete recovery within 1 month. When comparing these findings with those of 1997, earmuffs can reduce AAT by 15 times (95% confidence interval 5.3-40.5, p-value < 0.0001) to a negligible level.

CONCLUSION

Shooting training with an H.K. 33 produces a dangerous sound pressure level at the shooting site, resulting in a possible high risk of acute acoustic trauma. Earmuffs can effectively reduce this risk by approximately 15 times, and they should be widely used in all shooting training.

The natural history of HIV-1 infection in young Thai men after seroconversion

The natural history and progression of HIV-1 infection in Thailand and other developing countries in Asia and Africa have not been well defined. Nevertheless, valid data are needed to evaluate the effects of interventions, which are designed to delay progression. We evaluated the progression to AIDS and death in 235 men who seroconverted during their 2 years of service in the Royal Thai Army. The men were conscripted at age 21 and seroconverted within a 6-month window during follow-up while in the military. The seroconverters were matched with men who were seronegative when discharged. Of the HIV-positive men, 156 (66.4%) were alive, 77 (32.8%) had died, and 2 (0.8%) could not be located 5-7 years after their seroconversion and discharge from the military. The 5-year survival rate was 82.3%; the median times to clinical AIDS and a CD4 cell count of <200/microL was 7.4 years and 6.9 years, respectively. The mortality rate was 56.3 deaths per 1000 patient-years for HIV-positive men and 6.1 deaths per 1000 patient-years for HIV-negative men. Our data suggest a more rapid progression to AIDS and death after HIV-1 infection in young men in Thailand than has been reported for similarly aged cohorts in developed countries.

HIV infection in young men in northern Thailand, 1991-1998: increasing role of injection drug use

Epidemic HIV-1 infections were first recognized in Thailand in 1988 but increased dramatically in the 1990s primarily as a result of sexual transmission. The Ministry of Public Health instituted programs, including condom promotion during commercial sex, and health education to prevent HIV transmission. We assessed the HIV infection prevalence and risk behaviors among eight cohorts of 21-year-old randomly selected male military conscripts in northern Thailand between 1991 and 1998 to evaluate temporal trends in HIV infection and risk behavior. The prevalence of HIV was 11.4% to 11.9% in 1991 through 1993 and progressively fell to 2.4% in 1998. The men reported progressive decreases in commercial sex from 80% in 1991 to 38% in 1998, increases in condom use for commercial sex to greater than 95% in 1998, and decreases in lifetime history of a sexually transmitted infection from 42% in 1991 to 4.4% in 1997. There was an increasing proportion of men who reported a history of injecting illicit drugs, however, which involved 1.0% of the men in 1991 but 4.2% in 1997. The population attributable risk of drug use for HIV infection increased in recent years; the proportion of HIV-positive men with a history of drug use increased from 1.0% in 1991 to 25.8% in 1998. The public health program to prevent the sexual transmission of HIV in Thailand continues to be highly successful. Nevertheless, injection drug use has emerged as an important risk behavior and is maintaining endemic HIV transmission in Thailand.

Preventive intervention to reduce sexually transmitted infections: a field trial in the Royal Thai Army

BACKGROUND

During 1991 through 1993, sexually transmitted infections among conscripts in the Royal Thai Army in the upper-northern provinces were common: human immunodeficiency virus (HIV) prevalence at induction was 12%, HIV incidence was 2.4% per year, and incidence of sexually transmitted diseases was 17% per year. We evaluated a behavioral intervention to reduce incident sexually transmitted infections among conscripts inducted into the Thai Army in 1993.

METHODS

We developed a preventive intervention that addressed consistent condom use, reducing alcohol consumption and brothel patronage, and improving sexual negotiation and condom skills. Companies were assigned to 1 of 3 groups matched on military mission: 450 men were in the intervention group, 681 were in barracks at the same base but did not receive the intervention (diffusion group), and 414 were in distant camps (controls). Baseline HIV serological testing and behavioral interviews were conducted during basic training in 1993. The intervention was applied for 15 months, and men were followed up at 6-month intervals (with repeated HIV serological testing, sexually transmitted disease assessments, and behavioral interviews) through May 1995.

