Biomedical subjects

A J Copas

Publications and source records attributed to A J Copas.

At least 19 recordsLinked to original sources

PubMed2006

A comparison of the population diagnosed with chlamydia in primary care with that diagnosed in sexual health clinics: implications for a national screening programme.

OBJECTIVES: To compare demographic, behavioural and HIV testing characteristics of individuals diagnosed with chlamydia infection in primary care with those in genitourinary medicine clinics, in the absence of a screening programme. The aim was to explore the current and potential contribution of primary care to the control of chlamydia. STUDY DESIGN AND METHODS: We analysed data on individuals who reported one or more chlamydia diagnoses in the past 5 years in a large probability sample survey of the resident, UK general population aged 16-44 years. Estimates were weighted and odds ratios calculated. RESULTS: Women diagnosed in primary care reported fewer sexual partners, and were less likely to have had an HIV test in the past 5 years than their counterparts diagnosed in genitourinary medicine clinics. Age, ethnicity, social class, educational attainment and urbanization of area of residence did not differ between the two groups. Too few men were diagnosed in primary care to allow for such a comparison. CONCLUSIONS: Primary care already diagnoses a large number of women with chlamydia infection, who may perceive themselves as low risk through age or sexual behaviour, yet are likely to comprise a substantial proportion of all infections. Few men are diagnosed in primary care. These groups need to be strategically targeted in the context of a future chlamydia screening programme, which will focus on the screening of younger women at high risk, and in which the role of primary care is still in development.

Adolescent↗

PubMed2006

Factors associated with heterosexual transmission of HIV to individuals without a major risk within England, Wales, and Northern Ireland: a comparison with national probability surveys.

OBJECTIVE: To compare the prevalence of HIV risk behaviours reported by heterosexuals without major risks for HIV acquisition diagnosed with HIV in England, Wales, and Northern Ireland, with those of the heterosexual general population. METHODS: Demographic and sexual behaviour data for heterosexuals (without major risks for HIV) aged 16-44 from the British National Surveys of Sexual Attitudes and Lifestyles in 1990 and 2000 were compared to 139 HIV infected individuals without major risks for HIV aged 16+ at diagnosis, interviewed between December 1987 and March 2003. Comparisons were made overall and separately for the early and late 1990s. RESULTS: HIV infected heterosexual men without major risks were significantly more likely to report first heterosexual intercourse before age 16 (adjusted odds ratio (AOR): 2.75; 95% confidence interval (CI),1.65 to 4.57), while both HIV infected heterosexual men and women reported greater partner numbers (AOR: men 2.44; CI, 1.4 to 4.05; AOR women 2.17; CI, 1.28 to 3.66) and never using condoms (AOR: men 7.97; CI,4.78 to 13.3; AOR women 3.95; CI, 2.30 to 6.80) than the heterosexual general population. There is evidence to suggest that the two groups were more similar in their reporting of partner numbers in the late 1990s relative to the early 1990s. CONCLUSION: Heterosexual HIV infected individuals without major risks for HIV acquisition in England, Wales, and Northern Ireland are significantly more likely to report high risk sexual behaviours relative to the British heterosexual general population. However, these differences may have decreased over time, at least for the number of partners. Effective sexual health promotion, including the continued promotion of condom use, would impact on the rising rates of STI diagnoses and also prevent HIV transmission among the heterosexual general population.

Adolescent↗

PubMed2006

Refocusing health promotion for syphilis prevention: results of a case-control study of men who have sex with men on England's south coast.

