1,721,168 research outputs found
Prevalence of dyslipidaemia among adults in Africa: a systematic review and meta-analysis
Full text linkBackground
The burden of dyslipidaemia in Africa remains inadequately characterised. We aimed to estimate the prevalence of dyslipidaemia in African adults from hospital-based and community-based studies.
Methods
In this systematic review and meta-analysis, we searched MEDLINE via PubMed, EMBASE, African Journals Online, and African Index Medicus for studies published between Jan 1, 1980, and July 31, 2017, without language restriction. We assessed methodological quality of all crosssectional studies reporting on the prevalence of elevated concentrations of total cholesterol, LDL cholesterol, or triglycerides, or low concentrations of HDL cholesterol in adults residing in African countries. We excluded reports on Africans living outside Africa, studies of individuals selected on the basis of existing dyslipidaemia or those including children and adolescents, and case series with a small sample size. The most frequently used cutoffs in the included studies were chosen for the subgroup analysis. We used random-effect model meta-analysis to derive the pooled prevalence of elevated total cholesterol, low HDL cholesterol, elevated LDL cholesterol, and elevated triglyceride concentrations. This study is registered with PROSPERO, number CRD42014015376.
Findings
177 studies (294063 participants) were included in the meta-analysis. The pooled prevalence of dyslipidaemia in the general population from population-based studies was 25·5% (95% CI 20·0– 31·4) for elevated concentrations of total cholesterol with a cutoff of at least 5·2 mmol/L, 37·4% (29·4–45·7) for low concentrations of HDL cholesterol with a cutoff of less than 1·0 mmol/L, 28·6% (15·8–43·5) for elevated concentrations of LDL cholesterol with a cutoff of at least 3·3 mmol/L, and 17·0% (11·9–22·7) for elevated concentrations of triglycerides with a cutoff of at least 1·7 mmol/L.
Interpretation
The prevalence of dyslipidaemia is high in the general adult population in Africa. Ongoing efforts to reduce cardiovascular diseases in Africa should integrate effective detection and treatment of dyslipidaemia
The risk and severity of preeclampsia secondary to iodine deficiency and iodine deficiency-mediated subclinical hypothyroidism: mechanisms and early cardiovascular consequences
Full text linkBackground Iodine deficiency affects about 2 billion people globally and is the leading cause of Subclinical (SCH) and overt (OH) hypothyroidism that are some of the risk factors of preeclampsia. Iodine deficiency in pregnancy, which can be corrected by supplementation, has been suggested in the past three decades as a risk factor for preeclampsia. It is uncertain if this is mainly because of elevated thyroid-stimulating hormone (TSH) in women with iodine deficiency complicated by hypothyroidism. Alternatively, it may be because of reduced serum antioxidant capacity and other pathways that are associated with the more prevalent inadequate iodine intake in pregnancy, or both. Aims The current thesis had three major objectives: 1) To determine the burden of iodine deficiency in pregnancy in Africa; 2) To find out if there is an association between iodine deficiency in pregnancy, subclinical hypothyroidism, endothelial dysfunction and preeclampsia; 3) To find out possible mechanisms through which iodine deficiency in pregnancy may predispose to preeclampsia, eclampsia, endothelial dysfunction and early cardiovascular pathological changes. Methods In the first part of this thesis, two systematic reviews are presented. The first was carried out in order to estimate the burden of iodine deficiency in pregnancy in Africa. This was complemented with a regression analysis using the more readily available school-age children (SAC) median urinary iodine concentration (UIC) and the limited pregnancy median UIC data to estimate the level of iodine nutrition in pregnancy in all the African countries. The second systematic review was carried out to find out the relationship between inadequate iodine intake in pregnancy and preeclampsia. In the second part of this thesis, we present results of case-control studies in which women with preeclampsia, severe preeclampsia, eclampsia and normotensive pregnant controls were enrolled at Nelson Mandela Academic Hospital (NMAH) and Mthatha Regional Hospital (MRH) in Eastern Cape South Africa. Their iodine nutrition status, thyroid function, endothelial dysfunction and arterial stiffness were compared by assaying the urinary iodine concentration (UIC), thyroglobulin (Tg), thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), nitric oxide (NO), oxidised low-density lipoprotein (oxLDL), pulse wave velocity (PWV) and aortic augmentation index (AI). In the third part of the thesis, two studies aimed at exploring mechanisms through which iodine and other micronutrient deficiencies together with environmental factors predispose to preeclampsia and eclampsia are presented. The first is a study using Factor Analysis to find out how various nutritional and inflammatory markers interact in different pathways to predispose to preeclampsia using data collected at Lomo Medical Centre, Kinshasa Province, Democratic Republic of Congo. The second is a case-control study in which we compared the thyroid function status, urinary iodine and serum potassium of women with eclampsia, severe preeclampsia and normotensive pregnant controls to find out if iodine deficiency, the resultant thyroid dysfunction and serum potassium levels were associated with the risk of eclampsia. Results Prevalence of iodine deficiency in pregnancy in Africa: results from systematic reviews and meta-analyses and pregnancy median UIC estimated from SAC median UIC Pregnancy iodine nutrition status data was available for 23/54 African countries. Between 2005 and 2020 a few African countries had sufficient (pregnancy median urinary iodine concentration [pMUIC] 150 - 250 μg/L), most had mildly inadequate (pMUIC 100 - 149 μg/L), and some moderate-to-severe inadequate iodine nutrition in pregnancy (pMUIC 50). There was a non-significant risk of preeclampsia for women with UIC < 0.001) and the Pulse Wave Velocity 5.1, 5.7 and 6.3 m/s respectively for Eastern Cape normotensive, preeclampsia and severe preeclampsia women (p< 0.05). In linear regressions, TSH, age and hypertensive disease were independent predictors of elevated PWV which is associated with endothelial dysfunction and future cardiovascular disease. Possible mechanisms in the pathophysiology of preeclampsia associated with iodine deficiency, resultant thyroid dysfunction and other nutritional or inflammatory factors Using data of normotensive and preeclamptic women from Kinshasa Province, Democratic Republic of Congo, we have characterised four main pathophysiological pathways through which low iodine intake in pregnancy may predispose to preeclampsia. These are the interactions between selenium/iodine deficiency and elevated serum TSH, leading to endothelial dysfunction; serum ferritin, gamma-glutamyl transferase (GGT), C-reactive protein (CRP) and low urinary iodine excretion precipitating inflammatory oxidative stress. The others are elevated serum high sense-CRP (hs-CRP) and Rheumatoid factor subclinical inflammation and immune cell activation and high T3/T4 ratio acute TSH stimulation of thyroid with low thyroid iodine stores that may lead to excessive superoxide and hydroxyl production further exacerbating oxidative stress and endothelial dysfunction. Iodine deficiency, thyroid dysfunction in the pathophysiology of eclamptic fits Eclamptic women in the Eastern Cape (South Africa) had significantly lower urinary iodine concentration (UIC), free triiodothyronine (FT3), median serum potassium (K), but higher serum thyroglobulin (Tg) than women with severe preeclampsia and normotensive pregnant controls. The median values respectively for participants with eclampsia, severe preeclampsia and normotensive controls were UIC 69.5, 95.7, and 169.5 µg/L; FT3 3.8, 4.4 and 4.7 pmol/L; K 3.7, 4.2, 4.3 mmol/L; and Tg 39.0, 22.4, 19.5 µg/L. Low serum T3 and T4 levels coupled with a preferential transfer of T4 across the blood-brain barrier alter the physiological T3/T4 ratio in the CNS attenuating the inhibitory effects of GABA while the excitatory function of glutamate remains intact. Low serum potassium further attenuates GABAB receptor mediated tonic extra-synaptic inhibition resulting in net motor neurone stimulation and increased predisposition to the involuntary tonic-clonic convulsions observed in eclampsia. Conclusion There is still a high prevalence of inadequate iodine intake in pregnancy in Africa estimated to affect 45% of the African nations 25 years after commencement of iodine fortification of salt and other foodstuffs. While the complication of goitre and cretinism may have reduced, pregnant women in Africa may still be prone to high risk of preeclampsia, eclampsia, future cardiovascular disease and various degrees of reduced psychomotor development of the foetus depending on the severity and duration of insufficient iodine intake in pregnancy. Alternative measures need to be considered to mitigate the persistently high prevalence of iodine deficiency in pregnancy in Africa and other areas around the globe despite national salt iodization programs and other iodine fortification efforts that have been implemented for several decades. This will help reduce the risk of preeclampsia, eclampsia and related complications