RESULTS

Incident sexually transmitted diseases were 7 times less frequent among men assigned to the intervention than the combined controls (relative risk, 0.15; 95% confidence interval, 0.04-0.55), after adjusting for baseline risk factors (P<.005). There was no diffusion of the intervention to adjacent barracks. The intervention decreased incident HIV by 50% in the intervention group.

CONCLUSION

Intensive interventions in structured institutions can successfully reduce risk in settings confronting expanding heterosexual HIV epidemics.

Decreasing incidence of HIV and sexually transmitted diseases in young Thai men: evidence for success of the HIV/AIDS control and prevention program

OBJECTIVE

To determine whether HIV and sexually transmitted disease (STD) incidence rates among young men in northern Thailand have declined since the establishment of the '100% Condom Program', and to prospectively document changes in the association between behavioral risk factors and incident HIV and STD infections.

SETTING

Thirteen military bases in northern Thailand.

METHODS

Serial prospective cohorts of 19-23-year-old male conscripts (n = 4086) inducted into military service from six northern Thai provinces between 1991 and 1993 were followed at 6-month intervals for incident HIV and STD through May 1995. HIV incidence was determined by serology, and incident STD were reported by conscripts as diagnosed by health-care providers.

RESULTS

HIV incidence declined from a rate of 2.48 per 100 person-years during 1991-1993 to 0.55 per 100 person-years during 1993-1995. STD incidence showed an even greater decline, with a 10-fold decrease from 1991-1993 to 1993-1995. Behavioral risk factors for incident STD infections included a history of prior STD and sex with girlfriends and sex workers. Inconsistent condom use remained a strong predictor of incident STD among brothel visitors. Other previously-reported risk factors in 1991-1993 such as illicit drug use, frequency and cost of brothel visits, and low socioeconomic status were not associated with incident STD or HIV in 1993-1995.

CONCLUSIONS

Although several studies have recently reported decreased prevalence of HIV and STD infections in Thailand, these data demonstrate that a dramatic decrease in the incidence rates of STD, including HIV infection, has occurred among young men in military service in northern Thailand. The Thai AIDS prevention and control program might be implemented by other countries experiencing major epidemics of heterosexually transmitted HIV infections. Similar prevention programs targeted at other populations in Thailand and elsewhere in Asia are needed to decrease the spread of the HIV epidemic.

The association of herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and syphilis with HIV infection in young men in northern Thailand

To evaluate the association between sexually transmitted diseases that commonly may cause genital ulceration and prevalent and incident HIV infections, we conducted three case control studies in a cohort of 21-year-old male military conscripts in northern Thailand. The men were evaluated at baseline in 1991 and semiannually until their discharge 2 years later. Serologic evidence of infection with herpes simplex virus type 2 (HSV-2), Haemophilus ducreyi, and HIV were more frequent at baseline in 83 men with a history of genital ulcer than in 97 men without such a history. Seropositivity to H. ducreyi (odds ratio [OR] = 3.46), HSV-2 (OR = 3.83), and syphilis (OR = 1.53) were more common in HIV-positive than HIV-negative men. Men (N = 45) who seroconverted to HIV while in the military were more often seropositive for H. ducreyi and HSV-2 before HIV seroconversion and also were more likely to seroconvert to HSV-2 and H. ducreyi during the same interval as their HIV seroconversion compared with men who remained HIV-negative. These data suggest that HSV-2 and H. ducreyi may be both markers for high-risk sexual behavior and risk factors for HIV infection among young men in Thailand.

