Hypertension In Sub-Saharan Africa

Genetic and BMI risks for predicting blood pressure in three generations of West African Dogon women

The study of genetic polymorphisms and body mass index (BMI) among African women in Africa and in the United States contributes to our understanding of the genetic and environmental risk factors for hypertension. African American women have the highest prevalence of hypertension and obesity compared to other ethnic groups in the United States. Using a cross-sectional research design, we examined the effects of genetic and environmental risks of single nucleotide polymorphisms (SNPs) and BMI on blood pressure (BP) among three generations of West African Dogon women (N = 199). We genotyped six SNPs located in the candidate genes known to be related to hypertension. We tested the associations between these SNPs and systolic BP (SBP) and diastolic BP (DBP) with Fisher's exact tests, chi-square tests for independence, and multivariable linear mixed models. The SNP rs8179526 (SLC4A5) was significantly associated with SBP adjusted for age, age(2), and BMI (p = .02). The "C" allele variant of rs8179526 (allele frequency of 0.445) was associated with higher SBP. This SNP did not deviate from the Hardy-Weinberg equilibrium (HWE) with p value of .772. The SNP × BMI interaction effects associated with SBP and DBP were not significant. rs8179526 is located on the SLC4A5 gene on chromosome 2. SLC4A5 encodes a protein that transports sodium and bicarbonate across cell membranes while regulating cellular pH and contains several SNPs linked to elevated BP. Knowledge of the SNP's effect on hypertension among West African women can help health practitioners educate their patients about genetic risks of developing hypertension.

Achieving blood preSsure goals sTudy in uncontrolled hypeRtensive pAtients treated with a fixed-dose combination of ramipriL/hydrochlorothiazide: the ASTRAL study

Background

Hypertension is a common cardiovascular disease, affecting adults worldwide and it accounts for up to 30% of all deaths. The need for better control of arterial hypertension justifies observational studies designed to better understand the real-life management of hypertensive patients. The ASTRAL study was primarily designed to evaluate the percentage of hypertensive patients achieving blood pressure goals after eight weeks of treatment with a fixed-dose combination of ramipril/hydrochlorothiazide (HCTZ).

Methods

The study was a multi-centre, non-comparative, open-label, observational study conducted in 36 centres in five sub-Saharan African countries, namely Cameroon, Congo Brazzaville, Democratic Republic of Congo (DRC), Madagascar and Nigeria. Four hundred and forty-nine men and women 18 years of age or older with hypertension not controlled by an ACE inhibitor, a diuretic or any other monotherapy or anti-hypertensive combination not containing a diuretic in a fixed dose were considered eligible for inclusion in this eight-week study. The study consisted of three visits, visit one (V1) at baseline, visit two (V2) after four weeks and visit three (V3) after eight weeks.

Results

The mean age of the patients was 54.7 ± 11.7 years (20–90 years) and most were categorised by the WHO criteria as either overweight or obese (71.6%). After four and eight weeks of treatment with the study drug, systolic and diastolic blood pressures significantly changed from baseline: –24.7/–14.2 mmHg (p < 0.001) and –31.7/–17.9 mmHg (p < 0.001), respectively. There were 60.2% of the non-diabetics on prior monotherapy who, at eight weeks, fulfilled the primary blood pressure goal for SBP and DBP, versus 26.5% of the diabetic patients, also on monotherapy. Few adverse events were reported, with facial oedema and dry cough recurring twice in two patients.

Conclusion

Fixed-dose combination of ramipril/HCTZ is therefore effective, tolerable and has a good safety profile for blood pressure control in black Africans.

Cardiovascular disease prevention in Ghana: feasibility of a faith-based organizational approach

OBJECTIVE

To examine the feasibility of using community health workers (CHWs) to implement cardiovascular disease (CVD) prevention programmes within faith-based organizations in Accra, Ghana.

METHODS

Faith-based organization capacity, human resources, health programme sustainability/barriers and community members' knowledge were evaluated. Data on these aspects were gathered through a mixed method design consisting of in-depth interviews and focus groups with 25 church leaders and health committee members from five churches, and of a survey of 167 adult congregants from two churches.

FINDINGS

The delivery of a CVD prevention programme in faith-based organizations by CHWs is feasible. Many faith-based organizations already provide health programmes for congregants and involve non-health professionals in their health-care activities, and most congregants have a basic knowledge of CVD. Yet despite the feasibility of the proposed approach to CVD prevention through faith-based organizations, sociocultural and health-care barriers such as poverty, limited human and economic resources and limited access to health care could hinder programme implementation.

CONCLUSION

The barriers to implementation identified in this study need to be considered when defining CVD prevention programme policy and planning.

Hypertension and its management in countries in Africa and the Middle East, with special reference to the place of β-blockade

BACKGROUND

The prevalence and clinical consequences of hypertension in countries in Africa and the Middle East have not been studied as well as in other regions.

SCOPE

We have reviewed the literature on the epidemiology and management of hypertension and related cardiovascular complications in countries within Africa and the Middle East. A PubMed search for countries in the region and 'hypertension' was supplemented by articles identified from reviews, and by literature suggested by the authors.

FINDINGS

The prevalence of hypertension is >20% in some countries in the Middle East and Africa, despite an average population age that is some 10-15 years lower than those of developed countries. Hypertension in these countries is associated with an increased risk of cardiovascular risk factors and cardiovascular disease, as elsewhere. Awareness rates of hypertension are low. Hypertension and its complications are undertreated, and mortality rates from cardiovascular disease are higher than in developed countries.

CONCLUSION

Available resources should be brought to bear on the management of hypertension in these countries. In particular, a recent downgrading of the importance of β-blockers in hypertension management guidelines needs to be reassessed. These agents are as effective as other antihypertensive classes both on blood pressures and on cardiovascular event rates. General concerns over an increased rate of new-onset diabetes with β-blockers have been overstated, although these agents should be avoided in metabolic syndrome.

Non-communicable diseases in sub-Saharan Africa: what we know now

BACKGROUND

Sub-Saharan Africa (SSA) has a disproportionate burden of both infectious and chronic diseases compared with other world regions. Current disease estimates for SSA are based on sparse data, but projections indicate increases in non-communicable diseases (NCDs) caused by demographic and epidemiologic transitions. We review the literature on NCDs in SSA and summarize data from the World Health Organization and International Agency for Research on Cancer on the prevalence and incidence of cardiovascular diseases, diabetes mellitus Type 2, cancer and their risk factors.

METHODS

We searched the PubMed database for studies on each condition, and included those that were community based, conducted in any SSA country and reported on disease or risk factor prevalence, incidence or mortality.

RESULTS

We found few community-based studies and some countries (such as South Africa) were over-represented. The prevalence of NCDs and risk factors varied considerably between countries, urban/rural location and other sub-populations. The prevalence of stroke ranged from 0.07 to 0.3%, diabetes mellitus from 0 to 16%, hypertension from 6 to 48%, obesity from 0.4 to 43% and current smoking from 0.4 to 71%. Hypertension prevalence was consistently similar among men and women, whereas women were more frequently obese and men were more frequently current smokers.

CONCLUSIONS

The prevalence of NCDs and their risk factors is high in some SSA settings. With the lack of vital statistics systems, epidemiologic studies with a variety of designs (cross-sectional, longitudinal and interventional) capable of in-depth analyses of risk factors could provide a better understanding of NCDs in SSA, and inform health-care policy to mitigate the oncoming NCD epidemic.

