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Craig A, Breet Y, Gafane-Matemane LF, Norris SA, Kruger R. Detecting and Managing Childhood Onset Hypertension in Africa: A Call to Action. Curr Hypertens Rep 2023; 25:211-230. [PMID: 37318686 PMCID: PMC10491553 DOI: 10.1007/s11906-023-01247-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2023] [Indexed: 06/16/2023]
Abstract
PURPOSE OF REVIEW To review recent evidence on childhood hypertension across Africa, identifying knowledge gaps, challenges and priorities, and highlight clinical perspectives in managing primary hypertension. RECENT FINDINGS Only 15 of the 54 African countries reported on absolute blood pressure (BP) measures, elevated BP, pre- and/or hypertension. The reported hypertension prevalence ranged between 0.0 and 38.9%, while elevated BP and/or pre-hypertnesion ranged from 2.7 to 50.5%. Childhood BP nomograms are lacking across Africa and the rates of hypertension were based on guidelines developed in countries with the lowest to no number of children from African ancestry. The recent studies across Africa also showed little to no detail when reporting BP specific methodology. No recent data informing the use or effectiveness of antihypertensive agents in children and adolesents are available. Childhood hypertension is on the rise, while data from Africa remains vastly under-represented. Collaborative research, resources, and policies need to be strengthened in addressing the growing public health concern of childhood onset hypertension on this continent.
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Affiliation(s)
- A Craig
- SAMRC/Wits Developmental Pathways for Health Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Y Breet
- Hypertension in Africa Research Team (HART), North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
- MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa
| | - L F Gafane-Matemane
- Hypertension in Africa Research Team (HART), North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa
- MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa
| | - S A Norris
- SAMRC/Wits Developmental Pathways for Health Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Development and Health, University of Southampton, Southampton, UK
| | - R Kruger
- Hypertension in Africa Research Team (HART), North-West University, Private Bag X6001, Potchefstroom, 2520, South Africa.
- MRC Research Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa.
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Obikeze K, Sasi AA, Raji I. In-silico and in-vivo evaluation of the Cardiovascular effects of five Leonotis leonurus diterpenes. SCIENTIFIC AFRICAN 2022. [DOI: 10.1016/j.sciaf.2022.e01510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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Crouch SH, Soepnel LM, Kolkenbeck-Ruh A, Maposa I, Naidoo S, Davies J, Norris SA, Ware LJ. Paediatric Hypertension in Africa: A Systematic Review and Meta-Analysis. EClinicalMedicine 2022; 43:101229. [PMID: 34917909 PMCID: PMC8665406 DOI: 10.1016/j.eclinm.2021.101229] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 11/16/2021] [Accepted: 11/22/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The burden of cardiovascular disease (CVD) and hypertension is rapidly increasing in low- and middle-income countries. This is evident not only in adults, but also in children. Recent estimates of prevalence in children are lacking, particularly in Africa. As such, we conducted a systematic review and meta-analysis to provide updated estimates of paediatric hypertension in Africa. METHODS We searched PubMed and EBSCO to identify articles published from January 2017 to November 2020. Studies were assessed for quality. We combined results for meta-analyses using a random effects model (Freeman-Tukey arcsine transformation). Heterogeneity was quantified using the I2 statistic. FINDINGS In the narrative synthesis of 53 studies, publication bias was low for 28, moderate for 24, and high for one study. Hypertension prevalence ranged substantially (0·2%-38·9%). Meta-analysis included 41 studies resulting in data on 52918 participants aged 3 to 19 years from ten countries. The pooled prevalence for hypertension (systolic/diastolic BP≥95th percentile) was 7·45% (95%CI 5·30-9·92, I2=98.96%), elevated blood pressure (BP, systolic/diastolic BP≥90th percentile and <95th percentile) 11·38% (95%CI 7·94-15·33, I2=98.97%) and combined hypertension/elevated BP 21·74% (95%CI 15·5-28·69, I2=99.48%). Participants categorized as overweight/with obesity had a higher prevalence of hypertension (18·5% [95%CI 10·2-28·5]) than those categorized as underweight/normal (1·0% [95%CI 0·1-2·6], 4·8% [95%CI 2·9-7·1], p<0·001). There were significant differences in hypertension prevalence when comparing BP measurement methods and classification guidelines. INTERPRETATION Compared to a previous systematic review conducted in 2017, this study suggests a continued increase in prevalence of paediatric hypertension in Africa, and highlights the potential role of increasing overweight/obesity. FUNDING This research was funded in part by the Wellcome Trust [Grant number:214082/Z/18/Z]. LJW and SAN are supported by the DSI-NRF Centre of Human Development at the University of the Witwatersrand.