Antigenic analysis of influenza viruses isolated in Thailand between 1991 and 1994

We studied the epidemiology of influenza viruses in Thailand by isolating them and comparing their antigenic features with those of Japanese isolates. Between 1991 and 1994, 32 strains were isolated from 186 throat swab specimens. Twenty-one of the 32 isolates were of type A, subtype H3N2, and 11 strains were type B. It was suggested that the isolates of type A, subtype H3N2, drifted antigenically from A/Beijing/352/89-like to A/Kitakyusyu/159/93-like variants used as reference strains for comparison. The type B isolates in 1991 were suspected to be antigenically different from those of B/Bangkok/163/90, Thailand, in HI tests. These 1991 isolates were similar to B/Mie/1/93, which was isolated in the latter half of the epidemic in Japan in winter 1992/1993.

Human immunodeficiency virus infection and self-treatment for sexually transmitted diseases among northern Thai men

BACKGROUND AND OBJECTIVES

Self-treatment for sexually transmitted diseases (STD) is common, but little studied, in Thailand, and its influence on human immunodeficiency virus (HIV) infection is unknown.

GOALS

To assess STD self-treatment and self-prophylaxis behaviors as well as HIV risks and serostatus among northern Thai men.

STUDY DESIGN

Cross-sectional report from a cohort of military conscripts (N = 869). HIV and STD seroprevalence and reported risk behaviors, including STD history and antibiotic self-treatment, were obtained. Associations between STDs and self-treatment or prophylaxis and HIV infection were analyzed using t-tests, odds ratios, and logistic regression.

RESULTS

The prevalence rate for HIV was 12.3%, and for syphilis it was 2.2%. Men who were seropositive for HIV were more likely to report having sex with commercial sex workers (OR 9.1), to have had an STD (OR 5.96) and to report inconsistent condom use with commercial sex workers (OR 3.13). Of 282 men reporting any STD, 65.2% treated themselves with antibiotics, and 8.5% used them before commercial sex. Among those who frequented commercial sex workers, 98.7% took preventive steps after sex by increasing urine output (69.2%), washing the genital area (28.9%), and using antibiotics (0.9%). Men reporting STD self-treatment were less likely to be HIV infected (OR 0.53; 95% CI 0.31, 0.93).

CONCLUSIONS

These men are attempting to prevent HIV and STDs. Self-treatment with antibiotics may lower HIV risks associated with bacterial STD in a high-prevalence population.

Epidemiologic risk factors for incident sexually transmitted diseases in young Thai men

BACKGROUND AND OBJECTIVES

Prospective studies of incidental sexually transmitted diseases in developing countries rarely have been reported. As the human immunodeficiency virus epidemic widens, knowledge of the epidemiology of sexually transmitted diseases as co-factors for human immunodeficiency virus infection is viewed as vitally important.

GOAL

To determine epidemiologic risk factors for incidental sexually transmitted diseases in young men in northern Thailand.

STUDY DESIGN

A cohort of 2,417 men selected by lottery for military conscription was followed an average of 22 months, with epidemiologic risk factors and sexually transmitted disease histories assessed semiannually. Sexually transmitted diseases were determined by physician or symptom histories obtained by interview.

RESULTS

Sexually transmitted disease incidence was 17.04 per 100 person-years. Gonorrhea and chancroid were commonly reported, whereas incident syphilis was rare. Sexually transmitted disease incidence declined significantly in the 2-year period. Most sexually transmitted diseases were acquired through commercial sex patronage. However, among men who did not report visiting a brothel, there was a significant increase in sexually transmitted diseases among men reporting sex with a girlfriend. Other risk factors included inconsistent condom use, drug use, and low educational level. Frequent alcohol use was associated with incident sexually transmitted diseases in bivariate analysis, but drinking at the time of last brothel visit was not associated with increased sexually transmitted diseases.

CONCLUSIONS

Sexually transmitted disease control in Thailand is based on an integrated sexually transmitted disease clinic system. Many commercial sex workers are examined and treated routinely, but too infrequently to reduce sexually transmitted disease transmission between them and their male clients. Condom-use levels in commercial sex settings still may be too low to reduce sexually transmitted disease transmission. More consistent and effective sexually transmitted disease treatment of commercial sex workers and their clients and education of men on the effective and consistent use of condoms is required to reduce the risks of sexually transmitted disease transmission in this population.

