1,721,275 research outputs found
The impact of vitamin D supplementation on musculoskeletal health outcomes in children, adolescents, and young adults living with HIV: a systematic review
No full textObjective:HIV-positive children, adolescents, and young adults are at increased risk poor musculoskeletal outcomes. Increased incidence of vitamin D deficiency in youth living with HIV may further adversely affect musculoskeletal health. We investigated the impact of vitamin D supplementation on a range of musculoskeletal outcomes among individuals aged 0–25 years living with HIV.Methods:A systematic review was conducted using databases: PubMed/Medline, CINAHL, Web of Knowledge, and EMBASE. Interventional randomised control trials, quasi-experimental trials, and previous systematic reviews/meta-analyses were included. Outcomes included: BMD, BMC, fracture incidence, muscle strength, linear growth (height-for-age Z-score [HAZ]), and biochemical/endocrine biomarkers including bone turnover markers.Results:Of 497 records, 20 studies met inclusion criteria. Thirteen studies were conducted in North America, one in Asia, two in Europe, and four in Sub-Saharan Africa. High-dose vitamin D supplementation regimens (1,000–7,000 IU/day) were successful in achieving serum 25-hydroxyvitamin-D (25OHD) concentrations above study-defined thresholds. No improvements were observed in BMD, BMC, or in muscle power, force and strength; however, improvements in neuromuscular motor skills were demonstrated. HAZ was unaffected by low-dose (200–400 IU/day) supplementation. A single study found positive effects on HAZ with high-dose supplementation (7,000 vs 4,000IU/day).Conclusions:Measured bone outcomes were unaffected by high-dose vitamin D supplementation, even when target 25OHD measurements were achieved. This may be due to: insufficient sample size, follow-up, intermittent dosing, non-standardised definitions of vitamin D deficiency, or heterogeneity of enrolment criteria pertaining to baseline vitamin D concentration. High-dose vitamin D may improve HAZ and neuromuscular motor skills. Adequately powered trials are needed in settings where HIV burden is greatest
Prevalence of HIV-associated osteoporosis and fracture risk in mid-life women: a cross-sectional study in Zimbabwe
No full textAntiretroviral therapy roll-out has dramatically reduced HIV related-mortality; more women are living to reach menopause. Menopausal estrogen loss causes bone loss, as does HIV and some of its treatments. However, data describing HIV’s impact on osteoporosis prevalence and fracture risk are scarce in southern Africa.A cross-sectional study of women aged 40-60 years (49% women living with HIV (WLH)) was conducted in Harare, Zimbabwe. Menopause, fracture and HIV history were collected, and anthropometry and bone mineral density (BMD, by dual-energy x-ray absorptiometry (DXA)) measured, and FRAX® 10-year fracture probabilities quantified. The FRAX® probability of a major osteoporotic fracture (MOF) included HIV as a risk factor for secondary osteoporosis. Linear and Poisson regression determined the relationships between clinical risk factors and both femoral neck (FN) BMD and the 10-year FRAX® probability of MOF respectively.The 393 participants had mean(SD) age of 49.6(SD = 5.8) years and mean(SD) BMI 29.1(6) kg/m2. 95% of WLH were ART established (85% TDF) and 81% had a viral load <50 copies/mL. A BMD T-Score ≤ -2.5 was more common in WLH than those without, at both FN and lumbar spine (LS) (FN 22[11.4%] vs 5[2.5%], LS 40[20.8%] vs 9[4.5%]; respectively). Prior fracture was more prevalent in WLH: any fracture type (27[14%] vs. 14[7%]); MOF (14[7.3%] vs. 5[2.5%]). WLH had a higher 10-year MOF probability [median 1.2%; IQR: 0.9-1.8] compared with those without HIV [1.0%; IQR: 0.9-1.5] (P<.001), although probabilities were low. Older age, low weight, and HIV infection were strongly associated with lower FN BMD. Higher probability of MOF was associated with older age, HIV infection, parental hip fracture and prior fracture, though adjustment attenuated the association with HIV. No woman reported anti-osteoporosis medication use.While osteoporosis and previous fractures were common and untreated in this relatively young population, particularly in WLH, the FRAX® predicted 10-year MOF risk was low. Clinical risk factors considered in fracture risk prediction tools in Zimbabwe may need contextual modification
The association between antimicrobial resistance and HIV infection: a systematic review and meta-analysis
