CSIRO PUBLISHING
Sexual Health, 2015, 12, 276 http://dx.doi.org/10.1071/SH14121_CO
Corrigendum Grulich, A. E., de Visser, R. O., Badcock, P. B., Smith, A. M. A., Richters, J., Rissel, C., & Simpson, J. M. (2014). Knowledge about and experience of sexually transmissible infections in a representative sample of adults: the Second Australian Study of Health and Relationships. Sex Health 11(5), 481–494. doi: http://dx.doi.org/10.1071/SH14121. The authors wishes to advise that due to a data coding error, paragraph 2 of the right hand column on page 486 should be replaced with the following text: Questions regarding a history of STI testing are shown in Box 3. One-sixth (15%) of interviewees had undergone STI testing in the year before the interview, with women (17%) significantly more likely than men (13%) to have done so (P < 0.001). Whilst tests of blood (76%) and urine (72%) were most commonly conducted overall, vaginal swab was the most frequent test reported by women (71%). Women were significantly less likely than men to report urine, blood or other tests (all P < 0.001). Fewer respondents reported anal swabs (5%), some other test (9%) or throat swabs (6.8% of men).
Journal compilation CSIRO 2015
www.publish.csiro.au/journals/sh
CSIRO PUBLISHING
Sexual Health, 2014, 11, 481–494 http://dx.doi.org/10.1071/SH14121
Knowledge about and experience of sexually transmissible infections in a representative sample of adults: the Second Australian Study of Health and Relationships Andrew E. Grulich A,I, Richard O. de Visser B, Paul B. Badcock C,G, Anthony M. A. Smith C,H, Juliet Richters D, Chris Rissel E and Judy M. SimpsonF A
Kirby Institute, University of New South Wales, Sydney, NSW 2052, Australia. School of Psychology, Pevensey 1, University of Sussex, Falmer BN1 9QH, UK. C Australian Research Centre in Sex, Health and Society, La Trobe University, 215 Franklin Street, Melbourne, Vic. 3000, Australia. D School of Public Health and Community Medicine, University of New South Wales, Sydney, NSW 2052, Australia. E Sydney School of Public Health, Charles Perkins Centre (D17), University of Sydney, Sydney, NSW 2006, Australia. F Sydney School of Public Health, Edward Ford Building (A27), University of Sydney, Sydney, NSW 2006, Australia. G Present address: Centre for Youth Mental Health, University of Melbourne, Orygen Youth Health Research Centre, 35 Poplar Road, Parkville, Vic. 3052, Australia. H Deceased. I Corresponding author. Email: [email protected] B
Abstract. Background: Sexually transmissible infections (STIs) present a substantial public health burden, and are related to modifiable sexual behaviours. Methods: Computer-assisted telephone interviews were completed by a population-representative sample of 20 094 men and women aged 16–69 years. The overall participation rate among eligible people was 66.2%. Respondents were asked questions regarding their knowledge about, self-reported history of, and testing for STIs. Results: STI knowledge was better in women, the young, people of higher socioeconomic status, those with a variety of indicators of being at high STI risk and those with a history of receiving sex education in school. Approximately one in six men and women reported a lifetime history of an STI. A history of STI testing in the last year was reported by ~one in six (17%) women and one in eight men (13%) and higher rates of testing in women were reported in most high-risk groups. The highest rates of STI testing (61%) and HIV testing (89%) were reported in homosexual men. Conclusion: Knowledge of STI-related health consequences and transmission is improving in Australians, and rates of STI testing were relatively high but were higher in women than in men. Further increases in testing rates in both sexes will be required to facilitate the early diagnosis and treatment of STIs, which is a cornerstone of STI control. Received 25 June 2014, accepted 19 August 2014, published online 7 November 2014
Introduction The World Health Organization has estimated that ~500 million people develop a curable sexually transmissible infection (STI) annually1 and an even greater number are estimated to have a viral STI at any point in time.2 Given the very high prevalence of some STIs, particularly human papillomavirus (HPV), most sexually active people will acquire a STI at some time in their lives, although most of these are asymptomatic. Incidence is highest in the young,3 who have higher rates of partner change. Although a large majority of STIs are asymptomatic, a variety of adverse health outcomes may occur, including genital and systemic symptoms and accompanying psychological distress, Journal compilation CSIRO 2014
pregnancy complications, cancer and infertility.2 Several STIs may also increase the risk of acquiring and transmitting HIV.4 The total direct cost of STIs diagnosed in 2008 in the US was estimated to be $15.6 billion.5 In recent years, increasing incidence of many STIs has been described in many high-income settings. For example, in Australia, in the 5 years leading up to 2012, age-standardised rates of diagnosis of HIV, chlamydia, gonorrhoea and infectious syphilis all increased, by 15%, 34%, 68% and 10% respectively.6 In Europe during the period 1990–2009, annual diagnoses of chlamydia continuously increased.7 Although the overall trend for gonorrhoea and syphilis was slightly www.publish.csiro.au/journals/sh
482
Sexual Health
decreasing, there were substantial regional variations within Europe, with epidemics of syphilis and gonorrhoea in men who have sex with men in some countries.7 In Canada, rates of diagnosis of chlamydia and gonorrhoea in young people have been increasing since the 1990s, and rates of infectious syphilis have increased dramatically since ~2000.8 In the US, during 2008–2012, the incidence of chlamydia, gonorrhoea and syphilis all increased, and the magnitude of the increase was largest in males.9 In most of these countries, the recent increases come after a period of relatively low rates. Surveillance data for gonorrhoea and syphilis have been collected for more than 50 years in some sites, and these data demonstrate that rates in the late 1980s and early 1990s were at a historic low point,10 possibly related to shifts towards increased condom use after the onset of the HIV/AIDS epidemic.11 In response to the growing understanding of the health burden of STIs, and the increases in STI rates described above, the Australian Government released a National Sexually Transmissible Infections Strategy in 2005.12 This was renewed with a