Share this article on:

Risk Factors for Sexually Transmitted Diseases and Casual Sex Among Chinese Patients Attending Sexually Transmitted Disease Clinics in Hong Kong


Sexually Transmitted Diseases: June 2002 - Volume 29 - Issue 6 - p 360-365

Background  The risk factors for sexually transmitted diseases (STDs) and having casual sex among the Chinese people are unknown.

Goal  The goal of the study was to estimate the prevalence of STDs and to develop a profile of risk behavior among patients attending STD clinics in Hong Kong.

Study Design  In a clinic-based, cross-sectional study, 448 patients attending two government STD clinics were randomly sampled and interviewed by means of a structured questionnaire.

Results  The prevalence of STDs was 51% (70% of men and 35% of women). Attendees who had STDs diagnosed were more likely to be male, never married, and smokers and alcohol users (ever) and to have had casual sex or sex during travel with someone not their usual partner. Those who did not always use condoms were more likely to be male and never married. Having had casual sex was reported by 63% of the respondents. Those who reported having had casual sexual encounters were more likely to have the following characteristics: male; never married; no religious belief; ever smoker and alcohol user; current STD; had sex during travel; history of STD; inconsistent condom user; and perception of being at low risk for STD. After adjustment, only male gender was associated with casual sexual encounters.

Conclusion  The results of this study indicated several risk factors among Chinese patients for the acquisition of STDs, for not using condoms, and for having casual sex. This information is useful in strengthening and evaluating currently available STD prevention and control strategies for the Chinese population in Hong Kong and elsewhere.

From the Department of Community Medicine, The University of Hong Kong, Hong Kong, China

A study among Chinese clients attending STD clinics in Hong Kong, China, showed that clients with diagnosed STDs were more likely to be male, never married, and ever smokers and alcohol users and to have had casual sex or sex with strangers during travel abroad. Men who were never married were less likely to use condoms.

The authors thank Dr. Shahul H. Ebrahim (Centers for Diseases Control and Prevention, Atlanta, GA, USA) for his helpful comments on a draft of the manuscript.

Reprint requests: Dr. Abu S. M. Abdullah, Department of Community Medicine, The University of Hong Kong, Patrick Manson Building South Wing, 7 Sassoon Road, Hong Kong SAR. E-mail:

Received for publication July 11, 2001, revised September 27, 2001, and accepted October 1, 2001.

SEXUALLY TRANSMITTED DISEASES (STDs) remain a major public health problem worldwide, 1 including Hong Kong. The HIV epidemic underlines the importance of controlling other STDs as a strategy to help limit HIV spread, because the epidemics are interdependent. 2,3 Although worldwide HIV prevention campaigns have played some part in the decreasing STD trends in some countries, 4 STD ratios continue to rise elsewhere. 5,6 In Hong Kong, the cumulative number of reported STD cases increased threefold between 1990 and 1999 (Table 1). 7

Table 1

Table 1

Increased cross-border population mobility between Hong Kong and southern China 8 after Hong Kong’s return to Chinese sovereignty facilitated access to cheap commercial sex services, mainly through increased access to China and increased illegal immigration of commercial sex workers into Hong Kong. In addition, unsafe sexual behavior among cross-border and other travelers 9 and other members of the public 10 appear to have contributed to increases in STDs in Hong Kong.

Although prostitution is not illegal in Hong Kong, there are no efforts to manage commercial sex workers or their health, such as licensing and regular health checks. These have proved effective elsewhere. The higher cost of local commercial sex workers in comparison with those in mainland China means that local efforts to maintain the health of prostitutes would be to little avail, given that prostitution, while illegal in China, is more accessible because of lower pricing, poor law enforcement, and easy cross-border travel. To design effective prevention strategies, it is essential to determine behavioral influences that make people vulnerable to STDs. Risky sexual behavior is the major cause of the subsequent development of STDs. 11–14 STDs themselves are a potentially serious health burden. It is also easier for those who have developed STDs to become infected with HIV and other serious pathogens. 14–16 Therefore, it is important to accurately estimate the risk behavior and perceptions of risk among this subgroup of the population. We therefore undertook to estimate the prevalence of STDs among patients attending two social hygiene clinics in Hong Kong, to describe their sexual behavior, and to identify risk factors for STDs and for having casual sex partners.