Elevated risk factors but low burden of heart disease in urban African primary care patients: a fundamental role for primary prevention

BACKGROUND

Few data describe the case burden of heart disease and cardiovascular risk factors relative to other conditions in urban Africans seeking primary health care.

METHODS

A clinical registry captured data on 1311 consecutive primary care patients (99% African) from two primary care clinics in Soweto, South Africa. Those with suspected sub-clinical heart disease had more advanced cardiologic assessment.

RESULTS

Overall, 862 women (66%, 41 ± 16 years) and 449 men (38 ± 14 years) were studied. Whilst more men were smokers (47% vs. 14%; OR 5.23, 95% CI 4.01-6.82), more women were obese (42% vs. 14%; OR 4.54, 95% CI 3.33-5.88); blood glucose levels doubling with age in obese women. Although 33% were hypertensive, only 4.9% had type 2 diabetes (n=45), heart disease (n=10) and/or cerebrovascular disease (n=12). Overall, 16% (n=205) had an abnormal 12-lead ECG with more men than women showing a major abnormality (24% vs. 11%; OR 2.63, 95% CI 1.89-3.46). Of 99 cases (7.6%) subject to advanced cardiologic assessment, 29 (2.2%) had newly diagnosed heart disease: including hypertensive heart failure (13 women vs. 2 men, OR 4.51 95% CI 1.00-21.2), coronary artery disease (n=3), valve disease (n=3), dilated cardiomyopathy (n=3) and 2 cases of acute myocarditis.

CONCLUSIONS

These data demonstrate a relatively low burden of heart disease in urban African patients seeking primary health care. Alternatively, high antecedent risk, particularly among obese women, highlights a key role for enhanced primary prevention.

Distribution of hyperglycaemia and related cardiovascular disease risk factors in low-income countries: a cross-sectional population-based survey in rural Uganda

BACKGROUND

Data on non-communicable disease (NCD) burden are often limited in developing countries in Africa but crucial for planning and implementation of prevention and control strategies. We assessed the prevalence of related cardiovascular disease risk factors (hyperglycaemia, high blood pressure and obesity) in a longstanding population cohort in rural Uganda.

METHODS

Trained field staff conducted a cross-sectional population-based survey of cardiovascular disease risk indicators using a questionnaire and simple measurements of body mass index (BMI), waist and hip circumference, waist/hip ratio (WHR), blood pressure and random plasma glucose. All members of the population cohort aged ≥13 years were eligible to participate in the survey.

RESULTS

Of the 4801 males and 5372 females who were eligible, 2719 (56.6%) males and 3959 (73.7%) females participated in the survey. Male and female participants had a mean standard deviation (SD) age of 31.8 (18.4) years and 33.7 (17.6) years, respectively. The observed prevalences of probable diabetes (glucose >11.0 mmol/l) and probable hyperglycaemia (7.0-11.0 mmol/l) were 0.4 and 2.9%, respectively. Less than 1% of males and 4% of females were obese (BMI ≥30 kg/m(2)), with 3.6% of males and 14.5% of females being overweight (BMI 25.0-29.9 kg/m(2)). However, in women, the prevalence of abdominal obesity was high (71.3% as measured by WHR and 31.2% as measured by waist circumference). The proportions of male and female current regular smokers were low (13.7 and 0.9%, respectively). The commonest cardiovascular disease risk factor was high blood pressure, with an observed prevalence of 22.5% in both sexes.

CONCLUSIONS

Population-based data on the burden of related cardiovascular disease risk factors can aid in the planning and implementation of an effective response to the double burden of communicable diseases and NCDs in this rural population of a low-income country undergoing epidemiological transition.

High prevalence and low awareness of hypertension in a market population in enugu, Nigeria

Background. A community-based study put the prevalence of hypertension in Nigeria at 32.8%. Market workers in Nigeria lead sedentary life style and often depend on salt-laden fast food while at work. Method. An unselected population of market workers were screened for hypertension and its risk factors by a pretested, structured questionnaire, clinical examination, and laboratory investigation. Hypertension was defined as BP ≥ 140 and/or ≥ 90 mmHg or being on drug therapy. Results. Forty-two percent of the screened population were hypertensive. Of this number, 70.6% did not know they were hypertensive before the screening. More males than females (P = .022) were hypertensive. Prevalence of hypertension increased with age from 5.4% in the age group <20 years to 80% in the age group ≥70 years. Conclusion. The prevalence of hypertension in market workers in this study was 42%, and the majority of them were unaware of their disease.

Optimising management of hypertension in primary care: the Valsartan Intensified Primary Care Reduction of Blood Pressure (Viper-Bp) study

BACKGROUND

The Valstartan Intensified Primary CarE Reduction of Blood Pressure Study (VIPER-BP) Study is an open-label, randomised controlled trial comparing usual primary care management with an intensive BP management strategy using three forms of valsartan-based therapy (mono-therapy, thiazide diuretic or calcium channel blocker combinations) to achieve individualised BP control.

METHODS

To identify the features of General Practitioner (GP) management of hypertension in Australia, we analyse the response to a case scenario-based survey of 500 GPs. We subsequently recruited a national cohort of GP Investigators to enrol up to 2500 patients into the VIPER-BP Study.

RESULTS

GP responses clearly demonstrated that, compared to the VIPER-BP intervention, a heterogeneous approach to the primary care management of hypertension persists in Australia. By November 2010, 2157 hypertensive patients from 272 actively recruiting GP Investigators were enrolled into the study. Of these, 1965 (91%) patients were entered into a standardised "run-in" phase of 28 days of valsartan 80 mg/day. Subsequently, 1285 patients were randomised to usual care (n=435) or the VIPER-BP intervention (n=850). There was a predominance of males (62%), whilst 55% had pre-existing diabetes or cardiovascular disease and 63% had been previously treated for hypertension. Mean systolic and diastolic BP on randomisation for men and women, respectively, was 148 ± 15/88 ± 11 and 148 ± 18/87 ± 10 mm Hg.

CONCLUSIONS

In contrast to typical primary care management of hypertension, VIPER-BP combines more intensive and aggressive therapies with structured management to more rapidly attain and sustain individualised BP targets in hypertensive patients.

[Management of stroke in sub-Saharan Africa: current issues]

In sub-Saharan Africa, stroke is likely to present an increasingly important public health problem with a larger relative share of overall morbidity and mortality. Overall, sub-Saharan Health Care is characterized by a lack of human resources, lack of facilities for special investigations, and especially an absence of specific programs addressing the prevention of cardiovascular conditions. Current data on the epidemiology of stroke in sub-Saharan Africa, although sparse and fragmentary, indicate a comparatively high incidence of cerebral hemorrhage associated with high blood pressure, while ischemic stroke in black Africans still appears to be related primarily to small artery disease, HIV infection, and sickle cell disease. With urbanization, the role of large-vessel atherosclerosis is increasing. It is thus essential to coordinate government funding, health care professionals and development agencies to address this rising health problem. Access to health care needs to be better structured, and screening programs should be developed in order to identify and treat vascular risk factors. Improved training of health care professionals is also required in the areas of prevention, diagnosis and management of stroke. Implementation of best-practice recommendations for the management of stroke adapted to the specificities and resources of African countries would help rationalize the scarce resources currently available.