second strategy in 2009, and a third was released in July 2014. The over-arching goal of the strategy is to reduce transmission of STIs, through a comprehensive prevention and control response. The elements of the response include health promotion and education, providing access to clinical care, screening, partner notification, treatment, and vaccination where relevant, with monitoring of outcomes by improved surveillance. The Strategy also identifies priority populations based on the epidemiology of STIs and risk behaviour; these include young people, Aboriginal and Torres Strait Islander peoples, gay men and other men who have sex with men, and sex workers. Of particular relevance to studies of STI knowledge is that in 2009, a nationwide STI awareness campaign aimed at young people was conducted with advertisements in magazines, on the radio, online and outdoors.13 In the population-representative sample recruited for the first Australian Study of Health and Relationships (ASHR1), levels of knowledge about hepatitis C were quite good, but levels of accurate knowledge about transmission routes and health consequences were lower for a series of questions about chlamydia, gonorrhoea, herpes and genital warts.14 Characteristics associated with better knowledge included being female, speaking English at home, having a homosexual or bisexual identity, higher educational levels and income, and a history of a previous STI. Overall, ~one in five men (20.2%) and slightly fewer women (16.9%) reported ever having had a STI,15 and general practice was the most common site of first seeking treatment. STI knowledge has also been assessed in a nationally representative repeated crosssectional study of Australian secondary school students aged 13–18 years between 1997 and 2013. STI knowledge improved over this period, but was not as accurate as knowledge of HIV transmission.16,17 We examined levels of knowledge about STIs, and prevalence and correlates of self-reported history of STIs, in the second Australian Study of Health and Relationships (ASHR2), and compared results for selected outcomes with those from ASHR1.
A. E. Grulich et al.
Methods The methodology used in ASHR2 is described elsewhere.18 Briefly, between October 2012 and November 2013, computerassisted telephone interviews were completed by a representative sample of 20 094 Australian men and women aged 16–69 years from all states and territories. Ethical approval was obtained from the researchers’ host universities. Respondents were selected using dual-frame modified random digit dialling (RDD), combining directory-assisted landlinebased RDD with RDD of mobile telephones. The overall participation rate among eligible people was 66.2%. To maximise the number of interviews with people who had engaged in less common and/or more risky behaviours, all respondents who had had no sexual partners in the previous year, who had had more than one partner in the previous year, and/or who reported homosexual experience completed a long form of the survey instrument, which collected detailed data on their sexual attitudes, relationships and behaviours. Of the larger proportion of respondents who reported one partner in the previous year and no homosexual experience, 20% were randomly selected to complete the longform interview and the other 80% completed a short-form interview. As a consequence, 8577 completed the long-form interview, and 11 517 completed the short-form interview. Answers to questions that occurred only in the long-form interview are reported after weighting to reflect the sample as a whole. Respondents completed an 8-item test of knowledge about STIs and blood-borne viruses (BBVs) by indicating whether they thought each of the statements in Table 1 was true or false, or they did not know. Correct responses were summed to give a knowledge score from zero to eight. Comparisons with ASHR1 were possible because all eight items were used in that survey.14 Respondents also indicated whether they had had any of several STIs and other conditions over two time periods: (1) ever, and if so (2) within the year before being interviewed. From their response to these items, it was possible to calculate the proportions of men and women who had had any STI ever, and during the last 12 months. For calculations of ‘any STI’, candida was not included. Respondents who reported a STI in the previous year were also asked where they first went for treatment. Respondents also indicated whether they had been tested for STIs in the year before being interviewed; if so, the type of test involved; whether they had ever been tested for HIV; if so, the result of their most recent test; and whether they knew anyone with HIV/AIDS. Correlates of the main outcomes examined in this paper included a range of demographic characteristics, which were recoded to facilitate analysis. Respondents’ ages were recoded into six groups: 16–19, 20–29, 30–39, 40–49, 50–59 and 60–69 years. Languages spoken at home were recoded as English or a language other than English. Sexual identity (in answer to the question ‘Do you think of yourself as . . .’) was coded as heterosexual, homosexual, or bisexual; too few respondents stated that they were ‘queer’, ‘other’, or ‘undecided’ to allow analysis of these groups. Respondents’ reported highest completed level of education was recoded to distinguish between those who had not (yet) completed secondary school, those who had completed secondary school
Sexually transmissible infections
Sexual Health
483
Table 1. Proportion of respondents giving a correct response to questions that tested knowledge about sexually transmissible infections and blood-borne viruses Statement People who have injected drugs are at risk for hepatitis C Cold sores and genital herpes can be caused by the same virus Once a person has caught genital herpes, they will always have the virus Hepatitis B can be transmitted sexually Gonorrhoea can be transmitted through oral sex Chlamydia can lead to infertility in women Genital warts can only be spread by intercourse Chlamydia affects only women
Correct response
Men (n = 9963)
Women (n = 10 131)
OR (95% CI)A
True
90.1%
89.8%
0.96 (0.78–1.17)
True
75.3%
75.8%
1.03 (0.89–1.18)
True
67.7%
76.8%
1.58 (1.38–1.81)
True True True False False
62.4% 66.9% 62.1% 55.9% 56.6%
57.4% 68.2% 76.8% 57.8% 56.8%
0.81 1.06 2.02 1.08 1.01
(0.72–0.92) (0.94–1.20) (1.77–2.31) (0.96–1.22) (0.89–1.14)
A
Unadjusted odds ratio (OR) and 95% confidence intervals for women versus men (a higher OR reflects better knowledge in women).
