Adeseye A Akintunde

Impact of urbanization and gender on frequency of metabolic syndrome among native Abuja settlers in Nigeria

Background: Metabolic syndrome (MetS) is an important cause of morbidity and mortality. Nigeria is currently undergoing rapid epidemiological transition. The objective was to study whether urbanization is associated with increased prevalence of MetS between native rural Abuja settlers and genetically related urban dwellers. Materials and Methods: It was a cross-sectional study. Three hundred and forty-two urban native Abuja settlers and 325 rural dwellers were used for the study. Fasting blood lipid, glucose, waist circumference, blood pressure, and body mass index were determined. MetS was defined according to three standard criteria. SPSS 16.0 was used for statistical analysis. P<0.05 was used as statistically significant. Results: Obesity, hypertriglyceridemia, and hypertension were commoner among urban dwellers than rural dwellers. MetS was associated more with the female gender. Urbanization significantly increases the frequency of MetS using the three standard definitions. The prevalence of MetS using International Diabetes Federation, World Health Organization, and National Cholesterol Education Program Adult Treatment Panel III among rural versus urban dwellers were 7.7% vs. 14.9%, P<0.05; 0% vs. 0.9%, P>0.05; and 3.7% vs. 13.7%, P<0.05, respectively. Conclusion: This study shows that MetS is a major health condition among rural and urban Nigerians and that urbanization significantly increases the prevalence of MetS. This can be explained on the basis of higher prevalence of dyslipidemia, obesity, and hypertension in urban setting, possibly as a result of stress, diet, and reduction in physical activity. Effective preventive strategy is therefore required to stem the increased risk associated with urbanization to reduce the cardiovascular risk associated with MetS among Nigerians.

Metabolic Syndrome: Comparison of Occurrence Using Three Definitions in Hypertensive Patients

Objective: To compare the frequency of occurrence of metabolic syndrome using three international definitions and to study the distribution of cardiovascular risk factors among newly diagnosed hypertensive Nigerian subjects. Design: Cross sectional study. Settings: Cardiology unit of LAUTECH Teaching Hospital, Osogbo, Nigeria. Participants: One hundred forty newly diagnosed hypertensive Nigerian subjects, and 70 normotensive controls (age- and sex-matched) were included in this study. Methods: Clinical history and relevant laboratory investigations were performed on all study participants. The definition of metabolic syndrome was based on three international definitions: World Health Organization (WHO), International Diabetes Federation (IDF), and National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III). Ethical approval was obtained for the study. Statistical analyses were performed using SPSS 16.0. Results: There was no difference in age and gender distribution between the hypertensive subjects and controls. (55.14 ± 10.83 years, females 53.6% vs. 54.67 ± 10.89 years, females 52.9% respectively, P>0.05). The frequency of occurrence of metabolic syndrome among hypertensives was 34.5% according to WHO, 35.0% according to NCEP ATP III, and 42.5% according to IDF criteria. Visceral obesity and reduced high-density lipoprotein (HDL) were the other common cardiovascular risk factors among newly diagnosed hypertensive subjects. Female hypertensives had a higher prevalence of visceral obesity and low HDL. Conclusion: Frequency of occurrence of metabolic syndrome was similar using the NCEP ATP III and WHO definitions. However, the IDF definition resulted in a higher frequency because of the lower cut-off for waist circumference used for identification of visceral obesity. Metabolic syndrome is present in a significant proportion of newly diagnosed hypertensive subjects. Therefore, appropriate screening and treatment are required.

