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.

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.

Who pays for sex? An analysis of the increasing prevalence of female commercial sex contacts among men in Britain

BACKGROUND

In the United Kingdom the incidence of sexually transmitted infections (STI) and risky sexual behaviours is increasing. The role of commercial sex in this trend is poorly understood. Little is known about the men who pay for sex. We examined the epidemiology of female commercial sex contacts reported by men in 1990 and 2000.

METHODS

National probability sample surveys of sexual attitudes and lifestyles (Natsal) of men aged 16-44 resident in Britain in 1990 (n = 6000) and 2000 (n = 4762).

RESULTS

The proportion of men who reported paying women for sex in the previous 5 years increased from 2.0% (95% CI 1.6 to 2.5) in 1990 to 4.2% in 2000 (95% CI 3.6 to 4.9). In both surveys, paying for sex was more frequent in men aged between 25 years and 34 years, who were never or previously married, and who lived in London. There was no association with ethnicity, social class, homosexual contact, or injecting drug use. Men who paid for sex were more likely to report 10 or more sexual partners in the previous 5 years; only a minority of their lifetime sexual partners (19.3%) were commercial. They were more likely to meet partners abroad and to report previous STI. Only 15% reported having had an HIV test.

CONCLUSION

The proportion of men who reported paying for heterosexual sex has increased, and these men have multiple commercial and non-commercial partners. Their higher rates of STI and low level of HIV testing suggest the need for prevention interventions for clients as well as sex workers.

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.

Comorbidity of rosacea and depression: an analysis of the National Ambulatory Medical Care Survey and National Hospital Ambulatory Care Survey--Outpatient Department data collected by the U.S. National Center for Health Statistics from 1995 to 2002

BACKGROUND

Psychogenic factors have been considered to be important in the exacerbation and possibly the onset of rosacea. However, there are very few studies that have reported conclusive findings.

OBJECTIVES

To examine the association between rosacea and major depressive disease, a common and usually treatable psychiatric disorder.

METHODS

Data from 1995 to 2002, collected by the National Ambulatory Medical Care Survey and the outpatient component of the National Hospital Ambulatory Care Survey, which are both nationally representative surveys of healthcare visits in the U.S.A., were studied. The basic sampling unit in both surveys is the patient visit or encounter. A "Rosacea" variable was created by grouping all rosacea (ICD-9-CM code 695.3) visits and a "Depression" variable was created by grouping the patient visits related to major depressive disorder (ICD-9-CM codes 296.2, 296.3 and 311). As alcohol abuse has been implicated in rosacea, and alcohol can confound symptoms of depression, an "Alcohol" variable was created by grouping all ICD-9-CM codes related to alcohol dependence and abuse (codes 303, 303.0, 303.9 and 305.0). All analyses were conducted using the Complex Samples module of SPSS version 13, to account for the multistage probability sampling design used to collect the data.

RESULTS

The weighted data were representative of over 608 million dermatology visits between 1995 and 2002. Logistic regression analysis using "Rosacea" as the dependent variable and age, sex, "Alcohol" and "Depression" as independent variables revealed that the odds ratio for depressive disease in the rosacea group was 4.81 (95% confidence interval 1.39-16.62). The association between "Alcohol" and "Rosacea" was not significant.

CONCLUSIONS

The comorbidity between major depressive disease and rosacea may have important clinical implications. Alcohol abuse does not appear to play a significant role in this association.

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.

Are Specific Antiretrovirals associated with an Increased Risk of Discontinuation due to Toxicities or Patient/Physician Choice in patients with Hepatitis C Virus Coinfection?

Background

Liver damage associated with hepatitis C (HCV) may influence the likelihood of experiencing discontinuation due to toxicities or patient/physician choice (TOXPC) in patients taking combination antiretroviral therapy (cART). Little information to address this concern is available from clinical trials as patients with HCV are often excluded.

Aims

To compare incidence rates of discontinuation due to TOXPC associated with specific antiretrovial drugs in patients with or without HCV.

Patients/methods

A total of 4929 patients from EuroSIDA under follow-up from January 1999 on a specific nucleoside pair (zidovudine/lamivudine, didanosine/stavudine, stavudine/lamivudine, or other) with a third drug (abacavir, nelfinavir, indinavir, nevirapine, efavirenz, lopinavir/ ritonavir or other boosted-protease inhibitor (PI)-containing regimen) and with known HCV serostatus were studied for the incidence of discontinuation of any nucleoside pair or third drug due to TOXPC. Incidence rate ratios were derived from Poisson regression models.

Results

In total 1358 patients had HCV (27.5%). During 12 799 person-years of follow-up there were 2141 discontinuations due to TOXPC for nucleoside pairs and 2501 for third drugs. The incidence of discontinuation due to TOXPC was consistently higher in patients with HCV after stratification by nucleoside pair or third drug. After adjustment for CD4+ count, gender, exposure group, time on HAART, region and treatment regimen, there were few differences in the rate of discontinuation due to TOXPC in those with HCV compared with those without for any nucleoside pairs or third drugs. Similar results were seen when concentrating on discontinuation due to toxicities alone.

Conclusions

Although patients with HCV generally had higher rates of discontinuation due to TOXPC compared with patients without HCV, there was little evidence to suggest that this was associated with any specific nucleoside pair or third drug used as part of cART. Our results do not suggest that any specific component of cART is more poorly tolerated in patients with HCV or that the presence of HCV should influence the choice between antiretrovirals used as part of a cART regimen.

Thymidine Analogue Mutation Profiles: Factors Associated with Acquiring Specific Profiles and their Impact on the Virological Response to Therapy

Background

Studies have suggested that HIV-1 may develop thymidine analogue mutations (TAMs) by one of two distinct pathways – the TAM1 pathway (including mutations 41L, 210W and 215Y) or the TAM2 pathway (including mutations 67N, 70R and 219E/Q) – under the pressure of a not fully suppressive thymidine-analogue-containing regimen.

Methods

Frozen plasma samples stored in the EuroSIDA repository were selected and sent to two central laboratories for genotypic analysis. We considered 733 patients with at least one genotypic test showing ≥1 TAMs (the first of these tests in chronological order was used). TAM1 and TAM2 genotypic profiles were defined in accordance with previous literature. Statistical modelling involved logistic regression and linear regression analysis for censored data.

Results

The observed frequencies of patterns classifiable as TAM1 or TAM2 profiles were markedly higher than the probabilities of falling into these classifications by chance alone. The chance of detecting a TAM2 profile increased by 25% per additional year of exposure to zidovudine. We found that mutations 67N and 184V were not associated with a particular TAM profile. In the presence of TAM2 profiles, the adjusted mean difference in the 6-month viral reduction was 0.96 log10 copies/ml (95% confidence interval: 0.20; 1.73) higher in patients who started stavudine-containing regimens instead of zidovudine-containing regimens.