and those who had completed post-secondary education. Respondents’ postcodes were used with the Accessibility/ Remoteness Index of Australia19 to determine whether respondents lived in a major city, a regional area, or a remote area (i.e. areas with relatively unrestricted, restricted, and very restricted access to goods, services and opportunities for social interaction, respectively). To approximate the gross annual household income quintiles reported by the Australian Bureau of Statistics for 2009–2010,20 respondents’ reported annual household incomes were grouped into five categories: up to $28 000, $28 001–$52 000, $52 001–$83 000, $83 001– $125 000, and more than $125 000. Respondents’ reported occupations were coded into the nine major categories of the Australian Standard Classification of Occupations,21 and then recoded to distinguish between managerial/professional occupations, white-collar occupations and blue-collar occupations. Additional correlates of STI knowledge scores examined included respondents’ reports of having had an STI both in their lifetime and in the year before being interviewed, and of having received sex education at school. Additional correlates of having had a STI and having been tested for HIV included respondents’ reports of having an Aboriginal/Torres Strait Islander background, having had more than one sexual partner in the year before being interviewed, having ever paid for sex, having ever been paid for sex, having ever injected drugs, and having received sex education at school. Finally, the main outcome variables were compared with those of ASHR1 to identify changes over time. Data were weighted to adjust for the probability of each respondent being selected for a landline or mobile phone interview, a long-form interview and (for landline participants) the number of in-scope adults in the household. Data were then weighted to match the Australian population on the basis of age, gender, area of residence (i.e. state by Accessibility/Remoteness Index of Australia category) and telephone ownership (i.e. mobile telephone only vs other), resulting in an adjusted sample of 10 056 men and 10 038 women (total 20 094). The data were thus weighted to account for the specifics of our sample design and the fact
that particular types of people were slightly over- or underrepresented. Therefore, the data presented describe the Australian population aged 16–69 years, subject to the biases noted elsewhere in this issue.18 Weighted data were analysed using the survey estimation commands in Stata Version 11.2 (StataCorp, College Station, TX, USA).22 Data were analysed using univariate logistic regression for dichotomous outcomes, including comparisons of ASHR1 and ASHR2. Correlates of continuous outcomes were identified using univariate linear regression. Percentages are presented in this article without standard errors or 95% confidence intervals. This decision was made to maximise both readability and brevity, and is in keeping with the style of other studies of a similar scope and intent.23,24 Further information about the precision of estimates is found elsewhere in this issue.18 Due to the number of participants in ASHR2, it is important to recognise that often there is the statistical power to detect even small changes as statistically significant, but these do not necessarily correspond to significant differences in a public health sense. Results Table 1 displays the proportion of men and women who correctly answered each question in relation to knowledge of STIs and BBVs. More than 50% gave the correct response for each item and respondents were most likely to correctly answer the questions about hepatitis C and herpes. The number of correct responses ranged from zero to eight; the mean score was 5.5 (95% CI: 5.4–5.6), and the median was 6. Overall, women (mean 5.6) reported significantly higher knowledge scores than did men (5.4, P < 0.001). Women were significantly more likely than men to know that genital herpes virus infection was lifelong (P < 0.001) and that chlamydia can cause female infertility (P < 0.001), but significantly less likely to know that hepatitis B can be transmitted sexually (P < 0.001). There were no sex differences in knowledge that injection drug users are at risk of infection with hepatitis C (P = 0.67), that cold sores and genital herpes are caused by the same virus (P = 0.69), that
484
Sexual Health
A. E. Grulich et al.
gonorrhoea can be transmitted via oral sex (P = 0.36), that genital warts can be spread by means other than intercourse (P = 0.20), and that chlamydia affects men and women (P = 0.89). Table 2 displays correlates of STI/BBV knowledge scores. Among men, factors associated with higher scores included being aged 20–39 years (P < 0.001), speaking English at home
Table 2. Correlates of STI/BBV knowledge among men and women aged 16–69 years Data show mean knowledge scores (out of 8), with 95% confidence intervals (CI) in parentheses. A higher score indicates better knowledge. STI, sexually transmissible infections; BBV, blood-borne viruses Correlate
Men (n = 9963)
Women (n = 10 131)
Overall
5.4 (5.3–5.5)
5.6 (5.5–5.7)
Age (years) 16–19 20–29 30–39 40–49 50–59 60–69
5.3 5.8 5.7 5.6 5.1 4.7
5.8 6.0 5.8 5.7 5.4 5.0
Language spoken at home English Other
5.5 (5.5–5.6) 3.8 (3.3–4.3)
5.7 (5.7–5.8) 3.7 (3.2–4.2)
Sexual identity Heterosexual Homosexual Bisexual
5.4 (5.3–5.5) 6.5 (6.2–6.7) 6.0 (5.6–6.4)
5.6 (5.5–5.7) 6.2 (5.9–6.6) 5.9 (5.5–6.3)