BACKGROUND: Prevention interventions have had little impact on syphilis outbreaks among men who have sex with men (MSM) and diagnosis rates continue to rise rapidly. Detailed studies of the determinants of syphilis transmission are needed to inform new prevention interventions. OBJECTIVE: To investigate factors associated with recent syphilis diagnosis and recommend strategies for improved prevention interventions. METHODS: A case-control study of MSM attending genitourinary medicine (GUM) and HIV outpatient clinics. Cases were MSM testing positive for early syphilis, based on either laboratory or microscopy results, with those testing negative being controls. All participants completed the same anonymous questionnaire covering demographics, lifestyle, sexual behaviour, and sexual partnerships. RESULTS: 50 cases and 108 controls returned questionnaires. Syphilis diagnosis was significantly associated with sexually transmitted infection history, recent recreational drug use, receptive anal sex practices, but not insertive ones, higher numbers of oral sex partners, but not specific oral sex practices. Overall, there were no differences between HIV positive and HIV negative/untested men in reporting of sexual behaviours or partnership combinations. The use of public sex settings (backrooms, saunas, "cruising grounds," etc) was reported by 68% of all participants and not significantly associated with syphilis diagnosis. CONCLUSIONS: Many key behavioural and partnership risk factors for syphilis are also risk behaviours for HIV transmission and point to the need for integrated strategies that tackle the two infections together. Simplified procedures for syphilis screening should be available in GUM clinical settings, along with targeted community outreach prevention interventions.

Adult↗

PubMed2006

Men who have sex with men: a comparison of a probability sample survey and a community based study.

We compared characteristics of men who have sex with men (MSM) in a probability sample survey with a community based study in London. The majority of men in both surveys reported male sex partner(s) in the last year but MSM recruited through the population based survey had lower levels of HIV risk behaviour, reported fewer sexually transmitted infections and HIV testing than those recruited from gay venues. Community samples are likely to overestimate levels of risk behaviour among all MSM.

Adolescent↗

PubMed2006

Behavioural predictors of subsequent hepatitis C diagnosis in a UK clinic sample of HIV positive men who have sex with men.

OBJECTIVE: To explore the associations between self reported high risk sexual behaviours and subsequent diagnosis with hepatitis C virus (HCV) infection. METHODS: The Sex, Health and Anti-Retrovirals Project (SHARP) was a cross sectional study of sexual behaviour in HIV positive, men who have sex with men (MSM) attending a London outpatient clinic. From July 1999 to August 2000 participants completed a computer assisted self interview questionnaire (CASI) on recent sexual behaviour, recreational drug use, and detailed reporting of the last two sexual episodes involving different partners. Results were combined with routine clinic data and subsequent testing for HCV up to 21 April 2005. A new HCV diagnosis was defined as anti-HCV antibody seroconversion or positive HCV RNA following a previous negative. Incident rate ratios (IRR) were calculated using Poisson regression in Stata (version 9). Men contributed time at risk from interview until either their diagnosis or their last negative test result. RESULTS: Of the 422 men who completed questionnaires, 308 (73%) had sufficient clinical and HCV testing data available for analysis. Incident HCV infection was identified in 11 men. Unprotected anal intercourse, more than 30 sex partners in the past year, higher numbers of new anal sex partners, rimming (oro-anal sex), fisting, use of sex toys, and intranasal recreational drug use were associated with HCV. In multivariate analysis only fisting remained associated with HCV (adjusted IRR 6.27, p = 0.005). CONCLUSIONS: In this study of HIV positive MSM, fisting is strongly associated with HCV infection. Where individuals report high risk sexual behaviours, clinicians should offer appropriate testing for HCV infection.

Adult↗

PubMed2006

Who uses condoms with whom? Evidence from national probability sample surveys.

OBJECTIVES: To explore the changing pattern of condom use from 1990 to 2000; to identify sociodemographic and behavioural factors associated with condom use; and reasons for condom use in 2000. METHODS: Large probability sample surveys administered among those resident in Britain aged 16-44 (n = 13 765 in 1990, n = 11 161 in 2000). Face to face interviews with self completion components collected sociodemographic, behavioural, and attitudinal data. RESULTS: Condom use in the past year among sexually active 16-24 year old men increased from 61.0% in 1990 to 82.1% in 2000 (p<0.0001), and from 42.0% to 63.2% (p<0.0001) among women of the same age, with smaller increases among older age groups. Among individuals reporting at least two partners in the previous 4 week period, approximately two thirds reported inconsistent or no condom use (63.1% (95% CI 55.9% to 69.8%) of the men and 68.5% (95% CI 57.6% to 77.7%) of the women). CONCLUSIONS: Rates of condom use increased substantially between 1990 and 2000, particularly among young people. However, inconsistent condom use by individuals with high rates of partner acquisition may contribute significantly to the recent resurgence in STIs. This group is an important target for intensive and specific sexual health interventions.