Conclusions

This study provides evidence that the suggested TAM clustering is a real phenomenon and that it may be driven by which thymidine analogue the patients has used. In patients with TAM2-resistant viruses, stavudine appears to retain greater viral activity than zidovudine.

Rapid ribosomal RNA sequencing and the phylogenetic analysis of protists

A newly described technique for rapidly obtaining the partial nucleotide sequence of ribosomal RNA is being applied to investigate phylogenetic relationships among living organisms. Alan Johnson and Peter Boverstock describe the importance of this method to parasitology in providing new information on the phylogenetic relationships of parasitic organisms previously placed in groups of convenience. The phylum Apicomplexo in particular, has been the object of much study using this technique, but the technology is likely to extend soon to the restructuring of the phylogenetic trees of many groups of parasites.

Speculation on possible life cycles for the clonal lineages in the genus toxoplasma

Recent evidence suggests that the strains currently classified in the genus Toxoplasma, ie. within the species Toxoplasma gondii, may actually comprise at least two clonal lineages correlated with their virulence in mice. Here, Alan Johnson reviews these data in the context of evolution and speciation within the genus, and raises hypotheses on how the virulent lineage may undergo an asexual life cycle in nature, similar to that found for the very closely related coccidian, Neospora camnum. The putative vertical transmission life cycle of this mouse virulent lineage of T. gondii could involve passage to the foetus late in pregnancy, or transmission in milk to the neonate after birth.

Lupus headaches in childhood-onset systemic lupus erythematosus: relationship to disease activity as measured by the systemic lupus erythematosus disease activity index (SLEDAI) and disease damage

The Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) is the most commonly used measure of disease activity for children with systemic lupus erythematosus (SLE). For headaches to be scored in the SLEDAI as a symptom of active disease, they have to be nonresponsive to narcotic analgesia. This may affect the overall estimation of disease activity, especially because headaches are common among children with SLE and narcotic analgesia is rarely used for headache therapy in paediatrics. Moreover, the importance of headaches for the development of damage and their relation to other clinical parameters and outcomes has not been well described for children with SLE. We reviewed the medical charts of an inception cohort of children (n = 63) who were newly diagnosed with SLE. Information on headaches and other disease parameters was obtained. Disease activity and damage were measured using the SLEDAI and the Systemic Lupus International Collaboration Clinics/American College of Rheumatology Damage Index (SDI), respectively. It has been shown that the accumulated burden of active disease as measured by serial SLEDAI scores over time is one of the best predictors of eventual damage to children with SLE. New-onset or significant increase of severe and/or persistent headaches (LHA) were reported in 43% of the patients during a mean follow-up of 3.6 years. LHA occurred preferentially among patients with elevated levels of antiphospholipid antibodies (aPL) (P < 0.02) and only 6% of all LHA episodes were treated with narcotics and thus considered for the measurement of disease activity in the SLEDAI. LHA were unrelated to proxy-measures of disease activity, such as the need to intensify therapies. When used in children, the insensitivity of the SLEDAI to capture LHA did not seem to decrease the responsiveness of the SLEDAI to detect clinically important worsening of disease, or negatively impact on its ability to predict damage.

Pupil-led sex education in England (RIPPLE study): cluster-randomised intervention trial

BACKGROUND

Improvement of sex education in schools is a key part of the UK government's strategy to reduce teenage pregnancy in England. We examined the effectiveness of one form of peer-led sex education in a school-based randomised trial of over 8000 pupils.

METHODS

29 schools were randomised to either peer-led sex education (intervention) or to continue their usual teacher-led sex education (control). In intervention schools, peer educators aged 16-17 years delivered three sessions of sex education to 13-14 year-old pupils from the same schools. Primary outcome was unprotected (without condom) first heterosexual intercourse by age 16 years. Analysis was by intention to treat.

FINDINGS

By age 16 years, significantly fewer girls reported intercourse in the peer-led arm than in the control arm, but proportions were similar for boys. The proportions of pupils reporting unprotected first sex did not differ for girls (8.4% intervention vs 8.3% control) or for boys (6.2% vs 4.7%). Stratified estimates of the difference between arms were -0.4% (95% CI -3.7% to 2.8%, p=0.79) for girls and -1.4% (-4.4% to 1.6%, p=0.36) for boys. At follow-up (mean age 16.0 years [SD 0.32]), girls in the intervention arm reported fewer unintended pregnancies, although the difference was borderline (2.3% vs 3.3%, p=0.07). Girls and boys were more satisfied with peer-led than teacher-led sex education, but 57% of girls and 32% of boys wanted sex education in single-sex groups.

INTERPRETATION

Peer-led sex education was effective in some ways, but broader strategies are needed to improve young people's sexual health. The role of single-sex sessions should be investigated further.

Increasing risk behaviour and high levels of undiagnosed HIV infection in a community sample of homosexual men

OBJECTIVES

To estimate changes in sexual behaviour over time. To examine the proportion of undiagnosed HIV infection in a community sample of homosexual men. To explore the relation between HIV status, diagnosis, and sexual behaviour.

METHODS

Five cross sectional surveys of men attending selected gay community venues in London between 1996 and 2000 (n = 8052). Men were recruited in 45 to 58 social venues (including bars, clubs, and saunas) across London. Participants self completed an anonymous behavioural questionnaire. In 2000, participants in community venues provided anonymous saliva samples for testing for anti-HIV antibody.

RESULTS

The proportion of men having unprotected anal intercourse (UAI) increased significantly each year from 30% in 1996 to 42% in 2000 (p<<0.001). In 2000, 132 of 1206 (10.9%) saliva samples were HIV antibody positive. Of the HIV saliva antibody positive samples, 43/132 (32.5%) were undiagnosed. Around half of both diagnosed and undiagnosed HIV saliva positive men reported UAI in the past year. Of the 83% of men who reported their current perceived HIV status, 4.1% reported an incorrect status. HIV antibody positivity was associated with increasing numbers of UAI partners, and having a sexually transmitted infection (STI) in the past year (OR 2.15).

CONCLUSIONS

Homosexual men continue to report increasing levels of UAI. HIV prevalence is high in this group, with many infections remaining undiagnosed. The high level of risky behaviour in HIV positive men, regardless of whether they are diagnosed, is of public health concern, in an era when HIV prevalence, antiretroviral resistance, and STI incidence are increasing.

Baseline Resistance and Virological Outcome in Patients with Virological Failure who Start a Regimen Containing Abacavir: Eurosida Study

Objectives

To investigate the ability of several HIV-1 drug-resistance interpretation systems, as well as the number of pre-specified combinations of abacavir-related mutations, to predict virological response to abacavir-containing regimens in antiretroviral therapy-experienced, abacavir-naive patients starting an abacavir-containing regimen in the EuroSIDA cohort.