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Affiliation(s)
- Simone H. Crouch
- SAMRC/Wits Developmental Pathways for Health Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Larske M. Soepnel
- SAMRC/Wits Developmental Pathways for Health Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Julius Global Health, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
- Correspondence and reprint to: Dr. Larske M. Soepnel. Julius Global Health, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Huispost nr. STR 6.131 P.O. Box 85500 3508 GA, Utrecht, The Netherlands
| | - Andrea Kolkenbeck-Ruh
- SAMRC/Wits Developmental Pathways for Health Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Innocent Maposa
- Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of Witwatersrand, Johannesburg, South Africa School of Public Health
| | - Sanushka Naidoo
- SAMRC/Wits Developmental Pathways for Health Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Justine Davies
- SAMRC/Wits Developmental Pathways for Health Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Institute of Applied Health Research, University of Birmingham, Birmingham, United Kingdom
| | - Shane A. Norris
- SAMRC/Wits Developmental Pathways for Health Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Health and Human Development, University of Southampton, Southampton, United Kingdom
| | - Lisa J. Ware
- SAMRC/Wits Developmental Pathways for Health Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- DSI-NRF Centre of Excellence in Human Development, University of the Witwatersrand, Johannesburg, South Africa
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du Plessis JP, Nienaber-Rousseau C, Lammertyn L, Schutte AE, Pieters M, Kruger HS. The Relationship of Circulating Homocysteine with Fibrinogen, Blood Pressure, and Other Cardiovascular Measures in African Adolescents. J Pediatr 2021; 234:158-163.e2. [PMID: 33775664 DOI: 10.1016/j.jpeds.2021.03.034] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 03/11/2021] [Accepted: 03/19/2021] [Indexed: 12/14/2022]
Abstract
OBJECTIVES To evaluate the associations between homocysteine (Hcy) and cardiovascular health in South African adolescents. STUDY DESIGN Circulating Hcy concentrations of 172 South African adolescents (105 girls, ages 13 to <18 years) were measured. Anthropometric and cardiovascular factors were also included and cross-sectionally analyzed through general linear models. RESULTS Hcy correlated positively with body weight (P = .03; after adjusting for multiple testing, it was not regarded as significant) and muscle mass (P = .01), but negatively with fibrinogen concentrations (P = .001). Across Hcy tertiles, blood pressure produced approximating U-shaped curves, with differences between the middle and upper tertiles (all P < .02). Forty percent of the adolescents had elevated blood pressure, of whom 37% fell in the lowest and 38% in the highest Hcy tertiles. Hcy differed between the sexes (with boys having higher Hcy), but not between subgroups based on puberty, weight, stunting, smoking, or alcohol consumption. CONCLUSIONS Both high and low Hcy could be early contributing risk factors to cardiovascular health. The associations between Hcy and blood pressure suggest that dietary and lifestyle manipulation, to achieve the optimal range of Hcy, may be beneficial in preventing Hcy-related hypertension in adulthood. The inverse relationship between Hcy and fibrinogen remains to be clarified.
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Affiliation(s)
- Jacomina P du Plessis
- Center of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
| | - Cornelie Nienaber-Rousseau
- Center of Excellence for Nutrition, North-West University, Potchefstroom, South Africa; Hypertension in Africa Research Team, North-West University, Potchefstroom, South Africa.
| | - Leandi Lammertyn
- Hypertension in Africa Research Team, North-West University, Potchefstroom, South Africa; Medical Research Council Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa
| | - Aletta E Schutte
- Hypertension in Africa Research Team, North-West University, Potchefstroom, South Africa; Medical Research Council Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa; School of Population Health, University of New South Wales, The George Institute for Global Health, Sydney, New South Wales, Australia
| | - Marlien Pieters
- Center of Excellence for Nutrition, North-West University, Potchefstroom, South Africa; Hypertension in Africa Research Team, North-West University, Potchefstroom, South Africa
| | - Herculina S Kruger
- Center of Excellence for Nutrition, North-West University, Potchefstroom, South Africa; Hypertension in Africa Research Team, North-West University, Potchefstroom, South Africa
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Jacobs A, Pieters M, Schutte AE. The association of PAI-1 with 24 h blood pressure in young healthy adults is influenced by smoking and alcohol use: The African-PREDICT study. Nutr Metab Cardiovasc Dis 2020; 30:2063-2071. [PMID: 32811735 DOI: 10.1016/j.numecd.2020.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 06/23/2020] [Accepted: 07/01/2020] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND AIMS The association between plasminogen activator inhibitor-1 (PAI-1) and blood pressure is well established, but it is debatable whether raised PAI-1 levels precede or result from raised blood pressure. Furthermore, it is unclear whether this association already exists in the absence of overt hypertension and to what degree it is influenced by health behaviours. Our aim was to investigate the association of 24 h blood pressure with PAI-1 activity (PAI-1act) in a young, healthy cohort, and to assess the influence of alcohol consumption and smoking on these associations. METHODS AND RESULTS Healthy black and white men and women (aged 20-30 years, n = 1156) were cross-sectionally analysed. Statistical analysis was performed first split by ethnicity and sex and then by alcohol consumption and smoking. Regression analyses adjusted for age revealed positive associations of 24 h blood pressure with PAI-1act in most groups (p < 0.05). In multivariate-adjusted analyses, significance was lost in all groups except black men, who also had higher monocyte chemoattractant protein-1 (MCP-1) and von Willebrand factor antigen (vWFag) compared to white men (both p < 0.001). Analyses in black men, split by self-reported alcohol use and smoking, revealed 24 h blood pressure-PAI-1act associations only in alcohol users (24 h SBP [B = 4.22, p < 0.001], DBP [B = 2.04, p = 0.015] and PP [B = 2.18, p = 0.013]) and smokers (24 h SBP [B = 6.10, p < 0.001] and PP [B = 4.33, p = 0.001]). CONCLUSION Our findings support a positive association between 24 h blood pressure and PAI-1, particularly in individuals with higher MCP-1 and vWFag levels. Furthermore, smoking and alcohol consumption play an important role in modifying the association between blood pressure and PAI-1.
