Helen A Weiss

London School of Hygiene and Tropical Medicine, Londinium, England, United Kingdom

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Publications (206)1069.26 Total impact

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    ABSTRACT: South Africa's HIV prevalence among young people remains among the highest in the world. A cross-sectional study was carried out in 2012 to estimate prevalences of sexual risk behavior and hazardous alcohol use (HAU) (via the Alcohol Use Disorder Identification Test) as well as to investigate potential associations between these outcomes and social media use. In all, 4485 students (mean age 15.66 years, SD 1.39) at 46 secondary schools in informal settlements in Cape Town and Port Elizabeth completed mobile-phone-assisted, self-administered baseline questionnaires within a cluster-randomized trial. In all, 312 females (12.5 %) and 468 males (23.5 %) screened positive for HAU (AOR = 1.98, 95 % CI 1.69-2.34). 730 males (39.9 %) and 268 females (11.8 %) reported having had two or more partners in the last year (AOR = 3.46, 95 % CI 2.87-4.16). Among females, having a Facebook account was associated with reported multiple partnerships in the last year (AOR = 1.81, 95 % CI 1.19-2.74), age-disparate sex in the last year (AOR = 1.96, 95 % CI 1.16-3.32) and HAU (AOR = 1.97, 95 % CI 1.41-2.74). Using Mxit-a popular mobile instant messaging application-was associated with higher odds of reported multiple partnerships in the last year among both males (AOR = 1.70, 95 % CI 1.35-2.14) and females (AOR = 1.45, 95 % CI 1.07-1.96) and with HAU among both males (AOR = 1.47, 95 % CI 1.14-1.90) and females (AOR = 1.50, 95 % CI 1.18-1.90). Further longitudinal and qualitative research should explore in more depth the observed links between social media and risk behavior.
    AIDS and Behavior 06/2014; · 3.49 Impact Factor
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    ABSTRACT: It is perceived that little is known about the epidemiology of HIV infection among people who inject drugs (PWID) in the Middle East and North Africa (MENA). The primary objective of this study was to assess the status of the HIV epidemic among PWID in MENA by describing HIV prevalence and incidence. Secondary objectives were to describe the risk behavior environment and the HIV epidemic potential among PWID, and to estimate the prevalence of injecting drug use in MENA.
    PLoS Medicine 06/2014; 11(6):e1001663. · 15.25 Impact Factor
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    ABSTRACT: Trachoma, caused by ocular infection with Chlamydia trachomatis, is hyperendemic on the Bijagós Archipelago of Guinea Bissau. An understanding of the risk factors associated with active trachoma and infection on these remote and isolated islands, which are atypical of trachoma-endemic environments described elsewhere, is crucial to the implementation of trachoma elimination strategies.
    PLoS neglected tropical diseases. 06/2014; 8(6):e2900.
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    ABSTRACT: No longitudinal data from population-based studies of eye disease in sub-Saharan-Africa are available. A population-based survey was undertaken in 2007/08 to estimate the prevalence and determinants of blindness and low vision in Nakuru district, Kenya. This survey formed the baseline to a six-year prospective cohort study to estimate the incidence and progression of eye disease in this population.