Back to Top | Article Outline


Patients and Method of Data Collection

A clinic-based cross-sectional study was conducted between July and August 1997 among patients attending two STD clinics in Hong Kong. These two clinics were conveniently selected from the eight public STD clinics in Hong Kong, and both were located in the downtown area. There were no differences in the characteristics of patients attending these two clinics other than in the sex ratios. We recruited all the female patients from one clinic and all the men from another. Patients aged 18 years or more who attended the STD clinic for consultation were approached by two (one male and one female) trilingual (English, Mandarin, and Cantonese) interviewers for participation in the study. Attendees to the clinics were either self-referred or physician-referred because of suspected STD. To ensure privacy the interviews were conducted in a separate room within the clinic. Interviewers were trained in techniques for conducting research in the sensitive area of sexual health, and regular meetings were held to discuss the progress of the survey and any special problems encountered. The study was approved by the ethics committee of the University of Hong Kong.

After patients completed their consultation with a physician, the staff nurse randomly selected every third person for an interview (if that person refused, the next person was selected). The questions on sexual behavior were given to the subjects for self-completion to improve the reliability of the responses. Questionnaires were also given to those participants who were willing and able to complete the questionnaire by themselves. In such cases, interviewers were available to answer any questions of the participants.

Back to Top | Article Outline


A structured questionnaire was designed mainly to obtain information on HIV-related knowledge, attitude, and risk behaviors. The questionnaire sought information in the following areas: demographics (age, sex, ethnicity, education, marital status, religion); history of casual sex (defined as having had sex with someone other than a spouse or regular sex partner within the 3 months before the survey); sex during travel (whether the respondent had had sex with a stranger during travels within the 12 months before the survey); history of STD (ever diagnosed with an STD); any HIV testing (yes/no forced-answer format); perception of STD risk (one yes/no question: Are you afraid of STD acquisition?); smoking history (current, occasional, ex-smoker, few times, or never; these answers were then condensed as ever or never smokers); and alcohol use (current, occasional, and never users, which were condensed as ever or never users). Additional data were gathered on the frequency of visits to the clinics, type of infections encountered (from the medical record), the person from whom the infection was believed to have been acquired, and time since last sexual contact.

Back to Top | Article Outline

Statistical Analysis

The total sample was analyzed to provide characteristics of the subjects. Respondents with STDs were compared with those who did not have an STD, and those who had reported having had casual sex were compared with those who did not. Proportionate differences were calculated with the chi-squared test. Crude odds ratios (ORs) with 95% CIs were determined to estimate relative risk of current STD acquisition and having had casual sex. Multiple regression analyses were performed to adjust ORs for potential confounders.

Back to Top | Article Outline


General Characteristics

Of 596 patients approached, 462 agreed to be interviewed, and 456 interviews were suitable for analysis, a response rate of 76%. We excluded eight non-Chinese respondents from the analysis, leaving a total of 448 Chinese subjects, of whom 72% were married, 44% were male, 36% were aged 18 to 35 years, 64% were aged 36 to 65 years, 93% had no more than secondary school education, and 7% at least a college education. Of the 448 respondents, 51% (227) had an STD diagnosed during that visit (70% of men and 35% of women), and the remaining 48% (214/448) were not confirmed to have an STD. For both men and women the most common diagnoses were genital warts (15%), gonorrhea (9%), and nongonococcal urethritis (9%), followed by nonspecific genital infection (7%), candidiasis (5%), syphilis (2%), trichomoniasis (2%), genital herpes (1%), and others (2%). Of the respondents (n = 448), 50% had previously had an STD diagnosed and 63% had had casual sex during the previous 3 months. The prevalence of different STDs was higher among those who reported having had casual sex (Table 2).

Table 2

Table 2

Back to Top | Article Outline

Risk Factors for Acquisition of STDs

Respondents who were male, never married, and reported ever being smokers, ever being alcohol users, having had casual sex, and having had sex during travel were most likely to have an STD (Table 3). A logistic regression model including all these variables revealed that no variables significantly predicted STD risk (data not shown).

