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BACKGROUND: Low-and-middle income countries face a disproportionate burden of non-communicable diseases (NCDs) that threaten to overwhelm under-resourced health systems. Community health workers (CHWs) can promote NCD prevention, reach patients, and connect them to local community health resources; however, little has been done to examine how referrals to these resources are utilized by community members. The purpose of this study is to examine the use of referrals to community-based health resources and investigate the factors influencing patient utilization of referrals connecting them to appropriate health resources for elevated blood pressure (BP). METHODS: CHWs conducted home visits, which included BP screening and brief counseling, with community members in Soweto, South Africa. Participants with elevated (systolic BP: 121-139/ diastolic BP: 81-89 mmHg) or high (≥ 140/90 mmHg) BP were referred to either a local, community-based physical activity (PA) program managed by a non-governmental organization or local health clinics. The number of participants that received and utilized their referrals was tracked. Follow-up interviews were conducted with individuals given a referral who: (1) went to the PA program, (2) did not go to the PA program, (3) went to a clinic, and (4) did not go to a clinic. Interviews were transcribed and analyzed to identify common themes and differences between groups regarding their decisions to utilize the referrals. RESULTS: CHWs visited 1056 homes, with 1001 community members consenting to the screening; 29.2% (n = 292) of adults were classified as having optimal BP (≤120/80 mmHg), 35.8% (n = 359) had elevated BP, and 35.0% (n = 350) had high BP. One hundred and seventy-three participants accepted a referral to the PA program with 46 (26.6%) enrolling. Five themes emerged from the interviews: (1) prior knowledge and thoughts on BP, (2) psychosocial factors associated with BP control, (3) perception about receiving the referral, (4) contextual factors influencing referral utilization, and (5) perceived benefits of utilizing the referral. CONCLUSION: CHWs can successfully increase community members' access to health resources by providing appropriate referrals. However, greater attention needs to address community members' barriers and hesitancy to utilize health resources.
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Hipertensión , Adulto , Humanos , Presión Sanguínea , Sudáfrica , Hipertensión/diagnóstico , Consejo , Derivación y Consulta , Agentes Comunitarios de SaludRESUMEN
Elevated blood pressure (BP) is a growing burden worldwide, leading to over 10 million deaths each year. In Sub-Saharan Africa, hypertension prevalence is higher and cardiovascular events occur at a younger age than in Europe or America. May Measurement Month (MMM) is a global campaign initiated by the International Society of Hypertension (ISH) aimed at raising awareness of high BP. In South Africa, the MMM campaign in 2017, 2018, and 2019 revealed that approximately one-third of adults had hypertension, only half of hypertensives were receiving antihypertensive therapy, and only a third of those with hypertension had controlled BP. These data highlight the need for continued BP screening and awareness campaigns in South Africa. From May to November 2021, a cross-sectional survey of volunteers aged ≥18 years was performed. Blood pressure measurements, definition of hypertension, and statistical analyses followed the MMM protocol. The screening sites targeted the general population mainly on university campuses and pharmacies in preference to hospitals and clinics, aiming to raise awareness and allow access to screening in those less likely to be aware of their BP status. Of the 2294 individuals (age 37.3 ± 16.9 years) screened, 30.8% had hypertension. Of those with hypertension, only 48.6% were aware and 43.5% were receiving treatment for hypertension. A large proportion (50.4%) of individuals receiving antihypertensive medication had uncontrolled BP (≥140/90â mmHg). In conclusion, the high prevalence of hypertension, despite the young adult age, and the high proportions of individuals unaware of their hypertension and with uncontrolled BP underscore the necessity for hypertension awareness campaigns and more rigorous management of hypertension.