    BMC Ophthalmology 05/2014; 14(1):60. · 1.44 Impact Factor
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    ABSTRACT: The leading mental health causes of the global burden of disease are depression in women and alcohol use disorders in men. A major hurdle to the implementation of evidence-based psychological treatments in primary care in developing countries is the non-availability of skilled human resources. The aim of these trials is to evaluate the effectiveness and cost-effectiveness of two psychological treatments developed for the treatment of depression and alcohol use disorders in primary care in India.Methods/design: This study protocol is for parallel group, randomized controlled trials (Healthy Activity Program for moderate to severe depression, Counselling for Alcohol Problems for harmful and dependent drinking) in eight primary health centres in Goa, India. Adult primary care attendees will be screened with the Patient Health Questionnaire for depression and, in men only, the Alcohol Use Disorders Identification Test for drinking problems. Screen-positive attendees will be invited to participate; men who screen positive for both disorders will be invited to participate in the Counselling for Alcohol Problems trial. Those who consent will be allocated in a 1:1 ratio to receive either the respective psychological treatment plus enhanced usual care or enhanced usual care only using a computer generated allocation sequence, stratified by primary health centre and, for depression, by sex. The enhanced usual care comprises providing primary health centre doctors with contextualized World Health Organization guidelines and screening results. Psychological treatments will be delivered by lay counsellors, over a maximum period of three months. Primary outcomes are severity of disorder and remission rates at three months post-enrolment and, for the Counselling for Alcohol Problems trial, drinking and the impact of drinking on daily lives. Secondary outcomes include severity of disorder and remission rates at 12 months, disability scores, suicidal behaviour and economic impact, and cost-effectiveness at three and 12 months. 500 participants with depression and 400 participants with harmful drinking will be recruited. Primary analyses will be intention-to-treat. These trials may offer a new approach for the treatment of moderate-severe depression and drinking problems in primary care that is potentially scalable as it relies on delivery by a single pool of lay counsellors.Trial registration: Both trials are registered with the International Society for the Registration of Clinical Trials (Healthy Activity Programme registration number ISRCTN95149997; Counselling for Alcohol Problems registration number ISRCTN76465238).
    Trials 04/2014; 15(1):101. · 2.21 Impact Factor
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    ABSTRACT: Cross-sectional studies have shown a strong association between Mycoplasma genitalium and HIV infections. We previously reported that in a cohort of female sex workers in Uganda, M genitalium infection at baseline was associated with HIV seroconversion. Here we examine the temporal association between the M genitalium infection status shortly before HIV seroconversion and HIV acquisition. A nested case-control study was conducted within a cohort of women at high risk for HIV in Kampala. Cases were those of women acquiring HIV within 2 years of enrolment. For each of the 42 cases, 3 controls were selected from women HIV negative at the visit when the corresponding case first tested HIV seropositive. The association between HIV acquisition and M genitalium infection immediately prior to HIV testing was analysed using conditional logistic regression. There was weak evidence of an association between M genitalium infection and HIV acquisition overall (crude OR=1.57; 95% CI 0.67 to 3.72, aOR=2.28: 95% CI 0.81 to 6.47). However, time of M genitalium testing affected the association (p value for effect-modification=0.004). For 29 case-control sets with endocervical samples tested 3 months prior to the first HIV-positive result, M genitalium infection increased the risk of HIV acquisition (crude OR=3.09; 95% CI 1.06 to 9.05, aOR=7.19; 95% CI 1.68 to 30.77), whereas there was little evidence of an association among the 13 case-control sets with samples tested at an earlier visit (crude OR=0.30: 95% CI 0.04 to 2.51; aOR=0.34; 95% CI 0.02 to 5.94). Our study showed evidence of a temporal relationship between M genitalium infection and HIV acquisition that suggests that M genitalium infection may be a co-factor in the acquisition of HIV infection.