High Rate of Obesity-Associated Hypertension among Primary Schoolchildren in Sudan

Cardiovascular disease (CVD) frequently has roots in childhood, including following childhood-onset hypertension. Incidence of CVD has increased in developing countries in East Africa during recent urbanization. Effects of these shifts on childhood hypertension are unclear. Our objectives were to (1) Determine the prevalence of hypertension among primary schoolchildren in Khartoum, Sudan; (2) Determine whether hypertension in this setting is associated with obesity. We performed a cross sectional study of 6-12y children from two schools randomly selected in Khartoum, Sudan. Height, weight, BMI, BP and family history of hypertension were assessed. Age-, height- and gender-specific BP curves were used to determine pre-hypertension (90–95%) and hypertension (>95%). Of 304 children, 45 (14.8%) were overweight; 32 (10.5%) were obese; 15 (4.9%) were pre-hypertensive and 15 (4.9%) were hypertensive. Obesity but not family history of hypertension was associated with current hypertension. In multiple logistic regression, adjusting for family history, children who were obese had a relative-risk of 14.7 (CI 2.45-88.2) for systolic hypertension compared to normal-weight children. We conclude that overweight and obesity are highly prevalent among primary schoolchildren in urban Sudan and are strongly associated with hypertension. That obesity-associated cardiovascular sequelae exist in the developing world at young ages may be a harbinger of future CVD in sub-Saharan Africa.

Standing at the crossroads between new and historically prevalent heart disease: effects of migration and socio-economic factors in the Heart of Soweto cohort study

AIMS

Migration, urbanization, and change in socio-economic factors have potentially profound effects on heart disease in low-to-middle income countries.

METHODS AND RESULTS

Chris Hani Baragwanath Hospital in Soweto, South Africa, provides health care to >1 million Africans. We systematically captured data from all de novo presentations of suspected heart disease (focusing on 'new' vs. historically prevalent forms) during 2006-2008. There were 3168 female (52 ± 18 years) vs. 2160 male (53 ± 17 years) cases. Overall, 999 (19%) presented with uncomplicated hypertension (n = 988) or type II diabetes, 1862 cases (35%) 'new' heart disease (1146 and 581 cases of hypertensive heart failure and coronary artery disease), and 2092 cases (39%) of historically prevalent heart disease (including 724 with primary valve disease and 502 idiopathic dilated cardiomyopathies). Level of education and non-communicable risk factors were important correlates of advanced disease. The rate of historically prevalent cases was higher in those aged 20-49 years (19-60 cases/100,000 population/annum) whilst being higher for "new" heart disease in those aged >50 years (155-343 cases/population/annum). Historically prevalent heart disease cases were younger [adjusted odds ratio (OR) 0.98, 95% 0.97-0.99 per year], more likely to be African (OR 4.59, 95% 2.76-7.60) while being less likely to originate from Soweto (OR 0.87, 95% 0.75-1.00) and be female (OR 0.67, 95% 0.49-0.92).

CONCLUSION

Dynamic socio-economic and lifestyle factors characteristic of epidemiological transition appear to have positioned the urban, mainly African community of Soweto at the crossroads between historically prevalent and 'new' forms of heart disease.

Task shifting to non-physician clinicians for integrated management of hypertension and diabetes in rural Cameroon: a programme assessment at two years

BACKGROUND

The burden of non-communicable chronic diseases, such as hypertension and diabetes, increases in sub-Saharan Africa. However, the majority of the rural population does still not have access to adequate care. The objective of this study is to examine the effectiveness of integrating care for hypertension and type 2 diabetes by task shifting to non-physician clinician (NPC) facilities in eight rural health districts in Cameroon.

METHODS

Of the 75 NPC facilities in the area, 69 (87%) received basic equipment and training in hypertension and diabetes care. Effectiveness was assessed after two years on status of equipment, knowledge among trained NPCs, number of newly detected patients, retention of patients under care, treatment cost to patients and changes in blood pressure (BP) and fasting plasma glucose (FPG) among treated patients.

RESULTS

Two years into the programme, of 54 facilities (78%) available for re-assessment, all possessed a functional sphygmomanometer and stethoscope (65% at baseline); 96% stocked antihypertensive drugs (27% at baseline); 70% possessed a functional glucose meter and 72% stocked oral anti-diabetics (15% and 12% at baseline). NPCs' performance on multiple-choice questions of the knowledge-test was significantly improved. During a period of two years, trained NPCs initiated treatment for 796 patients with hypertension and/or diabetes. The retention of treated patients at one year was 18.1%. Hypertensive and diabetic patients paid a median monthly amount of 1.4 and 0.7 Euro respectively for their medication. Among hypertensive patients with ≥ 2 documented visits (n = 493), systolic BP decreased by 22.8 mmHg (95% CI: -20.6 to -24.9; p < 0.0001) and diastolic BP by 12.4 mmHg (-10.9 to -13.9; p < 0.0001). Among diabetic patients (n = 79) FPG decreased by 3.4 mmol/l (-2.3 to -4.5; p < 0.001).

CONCLUSIONS

The integration of hypertension and diabetes into primary health care of NPC facilities in rural Cameroon was feasible in terms of equipment and training, accessible in terms of treatment cost and showed promising BP- and FPG-trends. However, low case-detection rates per NPC and a very high attrition among patients enrolled into care, limited the effectiveness of the programme.

Procyanidin-rich fractions from Parkia biglobosa (Mimosaceae) leaves cause redox-sensitive endothelium-dependent relaxation involving NO and EDHF in porcine coronary artery

AIM OF THE STUDY

Parkia biglobosa leaves are traditionally used as an antihypertensive agent in Benin. The present study assessed the vasorelaxant activity of different Parkia biglobosa leaf extracts using isolated porcine coronary artery rings.

MATERIALS AND METHODS

A hydroalcoholic leaf extract was submitted to a multi-step liquid-liquid fractionation with solvents of increasing polarity and the polyphenolic content of the different fractions was analyzed. Vascular reactivity of the different extracts was assessed using porcine coronary artery rings, in the presence or absence of specific pharmacological inhibitors.

RESULTS

The hydroalcoholic, ethyl acetate and butanolic extracts contained mainly procyanidins and monomeric flavonoids. Parkia biglobosa leaf crude extract induced a redox-sensitive endothelium-dependent relaxation mediated by both nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF). The fractionation of the butanolic extract generated 6 fractions, two of which induced stronger vasorelaxation than the original extract and they had a higher phenolic content.

CONCLUSIONS

Parkia biglobosa leaf extract is able to induce endothelium-dependent NO- and EDHF-mediated relaxation in porcine coronary artery rings. The vasorelaxant activity is dependent on their phenolic content and appears to involve mainly procyanidins.

Urbanization, ethnicity and cardiovascular risk in a population in transition in Nakuru, Kenya: a population-based survey

Background

Cardiovascular disease (CVD) is the leading cause of death among older people in Africa. This study aimed to investigate the relationship of urbanization and ethnicity with CVD risk markers in Kenya.