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BACKGROUND: Left ventricular hypertrophy (LVH) is a marker of increased risk in developing future life-threatening cardiovascular disease (CVD), however, it is unclear how CVD risk factors, such as obesity, blood pressure (BP), and tobacco use, are associated with left ventricular (LV) remodeling and LVH in urban African populations. Therefore, we aimed to identify the prevalence of LVH as well as the health factors associated with LV remodeling and LVH, within black South African adult women and their pre-pubescent children. METHODS: Black female adults (n = 123; age: 29-68 years) and their children (n = 64; age: 4-10; 55% female) were recruited from the Birth to Twenty Plus Cohort in Soweto, South Africa. Tobacco and alcohol use, physical activity, presence of diabetes mellitus, heart disease, and medication were self-reported. Height, weight, and blood pressure were measured in triplicate to determine the prevalence of obesity and hypertension respectively. Echocardiography was used to assess LV mass at end-diastole, based on linear measurements, and indexed to body surface area to determine LVH. RESULTS: Hypertension and obesity prevalences were 35.8% and 59.3% for adults and 45.3% and 6.3% for children. Self-reported tobacco use in adults was 22.8%. LVH prevalence was 35.8% in adults (75% eccentric: 25% concentric), and 6.3% in children. Concentric remodeling was observed in 15.4% of adults, however, concentric remodeling was only found in one child. In adults, obesity [OR: 2.54 (1.07-6.02; p = 0.02)] and hypertension [3.39 (1.08-10.62; p = 0.04)] significantly increased the odds of LVH, specifically eccentric LVH, while concentric LVH was associated with self-reported tobacco use [OR: 4.58 (1.18-17.73; p = 0.03)]. Although no logistic regression was run within children, of the four children LVH, three had elevated blood pressure and the child with normal blood pressure was overweight. CONCLUSIONS: The association between obesity, hypertension, tobacco use, and LVH in adults, and the 6% prevalence of LVH in children, calls for stronger public health efforts to control risk factors and monitor children who are at risk.
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Hipertensión , Remodelación Ventricular , Adulto , Anciano , Niño , Preescolar , Femenino , Humanos , Hipertensión/complicaciones , Hipertensión/diagnóstico , Hipertensión/epidemiología , Hipertrofia Ventricular Izquierda/diagnóstico por imagen , Hipertrofia Ventricular Izquierda/epidemiología , Hipertrofia Ventricular Izquierda/etiología , Masculino , Persona de Mediana Edad , Obesidad , Sudáfrica/epidemiología , Uso de Tabaco , Remodelación Ventricular/fisiologíaRESUMEN
OBJECTIVE: The age at which arteriosclerosis begins to contribute to events is uncertain. We determined, across the adult lifespan, the extent to which arteriosclerosis-related changes in arterial function occur in those with precipitous arterial events (stroke and critical limb ischemia). Approaches and Results: In 1082 black South Africans (356 with either critical limb ischemia [n=238] or stroke [n=118; 35.4% premature], and 726 age, sex, and ethnicity-matched randomly selected controls), arterial function was evaluated from applanation tonometry and velocity and diameter measurements in the outflow tract. Compared with age- and sex-matched controls, over 10-year increments in age from 20 to 60years, multivariate-adjusted (including steady-state pressures) aortic pulse wave velocity, characteristic impedance (Zc), forward wave pressures (Pf), and early systolic pulse pressure amplification were consistently altered in those with arterial events. Increases in Zc were accounted for by aortic stiffness (no differences in aortic diameter) and Pf by changes in Zc and not aortic flow or wave re-reflection. Multivariate-adjusted pulse wave velocity (7.48±0.30 versus 5.82±0.15 m/s, P<0.0001), Zc (P<0.0005), and Pf (P<0.0001) were higher and early systolic pulse pressure amplification lower (P<0.0001) in those with precipitous events than in controls. In comparison to age- and sex-matched controls, independent of risk factors, pulse wave velocity, and Zc (P<0.005 and <0.05) were more closely associated with premature events than events in older persons and Pf and early systolic pulse pressure amplification were at least as closely associated with premature events as events in older persons. CONCLUSIONS: Arteriosclerosis-related changes in arterial function are consistently associated with arterial events beyond risk factors from as early as 20 years of age.