    Sexually transmitted infections 03/2014; · 2.18 Impact Factor
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    ABSTRACT: Observational evidence suggests that community-based services for people with schizophrenia can be successfully provided by community health workers, when supervised by specialists, in low-income and middle-income countries. We did the COmmunity care for People with Schizophrenia in India (COPSI) trial to compare the effectiveness of a collaborative community-based care intervention with standard facility-based care. We did a multicentre, parallel-group, randomised controlled trial at three sites in India between Jan 1, 2009 and Dec 31, 2010. Patients aged 16-60 years with a primary diagnosis of schizophrenia according to the tenth edition of the International Classification of Diseases, Diagnostic Criteria for Research (ICD-10-DCR) were randomly assigned (2:1), via a computer-generated randomisation list with block sizes of three, six, or nine, to receive either collaborative community-based care plus facility-based care or facility-based care alone. Randomisation was stratified by study site. Outcome assessors were masked to group allocation. The primary outcome was a change in symptoms and disabilities over 12 months, as measured by the positive and negative syndrome scale (PANSS) and the Indian disability evaluation and assessment scale (IDEAS). Analysis was by modified intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN 56877013. 187 participants were randomised to the collaborative community-based care plus facility-based care group and 95 were randomised to the facility-based care alone group; 253 (90%) participants completed follow-up to month 12. At 12 months, total PANSS and IDEAS scores were lower in patients in the intervention group than in those in the control group (PANSS adjusted mean difference -3·75, 95% CI -7·92 to 0·42; p=0·08; IDEAS -0·95, -1·68 to -0·23; p=0·01). However, no difference was shown in the proportion of participants who had a reduction of more than 20% in overall symptoms (PANSS 85 [51%] in the intervention group vs 44 [51%] in the control group; p=0·89; IDEAS 75 [48%] vs 28 [35%]). We noted a significant reduction in symptom and disability outcomes at the rural Tamil Nadu site (-9·29, -15·41 to -3·17; p=0·003). Two patients (one in each group) died by suicide during the study, and two patients died because of complications of a road traffic accident and pre-existing cardiac disease. 18 (73%) patients (17 in the intervention group) were admitted to hospital during the course of the trial, of whom seven were admitted because of physical health problems, such as acute gastritis and vomiting, road accident, high fever, or cardiovascular disease. The collaborative community-based care plus facility-based care intervention is modestly more effective than facility-based care, especially for reducing disability and symptoms of psychosis. Our results show that the study intervention is best implemented as an initial service in settings where services are scarce, for example in rural areas. Wellcome Trust.
    The Lancet 03/2014; · 39.06 Impact Factor
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    ABSTRACT: Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) are common sexually transmitted infections (STI). We assessed the cumulative risk of NG and CT in a cohort of HIV-1-infected high-risk women taking antiretrovirals over 4 years in Burkina Faso. Between March 2007 and February 2011, participants were followed every 3-6 months. At each visit, participants underwent a gynaecological examination with collection of cervical and vaginal swabs. Random-effects logistic regression models were used to analyse associations of NG and CT infection with behavioural and biological factors. 172 women had samples tested for NG and CT during the study period, in a total of 1135 visits. NG was detected in 6.4% of women (11/172, 95% CI 2.7 to 10.1) at a rate of 2.76 cases (95% CI 1.53 to 4.99) per 100 person-years. CT was detected in 1.7% (3/172, 95% CI 0 to 3.7) of women at a rate of 0.75 cases (95% CI 0.24 to 2.34) per 100 person-years. The majority of women were asymptomatic (9/14). In the multivariable model, the presence of NG or CT was associated with tobacco use (aOR=11.85, 95% CI 1.13 to 124.17), and concurrent genital HIV-1 RNA shedding (aOR=4.78, 95% CI 1.17 to 19.46). Higher levels of education (aOR=0.17, 95% CI 0.03 to 0.92), and age greater than 35 years (aOR=0.07, 95% CI 0.01 to 0.92) were associated with lower odds of infection. The risk of NG or CT infection remains low among high-risk women in Bobo-Dioulasso. This provides some evidence that antiretroviral use does not contribute to behavioural disinhibition. The asymptomatic nature of most infections underscores the need for regular screening and treatment of STIs in core groups.
    Sexually transmitted infections 03/2014; 90(2):100-3. · 2.18 Impact Factor
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    ABSTRACT: Systematic review and meta-analysis of published studies of alcohol use among young people (age 15-24 years) in eastern Africa to estimate prevalence of alcohol use and determine the extent of use of standardised screening questionnaires in alcohol studies. Five databases (MEDLINE, EMBASE, Global Health, Africa-wide, and PsycINFO) were searched for publications until 30th June 2013. Results were summarised using the guidelines on preferred reporting items for systematic reviews and meta-analyses (PRISMA) and on quality assessment using the modified quality assessment tool for systematic reviews of observational studies (QATSO). Heterogeneity was assessed using the I(2) statistic (DerSimonian-Laird). We identified 2785 potentially relevant studies, of which 56 were eligible for inclusion. Only two studies (4%) used the standardised Alcohol Use Disorder Identification Test (AUDIT) questionnaire, and six studies (13%) used the Cut down, Annoyed, Guilt, Eye opener (CAGE) questionnaire. The reported median prevalence of alcohol use was ever-use 52% [interquartile range (IQR): 20-58%], use in the last month 28% (IQR: 17-37%), use in the last year 26% (IQR: 22-32%), and problem drinking as defined by CAGE or AUDIT 15% (IQR: 3-36%). We observed high heterogeneity between studies, with the highest prevalence of ever use of alcohol among university students (82%; 95%CI: 79-85%) and female sex workers (66%; 95%CI: 58-74%). Current use was most prevalent among male sex workers (69%; 95%CI: 63-75%). Reported alcohol use and problem drinking were common among diverse groups of young people in eastern Africa, indicating the urgent need for alcohol-focused interventions in this population. Few studies have used standardised alcohol screening questionnaires. Epidemiological research to investigate alcohol-focused interventions in young people should aim to apply such questionnaires that should be validated for use in this population.