Methods

A cross-sectional population-based survey was carried out in Nakuru Kenya in 2007-2008. 100 clusters of 50 people aged ≥50 years were selected by probability proportionate to size sampling. Households within clusters were selected through compact segment sampling. Participants were interviewed by nurses to collect socio-demographic and lifestyle information. Nurses measured blood pressure, height, weight and waist and hip circumference. A random finger-prick blood sample was taken to measure glucose and cholesterol levels.

Hypertension was defined as systolic blood pressure (SBP) ≥140 mm Hg, or diastolic blood pressure (DBP) ≥90 mm Hg or current use of antihypertensive medication; Diabetes as reported current medication or diet control for diabetes or random blood glucose level ≥11.1 mmol/L; High cholesterol as random blood cholesterol level ≥5.2 mmol/L; and Obesity as Body Mass Index (BMI)≥30 kg/m².

Results

5010 eligible subjects were selected, of whom 4396 (88%) were examined. There was a high prevalence of hypertension (50.1%, 47.5-52.6%), obesity (13.0%, 11.7-14.5%), diabetes (6.6%, 5.6-7.7%) and high cholesterol (21.1%, 18.6-23.9). Hypertension, diabetes and obesity were more common in urban compared to rural groups and the elevated prevalence generally persisted after adjustment for socio-demographic, lifestyle, obesity and cardiovascular risk markers. There was also a higher prevalence of hypertension, obesity, diabetes and high cholesterol among Kikuyus compared to Kalenjins, even after multivariate adjustment. CVD risk markers were clustered both across the district and within individuals. Few people received treatment for hypertension (15%), while the majority of cases with diabetes received treatment (68%).

Conclusions

CVD risk markers are common in Kenya, particularly in urban areas. Exploring differences in CVD risk markers between ethnic groups may help to elucidate the epidemiology of these conditions.

Dietary, social, and environmental determinants of obesity in Kenyan women

Aim: To assess the determinants of overweight and obesity in Kenyan women considered to be undergoing the nutrition transition. Methods: A nationally representative sample of women (n = 1008) was randomly drawn. Weight, height, waist, and hip circumference were measured. A 24-hour dietary recall was conducted with each participant and a socio-demographic questionnaire completed. Data was analysed by age, education, location, and socioeconomic status. Risk for obesity was calculated while adjusting for age and location. Results: Overweight and obesity (BMI ≥ 25 kg/m2) were highly prevalent in Kenya (43.3%). Urbanisation appears to be an important determinant of obesity since obesity was most prevalent in urban women in the high income group. Women in the high income group (7278 kJ) and in urban areas (7049 kJ) had the highest mean energy intakes. There were also significant urban/rural and income differences in the contribution of macronutrients to energy intake. Total fat intake was 34.5% of energy (E) in urban areas and 29.7% E in rural areas; while carbohydrates contributed 69.9% E in rural areas and 57.4% E in urban areas (p < 0.0001). Overweight was significantly more likely in the highest income group; among households where room density was low; electricity or gas was used for cooking; and households had own tap and/or own flush toilet. Conclusions: This study suggests that urbanisation and its associated economic advancement as well as changes in dietary habits are among the most important determinants of overweight and obesity in Kenyan women.

Effect of systemic hypertension on right ventricular morphology and function: an echocardiographic study

BACKGROUND

Hypertension is an important cardiovascular risk factor worldwide. It is associated with left ventricular hypertrophy (LVH). Both diastolic and systolic dysfunction may occur in hypertensive heart disease. The ventricles are structurally and functionally interdependent on each other. This was an echocardiographic study intended to describe the impact of left ventricular pressure overload and hypertrophy due to hypertension on right ventricular morphology and function.

METHODS

One hundred subjects with systemic hypertension and 50 age- and gender-matched normotensive control subjects were used for this study. Two-dimensional (2-D), M-mode and Doppler echocardiographic studies were done to evaluate the structure and function of both ventricles. Data analysis was done using the SPSS 16.0 (Chicago, Ill). Statistical significance was taken as p < 0.05.

RESULTS

Age and gender were comparable between the two groups. Hypertensive subjects had significantly increased left ventricular end-diastolic dimensions, posterior wall thickness, interventricular septal thickness, left atrial dimensions and left ventricular mass and index. The mitral valve E/A ratio was reduced among hypertensive subjects when compared to normal controls (1.15 ± 0.75 vs 1.44 ± 0.31, respectively; p < 0.05). A similar pattern was found in the tricuspid E/A ratio (1.14 ± 0.36 vs 1.29 ± 0.30, respectively; p < 0.05). Hypertensive subjects also had reduced right ventricular internal dimensions (20.7 ± 8.0 vs 23.1 ± 3.1 mm, respectively; p < 0.001) but similar peak pulmonary systolic velocity. The mitral e/a ratio correlated well with the tricuspid e/a ratio.

CONCLUSION

Systemic hypertension is associated with right ventricular morphological and functional abnormalities. Right ventricular diastolic dysfunction may be an early clue to hypertensive heart disease.

Epidemic of hypertension in Ghana: a systematic review

Background

Hypertension is a major risk factor for many cardiovascular diseases in developing countries. A comprehensive review of the prevalence of hypertension provides crucial information for the evaluation and implementation of appropriate programmes.

Methods

The PubMed and Google Scholar databases were searched for published articles on the population-based prevalence of adult hypertension in Ghana between 1970 and August 2009, supplemented by a manual search of retrieved references. Fifteen unique population-based articles in non-pregnant humans were obtained. In addition, two relevant unpublished graduate student theses from one university department were identified after a search of its 1996-2008 theses.

Results

The age and sex composition of study populations, sampling strategy, measurement of blood pressure, definition of hypertension varied between studies. The prevalence of hypertension (BP ≥ 140/90 mmHg ± antihypertensive treatment) ranged from 19% to 48% between studies. Sex differences were generally minimal whereas urban populations tended to have higher prevalence than rural population in studies with mixed population types. Factors independently associated with hypertension included older age group, over-nutrition and alcohol consumption. Whereas there was a trend towards improved awareness, treatment and control between 1972 and 2005, less than one-third of hypertensive subjects were aware they had hypertension and less than one-tenth had their blood pressures controlled in most studies.

Conclusion

Hypertension is clearly an important public health problem in Ghana, even in the poorest rural communities. Emerging opportunities such as the national health insurance scheme, a new health policy emphasising health promotion and healthier lifestyles and effective treatment should help prevent and control hypertension.

Prevalence, associated factors and relationship between prehypertension and hypertension: a study of two ethnic African populations in Northern Nigeria

To determine the prevalence and relationship between prehypertension and hypertension, we studied 782 ethnic Hausa and Fulanis (men, 409; women, 373) aged 38.9±13.9 years recruited by multistage cluster sampling. Demographic, anthropometry, metabolic and JNC VII-based blood pressure categories were obtained and analysed using univariate and multivariate models. The prevalence rates of prehypertension and hypertension were 58.7% (men 59.2%, women 58.2%) and 24.8% (men 25.9%, women 23.6%), respectively. Only 16.5% of the population had JNC VII defined optimum blood pressure. Compared to hypertension, prehypertension had earlier onset (second versus third decade) and peak (fourth versus fifth decade) of life. The peak and trough prevalence of hypertension and prehypertension, respectively were observed in the 5th decade of life. Obesity, abnormalities of glucose metabolism and insulin resistance were the major factors associated with prehypertension and hypertension. Multivariate analysis identified obesity and impaired glucose tolerance as independent predictors of hypertension. Of those with hypertension, 13.9% were aware of their high blood pressure status of which 85.7% were commenced on treatment and 12.5% achieved blood pressure control. Overall, 1.5% of the study population had blood pressure <140/90 mm Hg. It is concluded that less than 20% of people of Hausa and Fulani ethnicities had optimum blood pressure. These are predominantly in their second decade of life suggesting that rise in blood pressure begins early in this population. The fifth decade of life may represent a period of transition from prehypertension to hypertension.

