Michael O. Balogun

Relationship of anthropometric indicators with blood pressure levels and the risk of hypertension in Nigerian adults

Background and purpose: Studies on cardiovascular risks in relation to anthropometric factors are limited in Sub-Sahara Africa. The aims of this study were to examine the relationship between anthropometric parameters and blood pressure; and to evaluate body mass index (BMI) across the range of underweight and obesity as a primary risk factor of hypertension in adult Nigerians. Material and methods: 2097 adults aged between 20 and 100 years consented and participated in this door-to-door survey. All participants underwent blood pressure and anthropometric measurements using standard procedures. The population study was separated in normotensive and hypertensive males and females and the possible risk for hypertension were categorized into different classes of value based on BMI definition. Results: The relative risks (odds ratio [OR] and 95% confidence interval [CI]) of developing hypertension among the obese compared with the underweight, normal weight, and overweight persons were (OR 5.75; CI 5.67–5.83), (OR 1.73; CI 1.65–1.81), and (OR 1.54; CI 1.46–1.62) for all the participants, respectively. Among obese (BMI ≥ 30.0 Kg/m2) males, the OR for hypertension was three times (OR 2.78; CI 2.76–2.80) that of normal weight (BMI ≥ 18.5–24.9 Kg/m2) males. Females with obesity had a risk of hypertension three times (OR 3.34; CI 3.33–3.35) that of normal weight females. Conclusion: Our results indicated that the there was a significant positive correlation of obesity indicator with blood pressure. In Nigeria, we found a strong gradient between higher BMI and increased risk of hypertension among all ages. Approaches to reduce the risk of hypertension may include prevention of overweight and obesity.

Prevalence of hypertension in three rural communities of Ife North Local Government Area of Osun State, South West Nigeria.

Background The prevalence of hypertension is increasing rapidly in sub-Saharan Africa, but data are limited on hypertension prevalence. In addition, few population-based studies have been conducted recently in Nigeria on the prevalence and correlates of hypertension in both urban and rural communities. Therefore, we determined the prevalence of hypertension in adults in the three rural communities of Ipetumodu, Edunabon, and Moro, in South West Nigeria. Materials and methods One thousand adults between 15 and 90 years of age were recruited into this cross-sectional study, over a 6-month period, using a multistage proportional stratified random sampling technique. Sociodemographic data and anthropometric variables were obtained, and resting blood pressure (BP) was measured using an electronic sphygmomanometer. Diagnosis of hypertension was based on the JNC VII guidelines, the WHO/ISH 1999 guidelines, and the BP threshold of 160/95 mmHg. Results Four hundred and eighty-six men (48.6%) men and 514 women (51.4%) participated in the study. Their mean age, weight, height, and body mass index were 32.3±14.7 years, 62±13 kg, 1.5±0.1 m, and 23.02 kg/m2, respectively. The prevalence of hypertension, based on the 140/90 mmHg definition, was 26.4% (Male: 27.3%; Female: 25.4%). The prevalence of hypertension, based on the 160/95 mmHg definition, was 11.8% (Male: 13.5%; Female: 10.1%). There were significant positive correlations between BP and some anthropometric indicators of obesity. Conclusion The prevalence of hypertension in the three rural communities was 26.4%, indicating a trend towards increasing prevalence of hypertension. There was also a significant positive correlation between anthropometric indicators of obesity and BP in this population.

Assessment of exercise capacity in African patients with chronic heart failure using six minutes walk test.

