Cardiovascular Journal of Africa - Supplement 1, March 2015
Volumes & issues
Supplement 1, March 2015
Source: Cardiovascular Journal of Africa 26, pp 3 –5 (2015)More Less
With the advent of technology that made possible large-scale sequencing and genotyping studies, it quickly became apparent that the demographic history of our species had been recorded in the genome and we could reconstruct our wanderings across the globe by studying DNA. While the vast majority of genetic variation is shared among continental populations, the most prominent finding from these early surveys of regional populations was the substantially greater degree of heterozygosity found in contemporary African populations. The 'out of Africa' story has long been a central dogma in paleoanthropology, and the rich cultural and linguistic heritage of the continent has also been well documented; yet the implications of this phase of human history for biomedicine had never been fully appreciated.
Mortality from cardiovascular diseases in sub-Saharan Africa, 1990-2013 : a systematic analysis of data from the Global Burden of Disease Study 2013 : cardiovascular topicSource: Cardiovascular Journal of Africa 26, pp 6 –10 (2015) http://dx.doi.org/http://dx.doi.org/10.5830/CVJA-2015-036More Less
Background : Cardiovascular disease (CVD) has been the leading cause of death in developed countries for most of the last century. Most CVD deaths, however, occur in low- and middle-income, developing countries (LMICs) and there is great concern that CVD mortality and burden are rapidly increasing in LMICs as a result of population growth, ageing and health transitions. In sub-Saharan Africa (SSA), where all countries are part of the LMICs, the pattern, magnitude and trends in CVD deaths remain incompletely understood, which limits formulation of data-driven regional and national health policies.
Objective : The aim was to estimate the number of deaths, death rates, and their trends for CVD causes of death in SSA, by age and gender for 1990 and 2013.
Methods : Age- and gender-specific mortality rates for CVD were estimated using the Global Burden of Disease (GBD) 2010 methods with some refinements made by the GBD 2013 study to improve accuracy. Cause of death was estimated as in the GBD 2010 study and updated with a verbal autopsy literature review and cause of death ensemble modelling (CODEm) estimation for causes with sufficient information. For all quantities reported, 95% uncertainty intervals (UIs) were also computed.
Results : In 2013, CVD caused nearly one million deaths in SSA, constituting 38.3% of non-communicable disease deaths and 11.3% of deaths from all causes in that region. SSA contributed 5.5% of global CVD deaths. There were more deaths in women (512 269) than in men (445 445) and more deaths from stroke (409 840) than ischaemic heart disease (258 939). Compared to 1990, the number of CVD deaths in SSA increased 81% in 2013. Deaths for all component CVDs also increased, ranging from a 7% increase in incidence of rheumatic heart disease to a 196% increase in atrial fibrillation. The age-standardised mortality rate (per 100 000) in 1990 was 327.6 (CI: 306.2-351.7) and 330.2 (CI: 312.9-360.0) in 2013, representing only a 1% increase in more than two decades.
Conclusions : In SSA, CVDs are neither epidemic nor among the leading causes of death. However, a significant increase in the number of deaths from CVDs has occurred since 1990, largely as a result of population growth, ageing and epidemiological transition. Contrary to what has been observed in other world regions, the age-adjusted mortality rate for CVD has not declined. Another important difference in CVD deaths in SSA is the predominance of stroke as the leading cause of death. Attention to aggressive efforts in cardiovascular health promotion and CVD prevention, treatment and control in both men and women are warranted. Additionally, investments to improve directly enumerated epidemiological data for refining the quantitation of risk exposures, death certification and burden of disease assessment will be crucial.
Familial clustering of risk factors for cardiovascular disease among first-degree relatives of patients with chronic kidney disease in a sub-Saharan African population : cardiovascular topicSource: Cardiovascular Journal of Africa 26, pp 11 –14 (2015) http://dx.doi.org/http://dx.doi.org/10.5830/CVJA-2015-041More Less
Objective : To determine the prevalence of risk factors for cardiovascular disease (CVD) in first-degree relatives (FDRs) of patients with chronic kidney disease (CKD) in a sub-Saharan African population.
Methods : This was a cross-sectional survey of 460 subjects (230 FDRs of patients with CKD and 230 healthy controls). Anthropometrics and blood pressures were measured. Spot urine and fasting venous blood samples were obtained for biochemical analysis.
Results : The prevalence of hypertension, diabetes mellitus, obesity and dyslipidaemia were significantly higher in FDRs of patients with CKD compared with the controls: 56 (24.3%) vs 29 (12.6%), p = 0.01; 20 (8.7%) vs 6 (2.6%), p = 0.01; 40 (17.4%) vs 24 (10.4%), p = 0.03 and 171 (74.3%) vs 138 (60.0%), p = 0.01, respectively. Hypertension (OR, 1.65), dyslipidaemia (OR, 1.72) and albuminuria (OR, 1.61) were independently associated with being a FDR of patients with CKD.