Table 3

Table 3

Of the respondents with STDs, 16% (74% of women versus 26% of men) blamed sex partners for their current infections, whereas 78% (34% versus 66%) believed they acquired STDs by chance and 6% (27% versus 73%) were not sure. Of those respondents with confirmed STDs (n = 227), only 18% reportedly used condoms all the time, 57% used them sometimes or often, and 25% had never used them. Not using condoms during sexual intercourse was associated with being male (OR, 1.58; 95% CI, 1.01–2.45) and never being married (OR, 1.75; 95% CI, 1.10–2.79). Other demographic variables, smoking, and alcohol use were not significantly associated with not using condoms.

Back to Top | Article Outline

Risk Factors for Having Casual Sexual Encounters

Of the 284 respondents who had had casual sexual encounters, 65% were male, 64% were married, 94% had attained no more than secondary school education, and 6% had at least a college education. Those who had had casual sexual encounters were significantly more likely to be male, have never been married, have no religious belief, ever be smokers and alcohol users, have a current STD, have a history of STDs, have had sex during travel, be inconsistent condom users, and perceive low risk for STDs (Table 4). Logistic regression analysis including all these variables in the model identified only male sex (OR, 19.06; 95% CI, 2.94–123.75) as associated with having casual sex (data not shown).

Table 4

Table 4

Back to Top | Article Outline


Our study reconfirmed that the well-established risk factors (e.g., gender, marital status, smoking and alcohol use, and casual sex) 15–17 for the acquisition of STDs are important among the Chinese population in Hong Kong. The absence of any significant predictors in the logistic model indicates the homogeneity of subjects attending government social hygiene clinics, regardless of their STD diagnosis status. Usually these are people who have been involved in high-risk sexual activities and suspect that they are at risk of STDs. They therefore attend the clinic for free consultation (referral from a physician is not required to attend the social hygiene clinics in Hong Kong) or are referred to the clinic by other health care professionals or organizations.

Consistent with other reports, 17–19 having casual sex was most strongly associated with male sex, after adjustment for other confounders. Women were more reluctant than men to have casual sex because they have so much more than STDs to consider before engaging in sex, such as the risk of pregnancy. In addition, Chinese cultural values and social norms, which disapprove of casual sex for women, might also have contributed to this difference. Principally, however, it is likely to be the lack of availability or accessibility of male commercial sex workers. Lack of availability probably reflects lack of demand, and the unacceptability of male commercial sex workers in Hong Kong society might also contribute to this.

The association between having casual sex and other risk factors, such as smoking, alcohol use, inconsistent condom use, and history of STDs, supports the findings reported elsewhere, 15–17,19 reflecting the need to design interventions that will take into account all these factors.

Perceptions of risk from certain activities are associated with the intention of becoming involved in such activity and are affected by perceptions of the severity of the consequences, susceptibility to the consequences, and effectiveness of preventive means. 20 This in turn may be influenced by the anxiety or threat one feels on account of these intentions and activities. In the current study, those who were not afraid of being infected with STDs were more likely to have had casual sex, indicating their low perceptions of STD infection risk from casual sex. A higher proportion of these people did not use condoms consistently, thus increasing their risk of STD and HIV infection. Other studies indicate that those who engage in high-risk behaviors and have multiple sex partners are least likely to perceive themselves at risk of STD. 21 Such denial of personal risk can have a serious consequence for those involved in risky sexual activities and for their spouses or steady partners. It is appropriate to design interventions that would target the low perceptions of risk among this high-risk group in Hong Kong.

Respondents who attended the public STD clinics were more likely to be less educated and have lower income. This population group might be at higher risk of not using condoms consistently because of a lack of information on safer sex and an unwillingness to buy condoms. Alternatively, their financial difficulties might have prevented them from having sex with commercial sex workers and minimized their risk of STDs. However, it might also be possible that this group of people had bought sex from street sex workers or other high-risk groups (such as those with an infection) who are cheaper and less likely to follow any control measures that might be in place. These possible variations among patients attending government social hygiene clinics and private-sector clinics reflect the need for studies that target patients attending clinics in the private sector, which should examine the wider pattern of sexual risk-taking behavior in the Hong Kong population.