HIV infection and cardiovascular risk in black South Africans

The overall growth of the global AIDS epidemic appears to have stabilised and the number of new infections is declining.1 This and the significant reduction in mortality could be attributed to the effectiveness of antiretroviral therapy (ART). Human immunodeficiency virus (HIV) infection, although still fatal, has become a chronic and manageable disease. The therapy has increased the life expectancy of HIV-infected individuals and therefore more people are living with HIV. The region affected the most by HIV remains sub-Saharan Africa, and South Africa continues to be the country housing the largest population of people (an estimated 5.6 million people in 2009) living with HIV worldwide.1 Besides some very uncomfortable side effects due to both HIV infection and the therapy, another more serious side effect has emerged, namely an increased risk for cardiovascular disease (CVD).2,3 HIV infection paradoxically affects cardiovascular risk factors and circulatory disease within populations and individuals. Researchers have associated HIV infection and especially the use of ART with an increase in insulin resistance, dyslipidaemia,4 lipodystrophy5,6 endothelial dysfunction,7 accelerated atherosclerosis8 and coagulation disorders.9 In the past 15 years South Africa has experienced a rise in noncommunicable diseases, such as cardiovascular disease, which is predicted to increase in the next decades.10 This rise in incidence of non-communicable diseases is masked by the overwhelming presence of communicable diseases such as HIV and tuberculosis.11 Therefore, cardiovascular complications in the HIV-infected population could become a serious health problem in South Africa by increasing the burden of non-communicable diseases once patients are receiving ART for longer periods.11 Recent research has shown that atherosclerotic disease, historically not common in black Africans, is increasing in South Africa.12 The South African HIV-infected population has had access to free antiretroviral treatment since 2004 and the influence of ART on the cardiovascular system in this population is not yet established. The South African National AIDS Council updated the HIV treatment guidelines and adopted some of the recent recommendations made by the World Health Organisation (WHO), which will lead to more people receiving treatment.13 This expansion of antiretroviral therapy and the effect thereof on the burden of non-communicable diseases (such as cardiovascular disease) in South Africa is yet to be determined. The predominant virus responsible for the infections in South Africa is HIV-1, group M (major), subtype C,14,15 which accounts for 55 to 60% of all HIV-1 infections worldwide,16 and differs as much as 30% in its genome from HIV-1 subtype B, responsible for most infections in North America, Europe and Australia.14,16,17 The clinical consequences of these subtype variations remain unclear.18 Although the risk for the development of cardiovascular disease has been described in many different HIV-1-infected populations, data on the risk facing the South African HIV-infected population is scarce, as most of the research is done on Caucasians infected with HIV-1 subtype B. Therefore, the risk of cardiovascular disease in HIV-infected South Africans and how it is affected by the roll-out programme of ART remains largely unknown. The various effects of the virus itself – including its cardiovascular effects – are also important, since many HIV-infected South Africans are still without therapy and/or unaware of their infection status. Various factors seem to contribute to the latter, such as the lack of knowledge, poverty, stigma, scepticism and lack of interest.19 The Hypertension in Africa Research Team (HART) therefore individually matched 300 newly identified HIV-infected Africans from the South African Prospective Urban and Rural Epidemiology (PURE) study with 300 uninfected controls. They were matched according to age, gender, body mass index and locality (urban/rural). The larger PURE study is an epidemiological study that will address questions regarding the cause and development of cardiovascular risk factors and disease within populations, including South Africa.20 A minimum follow up of 10 years is planned. The South African leg of the study was performed in the North West Province where a total of 2 010 participants (1 004 urban and 1 006 rural) were randomly recruited from a rural and urban setting and screened during the baseline phase in 2005. A follow up on the PURE South Africa study was done in 2010. The newly identified HIV-infected participants and their controls of the baseline (2005) study were also followed up in 2008. In a cross-sectional analysis on the baseline data we aimed to evaluate if HIV-1 infection itself is associated with dyslipidaemia, inflammation and the occurrence of the metabolic syndrome in newly identified HIV-1-infected black South Africans who had never received antiretroviral therapy. We concluded that HIV-1 is associated with dyslipidaemia and an inflammatory state in newly identified HIV-infected, never-treated African individuals and that it may increase their risk for cardiovascular disease. The study showed that HIV-1, most likely subtype C, seems to influence the components of the metabolic syndrome in South Africans in the same way as HIV-1 subtype B does in Caucasians. It also showed that the virus does not increase the prevalence of the metabolic syndrome in these never-treated, HIV-infected South Africans.21 In this edition of the Cardiovascular Journal of Africa, a study is published in which we assessed cross-sectionally