Non-communicable diseases in sub-Saharan Africa: the case for cohort studies

Michelle Holmes and colleagues argue that there is an urgent need for longitudinal cohorts based in sub-Saharan Africa to address the growing burden of noncommunicable diseases in the region.

Treatment of hypertension in rural Cambodia: results from a 6-year programme

This study was aimed to describe the outcomes of a hypertension treatment programme in two outpatient clinics in Cambodia. We determined proportions of patients who met the optimal targets for blood pressure (BP) control and assessed the evolution of mean systolic and diastolic BP (SBP/DBP) over time. Multivariate analyses were used to identify predictors of BP decrease and risk factors for LTFU. A total of 2858 patients were enrolled between March 2002 and June 2008 of whom 69.2% were female, 30.5% were aged ≥64 years and 32.6% were diabetic. The median follow-up time was 600 days. By the end of 2008, 1642 (57.4%) were alive-in-care, 8 (0.3%) had died and 1208 (42.3%) were lost to follow-up. On admission, mean SBP and DBP were 162 and 94 mm Hg, respectively. Among the patients treated, a significant SBP reduction of 26.8 mm Hg (95% CI: 28.4-25.3) was observed at 6 months. Overall, 36.5% of patients reached the BP targets at 24 months. The number of young adults, non-overweight patients and non-diabetics reaching the BP targets was more. Older age (>64 years), uncontrolled DBP (≥90 mm Hg) on last consultation and coming late for the last consultation were associated with LTFU, whereas non-diabetic patients were 1.5 times more likely to default than diabetics (95% CI: 1.3-1.7). Although the definite magnitude of the BP decrease due to antihypertension medication over time cannot be assessed definitely without a control group, our results suggest that BP reduction can be obtained with essential hypertension treatment in a large-scale programme in a resource-limited setting.

[Epidemiology of chronic kidney disease in the Democratic Republic of Congo: review of cross-sectional studies from Kinshasa, the capital]

Chronic kidney disease (CKD) is a worldwide public health problem. Little is known about its burden in Africa. This paper reviews the knowledge of CKD in Kinshasa, summarizing four studies undertaken in the general population and traditional health system of Kinshasa. CKD was defined by either kidney damage (proteinuria> or =300 mg/day) or reduced kidney function (eGFR<60 ml/min/1.73 m(2)). In the general population, the prevalence of CKD all stage is 12.4 %. Our work shows also the high prevalence of proteinuria among subjects who do not have diabetes or hypertension, the lack of early detection and management of CKD risk factors in the traditional health care system leading to late referral or premature deaths, and the limits of renal replacement treatment. CKD affects young people in the DRC, in contrast to the United States, where CKD is more prevalent in older people. Major determinants of CKD in our studies were hypertension, diabetes, overweight, age, lower socioeconomic status, and Human immunodeficiency virus (HIV) infection. Glomerular nephropathy (mainly focal segmental glomerulosclerosis) remains the leading cause of end stage renal disease. An annual screening of the population for proteinuria and CKD risk factors is feasible and will, it is hoped, provide the basis for building a nationwide prevention strategy.

Developing effective chronic disease interventions in Africa: insights from Ghana and Cameroon

Background

Africa faces an urgent but 'neglected epidemic' of chronic disease. In some countries stroke, hypertension, diabetes and cancers cause a greater number of adult medical admissions and deaths compared to communicable diseases such as HIV/AIDS or tuberculosis. Experts propose a three-pronged solution consisting of epidemiological surveillance, primary prevention and secondary prevention. In addition, interventions must be implemented through 'multifaceted multi-institutional' strategies that make efficient use of limited economic and human resources. Epidemiological surveillance has been prioritised over primary and secondary prevention. We discuss the challenge of developing effective primary and secondary prevention to tackle Africa's chronic disease epidemic through in-depth case studies of Ghanaian and Cameroonian responses.

Methods

A review of chronic disease research, interventions and policy in Ghana and Cameroon instructed by an applied psychology conceptual framework. Data included published research and grey literature, health policy initiatives and reports, and available information on lay community responses to chronic diseases.

Results

There are fundamental differences between Ghana and Cameroon in terms of 'multi-institutional and multi-faceted responses' to chronic diseases. Ghana does not have a chronic disease policy but has a national health insurance policy that covers drug treatment of some chronic diseases, a culture of patient advocacy for a broad range of chronic conditions and mass media involvement in chronic disease education. Cameroon has a policy on diabetes and hypertension, has established diabetes clinics across the country and provided training to health workers to improve treatment and education, but lacks community and media engagement. In both countries churches provide public education on major chronic diseases. Neither country has conducted systematic evaluation of the impact of interventions on health outcomes and cost-effectiveness.

Conclusions

Both Ghana and Cameroon require a comprehensive and integrative approach to chronic disease intervention that combines structural, community and individual strategies. We outline research and practice gaps and best practice models within and outside Africa that can instruct the development of future interventions.

Vasorelaxant effects of extracts of the stem bark of Terminalia superba Engler & Diels (Combretaceae)

AIM OF THE STUDY

The stem bark of Terminalia superba (Combretaceae) (TS) is used in traditional Cameroonian medicine as antihypertensive remedy. In the present study, we investigated the vasorelaxant properties of different extracts of TS and their underlying mechanisms.

MATERIALS AND METHODS

Activities of aqueous (AQU), methanolic (MET), methylene chloride (MC), and methylene chloride-methanol (MCM) extracts of TS were evaluated on isolated rat aortic rings precontracted with phenylephrine (PE) or high KCl.

RESULTS

All extracts induced a vasodilating effect both on KCl- and PE-induced contractions. The effects of MC and MCM extracts were greater than those of AQU or MET extracts (P<0.05). MC had an endothelium-independent effect and reduced Ca(++)-induced contraction following PE or KCl challenge (P<0.05). After incubation with verapamil, MC induced a relaxation in rings precontracted by PE (P<0.001). By contrast, the effect of MCM was endothelium-dependent and decreased by the nitric oxide synthase inhibitor N(W)-nitro-L-arginine methyl ester (P<0.05).

CONCLUSIONS

These data demonstrate that the MC extract exhibits vasorelaxant effects that are partly due to inhibition of extracellular Ca(++) influx and/or inhibition of intracellular Ca(++) release in vascular smooth muscle cells. By contrast, the effect of the MCM extract was found to be endothelium- and nitric oxide dependent.