    Tropical Medicine & International Health 01/2014; · 2.94 Impact Factor
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    ABSTRACT: Psychological treatments delivered by lay therapists, with little or no previous mental health training, have been shown to be effective in treating a range of mental health problems. In low resource settings, the dearth of available experts to assess therapy quality potentially leads to a bottleneck in scaling up lay therapist delivered psychological treatments. Peer-led supervision and the assessment of therapy quality may be one solution to address this barrier. The purpose of this study was two-fold: 1) to assess lay therapist quality ratings compared to expert supervisors in a multisite study where lay therapists delivered locally developed, psychological treatments for harmful and dependent drinking and severe depression; 2) assess the acceptability and feasibility of peer-led supervision compared to expert-led supervision. We developed two scales, one for each treatment, to compare lay therapist and expert ratings on audio-taped treatment sessions (n=189). Our findings confirmed our primary hypothesis of increased levels of agreement between peer and expert ratings over three consecutive time periods as demonstrated by a decrease in the differences in mean therapy quality rating score. This study highlights that lay therapists can be trained to effectively assess each other’s therapy sessions as well as experts, and that peer-led supervision is acceptable for lay therapists, thus, enhancing the scalability of psychological treatments in low-resource settings.
    Behaviour Research and Therapy. 01/2014;
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    ABSTRACT: To examine the reliability of clinical examination and in vivo confocal microscopy (IVCM) in distinguishing ocular surface squamous neoplasia (OSSN) from benign conjunctival lesions. Case-control study. Sixty individuals with conjunctival lesions (OSSN and benign) and 60 age-matched controls with normal conjunctiva presenting to Kilimanjaro Christian Medical Centre, Moshi, Tanzania. Participants were examined and photographed, and IVCM was performed. Patients with conjunctival lesions were offered excisional biopsy with histopathology and a human immunodeficiency virus (HIV) test. The IVCM images were read masked to the clinical appearance and pathology results. Images were graded for several specific features and given an overall categorization (normal, benign, or malignant). A group of 8 ophthalmologists were shown photographs of conjunctival lesions and asked to independently classify as OSSN or benign. Comparison of the histopathology diagnosis with the clinical and IVCM diagnosis. Fifty-two cases underwent excisional biopsy with histopathology; 34 were on the OSSN spectrum, 17 were benign, and 1 was lymphoma. The cases and controls had comparable demographic profiles. Human immunodeficiency syndrome infection was more common in OSSN compared with benign cases (58.8% vs. 5.6%; odds ratio, 24.3, 95% confidence interval [CI], 2.8-204; P = 0.003). Clinically, OSSN lesions more frequently exhibited feeder vessels and tended to have more leukoplakia and a gelatinous appearance. Overall, the ophthalmologists showed moderate agreement with the histology result (average kappa = 0.51; 95% CI, 0.36-0.64). The masked grading of IVCM images reliably distinguished normal conjunctiva. However, IVCM was unable to reliably distinguish between benign lesions and OSSN because of an overlap in their appearance (kappa = 0.44; 95% CI, 0.32-0.57). No single feature was significantly more frequent in OSSN compared with benign lesions. The sensitivity and specificity of IVCM for distinguishing OSSN from benign conjunctival lesions were 38.5% and 66.7%, respectively. In East Africa, conjunctival pathology is relatively common and can present significant diagnostic challenges for the clinician. In this study, neither clinical examination nor IVCM was found to reliably distinguish OSSN from benign conjunctival pathology because of an overlap in the features of these groups. Therefore, IVCM cannot currently replace histopathology, and management decisions should continue to rely on careful clinical assessment supported by histopathology as indicated. The author(s) have no proprietary or commercial interest in any materials discussed in this article.