Hepatitis B immunization: a potential incentive to HIV vaccine trial participation in Thailand?

To assess the effectiveness of hepatitis B immunization as an incentive to retention in HIV seroincidence studies and future HIV vaccine trials in northern Thailand, subjects enrolled in three HIV seroincidence cohorts were screened for hepatitis B markers and seronegatives were offered free hepatitis B immunization. Cohorts studied included female commercial sex workers (CSWs), male sexually transmitted disease (STD) patients, and recently discharged military conscripts. Subjects who agreed to the immunization program were compared with those not enrolled to determine the utility of immunization as an incentive to cohort retention. Full immunization was achieved for 273 (89.5%) of 305 vaccinees; only 323 (60.6%) of 533 subjects not immunized completed the same follow-up visits (OR = 1.49, 95% and CI = 1.27, 1.75). Hepatitis B vaccination was a significant incentive for completion of the follow-up program. The vaccination program had the greatest effect on the CSWs; a similar effect was seen for male STD patients, but not for discharged conscripts. Despite the immunization program, follow-up rates at 12 months were similar in the immunized and nonimmunized groups.

Risk factors for HIV-1 seroconversion among young men in northern Thailand

OBJECTIVE

To identify behavioral and sociodemographic risk factors for incident human immunodeficiency virus-1 (HIV-1) infection among healthy young men in northern Thailand.

DESIGN

Men inducted into military service in northern Thailand in May and November 1991 were followed at 6-month intervals until discharge 2 years later. Trained nonmilitary interviewers identified risk factors for HIV-1 infection through interviews with the men.

SETTING

Thirteen military bases in northern Thailand.

PARTICIPANTS

A total of 1932 seronegative men, aged 19 to 23 years (average age, 21 years) at enrollment, conscripted into the Royal Thai Army and Air Force from six upper-northern Thai provinces.

MAIN OUTCOME MEASURES

Human immunodeficiency virus-1 seroincidence as determined through enzyme-linked immunosorbent assay and verified by Western blot, and univariate and multivariate analyses of risk factors related to HIV-1 incidence.

RESULTS

A total of 85 men seroconverted to HIV-1 over the period of observation, giving an incidence rate of 2.43 per 100 person-years. Factors strongly associated with HIV-1 seroconversion were frequency of visits to female commercial sex workers (CSWs), sex with men, and incident sexually transmitted diseases (STDs). High frequency of condom use showed a significant (P < .001) protective effect for HIV-1 incidence among men with a history of recent sex with female CSWs in univariate analysis, but a multivariate model demonstrated no difference in HIV-1 seroconversion rates by consistency of condom use. Multivariate analysis incorporating condom use showed that having sex with men (adjusted relative risk [RR], 2.59; 95% confidence interval [CI], 1.08 to 6.25), having sex with CSWs (adjusted RR ranged from 2.54 [95% CI, 1.81 to 3.58] to 2.74 [95% CI, 1.56 to 4.81]), and incident STDs (adjusted RR, 2.38 [95%, CI, 1.31 to 4.32]) to be predictors of incident HIV-1 infection. Substance use was not associated with HIV-1 seroconversion rates in multivariate analysis.

CONCLUSION

The HIV-1 incidence in this cohort of young men appears to be primarily attributable to having sex with female CSWs. Condom use provided some protection, although not in multivariate analysis; however, condom use has previously been shown likely to be useful in preventing HIV-1 transmission. Thus, programs to increase effective condom use in brothels are essential. Efforts to extend condom use to non-CSW partners are especially needed. More effective prevention and treatment of STDs may also be necessary to decrease HIV-1 infection in this population.