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Arterias/fisiopatología , Arteriosclerosis/fisiopatología , Adulto , Anciano , Envejecimiento , Aorta/fisiopatología , Presión Arterial , Población Negra , Presión Sanguínea , Extremidades/irrigación sanguínea , Femenino , Humanos , Isquemia/fisiopatología , Masculino , Persona de Mediana Edad , Análisis de la Onda del Pulso , Factores de Riesgo , Sudáfrica , Accidente Cerebrovascular/fisiopatología , Rigidez VascularRESUMEN
Elevated blood pressure (BP) is a growing burden worldwide, leading to over 10 million deaths each year. May Measurement Month (MMM) is a global initiative of the International Society of Hypertension (ISH) aimed at raising awareness of high BP and to act as a temporary solution to the lack of screening programs worldwide. A surveillance study in 2016 in South Africa revealed that 45% of adults have hypertension and only 6-9% of men and women respectively had controlled BP on medication, highlighting the need for regular screening and awareness campaigns. An opportunistic cross-sectional survey of volunteers aged ≥18 years was carried out in May 2017. Blood pressure measurement, the definition of hypertension, and statistical analyses followed the MMM protocol. The sites screened were primarily university campuses and general populations in preference to hospitals and clinics, aiming to raise awareness and allow access to screening in those less likely to be aware of their BP. In total, 3250 individuals (mean age 31.0 ± 13.3 years) were screened. After multiple imputation for missing BP readings, 795 (24.5%) had hypertension. Of individuals not receiving antihypertensive medication, 459 (15.7%) were hypertensive, and 157 (46.9%) of individuals receiving antihypertensive medication had uncontrolled BP. These results suggest that opportunistic screening campaigns can identify significant numbers with undiagnosed and uncontrolled hypertension, even amongst the fairly young. The high proportions of individuals with undiagnosed and treated uncontrolled hypertension, highlight the need for campaigns to increase hypertension awareness and control.
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Background: Low-middle-income countries (LMICs) face increasing burdens from non-communicable disease (NCDs) requiring primary care task shifting to community health workers (CHWs). This study explored community members' perceptions of NCD-focused, CHW-led home visits in a historically disadvantaged township of South Africa. Methods: Trained CHWs visited community member homes, performing blood pressure and physical activity (PA) screenings, followed by brief counselling and a satisfaction survey. Semi-structured interviews were conducted within 3 days of the visit to learn about their experiences. Results: CHWs visited 173 households, with 153 adult community members consenting to participate (88.4%). Participants reported that it was easy to understand CHW-delivered information (97%), their questions were answered well (100%), and they would request home service again (93%). Twenty-eight follow-up interviews revealed four main themes: 1) acceptance of CHW visits, 2) openness to counselling, 3) satisfaction with screening and a basic understanding of the results, and 4) receptiveness to the PA advice. Conclusion: Community members viewed CHW-led home visits as an acceptable and feasible method for providing NCD-focused healthcare services in an under-resourced community. Expanding primary care reach through CHWs offers more accessible and individualized care, reducing barriers for individuals in under-resourced communities to access support for NCD risk reduction.
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Cardiovascular disease (CVD) is a leading cause of death in South Africa (SA) and high blood pressure (BP) is the primary risk factor. However, hypertension prevalence is high, BP control is poor and CV events occur at a younger age than in Europe or America. Increasing screening, raising awareness and improving management of hypertension are critical to prevent CVD in SA. May Measurement Month (MMM) is a global initiative of the International Society of Hypertension aimed at raising awareness of high BP. As part of the MMM campaign, in SA (2017, 2018, 2019 and 2021), BP measurements and a cross-sectional survey of volunteers aged ≥ 18years were performed. Of 11,320 individuals (age 36.6 ± 16.8years) screened, 29.7% had hypertension (systolic BP/diastolic BP ≥ 140/90 mmHg or antihypertensive medication use) and the prevalence was higher (p < 0.0001) in men (35.6%) than in women (26.3%). Of those with hypertension, only 54.3% were aware and 46.8% were receiving antihypertensive medication, and 53.7% of these had controlled BP. In men with hypertension, awareness (45.2%, treatment (38.2%) and controlled BP on antihypertensive medication (45.2%) were lower (p < 0.0001) than in women (awareness: 60.8%; treatment: 53.5%; controlled BP: 58.3%). In young participants (age < 40years), 15.6% had hypertension, 18.6% of these were on treatment but 76.0% were not aware, and only 57.7% had controlled BP. The high prevalence of hypertension, but low levels of awareness, treatment, and BP control in SA, especially in young adults and men, highlight the need for systematic BP screening programmes and improvements in education and management of hypertension.