Conclusion : In this sub-Saharan African population, risk factors for CVD were more prevalent in the FDRs of patients with CKD than in healthy controls.
Strategic investments in non-communicable diseases (NCD) research in Africa : the GSK Africa NCD Open Lab : cardiovascular topicSource: Cardiovascular Journal of Africa 26, pp 15 –17 (2015) http://dx.doi.org/http://dx.doi.org/10.5830/CVJA-2015-042More Less
In March 2014, GSK announced a number of new strategic investments in Africa. One of these included investment of up to 25 million Pounds Sterling (£25 million) to create the world's first R&D Open Lab to increase understanding of non-communicable diseases (NCDs) in Africa. The vision is to create a new global R&D effort with GSK working in partnership with major funders, academic centres and governments to share expertise and resources to conduct high-quality research. The Africa NCD Open Lab will see GSK scientists collaborate with scientific research centres across Africa. An independent advisory board of leading scientists and clinicians will provide input to develop the strategy and selection of NCD research projects within a dynamic and networked open-innovation environment. It is hoped that these research projects will inform prevention and treatment strategies in the future and will enable researchers across academia and industry to discover and develop new medicines to address the specific needs of African patients.
NHLBI perspectives on the growth of heart, lung, blood and sleep conditions in Africa : global and domestic insights, challenges and opportunities : cardiovascular topicSource: Cardiovascular Journal of Africa 26, pp 18 –20 (2015) http://dx.doi.org/http://dx.doi.org/10.5830/CVJA-2015-044More Less
The mission of the National Heart, Lung, and Blood Institute (NHLBI) centres on global leadership in research, training and education aimed at promoting the prevention and treatment of heart, lung, blood and sleep (HLBS) disorders, and thereby enhance the pursuit of a healthy, long and fulfilling existence by all individuals. The global horizon of this mission reflects an appreciation of the collective destiny shared by all humanity.
Author Ana Olga MocumbiSource: Cardiovascular Journal of Africa 26, pp 21 –26 (2015) http://dx.doi.org/http://dx.doi.org/10.5830/CVJA-2015-037More Less
Rheumatic heart disease (RHD) constitutes a leading cause of premature death and incapacity in Africa, where it is encountered in younger people, and shows a much faster and more malignant course than that seen in Europe or North America. While it is well established that RHD is a consequence of recurrent, untreated group A β-haemolytic streptococcal infections (GAS), the pathogenesis is incompletely understood, and the variation in natural history and phenotypes are not fully explained. In Africa patients are rarely diagnosed with acute rheumatic fever (ARF). They usually present in the late stages of RHD, with the severe and virulent forms occurring at early ages, therefore leading to high morbidity and mortality in young patients.
Evidence suggests that genetic factors may be involved in determining susceptibility to ARF as well as the severity and outcomes of RHD. However, the results of genetic studies have been inconsistent, and conflicting results have been found in series from Africa when compared to other parts of the globe. Genetic studies in the African context are therefore justified to understand the genomic and epigenetic drivers of heterogeneity in individual responses to GAS infections and progression to RHD. Platforms such as the global registry of RHD represent an opportunity for adequately powered genome-wide association studies. The discovery of all genetic susceptibility loci through whole-genome scanning may provide a clinically useful genetic risk-prediction tool that will potentially allow echocardiographic screening and secondary prophylaxis for moderate lesions to be directed to those at higher risk, therefore reducing the burden of the disease to the health system, the work health force and the communities of this resource-strained continent.
The burden of stroke in Africa : a glance at the present and a glimpse into the future : review articleAuthors: Mayowa O. Owolabi, Oyedunni Arulogun, Sylvia Melikam, Abiodun M. Adeoye, Sally Akarolo-Anthony, Rufus Akinyemi, Donna Arnett, Hemant Tiwari, Mulugeta Gebregziabher, Carolyn Jenkins, Daniel Lackland, Bruce Ovbiagele, Albert Akpalu, Kwamena Sagoe, Fred Stephen Sarfo, Reginald Obiako and Lukman OwolabiSource: Cardiovascular Journal of Africa 26, pp 27 –38 (2015) http://dx.doi.org/http://dx.doi.org/0.5830/CVJA-2015-038More Less
Objective : Information on the current burden of stroke in Africa is limited. The aim of this review was to comprehensively examine the current and projected burden of stroke in Africa.
Methods : We systematically reviewed the available literature (PubMed and AJOL) from January 1960 and June 2014 on stroke in Africa. Percentage change in age-adjusted stroke incidence, mortality and disability-adjusted life years (DALYs) for African countries between 1990 and 2010 were calculated from the Global Burden of Diseases (GBD) model-derived figures.