    Ophthalmology 12/2013; · 5.56 Impact Factor
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    ABSTRACT: The World Health Organization recommends the use of syndromic management for patients presenting with genital ulcer disease (GUD) in developing countries. However, effective treatment guidelines depend on a current country-specific GUD etiological profile, which may change over time. From 2004 to 2006, we conducted a cross-sectional analysis of baseline data from patients presenting with GUD at a reference STI clinic in Lilongwe, Malawi. Participants were enrolled in a randomized clinical trial of acyclovir added to syndromic management and followed up for up to 28 days. Serologies for HIV (using parallel rapid tests), herpes simplex virus type 2 (HSV-2; using Focus HerpeSelect IgG2 ELISA [Focus Technologies, Cypress Hill, CA]), and syphilis (rapid plasma reagin confirmed by Treponema pallidum hemagglutination) were determined, with plasma HIV-1 RNA and CD4 count in HIV-positive patients. Genital ulcer disease etiology was determined by real-time multiplex polymerase chain reaction from lesional swabs. A total of 422 patients with GUD (313 men; 74%) were enrolled. Overall seroprevalence of HIV-1, HSV-2, and syphilis were 61%, 72%, and 5%, respectively. Ulcer etiology was available for 398 patients and showed the following: HSV-2, 67%; Haemophilus ducreyi, 15%; T. pallidum, 6%; lymphogranuloma venereum, 6%; mixed infections, 14%, and no etiology, 20%. Most HSV-2 ulcers were recurrent (75%). Among all patients with HSV-2, HIV prevalence was high (67%) and HIV seroprevalence was higher among patients with recurrent HSV-2 compared with patients with first-episode HSV-2 (78% vs. 39%, P < 0.001). Herpes simplex virus type 2 ulcers are highly prevalent in this symptomatic population and strongly associated with HIV. Unlike most locations in sub-Saharan Africa, H. ducreyi remains prevalent in this population and requires periodic monitoring and an appropriate treatment regimen.
    Sexually transmitted diseases 12/2013; 40(12):923-8. · 2.58 Impact Factor
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    ABSTRACT: To describe the epidemiology and an aetiological model of ocular surface squamous neoplasia (OSSN) in Africa. Systematic and non-systematic review methods were used. Incidence was obtained from the International Agency for Research on Cancer. We searched PubMed, EMBASE, Web of Science and the reference lists of articles retrieved. Meta-analyses were conducted using a fixed-effects model for HIV and cigarette smoking and random effects for human papilloma virus (HPV). The incidence of OSSN is highest in the Southern Hemisphere (16° South), with the highest age-standardised rate (ASR) reported from Zimbabwe (3.4 and 3.0 cases/year/100 000 population for males and females, respectively). The mean ASR worldwide is 0.18 and 0.08 cases/year/100 000 among males and females, respectively. The risk increases with exposure to direct daylight (2-4 h, OR = 1.7, 95% CI: 1.2-2.4 and ≥5 h OR = 1.8, 95% CI: 1.1-3.1) and outdoor occupations (OR = 1.7, 95% CI: 1.1-2.6). Meta-analysis also shows a strong association with HIV (6 studies: OR = 6.17, 95% CI: 4.83-7.89) and HPV (7 studies: OR = 2.64, 95% CI: 1.27-5.49) but not cigarette smoking (2 studies: OR = 1.40, 95% CI: 0.94-2.09). The effect of atopy, xeroderma pigmentosa and vitamin A deficiency is unclear. Africa has the highest incidence of OSSN in the world, where males and females are equally affected, unlike other continents where male disease predominates. African women probably have increased risk due to their higher prevalence of HIV and HPV infections. As the survival of HIV-infected people increases, and given no evidence that anti-retroviral therapy (ART) reduces the risk of OSSN, the incidence of OSSN may increase in coming years.