Dynamics of risk behavior for HIV infection among young Thai men

The objective of this investigation was to analyze the dynamics of risk for HIV-1 infection among young men in Thailand. We conducted a prospective study in a cohort (n = 1,236) of young men, aged 19-23 years at conscription into the Royal Thai Army and Air Force from six provinces in northern Thailand in May 1991 who were followed until their discharge in April 1993. The outcome measure was change since conscription in the frequency of self-reported sex with female commercial sex workers (CSW) during military service. Although 42% of conscripts reported no visit to a female CSW in the year prior to conscription, most had a visit during military service. Men who visited female CSWs infrequently at baseline increased their visits somewhat over time, whereas those with high initial rates of CSW visits decreased. Based on an assumed stable distribution over time, change from baseline was not statistically significant. Only marital status and high baseline CSW visit rates were associated with diminished visit frequency in multivariate analysis. No differences were seen in patterns of change in CSW visits by HIV-1 serostatus. More aggressive preventive interventions are needed to reduce the frequency of CSW visits in northern Thailand, a setting where 40-80% of all female CSWs working in brothels are now HIV seropositive.

Willingness to participate in AIDS vaccine trials among high-risk populations in northern Thailand

OBJECTIVES

To determine the anticipated participation in a prophylactic AIDS vaccine trial and to identify perceived benefits and barriers to enrollment of HIV-seronegative volunteers at risk of HIV infection in northern Thailand.

DESIGN

A cross-sectional survey.

METHODS

Subjects interviewed in a cross-sectional survey included female commercial sex workers (n = 215), men attending sexually transmitted disease clinics (n = 219), conscripts in the Royal Thai Army (n = 1453), and men discharged from the army (n = 293) who had returned to civilian life. We determined AIDS vaccine knowledge and attitudes, perceived vulnerability to HIV infection, barriers and incentives to participate in a future vaccine trial and agreement to participate in a randomized trial.

RESULTS

Awareness of vaccines (88-97%) and AIDS vaccine development efforts (62-77%) were common and viewed to be a complement to behavior change (74-94%). Approximately 25% of subjects would definitely join a trial if asked, and an additional 38% would accept an AIDS vaccine if they were convinced it would be safe and effective. Important barriers to participation included concerns with discrimination (16-45%), short- (37-60%) and long-term (30-55%) vaccine side-effects, fear of disability and death (36-58%), and beliefs that partners would refuse to have sex (24-49%) after immunization. The principal inducement to join a trial was health insurance (62%).

CONCLUSION

Potential HIV vaccine trial participants have several fears of joining a vaccine study at this time. Information derived from Phase I/II trials is needed to address these concerns if enrollment in efficacy trials is to be successful in the near future.

Same-sex behavior, sexually transmitted diseases and HIV risks among young northern Thai men

OBJECTIVES

To assess the risks for HIV infection and sexually transmitted diseases (STD) among young northern Thai men who have sex with men (MSM), and to examine the possible role of male same-sex behavior in the northern Thai HIV/AIDS epidemic.

METHODS

Two cohorts of northern Thai military conscripts and one cohort of recently discharged conscripts, a total of 2047 men, were studied. Data were collected by interview on behavioral risk factors, and sera were examined for syphilis and HIV-1 antibodies. Univariate and multiple logistic regression analyses were used to determine risk factors associated with HIV and STD, and to assess the frequency and patterns of same-sex behaviors among these men.

RESULTS

Of 2047 men, 134 (6.5%) reported one or more male lifetime sex partners. Of these MSM, 130 (97.0%) also had female partners, and four (3.0%) had exclusively male partners. Compared with men who reported only female sex partners, MSM had a higher number of lifetime sex partners, a higher mean number of female sex partners, more female and male commercial sex worker (CSW) partners, and were more likely to be married. MSM were significantly more likely than exclusively heterosexual men to report having had any STD [odds ratio (OR), 2.72], gonorrhea (OR, 2.05), syphilis (OR, 3.17), non-gonococcal urethritis (OR, 4.54) and penile discharges (OR, 6.24). They were at borderline increased risk for HIV infection [OR, 1.51; 95% confidence interval (CI), 0.95-2.41]. Men with more than one lifetime male sex partner compared with those with only one partner were significantly more likely to be HIV-infected (OR, 2.81; 95% CI, 1.09-7.19).