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Affiliation(s)
- Adriaan Jacobs
- Centre of Excellence for Nutrition (CEN), North-West University, Potchefstroom, South Africa; Hypertension in Africa Research Team (HART), Medical Research Council Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa.
| | - Marlien Pieters
- Centre of Excellence for Nutrition (CEN), North-West University, Potchefstroom, South Africa.
| | - Aletta E Schutte
- Hypertension in Africa Research Team (HART), Medical Research Council Unit for Hypertension and Cardiovascular Disease, North-West University, Potchefstroom, South Africa; School of Public Health and Community Medicine, University of New South Wales, The George Institute for Global Health, Sydney, Australia.
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Maat M, Jerling J, Hoekstra T, Kruger A, Pieters M. Fibrinogen concentration and its role in CVD risk in black South Africans – effect of urbanisation. Thromb Haemost 2017; 106:448-56. [DOI: 10.1160/th11-03-0192] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 06/08/2011] [Indexed: 12/15/2022]
Abstract
SummaryThe aim of this study was to investigate correlates of fibrinogen concentration in black South Africans, as well as its association with cardiovascular disease (CVD) risk and whether urbanisation influences this association. A total of 1,006 rural and 1,004 urban black South Africans from the PURE study were cross-sectionally analysed. The association of fibrinogen with CVD risk was determined by investigating the association of fibrinogen with other CVD risk markers as well as with predicted CVD risk using the Reynolds Risk score. The rural group had a significantly higher fibrinogen concentration than the urban group, despite higher levels of risk factors and increased predicted CVD risk in the urban group. Increased levels of CVD risk factors were, however, still associated with increased fibrinogen concentration. Fibrinogen correlated significantly, but weakly, with overall predicted CVD risk. This correlation was stronger in the urban than in the rural group. Multiple regression analysis showed that a smaller percentage of the variance in fibrinogen is explained by the traditional CVD risk factors in the rural than in the urban group. In conclusion, fibrinogen is weakly associated with CVD risk (predicted overall risk as well with individual risk factors) in black South Africans, and is related to the degree of urbanisation. Increased fibrinogen concentration, in black South Africans, especially in rural areas, is largely unexplained, and likely not strongly correlated with traditional CVD-related lifestyle and pathophysiological processes. This does, however, not exclude the possibility that once increased, the fibrinogen concentration contributes to future development of CVD.
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Cronjé HT, Nienaber-Rousseau C, Zandberg L, de Lange Z, Green FR, Pieters M. Fibrinogen and clot-related phenotypes determined by fibrinogen polymorphisms: Independent and IL-6-interactive associations. PLoS One 2017; 12:e0187712. [PMID: 29099861 PMCID: PMC5669433 DOI: 10.1371/journal.pone.0187712] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/24/2017] [Indexed: 12/04/2022] Open
Abstract
Interleukin-6 (IL-6) induces the expression of fibrinogen, and polymorphic variation within the fibrinogen genes is believed to alter the magnitude of this expression. The identification of the functional relevance of individual fibrinogen single nucleotide polymorphisms (SNPs) has been hindered by the high linkage disequilibrium (LD) reported in the European fibrinogen gene locus. This study investigated two novel and 12 known fibrinogen SNPs of potential functional relevance, in 2010 Tswana individuals known to have low LD. We aimed to identify functional polymorphisms that contribute to clot-related phenotypes and total and γ’ fibrinogen concentrations independently and through their interaction with IL-6, by taking advantage of the high fibrinogen and IL-6 concentrations and the low LD reported in black South Africans. Fibrinogen was significantly associated with IL-6, thereby mediating associations of IL-6 with clot formation and structure, although attenuating the association of IL-6 with clot lysis time. None of the common European fibrinogen haplotypes was present in this study population. Putative functional fibrinogen SNPs FGB–rs7439150, rs1800789 (–1420G/A) and rs1800787 (–148C/T) were significantly associated with fibrinogen concentration and altered clot properties, with several associations significantly influenced by IL-6 concentrations. The impact of harbouring several minor fibrinogen SNP alleles on the association of IL-6 and fibrinogen concentration was cumulative, with possession of each additional minor allele showing a stronger relationship of IL-6 with fibrinogen. This was also reflected in differences in clot properties, suggesting potential clinical relevance. Therefore, when investigating the effect of fibrinogen genetics on fibrinogen concentrations and CVD outcome, the possible interactions with modulating factors and the fact that SNP effects seem to be additive should be taken into account.