Primary health care for hypertension by nurses in rural and urban sub-Saharan Africa

To implement a nurse-led protocol for the care of hypertension, 5 clinics were established in Yaounde (urban) and Bafut (rural) in Cameroon. International guidelines were adapted and 10 nurses were trained. The initial cohort of patients was referred from a field survey. The program proceeded for 26 months and 454 patients (45% urban) were registered in the clinics. Relative to urban participants, rural participants were more often women (59% vs 45%, P=.002) and less likely to have diabetes (7.2% vs 41.2%, P<.001). Between baseline and final visits, systolic and diastolic blood pressures dropped by 11.7 mm Hg (95% confidence interval, 8.9-14.4) and 7.8 (95% confidence interval, 5.9-9.6), respectively (P<.001). These changes were consistent in subgroups and after adjustment. Most dropouts occurred around the initial visit and among urban participants and nondiabetics. Nurse-led clinics are effective for improving hypertension care in these settings and require implementation and validation through controlled trials.

Incidence and predictors of hypertension among rural Chinese adults: results from Liaoning province

OBJECTIVE We wanted to determine the incidence of hypertension and its risk factors among rural Chinese adults.

METHODS

A population-based sample of 24,360 rural Chinese adults aged 35 years and older and free from hypertension at baseline was observed from 2004-2006 to 2008. Incident hypertension was defined as a systolic pressure of 140 mm Hg or greater, diastolic pressure of 90 mm Hg or greater, or current use of antihypertensive medication.

RESULTS

During a mean follow-up period of 28 months, 29.6% of men and 23.4% of women developed hypertension. The age-adjusted incidence was higher in men (12.75 per 100 person-years) than in women (10.04 per 100 person-years). Among men, independent predictors of incident hypertension were baseline age (hazard ratio [HR] = 1.11; 95% confidence interval [CI], 1.10-1.13), Mongolian ethnicity (HR = 1.09; 95% CI, 1.01-1.18), use of alcohol, (HR = 1.14; 95% CI, 1.06-1.23), high income vs low income (HR = 1.11; 95% CI, 1.00-1.22; and HR = 1.11; 95% CI, 1.03-1.20), prehypertension vs normotension (HR = 1.18; 95% CI, 1.08-1.28), overweight and obesity (HR = 1.28; 95% CI, 1.17-1.40), baseline salt intake (HR = 1.00; 95% CI, 1.00-1.01) and family history of hypertension (HR = 1.14; 95% CI, 1.03-1.27). With the exception of use of alcohol and mean income, the results were similar for women, except that low physical activity was shown as a risk factors as well. The awareness, treatment, and control rates for newly developed hypertension were 29.9%, 19.5%, and 1.5%, respectively.

CONCLUSIONS

These data indicate that the incidence of hypertension is high among these rural Chinese adults and that it is associated with many risk factors. Our findings further suggest that most newly developed hypertension cases are not treated. The increases in hypertension are probably related to rapid social changes in our country and may apply to other areas of the developing world. These findings call for urgent improvements in hypertension prevention and control programs in rural China.

Hypertension in the developing world: challenges and opportunities

Hypertension is a major public health problem and a leading cause of death and disability in developing countries. One-quarter of the world's adult population has hypertension, and this is likely to increase to 29% by 2025. Modeled projections indicate an increase to 1.15 billion hypertensive patients by 2025 in developing countries. There is variability in the global prevalence of hypertension: hypertension is present in approximately 35% of the Latin American population, 20%-30% of the Chinese and Indian population, and approximately 14% in Sub-Saharan African countries. This heterogeneity has been attributed to several factors, including urbanization with its associated changes in lifestyle, racial ethnic differences, nutritional status, and birth weight. Compounding this high burden of hypertension is a lack of awareness and insufficient treatment in those with hypertension. The public health response to this challenge should drive greater promotion of awareness efforts, studies of risk factors for hypertension, and understanding of the impact of lifestyle changes. Also important are efforts to develop multipronged strategies for hypertension management in developing nations.

How to treat hypertension in blacks: review of the evidence

Presentation, response to therapy, and clinical outcome differ according to race for patients with hypertension. Black patients have a higher prevalence and earlier onset of hypertension than other ethnic groups, with poorer prognosis than white patients. Blacks are more likely to be salt-sensitive, and to have a low plasma renin activity than are whites. They are at much greater risk of developing cardiovascular and renal complications. Despite many advances in the understanding and treatment of cardiovascular diseases, black patients continue to have increased morbidity and mortality from the end-organ complications of hypertension. The explanations for these observations remain incompletely understood, but genetic differences, added to socio-economic and environmental factors, have been proposed to explain this disparity. The first therapeutic approach is to decrease salt and increase potassium intakes. Diuretics (thiazides and potassium-sparing agents) and calcium channel blockers constitute the first antihypertensive drug choices. The angiotensin-converting-enzyme inhibitors, the angiotensin II receptor blockers and beta-blockers appear to be less effective in blacks with regard to uncomplicated hypertension, especially in older people, but addition of a small dose of diuretic improves their efficacy. These combinations are preferred among patients with chronic kidney disease or heart failure. The goal for blood pressure target is the same in blacks as it is in whites, being a blood pressure of less than 140/90 mmHg in uncomplicated hypertension and less than 130/80 mmHg in patients with diabetes mellitus or chronic kidney disease.

An overview of cardiovascular risk factor burden in sub-Saharan African countries: a socio-cultural perspective

Background

Sub-Saharan African (SSA) countries are currently experiencing one of the most rapid epidemiological transitions characterized by increasing urbanization and changing lifestyle factors. This has resulted in an increase in the incidence of non-communicable diseases, especially cardiovascular disease (CVD). This double burden of communicable and chronic non-communicable diseases has long-term public health impact as it undermines healthcare systems.

Purpose

The purpose of this paper is to explore the socio-cultural context of CVD risk prevention and treatment in sub-Saharan Africa. We discuss risk factors specific to the SSA context, including poverty, urbanization, developing healthcare systems, traditional healing, lifestyle and socio-cultural factors.

Methodology

We conducted a search on African Journals On-Line, Medline, PubMed, and PsycINFO databases using combinations of the key country/geographic terms, disease and risk factor specific terms such as "diabetes and Congo" and "hypertension and Nigeria". Research articles on clinical trials were excluded from this overview. Contrarily, articles that reported prevalence and incidence data on CVD risk and/or articles that report on CVD risk-related beliefs and behaviors were included. Both qualitative and quantitative articles were included.

Results

The epidemic of CVD in SSA is driven by multiple factors working collectively. Lifestyle factors such as diet, exercise and smoking contribute to the increasing rates of CVD in SSA. Some lifestyle factors are considered gendered in that some are salient for women and others for men. For instance, obesity is a predominant risk factor for women compared to men, but smoking still remains mostly a risk factor for men. Additionally, structural and system level issues such as lack of infrastructure for healthcare, urbanization, poverty and lack of government programs also drive this epidemic and hampers proper prevention, surveillance and treatment efforts.

Conclusion

Using an African-centered cultural framework, the PEN3 model, we explore future directions and efforts to address the epidemic of CVD risk in SSA.

Ten-year change in blood pressure levels and prevalence of hypertension in urban and rural Cameroon

BACKGROUND

Hypertension is becoming increasingly important in sub-Saharan Africa. However, evidences in support of this trend with time are still not available. The aim of this study was to evaluate the 10-year change in blood pressure levels and prevalence of hypertension in rural and urban Cameroon.