whether these newly identified, never-treated, HIV-1-infected Africans showed signs of inflammatory injury of the endothelium. This could lead to endothelial dysfunction, accelerated atherosclerosis and increased coagulation, which could result in thrombosis. Our findings suggest inflammatory injury of the endothelium, which was probably worsened by the attenuation of the protective effect of high-density lipoprotein cholesterol (HDL-C). The high levels of protective HDL-C in black South Africans is thought to be the reason for the fairly low prevalence of ischaemic heart disease in the general population.22 Although there was no indication of a prothrombotic state which could result in atherosclerotic disease, there was an indication of accelerated vascular aging and probable early atherosclerosis in the older HIV-infected South Africans. The latter indicates a decrease in vascular function of the never-treated, HIV-1-infected older population.23 After being identified as HIV infected, the participants were referred to their nearest hospital or clinic for follow up on the diagnosis of HIV infection and commencement of treatment if needed. Some of the participants were eligible, by CD4 cell count, for enrollment in the ART roll-out programme but chose not to initiate treatment. During the 2008 follow up, our results showed lower systolic blood pressure and dyslipidaemia in the never-treated, HIV-1-infected South Africans compared to the control participants. In the treated HIV-infected participants, we observed an increase in systolic blood pressure, but no hypertension, and an improvement in lipid profile. Although the antiretroviral treatment stabilised the lipid profile, an increase in lipodystrophy was seen in the treated group, which may influence the development of future cardiovascular disease. Indeed, changes in body composition were one of the most prominent results of this study. These changes in the treated group confirm the possible development of lipodystrophy, expected after the introduction of antiretroviral treatment.5,6 Stavudine, the nucleoside reverse transcriptase inhibitor (NRTI) of the first-line therapy of the roll-out programme is incriminated in the development of lipodystrophy.24 New guidelines on the WHO’s first-line therapy, which came into effect on 1 April 2010 in South Africa, phase out the use of stavudine in favour of tenofovir.13 Whether this could have an effect on the development of lipodystrophy in the South African population remains to be seen. The novel biomarker, soluble urokinase plasminogen activator receptor (suPAR) is a stable plasma protein25 and is associated with inflammation and progression of disease in HIV-1 infection.26 It was suggested that suPAR may be a marker linking inflammatory and metabolic characteristics (lipid and glucose metabolism, as well as fat redistribution) of HIV-infected patients on ART.25 We therefore hypothesised that the HIV-1-infected black South Africans would have significantly higher suPAR levels than their uninfected controls. While the latter was confirmed by our results, the treated HIV-1-infected Africans unexpectedly showed a significantly greater increase in blood suPAR levels than never-treated infected or uninfected Africans after a three-year period. Furthermore, this study indicates an association of suPAR with the development of lipodystrophy in HIV-1-infected black South Africans on the WHO’s recommended first-line antiretroviral therapy.27 In summary, our results clearly indicate a detrimental health profile in the HIV-infected black population of South Africa (whether receiving treatment or not). Therefore it remains of the utmost importance to gain knowledge about the influence of HIV infection and the treatment thereof on the cardiovascular system of the South African population.Introduction Left ventricular geometry is associated with cardiovascular events and prognosis. The Tei index of myocardial performance is a combined index of systolic and diastolic dysfunction and has been shown to be a predictor of cardiovascular outcome in heart diseases. The relationship between the Tei index and left ventricular geometry has not been well studied. This study examined the association between the Tei index and left ventricular geometry among hypertensive Nigerian subjects. Methods We performed echocardiography on 164 hypertensives and 64 control subjects. They were grouped into four geometric patterns based on left ventricular mass and relative wall thickness. The Tei index was obtained from the summation of the isovolumic relaxation time and the isovolumic contraction time, divided by the ejection time. Statistical analysis was done using SPSS 16.0. Results Among the hypertensive subjects, 68 (41.4%) had concentric hypertrophy, 43 (26.2%) had concentric remodelling, 24 (14.6%) had eccentric hypertrophy, and 29 (17.7%) had normal geometry. The Tei index was significantly higher among the hypertensives with concentric hypertrophy (CH), concentric remodelling (CR) and eccentric hypertrophy (EH) compared to the hypertensives with normal geometry (0.83 ± 1.0, 0.71 ± 0.2, 0.80 ± 0.2 vs 0.61 ± 0.2, respectively). The Tei index was higher among hypertensives with CH and EH than those with CR. Stepwise regression analysis showed that the Tei index was related to ejection fraction, fractional shortening and mitral E/A ratio. Conclusion Among Nigerian hypertensives, LV systolic and diastolic functions (using the Tei index) were impaired in all subgroups of hypertensive patients according to their left ventricle geometry compared to the control group. This impairment was more advanced in patients with concentric and eccentric hypertrophy.