Adolescent↗

PubMed2006

Estimating adult HIV prevalence in the UK in 2003: the direct method of estimation.

BACKGROUND: Estimates of the total number of prevalent HIV infections attributable to the major routes of infection make an important contribution to public health policy, as they are used for planning services. METHODS: In the UK, estimates were derived through the "direct method" which estimated the total number of diagnosed and undiagnosed HIV infections in the population. The direct method has been improved over a number of years since first used in 1994, as further data became available such as the inclusion of newly available behavioural survey data both from the National Survey of Sexual Attitudes and Lifestyles (Natsal 2000) and community surveys of men who have sex with men (MSM). These data were used to re-estimate numbers of people unaware of their infection and provided ethnic breakdowns within behavioural categories. The total population was divided into 10 mutually exclusive behavioural categories relevant to HIV risk in the UK-for example, MSM and injecting drug users. Estimates of the population size within each group were derived from Natsal 2000 and National Statistics mid-year population estimates. The total number of undiagnosed HIV infections was calculated by multiplying the undiagnosed HIV prevalence for each group, derived from the Unlinked Anonymous HIV Prevalence Monitoring Programme surveys (UAPMP), by the population size. These estimates were then added to the prevalent diagnosed HIV infections within each group derived from the national census of diagnosed HIV infections, the Survey of Prevalent HIV Infections Diagnosed (SOPHID). The estimates were then adjusted to include all adults in the UK. Because undiagnosed HIV prevalence estimates were not available for each of the behavioural categories, the UAPMP prevalence estimates were adjusted using available data to provide the best estimates for each group. RESULTS: It is estimated that 53,000 individuals are infected with HIV in the UK in 2003, of whom 27% were unaware of their infection. Of the total of 53,000, an estimated 26,000 were among heterosexually infected and 24,500 among MSM. CONCLUSION: The direct method uses an explicit framework and data from different components of the HIV surveillance system to estimate HIV prevalence in the UK, allowing for a comprehensive picture of the epidemic.

Adolescent↗

PubMed2005

The effects of urethritis on seminal plasma HIV-1 RNA loads in homosexual men not receiving antiretroviral therapy.

OBJECTIVES: To examine the effects of urethritis and its treatment on semen plasma HIV-1 RNA load in HIV-1 infected men not receiving antiretroviral therapy (ART), in a developed world setting. METHODS: Prospective case-control study. HIV-1 infected homosexual men, not receiving ART for at least 3 months, with (cases) and without (controls) symptomatic urethritis, were recruited. Blood and semen were collected for HIV-1 RNA quantification at presentation, before antibiotic therapy, and at 1 and 2 weeks. RESULTS: 20 cases (13 gonococcal urethritis and/or chlamydial urethritis (GU/CU) and seven non-specific urethritis (NSU)) and 35 controls were recruited. Baseline characteristics and blood plasma viral load were similar in cases and controls. Mean log semen plasma viral loads were higher among those with GU/CU compared with controls (4.27 log versus 3.55 log respectively; p = 0.01) but not in those with NSU (3.48 log; p = 0.82). Following antibiotics, semen plasma viral loads fell by a mean of 0.25 log (95% CI: 0.03 to 0.47) in those with GU/CU. Semen plasma viral loads did not fall in those with NSU. CONCLUSIONS: In this study of 55 homosexual men not on ART, semen plasma viral loads were approximately fivefold higher in those with GU/CU, but not NSU, compared with controls. Treatment of GU/CU resulted in reduction in semen plasma viral loads. Although absolute effects were considerably lower when compared to patients from a similar study from sub-Saharan Africa, our data demonstrate the potential for sexually transmitted infections to enhance HIV infectivity of men not receiving ART in the developed world.

Adult↗

PubMed2005

The effects of early syphilis on CD4 counts and HIV-1 RNA viral loads in blood and semen.