Education Lower secondary Secondary Post-secondary
4.9 (4.7–5.1) 5.5 (5.4–5.6) 5.5 (5.4–5.6)
5.1 (5.0–5.3) 5.8 (5.6–5.9) 5.7 (5.6–5.9)
Household income $125 000
5.4 5.1 5.3 5.4 5.7
5.5 5.4 5.7 5.8 5.9
Region of residence Major city Regional Remote
5.4 (5.3–5.5) 5.3 (5.2–5.4) 5.0 (4.5–5.5)
5.6 (5.5–5.7) 5.7 (5.5–5.8) 5.9 (5.3–6.4)
Occupational classification Blue collar White collar Manager/professional
5.3 (5.1–5.4) 5.6 (5.4–5.8) 5.4 (5.3–5.6)
5.3 (5.1–5.6) 5.6 (5.5–5.7) 5.7 (5.6–5.9)
Ever diagnosed with a STI No Yes
5.3 (5.2–5.4) 5.7 (5.6–5.9)
5.5 (5.4–5.6) 6.1 (6.0–6.3)
Diagnosed with a STI in the last year No 5.4 (5.3–5.5) Yes 6.0 (5.7–6.4)
5.6 (5.5–5.7) 6.4 (6.1–6.7)
Received sex education at school No 4.7 (4.5–5.8) Yes 5.7 (5.6–5.8)
5.0 (4.8–5.1) 5.8 (5.8–6.0)
(5.0–5.6) (5.5–6.0) (5.5–5.9) (5.4–5.8) (4.9–5.2) (4.5–4.9)
(5.1–5.6) (4.8–5.3) (5.1–5.5) (5.3–5.6) (5.6–5.9)
(5.5–6.0) (5.7–6.2) (5.6–6.0) (5.5–5.8) (5.2–5.5) (4.8–5.1)
(5.3–5.7) (5.2–5.6) (5.5–5.9) (5.6–6.0) (5.7–6.0)
(P < 0.001), homosexual or bisexual identity (P < 0.001), higher educational levels (P < 0.001), being in the highest income quintile P < 0.001), white collar occupations (P < 0.001), previous STI diagnosis (P < 0.001) and having received any sex education at school (P < 0.001). Knowledge was not significantly related to region of residence (P = 0.11). Among women, factors associated with higher knowledge scores included being aged 16–49 years (P < 0.001), speaking English at home (P < 0.001), homosexual identity (P < 0.001), higher educational levels (P < 0.001), higher income (P = 0.008), higher occupational level (P = 0.03), previous STI diagnosis (P < 0.001) and having received any sex education at school (P < 0.001). Knowledge was not related to women’s region of residence (P = 0.66). STI history The questions about history of STIs are shown in Box 1. Table 3 presents the proportion of respondents who had ever been diagnosed with a STI, the proportion who had been diagnosed with particular STIs, and the proportion diagnosed with an STI in the year before being interviewed. As candida/ thrush is frequently not sexually transmitted, it was not included in the calculation of lifetime or last year experience of STIs. Women were somewhat more likely than men to have ever had a STI (P = 0.07) and significantly more so in the year before being interviewed (P < 0.001). In terms of lifetime history, the most commonly reported condition among women was candida or thrush (59.5% of respondents). The most common STIs among men and women were pubic lice or crabs (5.2%), genital warts (4.0%), chlamydia (4.0%), herpes (2.6%), and gonorrhoea (1.3%). In the last year, both men and women reported that candida or thrush was most common: one in six women had candida, compared with 1% of men. STIs in the last year were reported by 1% of men, and the most common were genital herpes, chlamydia and genital warts. Among women, the most common were genital herpes and wart virus detected by a Pap smear. The questions regarding place of treatment for STIs are shown in Box 2. The data in Table 4 show that respondents who had had an STI in the year before being interviewed were most likely to seek treatment from their usual GP. Among all respondents who had a STI in the year before being interviewed, 6.1% sought treatment at a sexual health clinic, and these clinics treated 10–25% of people with recent chlamydia, genital warts, non-specific urethritis and gonorrhoea. For most of the STIs listed, respondents sought some form of treatment. Half of the women who had been diagnosed with pelvic inflammatory disease reported that they received treatment at locations other than those specified in Table 4, all of whom were treated in private hospitals, family planning clinics, or by medical specialists such as obstetricians and gynaecologists. For other STIs, the ‘other’ places of treatment were 24-h clinics, public hospitals, private hospitals, and family planning clinics. The data in Table 5 identify correlates of ever having had a STI. Among men, these were older age (P < 0.001), speaking English at home (P < 0.001), homosexual or bisexual identity (P < 0.001), higher income (P = 0.006), managerial/professional
Sexually transmissible infections
Sexual Health
Box 1.
485
Ascertainment of history of sexually transmissible infections
The next section is about sexual health. Not all the questions are about sexually transmissible infections. (If the respondent answered ‘Yes’ for lifetime history of each of the conditions, the interviewer also asked if it was in the past 12 months). In your lifetime, have you ever had any of the following? I’ll read out a list, and ask you to say ‘Yes’ or ‘No’ to each one. 1. Pubic lice or crabs? 2. Chlamydia? 3. Genital herpes? 4. Syphilis? 5. Gonorrhoea? 6. Genital warts – not including wart virus on a Pap smear? (The interviewer was instructed to include anal warts if the participant asked about it) (Questions asked of men only) 7. Non-specific urethritis or NSU (The interviewer was instructed not to include other kinds of urethritis such as those due to urinary tract infection or having a catheter inserted). 8. Anal warts? 9. Penile candida or thrush? (Questions asked of women only) 10. Wart virus (HPV) indication on a Pap smear? 11. Pelvic inflammatory disease (PID)? Pelvic infection and salpingitis are other common names. 12. Bacterial vaginosis or gardnerella? 13. Trichomoniasis or ‘trike’? 14. Vaginal candida or thrush?