Results : Community-based studies revealed an age-standardised annual stroke incidence rate of up to 316 per 100 000 population, and age-standardised prevalence rates of up to 981 per 100 000. Model-based estimates showed significant mean increases in age-standardised stroke incidence. The peculiar factors responsible for the substantial disparities in incidence velocity, ischaemic stroke proportion, mean age and case fatality compared to high-income countries remain unknown.
Conclusions : While the available study data and evidence are limited, the burden of stroke in Africa appears to be increasing.
Source: Cardiovascular Journal of Africa 26, pp 39 –49 (2015) http://dx.doi.org/http://dx.doi.org/10.5830/CVJA-2015-039More Less
One in six people worldwide will experience a stroke in his/her lifetime. While people in Africa carry a disproportionately higher burden of poor stroke outcomes, compared to the rest of the world, the exact contribution of genomic factors to this disparity is unknown. Despite noteworthy research into stroke genomics, studies exploring the genetic contribution to stroke among populations of African ancestry in the United States are few. Furthermore, genomics data in populations living in Africa are lacking. The wide genomic variation of African populations offers a unique opportunity to identify genomic variants with causal relationships to stroke across different ethnic groups. The Stroke Investigative Research and Educational Network (SIREN), a component of the Human Health and Heredity in Africa (H3Africa) Consortium, aims to explore genomic and environmental risk factors for stroke in populations of African ancestry in West Africa and the United States. In this article, we review the literature on the genomics of stroke with particular emphasis on populations of African origin.
Sickle cell disease and H3Africa : enhancing genomic research on cardiovascular diseases in African patients : review articleSource: Cardiovascular Journal of Africa 26, pp 50 –55 (2015) http://dx.doi.org/http://dx.doi.org/10.5830/CVJA-2015-040More Less
Background : Sickle cell disease (SCD) has a high prevalence in sub-Saharan Africa. There are several cardiovascular phenotypes in SCD that contribute to its morbidity and mortality.
Discussion : SCD is characterised by marked clinical variability, with genetic factors playing key modulating roles. Studies in Tanzania and Cameroon have reported that single-nucleotide polymorphisms in BCL11A and HBS1L-MYB loci and co-inheritance of alpha-thalassaemia impact on foetal haemoglobin levels and clinical severity. The prevalence of overt stroke among SCD patients in Cameroon (6.7%) and Nigeria (8.7%) suggests a higher burden than in high-income countries. There is also some evidence of high burden of kidney disease and pulmonary hypertension in SCD; however, the burden and genetics of these cardiovascular conditions have seldom been investigated in Africa.
Conclusions : Several H3Africa projects are focused on cardiovascular diseases and present major opportunities to build genome-based research on existing SCD platforms in Africa to transform the health outcomes of patients.
Endothelial dysfunction : a unifying hypothesis for the burden of cardiovascular diseases in sub-Saharan Africa : review articleSource: Cardiovascular Journal of Africa 26, pp 56 –60 (2015) http://dx.doi.org/http://dx.doi.org/10.5830/CVJA-2015-043More Less
It is well established that the leading causes of death and disability worldwide are cardiovascular diseases (CVD), chief among which is ischaemic heart disease. However, it is also recognised that ischaemic heart disease frequently coexists with other vascular conditions, such as cerebrovascular, renovascular and peripheral vascular disease, thus raising the notion of a common underlying pathobiology, albeit with differing manifestations, dictated by the implicated vascular bed.
The understanding that common metabolic and behavioural risk factors as well as social determinants and drivers are convergent in the development of CVD evokes the idea that the dysfunction of a common bio-molecular platform is central to the occurrence of these diseases. The state of endothelial activation, otherwise known as endothelial dysfunction, occurs when reactive oxygen signalling predominates due to an uncoupled state of endothelial nitric oxide synthase (eNOS). This can be a physiological response to stimulation of the innate immune system or a pathophysiological response triggered by cardiovascular disease risk factors.
The conventional wisdom is that the endothelium plays an important role in the initiation, progression and development of CVD and other non-communicable diseases. Consequently, the endothelium has remarkable relevance in clinical and public health practice as well as in health education, health promotion, and disease- and risk-factor prevention strategies. It also presents a plausible unifying hypothesis for the burden of CVD seen globally and in sub-Saharan Africa. Importantly, the heterogeneity in individual responses to metabolic, behavioural, and social drivers of CVD may stem from a complex interplay of these drivers with genomic, epigenetic and environmental factors that underpin eNOS uncoupling. Therefore, further biomedical research into the underlying genetic and other mechanisms of eNOS uncoupling may enlighten and shape strategies for addressing the burden of CVD in sub-Saharan Africa and other regions of the world.