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A major obstacle to tackling the growing burden of chronic disease in South Africa is lack of testing, particularly where individuals face multiple barriers to accessing health services. We conducted a pilot study to evaluate a cardiometabolic self-measurement kit, including assessment of blood pressure, obesity and urine analysis, amongst adults in Soweto, South Africa. Participants (N = 94) were recruited by researchers during community health screening and were provided with a home test kit including a tablet with self-measurement instructions. The participants entered their results on the tablet and, on completion, the researcher immediately repeated the measurements. We interviewed 10% of participants to understand their experience and views of the kits. Concordance correlation coefficients ranged from 0.78 for waist circumference to 0.93 for height, while the overall percentage agreement ranged from 80.5% for both urine protein and urine glucose testing to 91.4% for the identification of central obesity (ratio of waist circumference to height of ≥ 0.5). Participants saw the need for self-testing and found the process for the most part simple, though urine testing and height self-assessment presented some challenges. This pilot study suggests that self-assessment at home has the potential to facilitate the identification of individuals at risk for cardiometabolic disease in low-income settings, adding to a growing body of evidence on the use of self-testing in disease prevention and detection. However, we would not recommend self-testing for urine glucose and protein without further study.
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COVID-19 , Enfermedades Cardiovasculares , Adulto , Enfermedades Cardiovasculares/diagnóstico , Enfermedades Cardiovasculares/epidemiología , Glucosa , Humanos , Obesidad/diagnóstico , Obesidad/epidemiología , Pandemias , Proyectos Piloto , Reproducibilidad de los Resultados , Autoevaluación (Psicología) , Sudáfrica/epidemiologíaRESUMEN
BACKGROUND: Tobacco use is a major public health risk worldwide, which has increased on the African continent over the past 40 years. Socio-economic factors impact tobacco use and exposure, but little is known about the scope of this problem in young women living in an urban, historically disadvantaged township in contemporary South Africa. This study aimed to identify the prevalence of tobacco use in a cohort of young South African women using serum cotinine, and to assess the association between a number of socio-economic and social factors and tobacco use in this setting. METHODS: Secondary analysis was conducted on cross-sectional data from the Healthy Life Trajectories Initiative (HeLTI) study. Serum cotinine was measured and a cut-off of ≥ 10 ng/mL was classified as tobacco use. Household socio-economic, socio-demographic and health information were collected by an interviewer-administered questionnaire. RESULTS: Cotinine data was available for 1508 participants, of whom 29.2% (n = 441) had cotinine levels indicative of tobacco use. In regression analyses, moderate to severe socio-economic vulnerability (score 2-3 OR 1.66, p = 0.008; score ≥4: OR 1.63, p = 0.026) and multiparity (OR 1.74, p = 0.013) were associated with tobacco use. In addition, alcohol dependence (OR 3.07, p < 0.001) and drug use (OR 4.84, p < 0.001) were associated with tobacco use. CONCLUSION: Young women with multiple children, moderate to severe socio-economic vulnerability, and alcohol and drug use were identified as more likely to use tobacco, indicating the need for targeted anti-tobacco interventions to curb the impact of tobacco on the growing burden of noncommunicable diseases in this setting.
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Nicotiana , Uso de Tabaco , Niño , Estudios Transversales , Femenino , Humanos , Prevalencia , Sudáfrica/epidemiología , Uso de Tabaco/epidemiologíaRESUMEN
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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OBJECTIVES: Cardiovascular disease is increasing in many low and middle-income countries, including those in Africa. To inform strategies for the prevention of cardiovascular disease in South Africa, we sought to determine the broad heritability of phenotypic markers of cardiovascular risk across three generations. DESIGN: A cross-sectional study conducted in a longitudinal family cohort. SETTING: Research unit within a tertiary hospital in a historically disadvantaged, large urban township of South Africa. PARTICIPANTS: 195 individuals from 65 biological families with all three generations including third-generation children aged 4-10 years were recruited from the longest running intergenerational cohort study in Africa, the Birth to Twenty Plus cohort. All adults (grandparents and parents) were female while children were male or female. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was heritability of blood pressure (BP; brachial and central pressures). Secondary outcomes were heritability of arterial stiffness (pulse wave velocity), carotid intima media thickness (cIMT) and left ventricular mass indexed to body surface area (LVMI). RESULTS: While no significant intergenerational relationships of BP or arterial stiffness were found, there were significant relationships in LVMI across all three generations (p<0.04), and in cIMT between grandparents and parents (p=0.0166). Heritability, the proportion of phenotypic trait variation attributable to genetics, was estimated from three common statistical methods and ranged from 23% to 44% for cIMT and from 21% to 39% for LVMI. CONCLUSIONS: Structural indicators of vascular health, which are strong markers of future clinical cardiovascular outcomes, transmit between generations within African families. Identification of these markers in parents may be useful to trigger assessments of preventable risk factors for cardiovascular disease in offspring.