Table 3. Proportion of people reporting a sexually transmissible infection (STI) diagnosis ever and in the 12 months before being interviewed Data show the percentage of respondents in each group Diagnosis
Any STI Pubic lice Genital warts Wart virus on Pap smear (women) Anal warts (men) Chlamydia Genital herpes Non-specific urethritis Pelvic inflammatory disease (women) Gonorrhoea Syphilis Bacterial vaginosis/ gardnerella (women) Trichomoniasis (women) Candida or thrushA A
Ever In the last 12 months Men Women Men Women (n = 9963) (n = 10 131) (n = 9963) (n = 10 131) 15.6 7.0 3.4 –
16.6 3.3 4.5 6.8
1.1 0.1 0.3 –
2.7
Sexual Health, 2015, 12, 276 http://dx.doi.org/10.1071/SH14121_CO
Corrigendum Grulich, A. E., de Visser, R. O., Badcock, P. B., Smith, A. M. A., Richters, J., Rissel, C., & Simpson, J. M. (2014). Knowledge about and experience of sexually transmissible infections in a representative sample of adults: the Second Australian Study of Health and Relationships. Sex Health 11(5), 481–494. doi: http://dx.doi.org/10.1071/SH14121. The authors wishes to advise that due to a data coding error, paragraph 2 of the right hand column on page 486 should be replaced with the following text: Questions regarding a history of STI testing are shown in Box 3. One-sixth (15%) of interviewees had undergone STI testing in the year before the interview, with women (17%) significantly more likely than men (13%) to have done so (P < 0.001). Whilst tests of blood (76%) and urine (72%) were most commonly conducted overall, vaginal swab was the most frequent test reported by women (71%). Women were significantly less likely than men to report urine, blood or other tests (all P < 0.001). Fewer respondents reported anal swabs (5%), some other test (9%) or throat swabs (6.8% of men).
Journal compilation CSIRO 2015
www.publish.csiro.au/journals/sh
CSIRO PUBLISHING
Sexual Health, 2014, 11, 481–494 http://dx.doi.org/10.1071/SH14121
Knowledge about and experience of sexually transmissible infections in a representative sample of adults: the Second Australian Study of Health and Relationships Andrew E. Grulich A,I, Richard O. de Visser B, Paul B. Badcock C,G, Anthony M. A. Smith C,H, Juliet Richters D, Chris Rissel E and Judy M. SimpsonF A
Kirby Institute, University of New South Wales, Sydney, NSW 2052, Australia. School of Psychology, Pevensey 1, University of Sussex, Falmer BN1 9QH, UK. C Australian Research Centre in Sex, Health and Society, La Trobe University, 215 Franklin Street, Melbourne, Vic. 3000, Australia. D School of Public Health and Community Medicine, University of New South Wales, Sydney, NSW 2052, Australia. E Sydney School of Public Health, Charles Perkins Centre (D17), University of Sydney, Sydney, NSW 2006, Australia. F Sydney School of Public Health, Edward Ford Building (A27), University of Sydney, Sydney, NSW 2006, Australia. G Present address: Centre for Youth Mental Health, University of Melbourne, Orygen Youth Health Research Centre, 35 Poplar Road, Parkville, Vic. 3052, Australia. H Deceased. I Corresponding author. Email: [email protected] B
Abstract. Background: Sexually transmissible infections (STIs) present a substantial public health burden, and are related to modifiable sexual behaviours. Methods: Computer-assisted telephone interviews were completed by a population-representative sample of 20 094 men and women aged 16–69 years. The overall participation rate among eligible people was 66.2%. Respondents were asked questions regarding their knowledge about, self-reported history of, and testing for STIs. Results: STI knowledge was better in women, the young, people of higher socioeconomic status, those with a variety of indicators of being at high STI risk and those with a history of receiving sex education in school. Approximately one in six men and women reported a lifetime history of an STI. A history of STI testing in the last year was reported by ~one in six (17%) women and one in eight men (13%) and higher rates of testing in women were reported in most high-risk groups. The highest rates of STI testing (61%) and HIV testing (89%) were reported in homosexual men. Conclusion: Knowledge of STI-related health consequences and transmission is improving in Australians, and rates of STI testing were relatively high but were higher in women than in men. Further increases in testing rates in both sexes will be required to facilitate the early diagnosis and treatment of STIs, which is a cornerstone of STI control. Received 25 June 2014, accepted 19 August 2014, published online 7 November 2014
Introduction The World Health Organization has estimated that ~500 million people develop a curable sexually transmissible infection (STI) annually1 and an even greater number are estimated to have a viral STI at any point in time.2 Given the very high prevalence of some STIs, particularly human papillomavirus (HPV), most sexually active people will acquire a STI at some time in their lives, although most of these are asymptomatic. Incidence is highest in the young,3 who have higher rates of partner change. Although a large majority of STIs are asymptomatic, a variety of adverse health outcomes may occur, including genital and systemic symptoms and accompanying psychological distress, Journal compilation CSIRO 2014
pregnancy complications, cancer and infertility.2 Several STIs may also increase the risk of acquiring and transmitting HIV.4 The total direct cost of STIs diagnosed in 2008 in the US was estimated to be $15.6 billion.5 In recent years, increasing incidence of many STIs has been described in many high-income settings. For example, in Australia, in the 5 years leading up to 2012, age-standardised rates of diagnosis of HIV, chlamydia, gonorrhoea and infectious syphilis all increased, by 15%, 34%, 68% and 10% respectively.6 In Europe during the period 1990–2009, annual diagnoses of chlamydia continuously increased.7 Although the overall trend for gonorrhoea and syphilis was slightly www.publish.csiro.au/journals/sh
482
Sexual Health