METHODS

Two cross-sectional population-based surveys in Yaounde (urban area) and Evodoula (rural area) in 1994 (1762 subjects) and 2003 (1398 subjects) used similar methodologies in women and men aged >or=24 years. Data on systolic and diastolic blood pressures (SBP and DBP), body mass index, educational level, alcohol consumption and tobacco smoking were collected during the two periods.

RESULTS

Between 1994 and 2003, blood pressure levels significantly increased in rural women (SBP, +18.2 mm Hg; DBP, +11.9 mm Hg) and men (SBP, +18.8 mm Hg; DBP, +11.6 mm Hg), all p<0.001. In the urban area, SBP increased in women (+8.1 mm Hg, p<0.001) and men (+6.5 mm Hg, p<0.001), and DBP increased only in women (+3.3 mm Hg, p<0.001). The OR (95% CI) adjusted on confounders comparing the prevalence of hypertension (blood pressure >or= 140/90 mm Hg and/or treatment) between 2003 and 1994 ranged from 1.5 (1.1 to 2.2) in urban men to 5.3 (3.2 to 8.9) in rural men.

CONCLUSION

Blood pressure levels of this population have deteriorated over time, and the prevalence of hypertension has increased by twofold to fivefold. Adverse effects of risk factors could account for some of these changes. Prevention and control programmes are needed to reverse these trends and to avoid the looming complications.

Hypertensive target organ damage in Ghanaian civil servants with hypertension

Background

Low levels of detection, treatment and control of hypertension have repeatedly been reported from sub Saharan Africa, potentially increasing the likelihood of target organ damage.

Methods

A cross-sectional study was conducted on 1015 urban civil servants aged≥25 years from seven central government ministries in Accra, Ghana. Participants diagnosed to have hypertension were examined for target organ involvement. Hypertensive target organ damage was defined as the detection of any of the following: left ventricular hypertrophy diagnosed by electrocardiogram, reduction in glomerular filtration rate, the presence of hypertensive retinopathy or a history of a stroke.

Results

Of the 219 hypertensive participants examined, 104 (47.5%) had evidence of target organ damage. The presence of target organ damage was associated with higher systolic and diastolic blood pressure levels. The odds of developing hypertensive target organ damage was five to six times higher in participants with blood pressure (BP)≥180/110 mmHg compared to those with BP<140/90 mmHg, and there was a trend to higher odds of target organ damage with increasing BP (p = 0.001). Women had about lower odds of developing target organ damage compared to men.

Conclusions

The high prevalence of target organ damage in this working population associated with increasing blood pressure, emphasises the need for hypertension control programs aimed at improving the detection of hypertension, and importantly addressing the issues inhibiting the effective treatment and control of people with hypertension in the population.

Cardiovascular disease, diabetes and established risk factors among populations of sub-Saharan African descent in Europe: a literature review

Background

Most European countries are ethnically and culturally diverse. Globally, cardiovascular disease (CVD) is the leading cause of death. The major risk factors for CVD have been well established. This picture holds true for all regions of the world and in different ethnic groups. However, the prevalence of CVD and related risk factors vary among ethnic groups.

Methods

This article provides a review of current understanding of the epidemiology of vascular disease, principally coronary heart disease (CHD), stroke and related risk factors among populations of Sub-Sahara African descent (henceforth, African descent) in comparison with the European populations in Europe.

Results

Compared with European populations, populations of African descent have an increased risk of stroke, whereas CHD is less common. They also have higher rates of hypertension and diabetes than European populations. Obesity is highly prevalent, but smoking rate is lower among African descent women. Older people of African descent have more favourable lipid profile and dietary habits than their European counterparts. Alcohol consumption is less common among populations of African descent. The rate of physical activity differs between European countries. Dutch African-Suriname men and women are less physically active than the White-Dutch whereas British African women are more physically active than women in the general population. Literature on psychosocial stress shows inconsistent results.

Conclusion

Hypertension and diabetes are highly prevalent among African populations, which may explain their high rate of stroke in Europe. The relatively low rate of CHD may be explained by the low rates of other risk factors including a more favourable lipid profile and the low prevalence of smoking. The risk factors are changing, and on the whole, getting worse especially among African women. Cohort studies and clinical trials are therefore needed among these groups to determine the relative contribution of vascular risk factors, and to help guide the prevention efforts. There is a clear need for intervention studies among these populations in Europe.

Enhanced post-natal growth is associated with elevated blood pressure in young Senegalese adults

BACKGROUND

Evidence suggests that intrauterine growth restriction followed by rapid post-natal growth is associated with high blood pressure. We assessed the effect of early size and post-natal growth on blood pressure in a population from West Africa, where fetal growth retardation and childhood malnutrition are common.

METHODS

A total of 1288 Senegalese subjects were followed from infancy to young adulthood (mean age 17.9 years). Adult systolic blood pressure (SBP) was regressed on infant and adult anthropometric characteristics.

RESULTS

In unadjusted analyses, infant size was positively associated with adult SBP (1.1 +/- 0.3; P = 0.001 for weight; 0.7 +/- 0.3; P = 0.04 for length). With adjustment for current size, the regression coefficients for infant size were reversed (-0.2 +/- 0.3; P = 0.51 for weight; -0.3 +/- 0.3; P = 0.35 for length). SBP increased by 4.1 and 2.9 mmHg for 1 standard deviation (SD) increase in current weight or height, respectively. No interaction between infant size and current size was found in the overall models (P = 0.11 for weight, P = 0.95 for height), but this term interacted with sex for weight effect. A negative interaction was found in males (-0.9 +/- 0.4; P = 0.02) but not in females (0.3 +/- 0.4; P = 0.46). The association of current weight with SBP was stronger in lighter weight male infants.

CONCLUSIONS

These findings support the hypothesis that subjects who were small in early life and experienced enhanced post-natal growth have higher levels of SBP, even in low-income settings.

Pattern of blood pressure in Australian adults: results from a national blood pressure screening day of 13,825 adults

BACKGROUND

Recent national data of cardiovascular disease (CVD) risk factors in Australia are limited. Therefore this study sought to gain a contemporary snapshot of the blood pressure (BP) profile of Australian adults.

METHODS

We established 100 metropolitan and regional screening sites. Using a standardized protocol and the same automated, validated BP monitor, Registered Nurses recorded the BP and other risk factors for CVD of self-selected volunteers on a single day.

RESULTS

A total of 13,825 subjects (55% female, aged 48±16 years) were assessed. Mean systolic and diastolic BP was 131±18 and 79±12 mm Hg. Overall, 34% had an elevated BP while 10% being treated for hypertension (HT) were normotensive (combined total 44%). Elevated BP was more common in older individuals, men (42% versus 27% of women), regional dwelling residents (40% versus 32% of metropolitan) and people from lower socio-economic backgrounds (39% versus 30% of higher). Overall, 50% of subjects with a history of HT had elevated BP compared to 30% without a history of HT. Adjusting for age and sex, elevated BP was independently associated with obesity (OR: 1.77, 95% CI 1.52-2.06), regional location (OR: 1.32, 95% CI 1.19-1.45) and modifiable risk factors (OR: 1.28, 95% CI 1.21-1.35); those being treated for CVD or diabetes are less likely to have high BP.

CONCLUSIONS

In the largest study of its kind in Australia, the findings highlight the need for continued vigilance to detect, monitor and prevent elevated BP within an ageing population in whom metabolic disorders are becoming more frequent.