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Enfermedades Cardiovasculares , Hipertensión , Rigidez Vascular , Adulto , Presión Sanguínea/genética , Arteria Braquial , Enfermedades Cardiovasculares/complicaciones , Enfermedades Cardiovasculares/epidemiología , Enfermedades Cardiovasculares/genética , Grosor Intima-Media Carotídeo , Niño , Preescolar , Estudios de Cohortes , Estudios Transversales , Femenino , Humanos , Masculino , Análisis de la Onda del Pulso , Factores de Riesgo , Sudáfrica/epidemiologíaRESUMEN
BACKGROUND: Carotid-femoral pulse wave velocity (PWV) is the gold-standard noninvasive measure of arterial stiffness. Data comparing tonometry-based devices such as the SphygmoCor XCEL to simpler brachial-cuff-based estimates of PWV, such as from the Mobil-O-Graph in African populations are sparse. We therefore aimed to compare PWV measured by the Mobil-O-Graph and the SphygmoCor XCEL device in a sample of South African women and children. METHODS: Women (nâ=â85) 29 years [interquartile range (IQR): 29-69] and their children/grandchildren (nâ=â27) 7 years (IQR: 4-11) were recruited for PWV measurement with Mobil-O-Graph and SphygmoCor XCEL on the same day. Wilcoxon signed-rank test, regression analysis, spearman correlation and Bland-Altman plots were used for PWV comparison between devices. RESULTS: For adults, the SphygmoCor XCEL device had a significantly higher PWV (7.3âm/s, IQR: 6.4-8.5) compared with the Mobil-O-Graph (5.9âm/s, IQR: 5.0-8.1, Pâ=â0.001) with a correlation coefficient of 0.809 (Pâ≤â0.001). Bland--Altman analysis indicated an acceptable level of agreement but significant bias (mean difference PWV: 0.90â±â1.02âm/s; limits of agreement: -1.10 to 2.90). The odds of having a PWV difference more than 1âm/s decreased with a higher age [odds ratio (OR): 0.95, 95% confidence interval (95% CI)â=â0.92-0.98] and increased with greater height (OR: 1.10, 95% CIâ=â1.01-1.21, Pâ=â0.03) in multivariable analysis. In children, the Bland-Altman indicated an excellent level of agreement (-0.03â±â0.63âm/s; limits of agreement: -1.26 to 1.21), but no correlation was found (rsâ=â0.08, Pâ=â0.71). CONCLUSION: Particularly in younger and taller women, the Mobil-O-Graph significantly underestimated PWV compared with the SphygmoCor. Although no correlation was found between the two devices for children, further research is required due to the small sample size. Furthermore, the clinical value of both methods in young African populations requires further investigation.
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Análisis de la Onda del Pulso , Rigidez Vascular , Adulto , Presión Sanguínea , Arteria Braquial , Velocidad de la Onda del Pulso Carotídeo-Femoral , Niño , Femenino , HumanosRESUMEN
BACKGROUND: The long-term consequences for offspring born to mothers with hyperglycaemia first detected in pregnancy (HFDP) are not yet well understood and its influence on childhood blood pressure has not previously been assessed in sub-Saharan Africa. OBJECTIVE: The objective of this study was to evaluate the association between maternal HFDP and offspring blood pressure in 3 to 6-year-old children in Soweto, South Africa. METHODS: Oscillometric blood pressure was measured in 189 children born to mothers with and without HFDP diagnosed by 75âg 2-h oral glucose tolerance test. The 2017 AAP Guidelines for Childhood Hypertension were used as reference standard, and the term 'elevated blood pressure' referred to blood pressure readings above the 90th percentile for age, height and sex. The association between maternal HFDP and offspring blood pressure was analysed using multivariable linear regression. RESULTS: Elevated blood pressure was identified in 49.7% of children. Maternal hyperglycaemia was not associated with offspring blood pressure when adjusted for offspring age, height and sex (SBP: 0.199, Pâ =â0.888; DBP: 0.185, Pâ =â0.837) or after multivariable adjustment (SBP: -0.286, Pâ=â0.854; DBP: 0.215, Pâ=â0.833). In the full model for SBP, child BMI age z-score was a significant predictor of blood pressure at 3-6years (1.916, Pâ=â0.008). CONCLUSION: Although maternal HFDP was not associated with childhood blood pressure at 3-6âyears, the prevalence of elevated blood pressure in this group of preschool-aged children is concerning. Future research is needed to further evaluate childhood obesity as a modifiable risk factor to reduce hypertension and cardiovascular risk in an African setting.