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Affiliation(s)
- H. Toinét Cronjé
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
| | | | - Lizelle Zandberg
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
| | - Zelda de Lange
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
| | - Fiona R. Green
- Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine & Health, University of Manchester, Manchester, United Kingdom
| | - Marlien Pieters
- Centre of Excellence for Nutrition, North-West University, Potchefstroom, South Africa
- * E-mail:
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Cronjé HT, Nienaber-Rousseau C, Zandberg L, Chikowore T, de Lange Z, van Zyl T, Pieters M. Candidate gene analysis of the fibrinogen phenotype reveals the importance of polygenic co-regulation. Matrix Biol 2017; 60-61:16-26. [DOI: 10.1016/j.matbio.2016.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 09/20/2016] [Accepted: 10/13/2016] [Indexed: 12/19/2022]
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Fibrin Fiber Stiffness Is Strongly Affected by Fiber Diameter, but Not by Fibrinogen Glycation. Biophys J 2016; 110:1400-10. [PMID: 27028649 PMCID: PMC4816776 DOI: 10.1016/j.bpj.2016.02.021] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 01/24/2016] [Accepted: 02/02/2016] [Indexed: 11/24/2022] Open
Abstract
The major structural component of a blood clot is a mesh of fibrin fibers. Our goal was to determine whether fibrinogen glycation and fibrin fiber diameter have an effect on the mechanical properties of single fibrin fibers. We used a combined atomic force microscopy/fluorescence microscopy technique to determine the mechanical properties of individual fibrin fibers formed from blood plasma. Blood samples were taken from uncontrolled diabetic patients as well as age-, gender-, and body-mass-index-matched healthy individuals. The patients then underwent treatment to control blood glucose levels before end blood samples were taken. The fibrinogen glycation of the diabetic patients was reduced from 8.8 to 5.0 mol glucose/mol fibrinogen, and the healthy individuals had a mean fibrinogen glycation of 4.0 mol glucose/mol fibrinogen. We found that fibrinogen glycation had no significant systematic effect on single-fiber modulus, extensibility, or stress relaxation times. However, we did find that the fiber modulus, Y, strongly decreases with increasing fiber diameter, D, as Y∝D−1.6. Thin fibers can be 100 times stiffer than thick fibers. This is unusual because the modulus is a material constant and should not depend on the sample dimensions (diameter) for homogeneous materials. Our finding, therefore, implies that fibrin fibers do not have a homogeneous cross section of uniformly connected protofibrils, as is commonly thought. Instead, the density of protofibril connections, ρPb, strongly decreases with increasing diameter, as ρPb∝D−1.6. Thin fibers are denser and/or have more strongly connected protofibrils than thick fibers. This implies that it is easier to dissolve clots that consist of fewer thick fibers than those that consist of many thin fibers, which is consistent with experimental and clinical observations.
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Retinal vessel calibres and haemostasis in black and white South Africans: the SABPA study. J Hypertens 2016; 33:2483-90. [PMID: 26398852 DOI: 10.1097/hjh.0000000000000744] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Retinal arteriolar narrowing associates with hypertension development and indicates increased cardiovascular risk. Evidence on whether the retinal vessel calibres are related to the haemostatic system is limited, especially in the black hypertension-prone population with a high stroke incidence. We therefore investigated the relationships between haemostatic markers and retinal vessel calibres. METHODS We performed a cross-sectional study involving 170 black (mean age, 58 years; 44% women) and 189 white (mean age, 49 years; 52% women) teachers, and determined ambulatory blood pressure, haemostatic factors (fibrinogen, von Willebrand factor, D-dimer, plasminogen activator inhibitor-1 and clot lysis time) and retinal vessel calibres (central retinal artery and vein equivalent). The black and white groups were stratified by median split of the retinal arteriolar calibre. RESULTS Both ethnic groups with a smaller arteriolar calibre had higher SBP and narrower venular calibres. In the black population, the central retinal vein equivalent was positively (β = 0.293; P = 0.024) associated with fibrinogen, whereas in the white population, the central retinal artery equivalent (β = -0.256; P = 0.016) was negatively and central retinal vein equivalent (β = 0.234; P = 0.021) positively associated with von Willebrand factor. Furthermore, clot lysis time was negatively associated with the central retinal artery equivalent (β = -0.390; P = 0.014) in the black group and positively associated with the central retinal vein equivalent (β = 0.275; P = 0.008) in the white group. CONCLUSION Relationships between markers of haemostasis and the retinal vessel calibres exist, and vary between ethnicities. Haemostatic alterations are linked to early retinal microvascular changes, and future studies should investigate whether it translates into an elevated stroke risk.