    Tropical Medicine & International Health 12/2013; 18(12):1424-43. · 2.94 Impact Factor
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    AIDS (London, England) 11/2013; 27(17):2826-7. · 4.91 Impact Factor
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    ABSTRACT: Antiretroviral therapy (ART) reduces transmission of HIV-1. However, genital HIV-1 can be detected in patients on ART. We analyzed factors associated with genital HIV-1 shedding among high-risk women on ART in Burkina Faso. Plasma (PVL) and enriched cervico-vaginal lavage HIV-1 RNA were measured every 3-6 months for up to 8 years. Random-effects logistic and linear regression models were used to analyze associations of frequency and quantity of genital HIV-1 RNA with behavioral and biological factors, adjusting for within-woman correlation. The lower limit of detection of HIV-1 RNA in plasma and eCVL samples was 300 copies/ml. 188 participants initiated ART from 2004 to 2011. PVL was detectable in 16% (171/1050) of visits, in 52% (90/174) of women. Cervico-vaginal HIV-1 RNA was detectable in 16% (128/798) of visits with undetectable plasma HIV-1 RNA, in 45% (77/170) of women. After adjusting for PVL, detectable cervico-vaginal HIV-1 RNA was independently associated with abnormal vaginal discharge, and use of nevirapine or zidovudine vs. efavirenz and stavudine respectively; longer time on ART and hormonal contraception were not associated with increased shedding. The presence of bacterial vaginosis, Herpes Simplex Virus-2 (HSV-2) DNA, and the use of nevirapine vs efavirenz were independently associated with an increased quantity of cervico-vaginal HIV-1 RNA. Certain ART regimens, abnormal vaginal discharge, bacterial vaginosis and genital HSV-2 are associated with HIV-1 cervico-vaginal shedding or quantity in women on ART after adjusting for PVL. This may reduce the effectiveness of ART as prevention in high-risk populations.
    JAIDS Journal of Acquired Immune Deficiency Syndromes 11/2013; · 4.65 Impact Factor
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    ABSTRACT: To assess the long-term effects of population-level HSV-2 infection on HIV incidence. Data from a population-based cohort in south-western Uganda were used to estimate HIV incidence from 1990 to 2007. Stored blood samples were tested for HSV-2, and the impact of HSV-2 prevalence and incidence on HIV incidence was estimated by calculating population attributable fractions (PAFs). The association between population-level annual HIV incidence and annual HSV-2 incidence/prevalence was analysed using linear regression. HIV incidence declined over time among men, from 8.72/1000 person-years (pyr) in 1990 to 4.85/1000 pyr in 2007 (P-trend <0.001). In contrast, there was no decline in HIV incidence among women (4.86/1000 pyr in 1990 to 6.74/1000 pyr in 2007, P-trend = 0.18). PAFs of incident HIV attributable to HSV-2 were high (60% in males; 70% in females). There was no evidence of an association between long-term trends in HIV incidence and HSV-2 prevalence or incidence. Assuming a causal relationship, a substantial proportion of new HIV infections in this population are attributable to HSV-2. The study did not find an effect of HSV-2 prevalence/incidence on trends in HIV incidence. HIV incidence did not vary much during the study period. This may partly explain the lack of association.
    Tropical Medicine & International Health 10/2013; 18(10):1257-66. · 2.94 Impact Factor
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    ABSTRACT: HIV-infected individuals have an increased risk of age-related morbidity despite antiretroviral treatment (ART). Several anatomic and functional ophthalmological parameters are associated with increasing chronological age. These may, therefore, potentially serve as biomarkers of ageing. We investigated associations between ocular parameters (lens density, retinal vessel calibre, corneal endothelium and retinal nerve fibre layer thickness) and two 'cellular' biomarkers of ageing (leukocyte telomere length and CDKN2A expression) and with frailty in a cross-sectional study of 216 HIV-infected individuals. All ocular parameters, telomere length and frailty were associated with chronological age, whereas CDKN2A expression was not. Retinal venular calibre and lens density were associated with shorter telomere length (p-trend=0.04, and 0.08, respectively), whereas CDKN2A expression and frailty status were not associated with ocular parameters. Longitudinal studies are warranted to assess the integration of retinal vascular calibre and lens density with systemic markers to develop an overall index of biological ageing in HIV infection.