Despite the length of the questionnaire and the sensitive nature of the questions asked, this study achieved a good response rate of 76%. Other studies of sexual behavior among patients with STDs showed response rates of between 75%21–22 and greater than 90%. 23 Because of the small sample size of both the male and female groups and the homogeneity of patients with STDs, we reported results for men and women together. However, there are a few limitations to this type of study. The data were collected by different interviewers, who may have had different interviewing techniques, despite having being instructed on a standard technique. Although the randomization procedure of approaching every third patient was employed, this was not monitored by the researcher, and because the research assistants are external employees, the procedures may not have been followed exactly. Alternatively, many attendees of the clinic might have avoided being interviewed because of concerns about anonymity, but because of the anonymous nature of the study, we were unable to compare the characteristics of those nonparticipants. However, we assume that most (>80%) of the characteristics of the respondents were similar to those of the persons who refused to be interviewed, because the interviewers reported nothing to the contrary at the regular meetings.

Finally, bias (such as participation, reporting, and recall bias) could not be avoided, just as in other cross-sectional studies. The investigators recruited only those who were visiting these two clinics during a specific period of time. It should be noted that approximately 80% of the STD cases in Hong Kong are seen in the private sector. 24 Therefore, caution should be taken before generalizing the findings of the study to the entire population of Hong Kong.

Back to Top | Article Outline


STDs remain a major public health threat to the population of Hong Kong. The increase in the prevalence of STDs in recent years and the high prevalence of casual sexual activity among the patients indicate the need for rigorous interventions. Since the rates of condom use among the respondents were low and 100% condom use has been proven to be effective in reducing the STD burden in some nearby countries, 25 an increase in condom use must be promoted. Because many study participants considered themselves at low risk for STDs, it is clear that there is a need to make the public more aware of their risk. This could be done by warning people about the risk of STDs from unprotected casual sex and the prevalence of STDs in neighboring countries. Although there is a need for continuous monitoring of STDs at both the government and private-sector level, it might be worthwhile to incorporate STD surveillance in the HIV/AIDS-control program, a measure which has been effective in the overall control of STDs elsewhere. 26 Collaboration with the public health departments in neighboring provinces of mainland China should also be considered, because a recent survey showed that many patients (64%) had had casual sex in mainland China. 24