Patients and methods

A total of 100 HIV-infected patients with viral load (VL) >500 copies/ml who had a plasma sample available at the time of starting abacavir (baseline) were included. Resistance to abacavir was interpreted by using eight different commonly used systems that consisted of rules-based algorithms or tables of mutations. Correlation between baseline abacavir-resistance mutations and month 6 virological response was performed on this population using a multivariable linear regression model accounting for censored data.

Results

The baseline VL was 4.36 log10 RNA copies/ml [interquartile range (IQR): 3.65–4.99 log10 RNA copies/ml] and the median CD4 cell count was 210 cells/μl (IQR: 67–305 cells/μl). Our patients were pre-exposed to a median of seven antiretrovirals (2–12) before starting abacavir therapy. The median (range) number of abacavir mutations (according to the International AIDS Society-USA) detected at baseline was 3.5 (0–8). Overall, the Kaplan–Meier estimate of the median month 6 VL decline was 0.86 log10 RNA copies/ml [95% confidence intervals (95% CI): 0.45–1.24]. The VL in those patients ( n=31) who intensified treatment by adding only abacavir decreased by a median 0.20 log10 RNA copies/ml (95% CI: -0.18; +0.94). The proportion of patients who harboured viruses fully resistant to abacavir among the eight genotypic resistance interpretation algorithms ranged from 12% [Agence Nationale de Recherches sur le SIDA (ANRS)] to 79% [Stanford HIV RT and PR Sequence Database (HIVdb)]. Some interpretation systems showed statistically significant associations between the predicted resistance status and the virological response while others showed no consistent association. The number of active drugs in the regimen was associated with greater virological suppression (additional month 6 VL reduction per additional sensitive drug=0.51, 95% CI: 0.15–0.88, P=0.006); baseline VL was also weakly associated (additional month 6 VL reduction per log10 higher=0.30, 95% CI: -0.02; +0.62, P=0.06). In contrast, the number of drugs previously received was associated with diminished viral reduction (additional month 6 VL reduction per additional drug=-0.14, 95% CI: -0.28; 0.00, P=0.05).

Conclusions

Our results revealed a high degree of variability among several genotypic resistance interpretation algorithms currently in use for abacavir. Therefore, the interpretation of genotypic resistance for predicting response to regimens containing abacavir remains a major challenge.

How useful are high vaginal swabs in general practice? Results of a multicentre study

Vulvovaginal symptoms are a common reason for consultation with a general practitioner (GP). High vaginal swabs (HVS) are used to investigate symptoms, but their usefulness is poorly evaluated and microbiological tests performed vary between laboratories. In this multicentre study of 797 women with genital symptoms attending GPs, diagnostic yield of HVS was poor except for Candida spp. (22%). There is an urgent need to establish the most cost-effective approach for the management of these women.

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.

Cumulative meta-analysis of systemic antifungal agents for the treatment of onychomycosis

BACKGROUND

Onychomycosis is a common nail disease that is often chronic, difficult to eradicate, and has a tendency to recur. The most common oral therapies for dermatophyte toenail onychomycosis include terbinafine, itraconazole and fluconazole.

OBJECTIVES

A cumulative meta-analysis of the randomized controlled trials (RCTs) for antimycotic agents was performed to determine whether the pooled estimate of the cure rates has remained consistent over the years. Furthermore, for each agent we compared the overall meta-analytical average of both mycological and clinical response rates of RCTs vs. open studies.

METHODS

We searched MEDLINE (1966 to November 2002) for relevant studies evaluating the efficacy of the oral antifungal agents terbinafine, itraconazole (pulse or continuous), fluconazole and griseofulvin for treating dermatophyte toenail onychomycosis. Studies included in this meta-analysis required a standard accepted dosage regimen, treatment duration and follow-up period. To determine the cumulative meta-analytical average, studies were sequentially pooled by adding one study at a time according to the date of publication (i.e. earliest to the most recent).

RESULTS

There were 36 studies included in the analyses. For RCTs the change in efficacy of mycological cure rates from the first trial to the overall cumulative meta-average for each drug comparator is as follows (with 95% confidence interval): terbinafine, 78 +/- 6% (n = 2 studies, 79 patients) to 76 +/- 3% (n = 18 studies, 993 patients) (P = 0.68); itraconazole pulse, 75 +/- 10% (n = 1 study, 20 patients) to 63 +/- 7% (n = 6 studies, 318 patients) (P = 0.25); itraconazole continuous, 63 +/- 5% (n = 1 study, 84 patients) to 59 +/- 5% (n = 7 studies, 1131 patients) (P = 0.47); fluconazole, 53 +/- 6% (n = 1 study, 72 patients) to 48 +/- 5% (n = 3 studies, 131 patients) (P = 0.50); and griseofulvin, 55 +/- 8% (n = 2 studies, 109 patients) to 60 +/- 6% (n = 3 studies, 167 patients) (P = 0.41). The cumulative meta-analytical average of mycological cure rates when comparing RCTs vs. open studies was: terbinafine, 76 +/- 3% (n = 18 studies, 993 patients) vs. 83 +/- 12% (n = 2 studies, 391 patients) (P = 0.0028); itraconazole pulse, 63 +/- 7% (n = 6 studies, 318 patients) vs. 84 +/- 9% (n = 3 studies, 194 patients) (P = 0.0001); and fluconazole, 48 +/- 5% (n = 3 studies, 131 patients) vs. 79 +/- 3% (n = 3 studies, 208 patients) (P = 0.0001).

CONCLUSIONS

The cumulative meta-analysis of cure rates for RCTs suggests that over time, as new RCTs have been conducted, the efficacy rates have remained consistent. The efficacy rates of open studies are substantially higher compared with RCTs and may therefore overestimate cure rates.

A school-based randomized controlled trial of peer-led sex education in England

This article discusses the design of an ongoing cluster-randomized trial comparing two forms of school-based sex education in terms of educational process and sexual health outcomes. Twenty-nine schools in southern England have been randomized to either peer-led sex education or to continue with their traditional teacher-led sex education. The primary objective is to determine which form of sex education is more effective in promoting young people's sexual health. The trial includes an unusually detailed evaluation of the process of sex education as well as the outcomes. The sex education programs were delivered in school to pupils ages 13-14 years who are being followed until ages 19-20. Major trial outcomes are unprotected sexual intercourse and regretted intercourse by age 16 and cumulative incidence of abortion by ages 19-20. We discuss the rationale behind various aspects of the design, including ethical issues and practical challenges of conducting a randomized trial in schools, data linkage for key outcomes to reduce bias, and integrating process and outcome measures to improve the interpretation of findings.

Treating sexually transmitted infections in primary care: a missed opportunity?

OBJECTIVES

To explore patterns of primary care attendance, barriers to the use of primary care, and views on services in a population of first time genitourinary medicine (GUM) clinic attenders.