    Mechanisms of ageing and development 08/2013; · 4.18 Impact Factor
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    ABSTRACT: To compare in vivo confocal microscopy (IVCM) with the histopathological examination of tissue and cellular changes in normal and diseased conjunctiva. Participants underwent clinical examination and IVCM of the tarsal conjunctiva. A biopsy of the upper tarsal conjunctiva was collected and stained with tinctorial stains and by immunohistochemical staining for CD45 and CD83. Connective tissue scarring, inflammatory cell density and the presence of dendritiform cells were quantitatively assessed in a masked manner by both IVCM and histological assessments for comparative analysis. Thirty-four participants with severe trachomatous conjunctival scarring and 33 participants with healthy conjunctiva were recruited. The IVCM connective tissue scarring score was strongly associated with the histological grading of scarring (p<0.001). There was limited evidence of an association between the IVCM inflammatory cell infiltrate and the histological inflammatory cell grade (p=0.05). We did not find any evidence to support the hypothesis that dendritiform cells seen with IVCM are mature, conventional dendritic cells. The results show that IVCM can be used to robustly quantitate connective tissue scarring and also has a role in measuring the inflammatory cell infiltrate. The discordance between IVCM dendritiform cells and immunohistochemical dendritic cells may be a result of study limitations or may be because these dendritiform structures represent another cell type, such as fibroblasts, rather than dendritic cells.
    The British journal of ophthalmology 08/2013; · 2.92 Impact Factor
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    ABSTRACT: OBJECTIVES:: Little is known about the impact of HIV infection on biological aging in sub-Saharan Africa. The study aimed to assess biological aging in South African HIV-infected adults and HIV-seronegative individuals using two validated biomarkers, telomere length and CDKN2A expression (a mediator of cellular senescence). DESIGN:: Case-control study METHODS:: 236 HIV-infected adults aged ≥30 years and 250 age- and gender frequency-matched HIV-seronegative individuals were recruited from clinics in township communities in Cape Town. Biological aging was evaluated by measurement of telomere length and CDKN2A expression in peripheral blood leukocytes. RESULTS:: The median ages of the HIV-infected and HIV-seronegative participants were 39 years and 40 years respectively. Among HIV-infected participants, 87.1% were receiving anti-retroviral therapy (ART), their median CD4 count was 468 cells/μL and 84.3% had undetectable viral load. Both biomarkers were validated against chronological age in HIV-seronegative individuals. Telomere length was significantly shorter in HIV-infected individuals compared to HIV-seronegative individuals (mean relative T/S ratio±SE:0.91 ± 0.007 vs. 1.07 ± 0.008, p < 0.0001). CD2NKA expression was higher in HIV-infected participants compared to HIV-seronegative individuals (mean expression: 0.45 ± 0.02 vs. 0.36 ± 0.03, p = 0.003). Socio-economic factors were not associated with biological aging in HIV-infected participants. However, in participants on ART with undetectable viral load, biomarker levels indicated greater biological aging in those with lower current CD4 counts. CONCLUSIONS:: Telomere length and CDKN2A expression were both consistent with increased biological aging in HIV-infected individuals. Prospective studies of the impact of HIV on biological aging in sub-Saharan Africa are warranted.
    AIDS (London, England) 06/2013; · 4.91 Impact Factor
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    ABSTRACT: Certain anatomic and functional parameters of the eye change with increasing chronological age. They may, therefore, serve as potential biomarkers of ageing. We investigated associations between four such ocular parameters (lens density, retinal vessel calibre, corneal endothelial cells and retinal nerve fibre layer thickness) and two 'cellular' biomarkers of ageing (leukocyte telomere length and CDKN2A expression), with frailty (a clinical correlate of biological ageing) in a population of South African adults. All ocular parameters revealed an association with either telomere length or CDKN2A expression. However, lens density was most strongly correlated with age, increased CDKN2A expression, and with frailty (p=0.05 and 0.03, respectively). Narrow retinal arteriolar diameter, associated with increased chronological age, was also associated with increased CDK2NA expression (0.42 vs. 0.31, p=0.02) but not with frailty. Ocular parameters may aid in determining biological age, warranting investigation in longitudinal studies.