Back to Top | Article Outline


1. Fonck K, Kidula N, Kirui P, et al. Pattern of sexually transmitted diseases and risk factors among women attending an STD referral clinic in Nairobi, Kenya. Sex Transm Dis 2000; 27: 417–423.
2. Cameron DW, Simonsen JN, D’costa LJ, et al. Female to male transmission of human immunodeficiency virus type 1: risk factors for seroconversion in men. Lancet 1989; ii: 184–189.
3. Laga M, Manoka A, Kivuvu M, et al. Non-ulcerative sexually transmitted diseases as risk factors for HIV-1 transmission in women: results from a cohort study. AIDS 1993; 7: 95–102.
4. Van de Laar MJW, Pickering J, van den Hoek JAR, et al. Declining gonorrhoea rates in the Netherlands, 1976–88: consequences for the AIDS-epidemic. Genitourin Med 1990; 66: 148–155.
5. Borisenko KK, Tichonova LI, Renton AM. Syphilis and other sexually transmitted infections in the Russian Federation. Int J STD AIDS 1999; 10: 665–668.
6. Chen XS, Gong XD, Liang GJ, Zhang GC. Epidemiological trends of sexually transmitted diseases in China. Sex Transm Dis 2000; 27: 138–142.
7. Hong Kong STD/AIDS Update. Vol. 6, no. 3. Hong Kong: Department of Health, Government of the Hong Kong SAR. 2000:7–12. (Address: Special Preventive Programme, Department of Health, c/o Red Ribbon Centre, 2/F. Wang Tau Hom Jockey Club Clinic, 200 Junction Road East, Kowloon, Hong Kong; Web site:
8. Abdullah ASM, Hedley AJ, Fielding R. Cross border travel and HIV/AIDS risk among travellers in Hong Kong [abstract P13.3]. Presented at the 1st Asia Pacific Travel Health Congress, Hong Kong: Asia Pacific Travel Health Association, 1996.
9. Abdullah ASM, Hedley AJ, Fielding R. High risk sexual behaviour in travellers. Lancet 1999; 353: 595.
10. Hong Kong AIDS Foundation. Working Report on the Knowledge, Attitude, Behaviour and Practice Survey on AIDS in Hong Kong, 1992. Hong Kong SAR: Hong Kong AIDS Foundation, 1992 (Address: Red Ribbon Centre, 2/F. Wang Tau Hom Jockey Club Clinic, 200 Junction Road East, Kowloon, Hong Kong; Web site:
11. Evans BA, McCormack SM, Bond RA, MacRae KD. Trends in sexual behaviour and HIV testing among women presenting at a genitourinary medicine clinic during the advent of AIDS. Genitourin Med 1991; 67: 194–198.
12. Ekweozor CC, Olaleye OD, Tomori O, et al. Clinico-epidemiological patterns of HIV infection in STD patients in Ibadan. Afr J Med Sci 1995; 24: 321–327.
13. Suligoi B, Giuliani M, Binkin N. The national STD surveillance system in Italy: results of the first year of activity. STD Surveillance Working Group. Int J STD AIDS 1994; 5: 93–100.
14. Le Bacq F, Mason PR, Gwanzura L, Robertson VJ, Latif AS. HIV and other sexually transmitted diseases at a rural hospital in Zimbabwe. Genitourin Med 1993; 69: 352–356.
15. Karita E, Martinez W, Van de Perre P, et al. HIV infection among STD patients—Kigali, Rwanda, 1988 to 1991. Int J STD AIDS 1993; 4: 211–213.
16. Zekeng L, Yanga D, Trebucq A, Sokal D, Salla R, Kaptue L. HIV prevalence in patients with sexually transmitted diseases in Yaounde (Cameroon) in 1989 and 1990: necessity of an STD control programme. Genitourin Med 1992; 68: 117–119.
17. Passey M, Mgone CS, Lupiwa S, et al. Community based study of sexually transmitted diseases in rural women in the highlands of Papua New Guinea: prevalence and risk factors. Sex Transm Infect 1998; 74: 120–127.
18. Robain M, Carre N, Dussaix E, Salmon CD, Meyer L. Incidence and sexual risk factors of cytomegalovirus seroconversion in HIV-infected subjects. The SEROCO Study Group. Sex Transm Dis 1998; 25: 476–480.
19. Hecht ML, Driscoll GA. Comparison of selected communication, social, situational and individual factors associated with alcohol and other drugs. Int J Addict 1994; 29: 1225–1243.
20. James NJ, Gillies PA, Bignell CJ. AIDS-related risk perception and sexual behaviour among sexually transmitted disease clinic attenders. Int J STD AIDS 1991; 2: 264–271.
21. Mulvey G, Temple-Smith M. Managing people with HIV/AIDS: the involvement of Victorian general practitioners. Aust Fam Phys 1997; 26 (suppl 2): S66–S70.
22. Sonnex C, Hart GJ, Williams P, Adler MW. Condom use by heterosexuals attending a department of GUM: attitudes and behaviour in the light of HIV infection. Genitourin Med 1989; 65: 248–251.
23. Uribe SF, Hernandez AM, Juarez FL, Conde GCJ, Uribe ZP. Risk factors for herpes simplex virus type 2 infection among female commercial sex workers in Mexico City. Int J STD AIDS 1999; 10: 105–111.
24. Chow KY. STD control: a sentinel surveillance of the STD clinic attendees. Hong Kong Dermatol Venereol Bull 1999; 7: 52–58.
25. Rojanapityakorn W, Hanenberg R. The 100% condom programme in Thailand. AIDS 1996; 10: 1–7.
26. Lush L, Cleland J, Walt G, Mayhew S. Integrating reproductive health: myth and ideology. Bull World Health Organ 1999; 77 (9): 771–777.
© Copyright 2002 American Sexually Transmitted Diseases Association