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Hiperglucemia , Hipertensión , Obesidad Infantil , Presión Sanguínea , Niño , Preescolar , Femenino , Humanos , Hiperglucemia/epidemiología , Hipertensión/diagnóstico , Hipertensión/epidemiología , Madres , Embarazo , Sudáfrica/epidemiologíaRESUMEN
Due to the increasing non-communicable disease burden in Africa, several strategies that target the major lifestyle and physiological risk factors have been implemented to combat such diseases. The Healthy Aging Adult South Africa report card systematically reviews national and regional prevalence data of middle-aged South African adults (45-65 years) published between 2013 and 2020 on diet, physical activity, tobacco use and alcohol consumption, obesity, hypertension, dyslipidaemia and diabetes mellitus. Each indicator was assigned two grades, (1) based on the availability of prevalence data, and (2) based on whether policies have been proposed and implemented for the respective indicators. Alcohol consumption, obesity, hypertension and diabetes received an A grade for the availability of prevalence data. Tobacco use and diet received an A grade for policy and implementation. Gaps have been identified that need to be filled by future research focusing on continued surveillance of all indicators in order to inform and implement effective policies.
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Diabetes Mellitus , Envejecimiento Saludable , Hipertensión , Adulto , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/epidemiología , Ejercicio Físico , Femenino , Humanos , Hipertensión/diagnóstico , Hipertensión/epidemiología , Masculino , Persona de Mediana Edad , Obesidad/epidemiología , Prevalencia , Factores de Riesgo , Sudáfrica/epidemiologíaRESUMEN
Aims: A lower heart rate (HR) increases central blood pressure through enhanced backward wave pressures (Pb). We aimed to determine whether these relationships are modified by increases in aortic stiffness. Methods: Using non-invasive central pressure, aortic velocity and diameter measurements in the outflow tract (echocardiography), we assessed the impact of aortic stiffness on relationships between HR and arterial wave morphology in 603 community participants < 60 years of age, 221 ≥ 60 years, and in 287 participants with arterial events [stroke and critical limb ischemia (CLI)]. Results: As compared to community participants < 60 years, those ≥ 60 years or with events had increased multivariate adjusted proximal aortic characteristic impedance (Zc) and carotid femoral pulse wave velocity (PWV) (p < 0.05 to < 0.0001). Community participants ≥ 60 years and those with events also had a greater slope of the inverse relationship between HR and Pb (p < 0.001 for comparison). While in community participants < 60 years, no interaction between indexes of aortic stiffness and HR occurred, in those ≥ 60 years (p < 0.02) and in those with arterial events (p = 0.001), beyond aortic root diameter, an interaction between Zc and HR, but not between PWV and HR independently associated with Pb. This translated into stepwise increases in the slope of HR-Pb relationships at incremental tertiles of Zc. Although HR was inversely associated with the systemic reflection coefficient in community participants ≥ 60 years (p < 0.0001), adjustments for the reflection coefficient failed to modify HR-Pb relations. Conclusion: Beyond the impact on systemic wave reflection, increases in proximal aortic stiffness enhance the adverse effects of HR on Pb and hence central BP.
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The ability of carotid intima-media thickness (IMT) to predict risk beyond plaque is controversial. In 952 participants (critical limb ischemia [CLI] or stroke, n = 473; community, n = 479), we assessed whether relationships with events for IMT complement the impact of plaque in young patients depending on the extent of thrombotic versus atherosclerotic disease. The extent of atherosclerotic versus thrombotic occlusion was determined in 54 patients with CLI requiring amputations. Thrombotic occlusion in CLI was associated with younger age (P < .0001) and less plaque (P = .02). Independent relations between plaque and CLI were noted in older (>50 years; P < .005 to <.0001) but not younger (P > .38) participants, while independent relations between plaque and stroke (P < .005 to <.0001) and between IMT and CLI (P < .0001) were noted in younger participants. Although in performance (area under the receiver operating curve) for event detection, IMT thresholds failed to add to plaque alone in older patients (0.680 ± 0.020 vs 0.664 ± 0.017, P = .27), IMT improved performance for combined stroke and CLI detection when added to plaque in younger patients (0.719 ± 0.023 vs 0.631 ± 0.026, P < .0001). Because in younger participants the high prevalence of thrombotic occlusion in CLI is associated with less plaque, IMT adds information in associations with arterial vascular events.