OBJECTIVE: To examine the effect of early syphilis on blood and semen plasma HIV-1 viral loads and CD4 counts. METHODS: In a retrospective case-control study, blood plasma HIV-1 viral loads and CD4 counts in cases during early syphilis (n = 63, 27 receiving antiretroviral therapy) were compared to those before and after syphilis and with controls with non-systemic acute sexually transmitted infections (STI) (n = 104, 39 receiving antiretroviral therapy). In a prospective substudy in those not receiving antiretroviral therapy, semen plasma viral loads during early syphilis (n = 13) were compared with those 1 month, 3 months, and 6 months after treatment for syphilis and with controls with no STIs (n = 20). RESULTS: Retrospective study: CD4 counts were similar in cases (median 410, n = 139 counts) during early syphilis compared to before (485, n = 80) and after (475, n = 88). In a secondary analysis, a drop in CD4 count (21%) among those with early latent syphilis was observed compared with controls. Blood plasma viral loads did not change significantly overall or in those with primary, secondary, or early latent syphilis. Effects were similar on or off antiretroviral therapy. Prospective study: blood and semen viral loads were slightly higher in cases compared with controls but treatment of early syphilis did not reduce either. CONCLUSIONS: We detected no association between early syphilis and changes in blood or semen viral load or CD4 count. Increased HIV-1 infectivity associated with early syphilis is unlikely to be associated with increased levels of HIV-1 RNA in blood or semen.

CD4 Lymphocyte Count↗

PubMed2005

Factors associated with HIV testing among black Africans in Britain.

OBJECTIVE: To describe the factors associated with HIV testing among heterosexual black Africans aged 16-44 years living in Britain. DESIGN: We analysed data from the second British National Survey of Sexual Attitudes and Lifestyles (Natsal 2000)-a stratified national probability sample survey conducted between 1999-2001. Data from Natsal's main and ethnic minority boost (EMB) samples were analysed. Multivariate analysis was performed using complex survey functions to account for the clustered, stratified, and differential selection probabilities inherent within the survey. RESULTS: A total of 385 (216 women and 169 men) black African respondents were included in the study. 44.0% women and 36.4% men reported ever having had an HIV test. In univariate analysis, HIV testing was associated with being born abroad (OR 3.63), having a new partner(s) from abroad in past 5 years (OR 2.88), and attending a GUM clinic (OR 3.27) among men; and educational attainment (OR 3.50), perception of "not very much" personal risk of HIV (OR 2.75), and attending a GUM clinic (OR 2.91) among women. After adjusting for potential confounders, an increased likelihood of HIV testing was associated with being in the United Kingdom less than 5 years relative to being UK born (adjusted OR 9.49), and ever attending a GUM clinic (adj OR 5.53), for men; and educational attainment (adj OR 4.13), and low perception of HIV risk (adj OR 2.77) for women. CONCLUSIONS: Black Africans appear to have relatively high rates of HIV testing reflecting, at least partially, awareness of risk behaviours and potential exposure to HIV. Nevertheless, there remains substantial potential for health gain and innovative approaches are required to further increase timely HIV testing.

Adolescent↗

PubMed2005

Who reports sexual function problems? Empirical evidence from Britain's 2000 National Survey of Sexual Attitudes and Lifestyles.

OBJECTIVE: To identify sociodemographic, sexual, and health behavioural and attitudinal factors associated with reporting sexual function problems. METHODS: A probability sample survey of 11 161 men and women aged 16-44 years resident in Britain in 2000. Data collected by a combination of computer assisted face to face and self interviewing. Outcomes were self report of a range of sexual function problems, considered as "any problems" (1+ lasting 1+ months in the past year) and "persistent problems" (1+ lasting 6+ months in the past year), and associations with sociodemographic, behavioural, and attitudinal variables. RESULTS: Both "any" and "persistent" sexual function problems were more commonly reported by women than men. A variety of sociodemographic factors were associated with both measures but differed by gender. For example, the adjusted odds ratio (AOR) for reporting any problems for married v single respondents was 0.70 (95% confidence interval (CI) 0.57 to 0.87) v 1.31 (95% CI 1.10 to 1.56) for men and women, respectively. Sexual behaviours significantly associated with reporting sexual function problems included competence at first sex, paying for sex in the past 5 years, number of occasions of sex and masturbation, both in the past 4 weeks. For men (only), reporting STI diagnosis(es) was significantly associated with reporting "any" problems (AOR 2.1, 95% CI 1.4 to 3.2) and "persistent" problems (AOR 2.1, 95% CI 1.1 to 3.9). Both measures were significantly more likely among men and women who reported communication difficulties with their partners, with AORs in excess of 1.9. CONCLUSIONS: Sexual fulfilment is an important part of sexual health. Understanding factors associated with reporting sexual problems, and recognising that such factors maybe partnership specific, is an important step towards improving our understanding of sexual function and thus improving the provision of care and support available.