Co-morbid cardiometabolic diseases among people living with HIV/AIDS in Cameroon
Full text linkBackground and Purpose: To investigate the effects and mediators of HIV infection and related treatment on the prevalence and incidence of cardiometabolic diseases (CMDs) including hypertension, type 2 diabetes mellitus (T2D), and obesity in people living with HIV (PLWH) in Cameroon. Additionally, three systematic reviews were conducted to assess the global prevalence of hypertension, T2D, and obesity among ART-naïve PLWH; and to evaluate the methodological approaches to mediation analysis and handling missing data in studies on CMDs in PLWH. Methods: The study utilized data from 14,279 PLWH enrolled in the Cameroon arm of the International Epidemiology Databases to Evaluate AIDS (IeDEA). Analyses comprised multinomial and binomial logistic regressions, causal mediation analysis, and Cox proportional hazards regression. Systematic reviews were conducted by searching multiple databases, pooling the prevalence rates of hypertension, T2D, and obesity using a random-effects meta-analysis. Results: In Cameroon, significant determinants of hypertension and T2D included age over 50 years, male sex, and overweight/obesity. ART use was linked to lower odds of T2D, and BMI partially mediated the relationship between ART use and hypertension. Prevalence of overweight/obesity was 37.7% overall, and higher in females. Older age, female sex, and higher CD4 count were associated with increased odds of overweight/obesity, while current smoking was linked to reduced odds. The incidence rate of hypertension was 121.1 per 1,000 person-years, with older age, male sex, and overweight/obesity as predictors. ART exposure reduced the risk of hypertension. The systematic review with meta-analysis revealed a global prevalence of 13.6% for hypertension, 4.0% for T2D, and 12.3% for obesity among ART-naïve PLWH. The review on mediation analysis showed increased adoption of casual mediation frameworks but inconsistencies in reporting. The missing data review revealed both under reporting of missing data and how it was handled. Conclusion: The burden of CMDs in PLWH is significant, driven mainly by established risk factors. emphasizing the need for integrated healthcare strategies that address both HIV/AIDS and CMDs. It also underscores the importance of methodological rigor, which significantly impacts the interpretation and reliability of results
Higher adherence to plant-based diets are associated with lower likelihood of fatty liver
No full textSome plant-based diets have been suggested to have a beneficial impact on liver disease risk. We examined the association of the overall plant-based diet (PDI), hypothesized healthful PDI (hPDI) and unhealthful PDI (uPDI) with non-alcoholic fatty liver disease (NAFLD) in US adults from the 2005–2010 National Health and Nutrition Examination Survey (NHANES2005-2010). Analysis of covariance, linear and logistic regression models accounted for the survey design and sample weights. Overall, 18,345 participants were included, with a mean age of 47.9 years and comprising 51.7% women. Liver function tests including alanine aminotransferase (ALT), aspartate aminotransferase (AST) and fatty liver index (FLI) decreased across increasing thirds of PDI and hPDI (all p < 0.001), while adjusted mean of ALT, AST and FLI increased across increasing thirds of uPDI. Adjusted linear regressions showed that PDI and hPDI had negative and significant associations with ALT (PDI = β:-0.095, hPDI = β:-0.128), AST (PDI = β:-0.101, hPDI = β:-0.138) and FLI (PDI = β:-0.153, hPDI = β:-0.265), while uPDI had a positive and significant association with ALT (β: 0.103), AST (β: 0.112) and FLI (β: 0.241). After adjustment, participants in the upper third of PDI had 21% lower odd of NAFLD compared with those in the lowest third [odds ratio (OR): 0.79, 95% confidence interval (95%CI): 0.74–0.82]. A similar trend was observed with hPDI; and the opposite across increasing thirds of uPDI. Our findings confirm that healthy plant-based diets are associated with lower NAFLD risk and more favorable liver function tests profile
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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