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Aziz NA, Mohamed SS, Badara TA, Boubacar G, Gallo SP, Awa G, Anta TD. [Chronic noncommunicable diseases in Senegalese soldiers: cross-sectional study in 2013]. Pan Afr Med J 2015; 22:59. [PMID: 26834912 PMCID: PMC4725656 DOI: 10.11604/pamj.2015.22.59.4777] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Accepted: 03/02/2015] [Indexed: 11/11/2022] Open
Abstract
Introduction Méthodes Résultats Conclusion
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Affiliation(s)
- Ndiaye Abdoul Aziz
- Département de Santé Communautaire, Université de Bambey, Bambey, Sénégal; Service de Santé des Armées Sénégalaises, Sénégal
| | - Seck Sidy Mohamed
- Service de Santé des Armées Sénégalaises, Sénégal; Département de Médecine Interne et Néphrologie, UFR des Sciences de la Santé, Université Gaston Berger de Saint-Louis, Sénégal
| | | | - Gueye Boubacar
- Département de Santé Communautaire, Université de Bambey, Bambey, Sénégal
| | - Sow Papa Gallo
- Département de Santé Communautaire, Université de Bambey, Bambey, Sénégal
| | - Gaye Awa
- Département de Santé Communautaire, Université de Bambey, Bambey, Sénégal
| | - Tal-Dia Anta
- Département Santé Publique, Université Cheikh Anta Diop, Dakar, Sénégal
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The contribution of genetic and environmental factors to changes in total and γ' fibrinogen over 5 years. Thromb Res 2015; 135:703-9. [PMID: 25613928 DOI: 10.1016/j.thromres.2015.01.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 11/20/2014] [Accepted: 01/11/2015] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Increased fibrinogen is associated with cardiovascular disease risk. It is, however, not known to what extend environmental and genetic factors and/or their interaction influence changes in total and γ' fibrinogen over time. We aimed to determine how variation within the fibrinogen gene as well as environmental factors influence the change in total and γ' fibrinogen over time, and also whether gene-environment interactions influence total and γ' fibrinogen on a cross-sectional and prospective level in Africans. MATERIALS AND METHODS This prospective study consisted of 2010 participants at baseline and 1288 participants at follow-up (5 years). RESULTS The gene-environment interactions that were associated with fibrinogen concentration on a cross-sectional level were: FGA 2224 G>A (rs2070011) with age (p=0.005), FGB Arg448Lys (rs4220) with HIV status (p<0.0001) and FGB 1038 G>A (rs1800791) with HbA1c (p=0.01). The only factor that independently influenced the change in total fibrinogen levels over time, was baseline CRP (p<0.0001) and FGG 10034 C>T (rs2066865) was the only single nucleotide polymorphism that independently influenced the change in fibrinogen γ' levels over time (p=0.02). Only the FGG 9340 T>C (rs1049636) with HbA1c interaction was found to predict change in total fibrinogen concentrations over time (p=0.005). CONCLUSIONS Gene-environment interactions influenced fibrinogen levels cross-sectionally and also mediated changes in levels over time.
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Kotzé RC, Nienaber-Rousseau C, De Lange Z, De Maat MP, Hoekstra T, Pieters M. Genetic polymorphisms influencing total and γ′ fibrinogen levels and fibrin clot properties in Africans. Br J Haematol 2014; 168:102-12. [PMID: 25156046 DOI: 10.1111/bjh.13104] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 07/29/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Retha C. Kotzé
- Centre of Excellence for Nutrition; North-West University; Potchefstroom South Africa
| | | | - Zelda De Lange
- Centre of Excellence for Nutrition; North-West University; Potchefstroom South Africa
| | - Moniek P. De Maat
- Department of Haematology; Erasmus University Medical Centre; Rotterdam The Netherlands
| | - Tiny Hoekstra
- Centre of Excellence for Nutrition; North-West University; Potchefstroom South Africa
- Department of Clinical Epidemiology; Leiden University Medical Centre; Leiden The Netherlands
| | - Marlien Pieters
- Centre of Excellence for Nutrition; North-West University; Potchefstroom South Africa
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Ali AT, Crowther NJ. Factors predisposing to obesity: a review of the literature. S Afr Fam Pract (2004) 2014. [DOI: 10.1080/20786204.2010.10873970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Ali AT, Crowther NJ. Factors predisposing to obesity: a review of the literature. JOURNAL OF ENDOCRINOLOGY METABOLISM AND DIABETES OF SOUTH AFRICA 2014. [DOI: 10.1080/22201009.2009.10872198] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Relationship of coagulation and fibrinolytic variables with arterial structure and function in Africans. Thromb Res 2014; 134:78-83. [PMID: 24824291 DOI: 10.1016/j.thromres.2014.04.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 04/11/2014] [Accepted: 04/21/2014] [Indexed: 01/14/2023]
Abstract
INTRODUCTION Although both coagulation and fibrinolysis are associated with cardiovascular disease (CVD) the underlying nature and pathways of many of these associations are still unclear. Our aim was to determine which of the current or 5-year prior levels of total fibrinogen, fibrinogen γ', plasminogen activator inhibitor-1 (PAI-1act) and global fibrinolytic potential were the stronger determinant of arterial structure and function. MATERIALS AND METHODS This prospective study consisted of 2010 Africans over the age of 35 years with 5-year follow-up data available for 1288 participants. Cardiovascular measurements included arterial stiffness, blood pressure and carotid intima media thickness. RESULTS Fibrinogen γ' showed stronger associations with blood pressure than total fibrinogen also in the presence of other CVD risk factors. PAI-1act was positively associated with blood pressure both cross-sectionally and prospectively, with the longitudinal association being the stronger determinant, also after adjustment for known CVD risk factors. Clot lysis time (CLT) was positively associated, both prospectively and cross-sectionally, with intima media thickness and negatively with markers of arterial stiffness but not after adjustment for known CVD risk factors. CONCLUSIONS Fibrinogen γ' was more strongly associated with CVD function than total fibrinogen. PAI-1act was significantly associated with blood pressure with changes in PAI-1 levels preceding changes in blood pressure. Different mechanisms may be at play determining arterial wall stiffness/thickening and blood pressure as observed from the opposing associations with PAI-1act and CLT. CLT was not independently related to cardiovascular measures as its associations were weakened in the presence of other known CVD risk factors.