Full text linkBACKGROUND: People living with HIV (PLWH) are at increased risk of infections with resistant organisms due to more frequent healthcare utilisation.OBJECTIVES: investigate the association between HIV and antimicrobial resistance (AMR).DATA SOURCES: we searched MEDLINE, EMBASE, Web of Science, LILACS and African Journals Online.STUDY ELIGIBILITY CRITERIA: Studies reporting on AMR for colonisation or infection with bacterial pathogens excluding mycobacteria and bacteria causing sexual transmitted infections stratified by HIV status, species and antimicrobials tested.PARTICIPANTS: any.INTERVENTIONS: none.METHODS: Pooled odds ratios were used to evaluate the association between HIV and resistance.RESULTS: A total of 92 studies published between 1995 and 2020 were identified. The studies included the following organisms: Staphylococcus (n=47), Streptococcus pneumoniae (n=28), Escherichia coli (n=6) and other Gram-negative bacteria. PLWH had a 2.12 (95% CI 1.36-3.30) higher odds for colonization and 1.90 (95%CI 1.45-2.48) higher odds for infection with methicillin-resistant S. aureus; a 2.28 (95%CI 1.75-2.97) higher odds of infections with S. pneumoniae with decreased penicillin susceptibility and a 1.59 (95%CI 0.83-3.05) higher odds of resistance to third-generation cephalosporins in E. coli and Klebsiella pneumoniae.CONCLUSION: . This review shows an increased risk of AMR in PLWH across a range of bacterial pathogens and multiple drug classes. The lack of laboratory capacity for identifying AMR and limited access to alternative treatment options in countries with the highest burden of HIV highlights the need for more research on AMR in PLWH. Overall, the quality of studies was moderate or low which may impact the findings of this review
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The IMpact of Vertical HIV infection on child and Adolescent SKeletal development in Harare, Zimbabwe (IMVASK Study): a protocol for a prospective cohort study.
Full text linkINTRODUCTION: The scale-up of antiretroviral therapy (ART) across sub-Saharan Africa (SSA) has reduced mortality so that increasing numbers of children with HIV (CWH) are surviving to adolescence. However, they experience a range of morbidities due to chronic HIV infection and its treatment. Impaired linear growth (stunting) is a common manifestation, affecting up to 50% of children. However, the effect of HIV on bone and muscle development during adolescent growth is not well characterised. Given the close link between pubertal timing and musculoskeletal development, any impairments in adolescence are likely to impact on future adult musculoskeletal health. We hypothesise that bone and muscle mass accrual in CWH is reduced, putting them at risk of reduced bone mineral density (BMD) and muscle function and increasing fracture risk. This study aims to determine the impact of HIV on BMD and muscle function in peripubertal children on ART in Zimbabwe. METHODS AND ANALYSIS: Children with (n=300) and without HIV (n=300), aged 8-16 years, established on ART, will be recruited into a frequency-matched prospective cohort study and compared. Musculoskeletal assessments including dual-energy X-ray absorptiometry, peripheral quantitative computed tomography, grip strength and standing long jump will be conducted at baseline and after 1 year. Linear regression will be used to estimate mean size-adjusted bone density and Z-scores by HIV status (ie, total-body less-head bone mineral content for lean mass adjusted for height and lumbar spine bone mineral apparent density. The prevalence of low size-adjusted BMD (ie, Z-scores <-2) will also be determined. ETHICS AND DISSEMINATION: Ethical approval for this study has been granted by the Medical Research Council of Zimbabwe and the London School of Hygiene and Tropical Medicine Ethics Committee. Baseline and longitudinal analyses will be published in peer-reviewed journals and disseminated to research communities
HIV-associated cardiovascular disease pathogenesis: an emerging understanding through imaging and immunology
Full text linkCardiac abnormalities were identified early in the epidemic of AIDS, predating the isolation and characterization of the etiologic agent, HIV. Several decades later, the causation and pathogenesis of cardiovascular disease (CVD) linked to HIV infection continue to be the focus of intense speculation. Before the widespread use of antiretroviral therapy, HIV-associated CVD was primarily characterized by HIV-associated cardiomyopathy linked to profound immunodeficiency. With increasing antiretroviral therapy use, viral load suppression, and establishment of immune competency, the effects of HIV on the cardiovascular system are more subtle. Yet, people living with HIV still face an increased incidence of cardiovascular pathology. Advances in cardiac imaging modalities and immunology have deepened our understanding of the pathogenesis of HIV-associated CVD. This review provides an overview of the pathogenesis of HIV-associated CVD integrating data from imaging and immunologic studies with particular relevance to the HIV population originating from high-endemic regions, such as sub-Saharan Africa. The review highlights key evidence gaps in the field and suggests future directions for research to better understand the complex HIV-CVD interactions
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