Anthropometric differences among natives of Abuja living in urban and rural communities: correlations with other cardiovascular risk factors

BackgroundThere is an increase of obesity and other cardiovascular risk factors worldwide, but especially in developing countries where multifaceted transitions are occurring. There is need for more evidence for the cardio-metabolic effect of changing lifestyles and urbanization in Nigeria. This study aimed at defining rural–urban differences in anthropometric parameters in two Nigerian communities of the same ancestral origin and to determine the cardiovascular risk correlates of these anthropometric measurements. This was a cross-sectional epidemiological study using stratified cluster sampling method. We studied 335 and 332 urban and rural dwellers respectively. A complete cardiovascular profile as well as anthropometric measurements was compared between the two populations.ResultsAll anthropometric indices considered in this study (weight, BMI, waist circumference, waist circumference/height ratio, abdominal height; biceps, triceps, sub-scapular, abdominal, superior iliac skinfold thicknesses) were significantly higher in urban than in the rural population (p = <0.001). Overweight, obesity and hypertension were significantly prevalent among the urban population (p = <0.001) while there was no significant difference in the prevalence of dyslipidaemia (p = 0.096) and diabetes (p = 0.083) between the two cohorts. Females tend to have a higher chance of obesity than males although there was no gender difference in waist circumference and central skin fold thickness in the rural population. Age was the significant predictor of systolic blood pressure among the rural (R2 = 0.157, β = 0.258, p = 0.016) and urban female population (R2 = 0.201, β = 0.351, p = <0.001) while Abdominal height (R2 = 0.16, β = 0.281, p = 0.001) and waist circumference (R2 = 0.064 β = 0.064, p = .003) were predictors of systolic blood pressure in urban and rural men respectively.ConclusionAnthropometric indices were significantly higher among the urban than the rural populations. Cardiovascular risks were equally more prevalent among the urban population. Appropriate health education and lifestyle modification strategies may reduce the increased burden of cardiovascular risk factors associated with rural–urban migration.

Dyslipidemia among newly diagnosed hypertensives: pattern and clinical correlates.

BACKGROUND Hypertension and dyslipidemia are closely interrelated. We aim to determine the prevalence of dyslipidemia among newly diagnosed Nigerian hypertensive subjects and its associated clinical correlates. MATERIALS AND METHODS This was a cross-sectional study done at the Ladoke Akintola University of Technology (LAUTECH) Teaching Hospital, Osogbo, southwest Nigeria. One hundred sixty-three newly diagnosed hypertensive subjects and 88 controls were recruited and formed the study groups. Relevant history, examinations, and laboratory investigations were performed. Lipid parameters and atherogenic indices were determined. SPSS 16.0 was used for statistical analysis. RESULTS Hypertensive subjects and controls were well matched in age and gender distribution. Dyslipidemia was more common among the hypertensive subjects. Ninety-six (58.9%) newly diagnosed hypertensive subjects had at least 1 impaired lipid profile. Sixty-seven (41.1%) of them had isolated dyslipidemia, while 29 (17.8%) had combined dyslipidemia. Common patterns of dyslipidemia include low high-density lipoprotein cholesterol (HDL-C), 78 (47.9%); high atherogenic index (total cholesterol/HDL-C), 40 (24.5%) and elevated low-density lipoprotein cholesterol (LDL-C) in 38 (23.3%) subjects. Fasting blood glucose increased as the severity of dyslipidemia increased. CONCLUSIONS A significant proportion of newly diagnosed hypertensive subjects have dyslipidemia. Low HDL-C was the most common type of dyslipidemia in this study. The use of statins and other supportive therapy is therefore justified among newly diagnosed Nigerian hypertensive subjects with isolated or combined dyslipidemia.

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.

High Frequency of Variants of Candidate Genes in Black Africans with Low Renin-Resistant Hypertension.

OBJECTIVES Black subjects tend to retain salt and water, be more sensitive to aldosterone, and have suppression of plasma renin activity. Variants of the renal sodium channel (ENaC, SCNN1B) account for approximately 6% of resistant hypertension (RHT) in Blacks; other candidate genes may be important. METHODS Six candidate genes associated with low renin-resistant hypertension were sequenced in Black Africans from clinics in Kenya and South Africa. CYP11B2 was sequenced if the aldosterone level was high (primary aldosteronism phenotype); SCNN1B, NEDD4L, GRK4, UMOD, and NPPA genes were sequenced if the aldosterone level was low (Liddle phenotype). RESULTS There were 14 nonsynonymous variants (NSVs) of CYP11B2: 3 previously described and associated with alterations in aldosterone synthase production (R87G, V386A, and G435S). Out of 14, 9 variants were found in all 9 patients sequenced. There were 4 NSV of GRK4 (R65L, A116T, A142V, V486A): at least one was found in all 9 patients; 3 were previously described and associated with hypertension. There were 3 NSV of SCNN1B (R206Q, G442V, and R563Q); 2 previously described and 1 associated with hypertension. NPPA was found to have 1 NSV (V32M), not previously described and NEDD4L did not have any variants. UMOD had 3 NSV: D25G, L180V, and T585I. CONCLUSIONS A phenotypic approach to investigating the genetic architecture of RHT uncovered a surprisingly high yield of variants in candidate genes. These preliminary findings suggest that this novel approach may assist in understanding the genetic architecture of RHT in Blacks and explain their two fold risk of stroke.