METHOD

A cross sectional survey of new patients attending a mainly walk-in outer London GUM clinic, in which responses were linked to clinical data.

RESULTS

40.5% of all patients and 39.9% of those with an STI had already seen a GP for their current problem. This did not vary with age or symptom status. Duration of symptoms was highly significantly longer in patients who had attended a GP than in patients who attended a GUM clinic in the first instance. When patients who had not seen a GP were asked the reason for this, a third of responses cited the convenience of a GUM clinic or difficulty in accessing primary care services, while only 3% cited embarrassment and only 2% examination or gender issues.

CONCLUSION

Many patients initially attend GP services for STIs, and primary care is therefore already an important setting with potential for STI control. However, delay in treatment through attendance at primary care, and barriers in access to primary care, need to be addressed in the planning of future services.

Maintaining patient access to GUM clinics: is it compatible with appointments?

OBJECTIVES

To determine whether a planned change from a walk-in service to a system in which 35% of appointments were prebooked and 65% obtained on the day, preserved access to the service for patients with, or at risk of, STIs. To describe patients' attitudes and behaviours in relation to accessing the clinic, and relate these to disease status and other epidemiological factors. To evaluate the effect of the change on clinical outcomes. To develop a tool for evaluating access to services.

METHOD

A natural experiment was studied, in which a cohort of patients attending just before the change in appointments policy (phase 1) was compared with a cohort following the change (phase 2). A questionnaire was administered to all new patients, and linked to disaggregated epidemiological and demographic data and case notes.

RESULTS

The age, ethnic, symptom status, and disease mix of the clinic did not change significantly, and more patients were seen in phase 2. Time from telephoning to being seen did not change. Under 25s and Afro-Caribbeans used prebooked appointments less than others. Partner notification improved and HIV testing rates increased, while staff preferred the new system.

CONCLUSION

This specific appointment system in a GUM clinic preserved access for high risk groups. However, this may not generalise to systems with a higher proportion of prebooked appointments.

Herpes simplex virus type 1 infection: a sexually transmitted infection of adolescence?

OBJECTIVES

To examine the factors associated with antibodies to herpes simplex virus type 1 (HSV-1).

DESIGN

Cross sectional study with HSV-1 antibody testing performed by University of Washington western blot assay.

SETTING

Central London STD clinic (1990-1) and central London blood donation centre (1992).

PARTICIPANTS

Representative sample of 869 new and rebooked GUM clinic attenders and 1494 consecutive blood donors.

RESULTS

The prevalence of HSV-1 antibody among clinic attenders was 60.4% (95% CI 57.0 to 63.7) and among donors was 46.1% (95% CI 43.5 to 48.7). HSV-1 antibody was independently associated with increasing age in both populations (p<0.001). Among clinic attenders, HSV-1 was less common among heterosexual men than women and homosexual men (p<0.005), and was more common among black people (p=0.001) and those of lower socioeconomic status (p=0.05). Among blood donors, being single rather than married was independently associated with HSV-1 infection (p=0.03). Early age at first intercourse was strongly associated with presence of HSV-1 in both populations. The adjusted odds of HSV-1 among GUM clinic attenders was 0.37 (95% CI 0.21 to 0.65) for someone aged 20 at first intercourse compared with someone aged <or=15. Among blood donors, those aged 20 had an adjusted odds of 0.64 (95% CI 0.39 to 1.05) compared with someone aged 15. HSV-1 was not associated with increasing number of lifetime partners after adjustment for other factors.

CONCLUSIONS

Genital herpes due to HSV-1 antibody is increasing in the United Kingdom, particularly among young people. In this study we found that HSV-1 was strongly associated with early age of first sexual intercourse, which may reflect the sexual practices of people initiating sex in this age group.

Myosins of Babesia bovis: molecular characterisation, erythrocyte invasion, and phylogeny

Using degenerate primers, three putative myosin sequences were amplified from Australian isolates of Babesa bovis and confirmed as myosins (termed Bbmyo-A, Bbmyo-B, and Bbmyo-C) from in vitro cultures of the W strain of B. bovis. Comprehensive analysis of 15 apicomplexan myosins suggests that members of Class XIV be defined as those with greater than 35% myosin head sequence identity and that these be further subclassed into groups bearing above 50-60% identity. Bbmyo-A protein bears a strong similarity with other apicomplexan myosin-A type proteins (subclass XIVa), the Bbmyo-B myosin head protein sequence exhibits low identity (35-39%) with all members of Class XIV, and 5'-sequence of Bbmyo-C shows strong identity (60%) with P. falciparum myosin-C protein. Domain analysis revealed five divergent IQ domains within the neck of Pfmyo-C, and a myosin-N terminal domain as well as a classical IQ sequence unusually located within the head converter domain of Bbmyo-B. A cross-reacting antibody directed against P. falciparum myosin-A (Pfmyo-A) revealed a zone of approximately 85 kDa in immunoblots prepared with B. bovis total protein, and immunofluorescence inferred stage-specific myosin-A expression since only 25% of infected erythrocytes with mostly paired B. bovis were immuno-positive. Multiplication of B. bovis in in vitro culture was inhibited by myosin- and actin-binding drugs at concentrations lower than those that inhibit P. falciparum. This study identifies and classifies three myosin genes and an actin gene in B. bovis, and provides the first evidence for the participation of an actomyosin-based motor in erythrocyte invasion in this species of apicomplexan parasite.

Phase specific strategies for the prevention, control, and elimination of sexually transmitted diseases: background country profile, England and Wales

The development of non-invasive tests for evidence of current or past infection offers new prospects for carrying out population studies of sexually transmitted infection (STI) epidemiology, and for improved understanding of the behavioural and biological determinants of STI transmission. In turn this may guide screening, treatment, and behavioural interventions. The evidence base for many interventions is sparse and randomised trials of interventions are in their early days. Increasingly, linked behavioural and biological outcomes will be required to measure effectiveness. Integrated efforts are needed at a national level to achieve greater coordination between STD, HIV, and contraception services, school education, and broader public education and programmes.