decreasing, there were substantial regional variations within Europe, with epidemics of syphilis and gonorrhoea in men who have sex with men in some countries.7 In Canada, rates of diagnosis of chlamydia and gonorrhoea in young people have been increasing since the 1990s, and rates of infectious syphilis have increased dramatically since ~2000.8 In the US, during 2008–2012, the incidence of chlamydia, gonorrhoea and syphilis all increased, and the magnitude of the increase was largest in males.9 In most of these countries, the recent increases come after a period of relatively low rates. Surveillance data for gonorrhoea and syphilis have been collected for more than 50 years in some sites, and these data demonstrate that rates in the late 1980s and early 1990s were at a historic low point,10 possibly related to shifts towards increased condom use after the onset of the HIV/AIDS epidemic.11 In response to the growing understanding of the health burden of STIs, and the increases in STI rates described above, the Australian Government released a National Sexually Transmissible Infections Strategy in 2005.12 This was renewed with a second strategy in 2009, and a third was released in July 2014. The over-arching goal of the strategy is to reduce transmission of STIs, through a comprehensive prevention and control response. The elements of the response include health promotion and education, providing access to clinical care, screening, partner notification, treatment, and vaccination where relevant, with monitoring of outcomes by improved surveillance. The Strategy also identifies priority populations based on the epidemiology of STIs and risk behaviour; these include young people, Aboriginal and Torres Strait Islander peoples, gay men and other men who have sex with men, and sex workers. Of particular relevance to studies of STI knowledge is that in 2009, a nationwide STI awareness campaign aimed at young people was conducted with advertisements in magazines, on the radio, online and outdoors.13 In the population-representative sample recruited for the first Australian Study of Health and Relationships (ASHR1), levels of knowledge about hepatitis C were quite good, but levels of accurate knowledge about transmission routes and health consequences were lower for a series of questions about chlamydia, gonorrhoea, herpes and genital warts.14 Characteristics associated with better knowledge included being female, speaking English at home, having a homosexual or bisexual identity, higher educational levels and income, and a history of a previous STI. Overall, ~one in five men (20.2%) and slightly fewer women (16.9%) reported ever having had a STI,15 and general practice was the most common site of first seeking treatment. STI knowledge has also been assessed in a nationally representative repeated crosssectional study of Australian secondary school students aged 13–18 years between 1997 and 2013. STI knowledge improved over this period, but was not as accurate as knowledge of HIV transmission.16,17 We examined levels of knowledge about STIs, and prevalence and correlates of self-reported history of STIs, in the second Australian Study of Health and Relationships (ASHR2), and compared results for selected outcomes with those from ASHR1.
A. E. Grulich et al.
Methods The methodology used in ASHR2 is described elsewhere.18 Briefly, between October 2012 and November 2013, computerassisted telephone interviews were completed by a representative sample of 20 094 Australian men and women aged 16–69 years from all states and territories. Ethical approval was obtained from the researchers’ host universities. Respondents were selected using dual-frame modified random digit dialling (RDD), combining directory-assisted landlinebased RDD with RDD of mobile telephones. The overall participation rate among eligible people was 66.2%. To maximise the number of interviews with people who had engaged in less common and/or more risky behaviours, all respondents who had had no sexual partners in the previous year, who had had more than one partner in the previous year, and/or who reported homosexual experience completed a long form of the survey instrument, which collected detailed data on their sexual attitudes, relationships and behaviours. Of the larger proportion of respondents who reported one partner in the previous year and no homosexual experience, 20% were randomly selected to complete the longform interview and the other 80% completed a short-form interview. As a consequence, 8577 completed the long-form interview, and 11 517 completed the short-form interview. Answers to questions that occurred only in the long-form interview are reported after weighting to reflect the sample as a whole. Respondents completed an 8-item test of knowledge about STIs and blood-borne viruses (BBVs) by indicating whether they thought each of the statements in Table 1 was true or false, or they did not know. Correct responses were summed to give a knowledge score from zero to eight. Comparisons with ASHR1 were possible because all eight items were used in that survey.14 Respondents also indicated whether they had had any of several STIs and other conditions over two time periods: (1) ever, and if so (2) within the year before being interviewed. From their response to these items, it was possible to calculate the proportions of men and women who had had any STI ever, and during the last 12 months. For calculations of ‘any STI’, candida was not included. Respondents who reported a STI in the previous year were also asked where they first went for treatment. Respondents also indicated whether they had been tested for STIs in the year before being interviewed; if so, the type of test involved; whether they had ever been tested for HIV; if so, the result of their most recent test; and whether they knew anyone with HIV/AIDS. Correlates of the main outcomes examined in this paper included a range of demographic characteristics, which were recoded to facilitate analysis. Respondents’ ages were recoded into six groups: 16–19, 20–29, 30–39, 40–49, 50–59 and 60–69 years. Languages spoken at home were recoded as English or a language other than English. Sexual identity (in answer to the question ‘Do you think of yourself as . . .’) was coded as heterosexual, homosexual, or bisexual; too few respondents stated that they were ‘queer’, ‘other’, or ‘undecided’ to allow analysis of these groups. Respondents’ reported highest completed level of education was recoded to distinguish between those who had not (yet) completed secondary school, those who had completed secondary school
Sexually transmissible infections
Sexual Health
483
Table 1. Proportion of respondents giving a correct response to questions that tested knowledge about sexually transmissible infections and blood-borne viruses Statement People who have injected drugs are at risk for hepatitis C Cold sores and genital herpes can be caused by the same virus Once a person has caught genital herpes, they will always have the virus Hepatitis B can be transmitted sexually Gonorrhoea can be transmitted through oral sex Chlamydia can lead to infertility in women Genital warts can only be spread by intercourse Chlamydia affects only women
Correct response
Men (n = 9963)
Women (n = 10 131)
OR (95% CI)A
True
90.1%
89.8%
0.96 (0.78–1.17)
True
75.3%
75.8%
1.03 (0.89–1.18)
True
67.7%
76.8%
1.58 (1.38–1.81)
True True True False False
62.4% 66.9% 62.1% 55.9% 56.6%
57.4% 68.2% 76.8% 57.8% 56.8%
0.81 1.06 2.02 1.08 1.01
(0.72–0.92) (0.94–1.20) (1.77–2.31) (0.96–1.22) (0.89–1.14)
A
Unadjusted odds ratio (OR) and 95% confidence intervals for women versus men (a higher OR reflects better knowledge in women).