Some emerging issues in medical admission pattern in the tropics

BACKGROUND There is a changing pattern in terms of medical admissions worldwide with an alarming increase in the prevalence of noncommunicable diseases, especially in the tropics over the last decade. The aim of this study was to describe the pattern of medical admission and highlight emerging issues of noncommunicable diseases in a Nigerian University Teaching Hospital. MATERIALS AND METHODS A retrospective review of medical admission at the Ladoke Akintola University of Technology Teaching Hospital, Osogbo, South Western Nigeria, over a 3 years period (January 2005 to December 2007). Data were retrieved from the medical records of all medical admission over the study period. RESULTS During the study period, 1786 patients were admitted into the medical wards. This consisted of 1089 males (61.0%) and 697 females (39.0%). Their ages ranged from 14 to 96 years with mean ages of 51 ± 16.89 years. Subjects ≥60 years of age accounted for 27.3% and 29.8% of total males and female admissions which were the largest age group. Noncommunicable diseases were responsible for 47.99% of total medical admissions. The indications for admission in order of frequency include cerebrovascular accidents 239 (13.4%), diabetes mellitus 194 (10.9%), tuberculosis 151 (8.5%), and chronic kidney disease 116 (6.5%). Hypertension was the underlying risk factor in majority of patients with CVD and CKD. CONCLUSION Noncommunicable disease accounted for a significant number of admissions over 3 year duration. The elderly accounted for a major age group admitted for medical diseases. Therefore, preventive strategies against noncommunicable disease and effective geriatric care are advocated.

Physiological Phenotyping for Personalized Therapy of Uncontrolled Hypertension in Africa

OBJECTIVES African and African American hypertensives tend to retain salt and water, with lower levels of plasma renin and more resistant hypertension. We tested the hypothesis that physiological phenotyping with plasma renin and aldosterone would improve blood pressure control in uncontrolled hypertensives in Africa. METHODS Patients at hypertension clinics in Nigeria, Kenya, and South Africa with a systolic blood pressure >140 mm Hg or diastolic pressure > 90 mm Hg despite treatment were allocated to usual care (UC) vs. physiologically individualized care (PhysRx). Plasma renin activity and aldosterone were measured using ELISA kits. Patients were followed for 1 year; the primary outcome was the percentage of patients achieving blood pressure <140 mm Hg and diastolic <90 mm Hg. RESULTS Results are presented for the 94/105 participants who completed the study (42 UC, 52 PhysRx). Control of both systolic and diastolic pressures was obtained in 11.1% of UC vs. 50.0% of PhysRx (P = 0.0001). Systolic control was achieved in 13.9% of UC vs. 60.3% of PhysRx (P = 0.0001); diastolic control in 36.1% of UC vs. 67.2% of PhysRx, vs. (P = 0.003). Number of visits and total number of medications were not significantly different between treatment groups, but there were differences across the sites. There were important differences in prescription of amiloride as specified in the PhysRx algorithm. CONCLUSIONS Physiologically individualized therapy based on renin/aldosterone phenotyping significantly improved blood pressure control in a sample of African patients with uncontrolled hypertension. This approach should be tested in African American and other patients with resistant hypertension. Registered as ISRCTN69440037.

End digit preference in blood pressure measurement in a hypertension specialty clinic in southwest Nigeria.

Background One of the observer errors associated with blood pressure (BP) measurement using a mercury sphygmomanometer is end digit preference (EDP) which refers to the occurrence of a particular end digit more frequently than would be expected by chance alone. Published reports, mainly from outside Africa, have shown a high prevalence ranging from 22 to 90% of end digit zero in BP readings taken by healthcare workers (HCWs). This study examined the prevalence of EDP and patients’ and physicians’ characteristics influencing the occurrence of EDP. Methods A retrospective review was undertaken of BP readings of 114 patients seen over a two-month period at our hypertension specialty clinic. Results Nurses and physicians displayed a high frequency of preference for end digit zero in systolic blood pressure (SBP) and diastolic blood pressure (DBP) readings. The preference for end digit zero was, however, higher for nurses than for physicians (SBP: 98.5 vs 51.2%, p < 0.001; DBP: 98.5 vs 64.3%, p < 0.001). Among the physicians, the consultant staff displayed the least preference for end digit zero compared to resident doctors. There was no statistically significant difference in gender, age, weight, height and BMI of those with BP readings with end digit zero compared with those with non-zero end digits. Conclusion The high prevalence of EDP for zero argues for the training, retraining and certification of HCWs in BP measurement and the institution of a regular monitoring and feedback system on EDP in order to minimise this observer error.