Response to antiretroviral therapy among patients exposed to three classes of antiretrovirals: results from the EuroSIDA study

There is an increasing proportion of HIV-positive patients exposed to all licensed classes of antiretrovirals, and the response to salvage regimens may be poor. Among over 8500 patients in EuroSIDA, the proportion of treated patients exposed to nucleosides, protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitor (NNRTI) increased from 0% in 1996 to 47% in 2001. Four-hundred-and-thirteen patients, who had failed virologically two highly active antiretroviral therapy (HAART) regimens and experienced all three main drug classes, started a salvage regimen of at least three drugs, in which at least one new PI or NNRTI was included. Median viral load was 4.7 log copies/ml [Interquartile range (IQR) 4.2-5.2], CD4 lymphocyte count 150/mm3 (IQR 60-274/mm3) and follow-up 14 months. Of these patients, 283 (69%) subsequently experienced at least a 1 log decline in viral load and 202 (49%) achieved a viral load < 500 copies/ml. Conversely, the CD4 count halved from the baseline value in 88 (21%), and 45 (11%) experienced a new AIDS-defining disease. In multivariable analyses, a 1 log viral load reduction was related to baseline viral load [relative hazard (RH) 1.27 per 1 log higher; P = 0.008], a previous viral load of less than 500 copies/ml (RH 1.69; P = 0.002), more recent initiation of the regimen (RH 1.36 per year more recent; P = 0.02), number of new drugs in the regimen (RH 1.20 per drug; P = 0.02), time since start of antiretroviral therapy (RH 0.94 per extra year; P = 0.035) and time spent on HAART with viral load > 1000 copies/ml (RH 0.96 per extra month; P = 0.0001). Analysis of factors associated with CD4 count decline and new AIDS disease also indicated improved outcomes in more recent times and a tendency for a better response in those starting more new drugs, but no relationship with the total number of drugs. Outcomes in people starting salvage regimens appear to depend on the number of new drugs started but not on the total number of drugs being used.

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.

Response to Antiretroviral Therapy among Patients Exposed to Three Classes of Antiretrovirals: Results from the Eurosida Study

There is an increasing proportion of HIV-positive patients exposed to all licensed classes of antiretrovirals, and the response to salvage regimens may be poor. Among over 8500 patients in EuroSIDA, the proportion of treated patients exposed to nucleosides, protease inhibitors (PIs) and non-nucleoside reverse transcriptase inhibitor (NNRTI) increased from 0% in 1996 to 47% in 2001. Four-hundred-and-thirteen patients, who had failed virologically two highly active antiretroviral therapy (HAART) regimens and experienced all three main drug classes, started a salvage regimen of at least three drugs, in which at least one new PI or NNRTI was included. Median viral load was 4.7 log copies/ml [Interquartile range (IQR) 4.2–5.2], CD4 lymphocyte count 150/mm3 (IQR 60–274/mm3) and follow-up 14 months. Of these patients, 283 (69%) subsequently experienced at least a 1 log decline in viral load and 202 (49%) achieved a viral load <500 copies/ml. Conversely, the CD4 count halved from the baseline value in 88 (21%), and 45 (11%) experienced a new AIDS-defining disease. In multivariable analyses, a 1 log viral load reduction was related to baseline viral load [relative hazard (RH) 1.27 per 1 log higher; P=0.008], a previous viral load of less than 500 copies/ml (RH 1.69; P=0.002), more recent initiation of the regimen (RH 1.36 per year more recent; P=0.02), number of new drugs in the regimen (RH 1.20 per drug; P=0.02), time since start of antiretroviral therapy (RH 0.94 per extra year; P=0.035) and time spent on HAART with viral load >1000 copies/ml (RH 0.96 per extra month; P=0.0001). Analysis of factors associated with CD4 count decline and new AIDS disease also indicated improved outcomes in more recent times and a tendency for a better response in those starting more new drugs, but no relationship with the total number of drugs. Outcomes in people starting salvage regimens appear to depend on the number of new drugs started but not on the total number of drugs being used.

Sexual behaviour in Britain: reported sexually transmitted infections and prevalent genital Chlamydia trachomatis infection

BACKGROUND

Studies of the epidemiology of sexually transmitted infections (STI) are largely based on surveillance data. As part of a national survey of sexual attitudes and lifestyles (Natsal 2000) in Britain, we estimated the frequency of self-reported STIs, and the prevalence of urinary Chlamydia trachomatis infection.

METHODS

We did a stratified probability sample survey of 11161 men and women aged 16-44 years in Britain. Computer assisted self-interviews contained items on the nature and timing of previously diagnosed STIs. Half of all sexually experienced respondents aged 18-44 years were invited to provide a urine sample for ligase chain reaction testing for C trachomatis infection.

FINDINGS

10.8% of men and 12.6% of women reported ever having an STI, 3.6% of men and 4.1% of women reported ever being diagnosed with genital warts, and 1.4% of men and 3.1% of women reported previous infection with C trachomatis. 76% of men and 57% of women ever diagnosed with an STI had been to a GUM clinic. C trachomatis was found in 2.2% (95% CI 1.5-3.2) of men and 1.5% (95% CI 1.11-2.14) of women with age-specific prevalence being highest among men aged 25-34 (3.1%) and women aged 16-24 years (3.0%). Non-married status, age, and reporting partner concurrency or two or more sexual partners in the past year were independently associated with infection with C trachomatis.

INTERPRETATION

We show substantial heterogeneity in distribution of reported STIs, and the demographic and behavioural determinants of prevalent genital chlamydial infection. The results have potentially wide application for proposed chlamydia screening programmes which, given the demonstrated prevalence, must now proactively seek to involve men.

Sexual behaviour in Britain: early heterosexual experience

BACKGROUND

Relatively high rates of teenage conception and sexually transmitted infection among young people in Britain have focused attention on early sexual behaviour and its determinants. We report the results of the second National Survey of Sexual Attitudes and Lifestyles (Natsal 2000).

METHODS

We did a probability sample survey between 1999 and 2001, of men and women aged 16-44 years in Britain. Participants were interviewed using a combination of computer-assisted face-to-face and self-completion questionnaires, and asked questions regarding first heterosexual intercourse, communication about sex, pregnancy, and sexually transmitted infections (STIs).

FINDINGS

We recruited 11161 men and women to the survey (4762 men, 6399 women). The proportion of those aged 16-19 years at interview reporting first heterosexual intercourse at younger than 16 years was 30% for men and 26% for women; median age was 16 years. The proportion of women reporting first intercourse before 16 years increased up to, but not after, the mid-1990s. There has been a sustained increase in condom use and a decline in the proportion of men and women reporting no contraceptive use at first intercourse with decreasing age at interview. Among 16-24 year olds, non-use of contraception increased with declining age at first intercourse; reported by 18% of men and 22% of women aged 13-14 years at occurrence. Early age at first intercourse was significantly associated with pregnancy under 18 years, but not with occurrence of STIs. Low educational attainment was associated with motherhood before 18 years, but not abortion.

INTERPRETATION

The increase in the proportion of women reporting first intercourse before age 16 years does not appear to have continued throughout the past decade. Only a small minority of teenagers have unprotected first intercourse, and early motherhood is more strongly associated with educational level than with family background. Factors most strongly associated with risk behaviour and adverse outcomes have considerable potential for preventive intervention.

Sexual behaviour in Britain: partnerships, practices, and HIV risk behaviours

BACKGROUND

Sexual behaviour is a major determinant of sexual and reproductive health. We did a National Survey of Sexual Attitudes and Lifestyles (Natsal 2000) in 1999-2001 to provide population estimates of behaviour patterns and to compare them with estimates from 1990-91 (Natsal 1990).