CONCLUSIONS

Northern Thai MSM are a high-risk population for STD, including HIV. Reported same-sex behavior in this population appears to vary considerably with data collection techniques. HIV and STD prevention strategies aimed at changing unsafe sexual practices may need to be targeted to the general population of young Thai men.

Behavioral and sociodemographic risks for frequent visits to commercial sex workers among northern Thai men

OBJECTIVE

The transmission of HIV-1 in Thailand has recently been attributed to exposure to infected commercial sex workers (CSW). We sought to identify risk factors for patterns of CSW visits among northern Thai men.

DESIGN

Retrospective recall of lifetime and recent CSW visits and associated risk factors were obtained by interview.

SETTING

Two military bases in northern Thailand.

PARTICIPANTS

We enrolled two cohorts (n = 2417) of young men, aged 19-23 years, who were conscripted into the Royal Thai Army and Air Force from six provinces in northern Thailand in May and November 1991.

MAIN OUTCOME MEASURES

Frequency of self-reported lifetime and recent sex with CSW.

RESULTS

Multivariate results showed that lower socioeconomic status, early first intercourse and substance-use factors (alcohol, marijuana, other drugs, and smoking) associated with lifetime and recent sex with CSW. Sexual intercourse with other female partners, lower price paid at last CSW visit and frequency of condom use with CSW did not differentiate frequent from infrequent CSW visitors.

CONCLUSIONS

Limits in the frequency of sex with CSW, improved condom practices and reduction of drinking prior to CSW visits would all appear to provide substantial protection from exposure to HIV-1 in this setting.

Risk factors for HIV infection among young adult men in northern Thailand

OBJECTIVE

To determine the sociodemographic and behavioral risk factors associated with human immunodeficiency virus (HIV) infection in two cohorts of young men selected for military service in northern Thailand.

DESIGN

Military conscripts were studied cross-sectionally after conscription in May 1991 and November 1991. Risk factors were assessed by interview with trained nonmilitary interviewers.

SETTING

Two military training bases in Chiang Mai, Thailand.

PARTICIPANTS

A total of 2417 young men aged 19 to 23 years (mean age, 21 years) conscripted by lottery into military service in the Royal Thai Army or Royal Thai Air Force from six provinces in northern Thailand.

MAIN OUTCOME MEASURES

Human immunodeficiency virus seroprevalence by enzyme-linked immunosorbent assay confirmed by Western blot and univariate and multivariate analyses of sociodemographic and behavioral risk factors associated with HIV seroprevalence.

RESULTS

Overall, 289 (12.0%) of 2417 men were HIV-seropositive at baseline. The strongest associations with being HIV positive were heterosexual activities. History of sex with a female commercial sex worker (CSW) was frequent (96.5% of men who were HIV-positive and 79.0% of men who were HIV-negative) and strongly associated with HIV infection on univariate and multivariate analyses (adjusted odds ratio, 1.60 to 2.07, depending on the frequency of CSW contact). Also, sexually transmitted diseases were common and associated with HIV infection in both univariate and multivariate analyses (adjusted odds ratio, 3.36). Sex with other males and injection drug use were uncommon and not associated with HIV infection. Condom use was reported in 61.5% of men at last sex with a CSW but was not shown to be protective of prevalent HIV infection.

CONCLUSION

The epidemic of HIV infection has spread widely among young men in northern Thailand, despite reported frequent and recent use of condoms during sex with female CSWs. Control of HIV infection in this population will probably require more regular and effective use of condoms, prevention and treatment of sexually transmitted diseases, and reduction in the frequency of CSW contact.