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Kim H, Yoo WG, Park J, Kim H, Kang BC. Semantic Modeling for SNPs Associated with Ethnic Disparities in HapMap Samples. Genomics Inform 2014; 12:35-41. [PMID: 24748859 PMCID: PMC3990764 DOI: 10.5808/gi.2014.12.1.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 12/23/2013] [Accepted: 12/24/2013] [Indexed: 11/20/2022] Open
Abstract
Single-nucleotide polymorphisms (SNPs) have been emerging out of the efforts to research human diseases and ethnic disparities. A semantic network is needed for in-depth understanding of the impacts of SNPs, because phenotypes are modulated by complex networks, including biochemical and physiological pathways. We identified ethnicity-specific SNPs by eliminating overlapped SNPs from HapMap samples, and the ethnicity-specific SNPs were mapped to the UCSC RefGene lists. Ethnicity-specific genes were identified as follows: 22 genes in the USA (CEU) individuals, 25 genes in the Japanese (JPT) individuals, and 332 genes in the African (YRI) individuals. To analyze the biologically functional implications for ethnicity-specific SNPs, we focused on constructing a semantic network model. Entities for the network represented by "Gene," "Pathway," "Disease," "Chemical," "Drug," "ClinicalTrials," "SNP," and relationships between entity-entity were obtained through curation. Our semantic modeling for ethnicity-specific SNPs showed interesting results in the three categories, including three diseases ("AIDS-associated nephropathy," "Hypertension," and "Pelvic infection"), one drug ("Methylphenidate"), and five pathways ("Hemostasis," "Systemic lupus erythematosus," "Prostate cancer," "Hepatitis C virus," and "Rheumatoid arthritis"). We found ethnicity-specific genes using the semantic modeling, and the majority of our findings was consistent with the previous studies - that an understanding of genetic variability explained ethnicity-specific disparities.
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Affiliation(s)
- Hyoyoung Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Korea
| | - Won Gi Yoo
- Codes Division, Insilicogen, Inc., Suwon 441-813, Korea
| | - Junhyung Park
- Codes Division, Insilicogen, Inc., Suwon 441-813, Korea
| | - Heebal Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Korea
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In black South Africans from rural and urban communities, the 4G/5G PAI-1 polymorphism influences PAI-1 activity, but not plasma clot lysis time. PLoS One 2013; 8:e83151. [PMID: 24386152 PMCID: PMC3875438 DOI: 10.1371/journal.pone.0083151] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 10/30/2013] [Indexed: 01/28/2023] Open
Abstract
Data on genetic and environmental factors influencing PAI-1 levels and their consequent effect on clot lysis in black African populations are limited. We identified polymorphisms in the promoter area of the PAI-1 gene and determined their influence on PAI-1act levels and plasma clot lysis time (CLT). We also describe gene-environment interactions and the effect of urbanisation. Data from 2010 apparently healthy urban and rural black participants from the South African arm of the PURE study were cross-sectionally analysed. The 5G allele frequency of the 4G/5G polymorphism was 0.85. PAI-1act increased across genotypes in the urban subgroup (p = 0.009) but not significantly in the rural subgroup, while CLT did not differ across genotypes. Significant interaction terms were found between the 4G/5G polymorphism and BMI, waist circumference and triglycerides in determining PAI-1act, and between the 4G/5G polymorphism and fibrinogen and fibrinogen gamma prime in determining CLT. The C428T and G429A polymorphisms did not show direct relationships with PAI-1act or CLT but they did influence the association of other environmental factors with PAI-1act and CLT. Several of these interactions differed significantly between rural and urban subgroups, particularly in individuals harbouring the mutant alleles. In conclusion, although the 4G/5G polymorphism significantly affected PAI-1act, it contributed less than 1% to the PAI-1act variance. (Central) obesity was the biggest contributor to PAI-1act variance (12.5%). Urbanisation significantly influenced the effect of the 4G/5G polymorphism on PAI-1act as well as gene-environment interactions for the C428T and G429A genotypes in determining PAI-1act and CLT.
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Evidence that fibrinogen γ′ regulates plasma clot structure and lysis and relationship to cardiovascular risk factors in black Africans. Blood 2013; 121:3254-60. [DOI: 10.1182/blood-2012-12-471482] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Key Points
This paper describes the effect of fibrinogen γ′ on clot structure in plasma (previously shown in purified systems). This paper also describes the respective roles of total fibrinogen, fibrinogen γ′ concentration, and ratio on clot structure and lysis rates.