METHODS

We did a probability sample survey of men and women aged 16-44 years who were resident in Britain, using computer-assisted interviews. Results were compared with data from respondents in Natsal 1990.

FINDINGS

We interviewed 11161 respondents (4762 men, 6399 women). Patterns of heterosexual and homosexual partnership varied substantially by age, residence in Greater London, and marital status. In the past 5 years, mean numbers of heterosexual partners were 3.8 (SD 8.2) for men, and 2.4 (SD 4.6) for women; 2.6% (95% CI 2.2-3.1) of both men and women reported homosexual partnerships; and 4.3% (95% CI 3.7-5.0) of men reported paying for sex. In the past year, mean number of new partners varied from 2.04 (SD 8.4) for single men aged 25-34 years to 0.05 (SD 0.3) for married women aged 35-44 years. Prevalence of many reported behaviours had risen compared with data from Natsal 1990. Benefits of greater condom use were offset by increases in reported partners. Changes between surveys were generally greater for women than men and for respondents outside London.

INTERPRETATION

Our study provides updated estimates of sexual behaviour patterns. The increased reporting of risky sexual behaviours is consistent with changing cohabitation patterns and rising incidence of sexually transmitted infections. Observed differences between Natsal 1990 and Natsal 2000 are likely to result from a combination of true change and greater willingness to report sensitive behaviours in Natsal 2000 due to improved survey methodology and more tolerant social attitudes.

Effect of certified reference material 470 (CRM 470) on national quality assurance programs for serum proteins in Europe

The introduction of the international reference material for serum proteins, CRM 470, has resulted in significant reduction of the among-laboratory variance for most proteins assayed in European national quality assurance programs. In general, the CVs have decreased by 5 to 65%. However, both among- and within-manufacturer variances in many cases remain unacceptably high. In addition, concentration-dependent differences in variance and bias are present for some proteins. Although some variance will persist, reducing variance and bias to levels required for the institution of universal reference ranges will necessitate more accurate transfer of values to calibrants and controls and improved calibration curve fitting by manufacturers, as well as better quality control within laboratories.

Strategy for determining racial and environmental similarities and differences for plasma proteins

The aim of this protocol is to establish a common basis for the production of reference values and well-defined and documented reference intervals for plasma proteins, based on common standardization, using the IFCC/BCR/CAP Certified Reference Material CRM 470. The strategy is to search for racial and environmental/geographical similarities and sources of differences in order to describe the main causes for variability among smaller or larger groups in selected societies and to estimate the sizes of differences for the different proteins according to the investigated sources. For this purpose, groups of reference individuals are selected according to race and geographical/environmental location, e.g. African Americans and Caucasians from the US. The reference individuals are groups of approximately 160 healthy male blood donors, 20 to 60 years of age. Rule-out criteria are positivity for HIV, hepatitis B and C antibodies and blood hemoglobin below the lower reference limit. Exclusion in relation to different C-reactive protein (CRP) levels will be investigated. Coagulation, storage conditions, transport, and the procedure for thawing are specified. The laboratories undertaking the measurements must have adequate analytical performance, and calibration and quality of performance are defined and documented, together with recommended control materials and procedures. Statistical models for describing distributions and for comparing groups are described. It is recommended that the data be presented as reference limits with 90% confidence intervals of those limits.

Commutability of serum protein values: persisting bias among manufacturers using values assigned from the certified reference material 470 (CRM 470) in the United States

Significant among-manufacturer differences in values for serum proteins persist 7 years after the introduction of the international reference material (Certified Reference Material 470; Reference Preparation for Proteins in Human Serum). In some cases, such as transthyretin and C4, the biases actually continue to increase. Further efforts at standardization are needed in order to improve commutability of results among laboratories and are essential if universal reference intervals are to be developed.

The existing interim consensus reference ranges and the future approach

The release of the reference material for serum proteins, CRM 470/RPPHS, in 1993, has given rise to a great improvement in the between-laboratory variability of serum protein measurements worldwide. However, conversion to the new reference material has resulted in significant changes in reference values for some proteins. The establishment of new reference ranges is currently in progress; in the interim, several professional societies and diagnostic companies have agreed to use consensus reference ranges based on studies that were already undertaken.

Protein standardization IV: Value transfer procedure for the assignment of serum protein values from a reference preparation to a target material

A new approach for the assignment of values to serum proteins in a target material using a reference preparation has been developed. The procedure describes the general as well as the practical principles involved in the value assignment (with examples). Two models have been developed: 1) The direct value transfer between serum matrices and 2) the indirect value transfer from a pure protein preparation to a serum protein material. The necessary mathematical equations are developed and explained. The data reduction and statistical evaluation are discussed. The practical procedure (the transfer protocol) is based on six dilutions of the reference preparation assayed together with six dilutions of the target material. In this way imprecision is reduced and the proportionality of the two materials (i.e. the presence or absence of matrix effects) can be assessed directly by evaluating a single regression plot. If no matrix effects are found, the regression line will pass through zero with a slope equal to the ratio of the concentrations of the two materials. The transfer protocol is based on a multiple point value assignment obtained by several measurements a day repeated on several days, an important prerequisite being that all reconstitutions and dilutions are controlled by weighing.

Familial clustering of ruptured intracranial aneurysms in autosomal dominant polycystic kidney disease

Ruptured intracranial aneurysm (RICA) is a life-threatening complication of autosomal dominant polycystic kidney disease (ADPKD). A family history of RICA may be a risk factor for RICA. Six hundred eight adult members of 199 ADPKD families were interviewed, and family pedigrees were constructed. Individuals were classified as having definite, probable, or possible RICAs from evidence and history obtained in interviews. Central nervous system (CNS) events not consistent with RICA were classified as other CNS events. Seventy-seven CNS events occurred in 906 subjects with ADPKD (8.5%) versus 13 events in 823 subjects without ADPKD (1.6%; P < 0.0001). No event in subjects without ADPKD was consistent with an RICA. Twenty-seven other (non-RICA) CNS events occurred in subjects with ADPKD (3%) versus 13 events in subjects without ADPKD (1.6%; P = 0.05). The frequency of RICA was increased in subjects with ADPKD: 21 definite RICAs in subjects with ADPKD (2%) versus none in subjects without ADPKD (P < 0.001); 28 definite and probable RICAs in subjects with ADPKD (3%) versus none in subjects without ADPKD (P < 0.001); and 50 definite, probable, and possible RICAs in subjects with ADPKD (5.5%) versus none in subjects without ADPKD (P < 0.001). The null hypothesis that RICAs are randomly distributed among subjects with ADPKD was tested for definite RICAs (n = 21), definite and probable RICAs (n = 28), and definite, probable, and possible RICAs (n = 50). In the three categories, the null hypothesis was rejected at P less than 0.05, P less than 0.05, and P less than 0.005, respectively. Vascular CNS events occurred more frequently in ADPKD than non-ADPKD family members, and clustering of RICAs occurred in families with ADPKD.