Adolescent↗

PubMed2004

Polymorph count for predicting non-gonococcal urethral infection: a model using Chlamydia trachomatis diagnosed by ligase chain reaction.

BACKGROUND/OBJECTIVES: The criteria for the diagnosis of non-gonococcal urethritis (NGU) on a Gram stained urethral smear are derived from previous studies which used culture as a diagnostic test for Chlamydia trachomatis. Our objectives were (1). to re-assess the relation between urethral polymorph count and C trachomatis infection, using ligase chain reaction (LCR) as the diagnostic test; and (2). to assess other possible predictors of C trachomatis infection such as symptoms, signs, demographic and behavioural variables. METHODS: We collected data from 363 men consecutively attending a genitourinary medicine clinic (excluding those with gonorrhoea and follow up visits) who had a urethral smear and a urethral LCR test for C trachomatis. The sensitivity and specificity of a discrete cut off in urethral polymorphonuclear leucocyte (PMNL) count as a diagnostic test for chlamydia urethritis were calculated. The associations between other variables, such as age and symptoms, and this infection were also estimated. RESULTS: 8% of men had C trachomatis infection and 26% of men had a PMNL count of 5 or more. Of those men with chlamydia 37% did not have NGU; 20% of men with NGU had chlamydia. Adjusted odds ratios for risk of chlamydial infection were significant for age less than 30 relative to 40 years and over (adj OR 13.6; 95% confidence interval 1.69 to 110), a PMNL count of 20 or more (6.56; 2.15 to 20.0), a PMNL count of 5-19 (3.59; 1.41 to 9.15), and the symptom of dysuria (3.27; 1.32 to 8.08). However a PMNL count of 5 or more was only 63% sensitive and 77% specific for C trachomatis infection. No association between sexual behaviour and chlamydial infection was found in this setting. CONCLUSIONS: The PMNL count is associated with presence of chlamydial infection but a large proportion of men with chlamydia have PMNL counts below the recommended cut off for a diagnosis of NSU. Lower age and the presence of symptoms may be as predictive as the urethral polymorph count for chlamydial urethritis and possibly for other urethral infections.

Adolescent↗

PubMed2004

The impact of pump-priming funding on genitourinary medicine and modernization of services.

Genitourinary (GU) medicine services are under increasing pressure due to increased workload. The Department of Health responded to this crisis by allocating pump-priming funding of ?5 million direct to GU medicine clinics in 2002-03. A survey was performed of all clinics in England to determine if funding was received, its utilization and the extent of modernization of services. Response rate was 71% (147 of 206 clinics), with 95% (140) receiving their allocation. Additional clinics were instated by 54% (74/137) and of these 51% (35/69) had thus reduced their waiting times. Extensive modernization of services was under way, with 89% (130/146) reducing proportion of follow-up attendances, 87% (127/146) extending the nurse role and the majority of clinics looking at developing or extending their clinical networks. This study has shown the direct benefit of increased funding allocated to GU medicine and the extent of modernization under way.

Ambulatory Care Facilities↗

PubMed2003

Effect of social exclusion on the risk of teenage pregnancy: development of hypotheses using baseline data from a randomised trial of sex education.