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Raji I, Mugabo P, Obikeze K. The contributions of muscarinic receptors and changes in plasma aldosterone levels to the anti-hypertensive effect of Tulbaghia violacea. Altern Ther Health Med 2013; 13:13. [PMID: 23311308 PMCID: PMC3631126 DOI: 10.1186/1472-6882-13-13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 11/12/2012] [Indexed: 11/10/2022]
Abstract
BACKGROUND Tulbaghia violacea Harv. (Alliaceae) is used to treat various ailments, including hypertension (HTN) in South Africa. This study aims to evaluate the contributions of muscarinic receptors and changes in plasma aldosterone levels to its anti-hypertensive effect. METHODS In the acute experiments, methanol leaf extracts (MLE) of T. violacea (30-120 mg/kg), muscarine (0.16 -10 μg/kg), and atropine (0.02 - 20.48 mg/kg), and/or the vehicle (dimethylsulfoxide (DMSO) and normal saline (NS)) were respectively and randomly administered intravenously in a group of spontaneously hypertensive (SHR) weighing 300 to 350 g and aged less than 5 months. Subsequently, T. violacea (60 mg/kg) or muscarine (2.5 μg/kg) was infused into eight SHRs, 20 min after atropine (5.12 mg/kg) pre-treatment. In the chronic (21 days) experiments, the SHRs were randomly divided into three groups, and given the vehicle (0.2 ml/day of DMSO and NS), T. violacea (60 mg/kg/day) and captopril (10 mg/kg/day) respectively into the peritoneum, to investigate their effects on blood pressure (BP), heart rate (HR), and plasma aldosterone levels. Systolic BP and HR were measured using tail-cuff plethysmography during the intervention. BP and HR were measured via a pressure transducer connecting the femoral artery and the Powerlab at the end of each intervention in the acute experiment; and on day 22 in the chronic experiment. RESULTS In the acute experiments, T. violacea, muscarine, and atropine significantly (p < 0.05) reduced BP dose-dependently. T. violacea and muscarine produced dose-dependent decreases in HR, while the effect of atropine on HR varied. After atropine pre-treatment, dose-dependent increases in BP and HR were observed with T. violacea; while the BP and HR effects of muscarine were nullified. In the chronic experiments, the T. violacea-treated and captropril-treated groups had signicantly lower levels of aldosterone in plasma when compared to vehicle-treated group. Compared to the vehicle-treated group, significant reduction in BP was only seen in the captopril-treated group; while no difference in HR was observed among the groups. CONCLUSION The results obtained in this study suggest that stimulation of the muscarinic receptors and a reduction in plasma aldosterone levels contribute to the anti-hypertesive effect of T. violacea.
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Spearing K, Kolahdooz F, Lukasewich M, Mathe N, Khamis T, Sharma S. Nutritional composition of commonly consumed composite dishes from rural villages in Empangeni, KwaZulu-Natal, South Africa. J Hum Nutr Diet 2012; 26:222-9. [PMID: 23216447 DOI: 10.1111/jhn.12001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND Accurate nutrient composition data for composite dishes unique to a population is essential for the development of a nutrient database and the calculation of dietary intake. The present study aimed to provide the nutritional composition of composite dishes frequently consumed in rural KwaZulu-Natal, South Africa. METHODS Commonly consumed composite dishes were identified using 24-h recalls collected from 79 randomly selected community members. Multiple recipes were collected for each reported dish. The mean nutritional composition of each dish was calculated per 100 g using the nutribase clinical nutrition manager (Cybersoft Inc., Phoenix, AZ, USA). RESULTS A total of 79 recipes were collected for 16 commonly consumed dishes (seven meat-based, five starch-based and four legume/vegetable-based). 'Fried chicken' contained the most energy [1469 kJ (351 kcal)], protein (29.7 g), fat (23.7 g), cholesterol (123 mg) and niacin (8.4 mg). 'Fried beef' contained the most potassium (495 mg) and zinc (6.4 mg), whereas 'fish stew' had the most vitamin D (4.2 μg) and calcium (215 mg). 'Fried cabbage' and 'fried spinach' contained the largest percent energies from fat, at 79% and 76%, respectively. A traditional sweet bread, 'jeqe', made with fortified flour contributed significantly to iron (4.6 mg), niacin (4.5 μg) and folate (129 μg). The sodium content of dishes ranged from 88 to 679 mg per 100 g. CONCLUSIONS The nutritional composition data for commonly consumed dishes in rural KwaZulu-Natal is presented. Although the dishes are good sources of protein, vitamins and minerals, they also contain substantial amounts of fat. This culturally appropriate information will enable the calculation of dietary intake and can be used to encourage the consumption of recipes rich in key nutrients.