Preparing for the NSF: a clinical governance model for diabetic care

The imminent introduction of a National Service Framework for diabetes has highlighted the need to develop an appropriate nursing model of care. With over 1.4 million people affected by diabetes in the UK, a multidisciplinary approach is required. This paper discusses the benefits and difficulties associated with this during the development of a clinical governance model.

Quantitation of Cryptosporidium parvum infection in cell culture using a colorimetric in situ hybridization assay

A quantitative colorimetric in situ hybridization assay was developed for detecting Cryptosporidium parvum infection in cell cultures using a digoxigenin-labeled probe targeting 18S rRNA. Intra-cellular developmental stages of C. parvum such as trophozoites and meronts were clearly discerned by light microscopy as localized areas of dark purple/black precipitate against a colorless background. Infections developed focally and the term infectious focus was applied to each cluster of developmental stages. There were no significant differences in the number of infectious foci following 24 h or 48 h incubation. However, 24 h and 48 h dose response curves were significantly different when infectivity was measured as the number of developmental stages per monolayer, with an average of 5.3-fold more stages following 48 h incubation. When infectivity was expressed as the number of infectious foci per inoculum oocyst converted to a percentage, it was demonstrated that the rate of infection decreased with increasing oocyst age. Oocysts of the Iowa isolate that were 7-10 days old demonstrated 7.8+/-2.4% infectivity (mean +/- standard deviation) compared to 4.2+/-0.8% for 21-28 day-old oocysts and 1.4+/-1.3% for 42-70 day-old oocysts. The assay also detected infection with other genotype 2 oocysts and a genoptye 1 isolate. This assay provides a direct quantitative approach for measuring C. parvum infectivity in cell culture.

A cognitive behavioural intervention to reduce sexually transmitted infections among gay men: randomised trial

OBJECTIVE

To determine the effectiveness of a brief cognitive behavioural intervention in reducing the incidence of sexually transmitted infections among gay men.

DESIGN

Randomised controlled trial with 12 months' follow up.

SETTING

Sexual health clinic in London.

PARTICIPANTS

343 gay men with an acute sexually transmitted infection or who reported having had unprotected anal intercourse in the past year.

MAIN OUTCOME MEASURES

Number of new sexually transmitted infections diagnosed during follow up and self reported incidence of unprotected anal intercourse.

RESULTS

72% (361/499) of men invited to enter the study did so. 90% (308/343) of participants returned at least one follow up questionnaire or re-attended the clinic and requested a check up for sexually transmitted infections during follow up. At baseline, 37% (63/172) of the intervention group and 30% (50/166) of the control group reported having had unprotected anal intercourse in the past month. At 12 months, the proportions were 27% (31/114) and 32% ( 39/124) respectively (P=0.56). However, 31% (38/123) of the intervention group and 21% (35/168) of controls had had at least one new infection diagnosed at the clinic (adjusted odds ratio 1.66, 95% confidence interval 1.00 to 2.74). Considering only men who requested a check up for sexually transmitted infections, the proportion diagnosed with a new infection was 58% (53/91) for men in the intervention group and 43% (35/81) for men in the control group (adjusted odds ratio 1.84, 0.99 to 3.40). Using a regional database that includes information from 23 sexual health clinics in London, we determined that few participants had attended other sexual health clinics.

CONCLUSIONS

This behavioural intervention was acceptable and feasible to deliver, but it did not reduce the risk of acquiring a new sexually transmitted infection among these gay men at high risk. Even carefully designed interventions should not be assumed to bring benefit. It is important to evaluate their effects in randomised trials with objective clinical end points.

The acceptability of urinary LCR testing for Chlamydia trachomatis among participants in a probability sample survey of sexual attitudes and lifestyles

OBJECTIVES

To examine the factors that influence respondents' willingness to participate in urinary testing for Chlamydia trachomatis in a general population feasibility survey of sexual attitudes and lifestyles.

METHODS

199 sexually experienced, 18-44 year old participants, recruited as part of a larger (n=901) methodological study of sexual attitudes and lifestyles, were invited to provide a urine sample for chlamydial infection testing using ligase chain reaction (LCR) techniques. Analysis of the survey data and in-depth qualitative interviews were undertaken to explore the factors that influenced participants' decisions to participate.

RESULTS

143/199 (72%) participants agreed to provide a urine sample. The likelihood of providing a urine sample was reduced if other individuals were present in the home at the time of interview (OR 0.42, 95% confidence interval 0.20-0.90, p=0.03). Trust and rapport with the interviewer, understanding the aims of the test, sense of obligation, and perceived importance of the test were identified as additional influencing factors in the in-depth interviews.

CONCLUSIONS

Survey respondents' uncertainty or embarrassment at participating in urine testing can be overcome if they are well informed, motivated by the potential health gain, and briefed by trained and confident interviewers.

Progression of autosomal-dominant polycystic kidney disease in children

BACKGROUND

Although many case reports describe manifestations of autosomal-dominant polycystic kidney disease (ADPKD) in children, no longitudinal studies have examined the natural progression or risk factors for more rapid progression in a large number of children from ADPKD families.

METHODS

Since 1985, we have studied 312 children from 131 families with a history, a physical examination, blood and urine chemistries, an abdominal ultrasonography, and gene linkage analysis. One hundred fifteen of 185 affected children were studied multiple times for up to 15 years. Renal volumes were determined by ultrasound imaging. Graphs of mean renal volumes according to age were compared between affected and unaffected children, ADPKD children with and without early severe disease, and children with and without high blood pressure.

RESULTS

Affected children had faster renal growth than unaffected children. ADPKD children with severe renal enlargement at a young age continued to experience faster renal growth than those with mild enlargement or normal kidney size for their age, and affected children with high blood pressure had faster renal growth than those with lower blood pressure. Glomerular filtration rate did not decrease in any children except for two with unusually severe early onset disease.

CONCLUSIONS

The progression of ADPKD clearly occurs in childhood and manifests as an increase in cyst number and renal size. This study identifies children at risk for rapid renal enlargement who may benefit the most from future therapeutic interventions.

Progression of autosomal-dominant polycystic kidney disease in children

BACKGROUND

Although many case reports describe manifestations of autosomal-dominant polycystic kidney disease (ADPKD) in children, no longitudinal studies have examined the natural progression or risk factors for more rapid progression in a large number of children from ADPKD families.

METHODS

Since 1985, we have studied 312 children from 131 families with a history, a physical examination, blood and urine chemistries, an abdominal ultrasonography, and gene linkage analysis. One hundred fifteen of 185 affected children were studied multiple times for up to 15 years. Renal volumes were determined by ultrasound imaging. Graphs of mean renal volumes according to age were compared between affected and unaffected children, ADPKD children with and without early severe disease, and children with and without high blood pressure.