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Grosor Intima-Media Carotídeo , Isquemia/complicaciones , Isquemia/diagnóstico por imagen , Pierna/irrigación sanguínea , Pierna/diagnóstico por imagen , Placa Aterosclerótica/complicaciones , Placa Aterosclerótica/diagnóstico por imagen , Accidente Cerebrovascular/complicaciones , Accidente Cerebrovascular/diagnóstico por imagen , Trombosis/complicaciones , Trombosis/diagnóstico por imagen , Factores de Edad , Anciano , Enfermedad Crítica , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Valor Predictivo de las PruebasRESUMEN
BACKGROUND: The contribution of steady-state pressures and the forward (Pf) and backward (reflected) (Pb) wave pressure components of pulse pressure to risk prediction have produced contrasting results. We hypothesized that the independent contribution of steady-state pressures (mean arterial pressure [MAP]), Pf and Pb, to cardiovascular damage is organ specific and age dependent. METHODS: In 1,384 black South Africans from a community sample, we identified independent relations between MAP, Pf, or Pb (applanation tonometry and SphygmoCor software) and left ventricular mass index (LVMI) (n = 997) (echocardiography), carotid intima-media thickness (IMT) (n = 804) (B-mode ultrasound), or aortic pulse wave velocity (PWV) (n = 1,217). RESULTS: Independent of risk factors, relations between Pf and IMT were noted in those over 50 years (P < 0.02), whereas in those less than 50 years, MAP (P < 0.005) was independently associated with IMT. Pb failed to show independent relations with IMT at any age (P > 0.37) In contrast, independent relations between Pb and LVMI were noted in those less than (P < 0.0001), and greater than (P < 0.02) 50 years, whereas MAP was not independently associated with LVMI at any age (P > 0.07) and Pf tended to show significant relations only in the elderly (P = 0.05). Moreover, although MAP (P < 0.005) and Pb (P < 0.01) showed independent relations with PWV at any age, Pf failed to show independent relations (P > 0.10). CONCLUSION: Independent of confounders, steady-state and aortic Pf and Pb show associations with end-organ measures that are organ specific and age dependent.
Asunto(s)
Presión Sanguínea , Grosor Intima-Media Carotídeo , Hipertrofia Ventricular Izquierda/etiología , Análisis de la Onda del Pulso , Adulto , Factores de Edad , Anciano , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
AIM: Although chronic kidney disease (CKD) as determined from estimated glomerular filtration rate (eGFR) is recommended for risk prediction by current hypertension guidelines, the equations to derive eGFR may not perform well in black Africans. We compared whether across the adult lifespan, eGFR or CKD are as closely associated with noncardiac arterial vascular events, as carotid intima-media thickness (IMT), in Africa. METHODS: In 1152 black South Africans [480 with noncardiac arterial events (294 with critical lower limb ischemia, 186 with stroke) of which 37% were premature] and 672 age, sex and ethnicity-matched controls from a randomly selected community sample, we assessed relations between eGFR, CKD or carotid IMT (B-mode ultrasound) and arterial events. RESULTS: From 20 years until old age, with or without adjustments, IMT was increased in those with as compared with without events (Pâ<â0.01 at each decade of age). However, at any decade of age across the adult lifespan neither creatinine concentrations, nor eGFR were altered in those with arterial events (Pâ>â0.28). Although IMT was strongly and independently associated with the odds of an event [odds ratio per 1 SD (0.171âmm) effectâ=â2.19, confidence intervalâ=â1.75-2.78, Pâ<â0.0001], neither creatinine concentrations (Pâ=â0.89), modification of diet in renal disease-derived (Pâ=â0.07), nor Chronic Kidney Disease Epidemiology Collaboration-derived [odds ratio per 1 SD (22.5âml/min per 1.73âm) effectâ=â1.06, confidence intervalâ=â0.89-1.27, Pâ=â0.51] eGFR were independently associated with the odds of an event. Although many with premature events had an increased IMT (63%), few with either premature events (8%) or with events at an older age (21%) had CKD and CKD had a poor performance (0.539â±â0.011) and low sensitivity (16%) for event detection. CONCLUSION: In black South Africans, despite carotid IMT strongly associating with noncardiac arterial vascular events (stroke and critical lower limb ischaemia) consistently across the adult lifespan, few with events have CKD and CKD fails to associate with events.