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Affiliation(s)
- K Spearing
- Department of Medicine, University of Alberta, Edmonton, AB, Canada
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Pawloski LR, Curtin KM, Gewa C, Attaway D. Maternal-child overweight/obesity and undernutrition in Kenya: a geographic analysis. Public Health Nutr 2012; 15:2140-7. [PMID: 22414734 PMCID: PMC10271325 DOI: 10.1017/s1368980012000110] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 01/03/2012] [Indexed: 12/12/2022]
Abstract
OBJECTIVE The purpose of the study was to examine geographic relationships of nutritional status (BMI), including underweight, overweight and obesity, among Kenyan mothers and children. DESIGN Spatial relationships were examined concerning BMI of the mothers and BMI-for-age percentiles of their children. These included spatial statistical measures of the clustering of segments of the population, in addition to inspection of co-location of significant clusters. SETTING Rural and urban areas of Kenya, including the cities of Nairobi and Mombasa, and the Kisumu region. SUBJECTS Mother-child pairs from Demographic and Health Survey data including 1541 observations in 2003 and 1592 observations in 2009. These mother-child pairs were organized into 399 locational clusters. RESULTS There is extremely strong evidence that high BMI values exhibit strong spatial clustering. There were co-locations of overweight mothers and overweight children only in the Nairobi region, while both underweight mothers and children tended to cluster in rural areas. In Mombasa clusters of overweight mothers were associated with normal-weight children, while in the Kisumu region clusters of overweight children were associated with normal-weight mothers. CONCLUSIONS These findings show there is geographic variability as well as some defined patterns concerning the distribution of malnutrition among mothers and children in Kenya, and suggest the need for further geographic analyses concerning the potential factors which influence nutritional status in this population. In addition, the methods used in this research may be easily applied to other Demographic and Health Survey data in order to begin to understand the geographic determinants of health in low-income countries.
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Affiliation(s)
- Lisa R Pawloski
- Department of Nutrition and Food Studies, George Mason University, Fairfax, VA 22030, USA.
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Zatu MC, Van Rooyen JM, Schutte AE. Smoking and vascular dysfunction in Africans and Caucasians from South Africa. Cardiovasc J Afr 2011; 22:18-24. [PMID: 21298201 PMCID: PMC4650927 DOI: 10.5830/cvja-2010-034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Accepted: 03/14/2010] [Indexed: 11/21/2022] Open
Abstract
Background Smoking is an important modifiable risk factor for cardiovascular disease, with limited research having been done in Africans. We aimed to determine the association between smoking and measurements of vascular function in Africans and Caucasians. Methods We determined anthropometric and cardiovascular variables, serum cotinine and C-reactive protein (CRP) in African and Caucasian participants from South Africa (n = 630). Results Africans had significantly lower body mass index (BMI), higher blood pressure and lower socio-economic status (SES) than Caucasians. Only African smokers showed increased arterial stiffness and a significant correlation between smoking and arterial stiffness. African smokers had increased and Caucasian smokers decreased high-density lipoprotein cholesterol (HDL-C) than the non-smokers. After adjusting for confounders, smoking showed few correlations, mainly with heart rate and CRP. In Africans, smoking also correlated positively with HDL-C, with the opposite result in Caucasians. Conclusion African smokers had significantly increased arterial stiffness, which was not found in Caucasian smokers. Africans generally demonstrated more associations between smoking and cardiovascular dysfunction than Caucasians.
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Affiliation(s)
- M C Zatu
- Hypertension in Africa Research Team (HART), School for Physiology, Nutrition and Consumer Sciences, North-West University, Potchefstroom, South Africa
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Triglyceride concentration and waist circumference influence alcohol-related plasminogen activator inhibitor-1 activity increase in black South Africans. Blood Coagul Fibrinolysis 2011; 21:736-43. [PMID: 20881480 DOI: 10.1097/mbc.0b013e32834014e2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We investigated the association between alcohol consumption and plasminogen activator inhibitor-1 activity (PAI-1act) and fibrinogen concentration in a black South African population presenting with lower PAI-1act and higher fibrinogen than what is typically observed in white populations. We, furthermore, wanted to investigate the effect of urbanization, sex, central obesity, increased triglycerides, 4G/5G polymorphism (PAI-1 only) and BMI on the association of alcohol with PAI-1act and fibrinogen. Data from 2010 apparently healthy, randomly collected black South African volunteers from the Prospective Urban and Rural Epidemiological (PURE) study were cross-sectionally analyzed. Alcohol consumption was recorded using quantitative food frequency questionnaires and fasting blood samples were collected for biochemical analysis including PAI-1act and fibrinogen. Heavy alcohol consumption is associated with significantly increased PAI-1act, in the total population as well as in the women separately, and tended to be so in men. This alcohol-related PAI-1act increase was observed in volunteers with increased triglycerides and central obesity but not in volunteers with normal levels and waist circumference. Urbanization, the 4G/5G polymorphism and BMI did not affect the association of alcohol with PAI-1act. Moderate alcohol consumption is associated with decreased fibrinogen concentration. Sex and level of urbanization did not affect the association of alcohol with fibrinogen. Fibrinogen decreased in normal and overweight volunteers but not in obese and centrally obese volunteers following moderate alcohol consumption. Triglyceride levels and waist circumference influence alcohol-related PAI-1act increase potentially through modulating adipocyte and triglyceride-induced PAI-1 production. Obesity prevented alcohol-related fibrinogen decrease possibly by counteracting the anti-inflammatory effect of moderate alcohol consumption.
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