and those who had completed post-secondary education. Respondents’ postcodes were used with the Accessibility/ Remoteness Index of Australia19 to determine whether respondents lived in a major city, a regional area, or a remote area (i.e. areas with relatively unrestricted, restricted, and very restricted access to goods, services and opportunities for social interaction, respectively). To approximate the gross annual household income quintiles reported by the Australian Bureau of Statistics for 2009–2010,20 respondents’ reported annual household incomes were grouped into five categories: up to $28 000, $28 001–$52 000, $52 001–$83 000, $83 001– $125 000, and more than $125 000. Respondents’ reported occupations were coded into the nine major categories of the Australian Standard Classification of Occupations,21 and then recoded to distinguish between managerial/professional occupations, white-collar occupations and blue-collar occupations. Additional correlates of STI knowledge scores examined included respondents’ reports of having had an STI both in their lifetime and in the year before being interviewed, and of having received sex education at school. Additional correlates of having had a STI and having been tested for HIV included respondents’ reports of having an Aboriginal/Torres Strait Islander background, having had more than one sexual partner in the year before being interviewed, having ever paid for sex, having ever been paid for sex, having ever injected drugs, and having received sex education at school. Finally, the main outcome variables were compared with those of ASHR1 to identify changes over time. Data were weighted to adjust for the probability of each respondent being selected for a landline or mobile phone interview, a long-form interview and (for landline participants) the number of in-scope adults in the household. Data were then weighted to match the Australian population on the basis of age, gender, area of residence (i.e. state by Accessibility/Remoteness Index of Australia category) and telephone ownership (i.e. mobile telephone only vs other), resulting in an adjusted sample of 10 056 men and 10 038 women (total 20 094). The data were thus weighted to account for the specifics of our sample design and the fact
that particular types of people were slightly over- or underrepresented. Therefore, the data presented describe the Australian population aged 16–69 years, subject to the biases noted elsewhere in this issue.18 Weighted data were analysed using the survey estimation commands in Stata Version 11.2 (StataCorp, College Station, TX, USA).22 Data were analysed using univariate logistic regression for dichotomous outcomes, including comparisons of ASHR1 and ASHR2. Correlates of continuous outcomes were identified using univariate linear regression. Percentages are presented in this article without standard errors or 95% confidence intervals. This decision was made to maximise both readability and brevity, and is in keeping with the style of other studies of a similar scope and intent.23,24 Further information about the precision of estimates is found elsewhere in this issue.18 Due to the number of participants in ASHR2, it is important to recognise that often there is the statistical power to detect even small changes as statistically significant, but these do not necessarily correspond to significant differences in a public health sense. Results Table 1 displays the proportion of men and women who correctly answered each question in relation to knowledge of STIs and BBVs. More than 50% gave the correct response for each item and respondents were most likely to correctly answer the questions about hepatitis C and herpes. The number of correct responses ranged from zero to eight; the mean score was 5.5 (95% CI: 5.4–5.6), and the median was 6. Overall, women (mean 5.6) reported significantly higher knowledge scores than did men (5.4, P < 0.001). Women were significantly more likely than men to know that genital herpes virus infection was lifelong (P < 0.001) and that chlamydia can cause female infertility (P < 0.001), but significantly less likely to know that hepatitis B can be transmitted sexually (P < 0.001). There were no sex differences in knowledge that injection drug users are at risk of infection with hepatitis C (P = 0.67), that cold sores and genital herpes are caused by the same virus (P = 0.69), that
484
Sexual Health
A. E. Grulich et al.
gonorrhoea can be transmitted via oral sex (P = 0.36), that genital warts can be spread by means other than intercourse (P = 0.20), and that chlamydia affects men and women (P = 0.89). Table 2 displays correlates of STI/BBV knowledge scores. Among men, factors associated with higher scores included being aged 20–39 years (P < 0.001), speaking English at home
Table 2. Correlates of STI/BBV knowledge among men and women aged 16–69 years Data show mean knowledge scores (out of 8), with 95% confidence intervals (CI) in parentheses. A higher score indicates better knowledge. STI, sexually transmissible infections; BBV, blood-borne viruses Correlate
Men (n = 9963)
Women (n = 10 131)
Overall
5.4 (5.3–5.5)
5.6 (5.5–5.7)
Age (years) 16–19 20–29 30–39 40–49 50–59 60–69
5.3 5.8 5.7 5.6 5.1 4.7
5.8 6.0 5.8 5.7 5.4 5.0
Language spoken at home English Other
5.5 (5.5–5.6) 3.8 (3.3–4.3)
5.7 (5.7–5.8) 3.7 (3.2–4.2)
Sexual identity Heterosexual Homosexual Bisexual
5.4 (5.3–5.5) 6.5 (6.2–6.7) 6.0 (5.6–6.4)
5.6 (5.5–5.7) 6.2 (5.9–6.6) 5.9 (5.5–6.3)
Education Lower secondary Secondary Post-secondary
4.9 (4.7–5.1) 5.5 (5.4–5.6) 5.5 (5.4–5.6)
5.1 (5.0–5.3) 5.8 (5.6–5.9) 5.7 (5.6–5.9)
Household income $125 000
5.4 5.1 5.3 5.4 5.7
5.5 5.4 5.7 5.8 5.9
Region of residence Major city Regional Remote
5.4 (5.3–5.5) 5.3 (5.2–5.4) 5.0 (4.5–5.5)