    Mechanisms of ageing and development 05/2013; · 4.18 Impact Factor

Publication Stats

5k Citations
1,069.26 Total Impact Points

Institutions

  • 2000–2014
    • London School of Hygiene and Tropical Medicine
      • • Department of Infectious Disease Epidemiology
      • • Department of Population Health
      • • Department of Clinical Research
      • • Faculty of Epidemiology and Population Health
      • • Tropical Epidemiology Group (TEG)
      Londinium, England, United Kingdom
    • Centers for Disease Control and Prevention
      • Division of HIV/AIDS Prevention, Surveillance and Epidemiology
      Atlanta, MI, United States
  • 2013
    • University of Nairobi
      Nairoba, Nairobi Area, Kenya
    • Stellenbosch University
      • Department of Psychiatry
      Stellenbosch, Province of the Western Cape, South Africa
  • 2012–2013
    • University of Cape Town
      • Institute of Infectious Disease & Molecular Medicine (IIDMM)
      Cape Town, Province of the Western Cape, South Africa
    • University of Sydney
      • School of Medical Sciences
      Sydney, New South Wales, Australia
    • Medical Research Council / Uganda Virus Research Institute
      Entebbe, Central Region, Uganda
    • Johns Hopkins Bloomberg School of Public Health
      Baltimore, Maryland, United States
  • 2011–2013
    • Uganda Virus Research Institute
      Entebbe, Central Region, Uganda
    • South London and Maudsley NHS Foundation Trust
      Londinium, England, United Kingdom
    • Zambia AIDS Related Tuberculosis
      Lusaka, Lusaka, Zambia
    • Hôpital Européen Georges-Pompidou (Hôpitaux Universitaires Paris-Ouest)
      Lutetia Parisorum, Île-de-France, France
    • Paris Diderot University
      Lutetia Parisorum, Île-de-France, France
    • University of Manitoba
      • Department of Internal Medicine
      Winnipeg, Manitoba, Canada
    • University College London
      • Department of Infection and Population Health
      London, ENG, United Kingdom
    • University of Washington Seattle
      • Department of Global Health
      Seattle, WA, United States
  • 2010–2013
    • Kilimanjaro Christian Medical Centre
      • Department of Ophthalmology
      Moschi, Kilimanjaro, Tanzania
  • 2009
    • Fred Hutchinson Cancer Research Center
      • Biostatistics and Biomathematics Program
      Seattle, WA, United States
    • University of the Witwatersrand
      Johannesburg, Gauteng, South Africa
    • University of São Paulo
      San Paulo, São Paulo, Brazil
    • Ealing Hospital NHS Trust
      Londinium, England, United Kingdom
  • 2005–2009
    • Inštitut za vode Republike Slovenije
      Lubliano, Ljubljana, Slovenia
    • Instituto de Infectologia Emílio Ribas
      San Paulo, São Paulo, Brazil
  • 2003–2009
    • Imperial College London
      • • Department of Infectious Disease Epidemiology
      • • Faculty of Medicine
      London, ENG, United Kingdom
    • Oxford University Hospitals NHS Trust
      • Department of Paediatrics
      Oxford, ENG, United Kingdom
    • Latrobe Regional Hospital
      Latrobe, Tasmania, Australia
  • 2008
    • National Institute for Medical Research (NIMR)
      Dār es Salām, Dar es Salaam, Tanzania
  • 2001–2008
    • Université René Descartes - Paris 5
      Lutetia Parisorum, Île-de-France, France
  • 2004–2007
    • Kwame Nkrumah University Of Science and Technology
      • School of Medical Sciences
      Coomassie, Ashanti, Ghana