STUDY OBJECTIVE: The UK government argues that "social exclusion" increases risk of teenage pregnancy and that educational factors may be dimensions of such exclusion. The evidence cited by the government is limited to reporting that socioeconomic disadvantage and educational attainment influence risk. Evidence regarding young people's attitude to school is not cited, and there is a lack of research concerning the UK. This paper develops hypotheses on the relation between socioeconomic and educational dimensions of social exclusion, and risk of teenage pregnancy, by examining whether dislike of school and socioeconomic disadvantage are associated with cognitive/behavioural risk measures among 13/14 year olds in English schools. DESIGN: Analysis of data from the baseline survey of a study of sex education. SETTING AND PARTICIPANTS: 13/14 year old school students from south east England. MAIN RESULTS: The results indicate that socioeconomic disadvantage and dislike of school are associated with various risk factors, each with a different pattern. Those disliking school, despite having comparable knowledge to those liking school, were more likely to have sexual intercourse, expect sexual intercourse by age 16, and expect to be parents by the age of 20. For most associations, the crude odds ratios (ORs) and the ORs adjusted for the other exposure were similar, suggesting that inter-confounding between exposures was limited. CONCLUSIONS: It is hypothesised that in determining risk of teenage pregnancy, the two exposures are independent. Those disliking school might be at greater risk of teenage pregnancy because they are more likely to see teenage pregnancy as inevitable or positive.

Adolescent↗

PubMed2003

Is use of antiretroviral therapy among homosexual men associated with increased risk of transmission of HIV infection?

BACKGROUND/OBJECTIVE: There is concern that use of highly active antiretroviral therapy (HAART) may be linked to increased sexual risk behaviour among homosexual men. We investigated sexual risk behaviour in HIV positive homosexual men and the relation between use of HAART and risk of HIV transmission. METHODS: A cross sectional study of 420 HIV positive homosexual men attending a London outpatient clinic. Individual data were collected from computer assisted self interview, STI screening, and clinical and laboratory databases. RESULTS: Among all men, sexual behaviour associated with a high risk of HIV transmission was commonly reported. The most frequently reported type of partnership was casual partners only, and 22% reported unprotected anal intercourse with one or more new partners in the past month. Analysis of crude data showed that men on HAART had fewer sexual partners (median 9 versus 20, p=0.28), less unprotected anal intercourse (for example, 36% versus 27% had insertive unprotected anal intercourse with a new partner in the past year, p=0.03) and fewer acute sexually transmitted infections (33% versus 19%, p=0.004 in the past 12 months) than men not on HAART. Self assessed health status was similar between the two groups: 72% on HAART and 75% not on HAART rated their health as very or fairly good, (p=0.55). In multivariate analysis, differences in sexual risk behaviour between men on HAART and men not on HAART were attenuated by adjustment for age, time since HIV infection. CD4 count and self assessed health status. CONCLUSION: HIV positive homosexual men attending a London outpatient clinic commonly reported sexual behaviour with a high risk of HIV transmission. However, behavioural and clinical risk factors for HIV transmission were consistently lower in men on HAART than men not on HAART. Although use of HAART by homosexual men with generally good health is not associated with higher risk behaviours, effective risk reduction interventions targeting known HIV positive homosexual men are still urgently needed.

Adult↗

PubMed2003

Poor sensitivity and consistency of microscopy in the diagnosis of low grade non-gonococcal urethritis.

OBJECTIVES: To determine the reliability of the diagnosis of non-gonococcal urethritis (NGU), and the variation between and within microscopists, from urethral smears at a large London genitourinary medicine clinic. METHODS: A senior microscopist (SM) preselected 60 Gram stained urethral smear slides, 20 negative (<5 polymorphs/hpf), 20 low grade NGU (5-20 p/hpf), and 20 high grade NGU (>20 p/hpf). Ten experienced microscopists, blinded to these initial grades, examined all slides giving each a polymorph score. After relabelling and randomly changing their order, the slides were re-examined by the same microscopists. Finally, the SM determined whether the study had resulted in loss of cells from any of the slides. The SM's initial grading and the consensus among microscopists provide two gold standards for analysis. RESULTS: Nine low grade and five high grade slides were removed from analysis because of loss of cells. By SM standard, considering microscopists' readings as simply non-NGU (<5 p/hpf) or NGU (>or=5 p/hpf), 97% from negative slides were correct (variation 93-100 across microscopists), 68% from low grade slides (45-95), and 94% from high grade slides (83-100). Consistency between repeat readings by the same microscopist was 96% for negatives, 75% for low grade and 89% for high grade slides. Results were similar by consensus standard. CONCLUSIONS: There was considerable variation between and within microscopists in the diagnosis of NGU. Sensitivity was strongly related to grade of urethritis, with an appreciable proportion of low grade urethritis falsely diagnosed as negative. With increasing attendances for sexual health screening, a false positive rate of only 3% may lead to many false diagnoses.