5.6 (5.5–5.7) 5.7 (5.5–5.8) 5.9 (5.3–6.4)
Occupational classification Blue collar White collar Manager/professional
5.3 (5.1–5.4) 5.6 (5.4–5.8) 5.4 (5.3–5.6)
5.3 (5.1–5.6) 5.6 (5.5–5.7) 5.7 (5.6–5.9)
Ever diagnosed with a STI No Yes
5.3 (5.2–5.4) 5.7 (5.6–5.9)
5.5 (5.4–5.6) 6.1 (6.0–6.3)
Diagnosed with a STI in the last year No 5.4 (5.3–5.5) Yes 6.0 (5.7–6.4)
5.6 (5.5–5.7) 6.4 (6.1–6.7)
Received sex education at school No 4.7 (4.5–5.8) Yes 5.7 (5.6–5.8)
5.0 (4.8–5.1) 5.8 (5.8–6.0)
(5.0–5.6) (5.5–6.0) (5.5–5.9) (5.4–5.8) (4.9–5.2) (4.5–4.9)
(5.1–5.6) (4.8–5.3) (5.1–5.5) (5.3–5.6) (5.6–5.9)
(5.5–6.0) (5.7–6.2) (5.6–6.0) (5.5–5.8) (5.2–5.5) (4.8–5.1)
(5.3–5.7) (5.2–5.6) (5.5–5.9) (5.6–6.0) (5.7–6.0)
(P < 0.001), homosexual or bisexual identity (P < 0.001), higher educational levels (P < 0.001), being in the highest income quintile P < 0.001), white collar occupations (P < 0.001), previous STI diagnosis (P < 0.001) and having received any sex education at school (P < 0.001). Knowledge was not significantly related to region of residence (P = 0.11). Among women, factors associated with higher knowledge scores included being aged 16–49 years (P < 0.001), speaking English at home (P < 0.001), homosexual identity (P < 0.001), higher educational levels (P < 0.001), higher income (P = 0.008), higher occupational level (P = 0.03), previous STI diagnosis (P < 0.001) and having received any sex education at school (P < 0.001). Knowledge was not related to women’s region of residence (P = 0.66). STI history The questions about history of STIs are shown in Box 1. Table 3 presents the proportion of respondents who had ever been diagnosed with a STI, the proportion who had been diagnosed with particular STIs, and the proportion diagnosed with an STI in the year before being interviewed. As candida/ thrush is frequently not sexually transmitted, it was not included in the calculation of lifetime or last year experience of STIs. Women were somewhat more likely than men to have ever had a STI (P = 0.07) and significantly more so in the year before being interviewed (P < 0.001). In terms of lifetime history, the most commonly reported condition among women was candida or thrush (59.5% of respondents). The most common STIs among men and women were pubic lice or crabs (5.2%), genital warts (4.0%), chlamydia (4.0%), herpes (2.6%), and gonorrhoea (1.3%). In the last year, both men and women reported that candida or thrush was most common: one in six women had candida, compared with 1% of men. STIs in the last year were reported by 1% of men, and the most common were genital herpes, chlamydia and genital warts. Among women, the most common were genital herpes and wart virus detected by a Pap smear. The questions regarding place of treatment for STIs are shown in Box 2. The data in Table 4 show that respondents who had had an STI in the year before being interviewed were most likely to seek treatment from their usual GP. Among all respondents who had a STI in the year before being interviewed, 6.1% sought treatment at a sexual health clinic, and these clinics treated 10–25% of people with recent chlamydia, genital warts, non-specific urethritis and gonorrhoea. For most of the STIs listed, respondents sought some form of treatment. Half of the women who had been diagnosed with pelvic inflammatory disease reported that they received treatment at locations other than those specified in Table 4, all of whom were treated in private hospitals, family planning clinics, or by medical specialists such as obstetricians and gynaecologists. For other STIs, the ‘other’ places of treatment were 24-h clinics, public hospitals, private hospitals, and family planning clinics. The data in Table 5 identify correlates of ever having had a STI. Among men, these were older age (P < 0.001), speaking English at home (P < 0.001), homosexual or bisexual identity (P < 0.001), higher income (P = 0.006), managerial/professional
Sexually transmissible infections
Sexual Health
Box 1.
485
Ascertainment of history of sexually transmissible infections
The next section is about sexual health. Not all the questions are about sexually transmissible infections. (If the respondent answered ‘Yes’ for lifetime history of each of the conditions, the interviewer also asked if it was in the past 12 months). In your lifetime, have you ever had any of the following? I’ll read out a list, and ask you to say ‘Yes’ or ‘No’ to each one. 1. Pubic lice or crabs? 2. Chlamydia? 3. Genital herpes? 4. Syphilis? 5. Gonorrhoea? 6. Genital warts – not including wart virus on a Pap smear? (The interviewer was instructed to include anal warts if the participant asked about it) (Questions asked of men only) 7. Non-specific urethritis or NSU (The interviewer was instructed not to include other kinds of urethritis such as those due to urinary tract infection or having a catheter inserted). 8. Anal warts? 9. Penile candida or thrush? (Questions asked of women only) 10. Wart virus (HPV) indication on a Pap smear? 11. Pelvic inflammatory disease (PID)? Pelvic infection and salpingitis are other common names. 12. Bacterial vaginosis or gardnerella? 13. Trichomoniasis or ‘trike’? 14. Vaginal candida or thrush?
Table 3. Proportion of people reporting a sexually transmissible infection (STI) diagnosis ever and in the 12 months before being interviewed Data show the percentage of respondents in each group Diagnosis
Any STI Pubic lice Genital warts Wart virus on Pap smear (women) Anal warts (men) Chlamydia Genital herpes Non-specific urethritis Pelvic inflammatory disease (women) Gonorrhoea Syphilis Bacterial vaginosis/ gardnerella (women) Trichomoniasis (women) Candida or thrushA A
Ever In the last 12 months Men Women Men Women (n = 9963) (n = 10 131) (n = 9963) (n = 10 131) 15.6 7.0 3.4 –
16.6 3.3 4.5 6.8
1.1 0.1 0.3 –
2.7