The clinical consequences and challenges of hypertension in urban-dwelling black Africans: insights from the Heart of Soweto Study

BACKGROUND

There is a paucity of data to describe advanced forms of cardiovascular disease (CVD) in urban black Africans with hypertension (HT).

METHODS

Chris Hani Baragwanath Hospital services the black African community of 1.1 million people in Soweto, South Africa. We prospectively collected detailed demographic and clinical data from all de novo presentations to the hospital's Cardiology Unit in 2006.

RESULTS

Overall, 761 black African patients (56% of de novo cases) presented with a diagnosis of HT with more women (63%, aged 58.5±14.9 years) than men (aged 58.0±15.6 years). On presentation, 396 women (82%) versus 187 men (67%) had dizziness, palpitations and/or chest pain (OR 1.23, 95% 1.12-1.34: p<0.0001). HT was the primary diagnosis in 266 cases (35%). In the rest (n=495), non-ischaemic forms of heart failure were common (54% of total) while only 6.2% had coronary artery disease. Concurrent left ventricular hypertrophy, renal dysfunction and anaemia were present in 39%, 24% and 11% of cases, respectively, with a similar age-adjusted pattern of co-morbidity according to sex. However, men were more likely to present with impaired systolic function (OR 2.13, 95% CI 1.50 to 3.00; p<0.0001).

CONCLUSIONS

In the absence of effective primary and secondary prevention strategies, these unique data highlight the potentially devastating impact of advanced forms of hypertensive heart disease in urban black African communities with more women than men affected.

Preventing Diabetes and Atherosclerosis in Sub-Saharan Africa: Should the Metabolic Syndrome Have a Role?

Obesity, hypertension, atherosclerosis, and type 2 diabetes mellitus are increasing in all regions of sub-Saharan Africa. The metabolic syndrome is a valuable tool in predicting atherosclerosis and type 2 diabetes in populations in Europe and North America. However, the applicability of the metabolic syndrome to African populations has not been studied. Prior to investing scarce funds into diagnosing and treating the metabolic syndrome, primary research needs to be designed to determine the prevalence of the metabolic syndrome and its ability to detect early, treatable disease in Africa. Assessment of these data should make it possible to determine if it is more effective to focus on the metabolic syndrome as a whole or on obesity, hypertension, atherosclerosis, and type 2 diabetes as individual conditions. This article is an overview of the presentation of metabolic syndrome variables in the Eastern, Western, and Southern regions of sub-Saharan Africa.

Classical cardiovascular risk factors and all-cause mortality in rural Cameroon

BACKGROUND

High levels of cardiovascular risk factors have been reported in rural Africa. How these translate into major outcomes remain unknown.

AIM

To assess the association between selected risk factors and all-cause mortality in rural Cameroon.

DESIGN

Nine-year's prospective cohort study.

METHODS

The 9-year's vital status was ascertained for 350 participants screened for cardiovascular risk factors in Bafut, Cameroon in 1998. Cox models were used to compute the hazard ratio (HR) and 95% confidence interval (CI) for selected risk factors.

RESULTS

Vital status was available for all participants, except 22 (6.3%) who were excluded from analyses. At baseline, compared with women, men had significantly higher waist-to-hip ratio, were more likely to be ex- or current smokers and alcohol consumers (all P < or = 0.008). The total duration of follow-up was 2771 person-years. This duration was longer for women (P = 0.04). During follow-up 47 deaths were recorded, 31 (66%) in men (P = 0.023). In multivariate Cox analyses, age, male gender, current smoking, systolic blood pressure and fasting capillary glucose were significant predictors of total mortality during follow-up.

CONCLUSION

Gender, smoking, fasting capillary glucose, blood pressures and age are potential determinants of overall death in rural Cameroon. More elaborated cohort studies are needed to refine these conclusions and monitor the progression of these populations through epidemiological transition stages.

Blood pressure patterns in relation to geographic area of residence: a cross-sectional study of adolescents in Kogi state, Nigeria

Background

The prevalence of hypertension, an important risk factor for cardiovascular disease (CVD), is increasing in the developing countries and this may be connected with the economic transition in those countries. Adult hypertension is thought to be related to childhood and adolescent increases in blood pressure, and hence the need to monitor patterns in early life. This study investigates the BP patterns, and their correlates, of adolescents from different geographic areas of residence in Nigeria.

Methods

A total of 1,088 Nigerian adolescents from different geographic areas of residence were recruited for the study. Their blood pressures and anthropometric indices were measured using standard procedures. The association of blood pressure with height, weight, body mass index (BMI) and geographic area of residence was assessed.

Results

Male and female urban-dwelling adolescents had significantly (p < 0.05) higher systolic blood pressure (117.45 ± 21.53 mmHg and 114.82 ± 17.95 mmHg respectively) compared to their counterparts living in the non-urban areas (108.20 ± 12.12 mmHg and 106.03 ± 13.06 mmHg respectively), even after adjusting for age and height. Conversely, non-urban boys (but not the girls) had significantly (p < 0.05) higher diastolic blood pressure compared to their urban counterparts. Adolescents in the urban areas had higher BMI (20.74 ± 3.27 kg/m² for males and 21.35 ± 3.37 kg/m² for females) than those in the non-urban areas (20.33 ± 3.11 kg/m² for males and 21.35 ± 3.37 kg/m² for females) though the difference was significant (p < 0.05) only in the females. Blood pressures were found to increase with age, and to be associated with BMI.

Conclusion

These findings underscore the need for efforts to be made towards addressing adolescent blood pressure elevation (in both urban and non-urban areas) as they are a reflection of adult morbidity and mortality from hypertension and the associated disorders.

Low utilization of health care services following screening for hypertension in Dar es Salaam (Tanzania): a prospective population-based study

Background

Drug therapy in high-risk individuals has been advocated as an important strategy to reduce cardiovascular disease in low income countries. We determined, in a low-income urban population, the proportion of persons who utilized health services after having been diagnosed as hypertensive and advised to seek health care for further hypertension management.

Methods

A population-based survey of 9254 persons aged 25–64 years was conducted in Dar es Salaam. Among the 540 persons with high blood pressure (defined here as BP ≥ 160/95 mmHg) at the initial contact, 253 (47%) had high BP on a 4^th visit 45 days later. Among them, 208 were untreated and advised to attend health care in a health center of their choice for further management of their hypertension. One year later, 161 were seen again and asked about their use of health services during the interval.

Results

Among the 161 hypertensive persons advised to seek health care, 34% reported to have attended a formal health care provider during the 12-month interval (63% public facility; 30% private; 7% both). Antihypertensive treatment was taken by 34% at some point of time (suggesting poor uptake of health services) and 3% at the end of the 12-month follow-up (suggesting poor long-term compliance). Health services utilization tended to be associated with older age, previous history of high BP, being overweight and non-smoking, but not with education or wealth. Lack of symptoms and cost of treatment were the reasons reported most often for not attending health care.

Conclusion

Low utilization of health services after hypertension screening suggests a small impact of a patient-centered screen-and-treat strategy in this low-income population. These findings emphasize the need to identify and address barriers to health care utilization for non-communicable diseases in this setting and, indirectly, the importance of public health measures for primary prevention of these diseases.