RESULTS

Affected children had faster renal growth than unaffected children. ADPKD children with severe renal enlargement at a young age continued to experience faster renal growth than those with mild enlargement or normal kidney size for their age, and affected children with high blood pressure had faster renal growth than those with lower blood pressure. Glomerular filtration rate did not decrease in any children except for two with unusually severe early onset disease.

CONCLUSIONS

The progression of ADPKD clearly occurs in childhood and manifests as an increase in cyst number and renal size. This study identifies children at risk for rapid renal enlargement who may benefit the most from future therapeutic interventions.

Weight-related body image concerns among 18-24-year-old women in Canada and India: an empirical comparative study

OBJECTIVE

Sociocultural factors are important in the pathogenesis of eating disorders. We examined some core (DSM IV) features of eating disorders, i.e., drive for thinness and dissatisfaction with the weight of the abdomen, hips, and thighs among women in Canada and India.

METHODS

A total of 65 Canadian (mean+/-S.D. age: 21.4+/-2.0 years) and 47 Indian (mean+/-S.D. age: 18.7+/-4.1 years) women completed the Drive for Thinness (DT) and Body Dissatisfaction (BD) subscales of the Eating Disorder Inventory (EDI) and in addition rated the degree to which they believed all major regions of their body were overweight.

RESULTS

After the effects of body mass index (BMI) were partialled out statistically, the DT (EDI) and BD (EDI) scores were not significantly different between the two countries. In both groups, concerns about the weight of the abdomen, hips, thighs, and legs loaded on a factor that essentially described the 'body dissatisfaction' construct. After the effects of BMI were partialled out, however, the factor scores from this factor correlated with BD (EDI) in the Canadian but not the Indian sample.

DISCUSSION

In contrast to the Canadian women, the Indian women did not overestimate the 'fatness' of their abdomen, hips, thighs, and legs. Among the Indian women, concerns about the weight of the upper torso (i.e., face, neck, shoulders, and chest) emerged as a distinct body image construct. In conclusion, after the effect of BMI was controlled for statistically, the Canadian and Indian women scored similarly on some of the core features of eating disorders, as measured by the DT (EDI) and BD (EDI) subscales, however, the nature of the underlying body image construct was different between the two groups.

Von Hippel-Lindau disease masquerading as autosomal dominant polycystic kidney disease

The diagnostic confusion in differentiating the various causes of renal cystic diseases in adults is well documented. This confusion can include misclassifications between autosomal dominant polycystic kidney disease (ADPKD) and von Hippel-Lindau disease (VHL). We describe such a case of VHL. A review of the literature and of the patients in our database regarding typical features of each disease, mean age of onset, and frequency of these features was undertaken to provide helpful differentiating features. Pancreatic cysts are one differentiating feature. In VHL, pancreatic cysts can occur in 70% of patients, often are multiple, and rarely may cause exocrine or endocrine insufficiency. Pancreatic islet cell tumors occur. In ADPKD, pancreatic cysts are found in only 9% of patients, usually are single and asymptomatic, generally occur in conjunction with cystic liver disease, and are not found in children or unaffected family members. Pancreatic malignancies do not occur with increased frequency in ADPKD. A different pattern, especially in patients without a strong family history of ADPKD, may be a clue to VHL masquerading as ADPKD. Genetic mutation screening of the VHL gene should be used in these patients.

Diuretics versus angiotensin-converting enzyme inhibitors in autosomal dominant polycystic kidney disease

Hypertension, which occurs commonly and early in autosomal dominant polycystic kidney disease (ADPKD), affects both renal and patient outcome. However, there is no consensus about the type of antihypertensive therapy that is most appropriate for patients with ADPKD. This historical prospective, nonrandomized study was designed to investigate the effect on renal function of diuretics versus angiotensin-converting enzyme (ACE) inhibitors in hypertensive patients with ADPKD who entered the study with comparable renal function. Among hypertensive ADPKD patients followed in our center, patients taking diuretics without any ACE inhibitors were included in the diuretic group (n = 14, male/female ratio 5/9, mean age 47 years), whereas patients taking ACE inhibitors but no diuretics were included in the ACE inhibitor (ACEI) group (n = 19, male/female ratio 11/8, mean age 41 years). For comparable blood pressure control, 21% of the ACEI group and 64% of the diuretic group (p < 0.05) needed additional antihypertensive medications. After an average follow-up period of 5.2 years, the creatinine clearance decreased significantly in the diuretic group (74 vs. 46 ml/min/1.73 m2, p < 0.0001) and in the ACEI group (83 vs. 71 ml/min/1.73 m2, p = 0.0005). The decrement in creatinine clearance was significantly larger in the diuretic group than the ACEI group (p < 0.05). The annual decrease in creatinine clearance was 5.3 ml/min/1.73 m2 in the diuretic group and 2.7 ml/min/1.73 m2 in the ACEI group (p < 0.05). A significant increase in urinary protein excretion occurred in the diuretic but not in the ACEI group. Hypertensive ADPKD patients treated with diuretics had a faster loss of renal function as compared with patients treated with ACE inhibitors, despite similar blood pressure control. This result will need to be further examined in a randomized study.

Effect of computer-assisted self-interviews on reporting of sexual HIV risk behaviours in a general population sample: a methodological experiment

OBJECTIVES

To develop methods to maximize the accuracy of reporting HIV risk behaviours in a general population survey. We assessed the feasibility of using a computer-assisted self-completion interview (CASI) in comparison with pen-and-paper self-completion interview (PAPI).

DESIGN

A probability sample survey of residents aged 16-44 years in Britain, with alternate assignment of addresses to interview by CASI (462) or PAPI (439).

METHODS

Personal interviews exploring demographic and sexual behaviour variables. Principal outcome measures were the impact of CASI in relation to PAPI on data quality and rates of reporting a range of behaviours.

RESULTS

A total of 901 interviews were completed; 829 individuals were eligible for and accepted the self-completion module. Internal consistency of data items was greater with CASI than PAPI and item non-response was lower. Overall, there was no significant difference in rates of reporting between CASI and PAPI. The main effect for CASI compared with PAPI in a generalized estimating equation (GEE) analysis was an OR (95% CI) of 1.04 (0.92-1.17). Variables were also examined individually, including homosexual partnership (adjusted OR 1.26 95%, CI 0.69-2.29), payment for sex (adjusted OR 0.68 95% CI 0.29-1.59), masturbation (adjusted OR 0.89 95% CI 0.66 1.22) and five or more partners in the past 5 years (OR 0.85 95% CI 0.61 -1.19).

CONCLUSION

We found no evidence of a consistent effect of CASI on rates of reporting sexual HIV risk behaviours in this sample. CASI resulted in improvement in internal consistency and a reduction in missed questions.