Humans↗

PubMed2002

The accuracy of reported sensitive sexual behaviour in Britain: exploring the extent of change 1990-2000.

OBJECTIVES: The 1990-1 British national probability sample survey of sexual attitudes and lifestyles (Natsal 1990) was repeated in 1999-2001 (Natsal 2000) to update population estimates of risk behaviours, and assess change over time. We examine whether changes in prevalence estimates may partly result from changes in measurement accuracy. METHODS: Taking Natsal 2000 (11 161 respondents) and Natsal 1990 (13 765 respondents aged 16-44) we compared the response rate, sample representativeness, reporting of abortion last year (relative to official statistics), and selected attitudes. Among the common birth cohort eligible for both surveys (aged 16-34 Natsal 1990, 26-44 Natsal 2000), we compared reporting of experiences before 1990. RESULTS: The response rate (66.8% Natsal 1990, 65.4% Natsal 2000) and completeness of reporting abortion were unchanged (84% Natsal 1990, 86% Natsal 2000). Attitudes were significantly changed in Natsal 2000 relative to Natsal 1990--for example, increased tolerance of male homosexual sex, OR (95% CI) 2.10 (1.93-2.29) men and 2.95 (2.74 to 3.18) women. In the common birth cohort reporting of heterosexual intercourse before 16 (OR 1.15 (1.02 to 1.29) men, 1.49 (1.31 to 1.69) women), and homosexual experience (OR 1.80 (1.46 to 2.21) men, 2.00 (1.61 to 2.48) women) were significantly increased. CONCLUSIONS: The results are consistent with improved reporting accuracy for some sensitive behaviours in Natsal 2000, in line with greater social tolerance and improved survey methodology. However, the evidence is not conclusive, and may not be generalisable to all such behaviours. The increase found in the reported prevalence of STI risk behaviours between Natsal 1990 and Natsal 2000 is likely to be somewhat overstated.

Adolescent↗

PubMed2002

An evidence based approach to testing for antibody to herpes simplex virus type 2.

OBJECTIVES: To establish whether a simple risk scoring system, based on limited information, can reflect the variation in HSV-2 prevalence in a population, and whether a common system can be used across settings. To establish whether knowledge of a patient's score can aid the interpretation of the result from one of the commercial type specific assays. METHODS: Four previous cross sectional studies are considered, with HSV-2 antibody results by western blot or type specific ELISA tests. The clinical settings were a blood donor centre (1359 participants) and STD clinic (808 participants), London, United Kingdom, an antenatal clinic, Sydney, Australia (2317 participants), and a family medical centre, Seattle, United States (478 participants). We determined the factors associated with HSV-2 prevalence, the similarity of associations across settings, and the variation in HSV-2 prevalence by risk score. RESULTS: A simple scoring captured much variation in HSV-2 prevalence in each population-for example, for London blood donors, scoring based on sex, age, and number of lifetime partners, prevalence varied from 0.7% (95% CI 0.1 to 2.0) to 47.3% (37.9 to 56.6) across five risk groups. For number of lifetime partners, and sex, the association with HSV-2 varied significantly across studies. CONCLUSIONS: A scoring system can aid test interpretation-for example, in London blood donors the post-test probability of infection following a positive result varies from around 25% to 98% across risk groups for a typical type specific assay. Further work could address whether this theoretical benefit can be realised in practice. A common risk scoring probably could not be used across settings.

Adult↗