Background: The purpose of this study was to assess the functional capacity during a 6-minute corridor walk and a 6-minute bicycle ergometry exercise in patients with chronic heart failure (CHF). Method: Thirty five patients with stable CHF were recruited for the study. Each subject performed six minutes corridor walk and 6-minute bicycle ergometry testing. The 6-minute walk required the subjects to walk at a self selected speed on a 20 meter marked level ground for 6-minute. All the subjects also performed a 6-minute exercise on a stationary bicycle ergometer with initial resistance of 20 watts and increased by 10 watts after 3-minutes. The perceived rate of exertion was assessed using a modified Borg Scale after each exercise mode. The maximum oxygen consumption was derived using American College of Sport Medicine equations. Results: Result showed high positive correlation between distance walked in the 6-minute and the maximum volume of oxygen (VO2 max) (r = 0.65, P < 0.01). The average distance walked was 327 m ± 12.03 m. The VO2 max estimated during bicycle ergometry was higher (13.7 ± 1.9 L) than during the six minutes walk (8.9 ± 1.2 L). Conclusion: Six minutes walk could be useful to evaluate exercise tolerance in patients with chronic heart failure, while the bicycle ergometer could be more appropriate in the assessment of maximum functional capacity in these patients.

Prevalence and pattern of overweight and obesity in three rural communities in southwest Nigeria

Background Limited data exist on the prevalence of overweight and obesity in the Nigerian adult rural population. This study therefore assessed the prevalence and pattern of overweight and obesity in adults in three rural communities of the Ife North Local Government Area, Nigeria. Materials and methods A total of 777 adults between 20 and 90 years of age were recruited into this cross-sectional study, which was performed over a 6-month period using a multistage proportional stratified random sampling technique. Sociodemographic data and anthropometric variables were obtained. Results A total of 385 (49.5%) men and 395 (50.5%) women participated in the study. The mean age and body mass index of the participants were 36.3±14.3 years and 23.53±4.6 kg/m2, respectively. The overall crude prevalence of overweight and obesity in the total population were 20.8% and 8.4%, respectively. Obesity increased across the age gradient, peaking in the 51- to 60-year age-group in men and women. Among the overweight and obese subjects (n=227), 70.9% of them were overweight and the remaining 29.1% were obese, with class I obesity accounting for 20.7% of these overweight and obese subjects. Conclusion The prevalence of overweight and obesity in these communities was 20.8% and 8.4% respectively, indicating a trend towards increased prevalence. Class I obesity is the most common obesity pattern, and obesity increased across the age gradient, peaking in the 51- to 60-year age-group. There is a need for regular community education on healthy lifestyles, and regular health screening to control the rising prevalence of overweight and obesity, as well as to prevent or reduce the risk of obesity comorbidities in these communities.

Two dimensional and Doppler echocardiographic evaluation of patients presenting at Obafemi Awolowo University Teaching Hospitals Complex Ile Ife Nigeria a prospective study of 2501 subjects

Background Echocardiography remains a key noninvasive cardiac investigative tool in the management of patients, especially in a developing economy like Nigeria. In this study, we investigated the indications for transthoracic echocardiography and spectrum of cardiac disease found in patients referred to our cardiac unit for echocardiography. Methods A prospective two-dimensional, pulsed, continuous, and color-flow Doppler echocardiographic evaluation was done using the transthoracic approach in 2501 patients over an eight-year period. Univariate data analysis was performed for mean age, gender, clinical indications, and diagnoses. Results The subject age range was less than 12 months to 97 years (mean 52.39 years). There were 1352 (54.06%) males and 1149 (45.94%) females. The most common indication for echocardiography was hypertension (52.1%) followed by congestive cardiac failure (13.9%). Others were for screening (6.1%), arrhythmias (5%), cerebrovascular disease (5%), chest pain (3.3%), chronic kidney disease (3.2%), congenital heart disease (2.6%), cardiomyopathy (1.8%), rheumatic heart disease (1.7%), diabetes mellitus (1.3%), thyrocardiac disease (1.2%), ischemic heart disease (1.2%), and pericardial disease (1.1%). The echocardiographic diagnosis was hypertensive heart disease in 59.4% of subjects and normal in 14.1%. Other echocardiographic diagnoses included rheumatic heart disease (3.1%), congenital heart disease (2.1%), cardiomyopathy (1.7%), pericardial disease (1.1%), and ischemic heart disease (0.1%). Conclusion Hypertension and its cardiac complications is the most common echocardiographic indication and diagnosis at our unit.

Cardiovascular responses to treadmill exercise in Nigerian hypertensives with left ventricular hypertrophy

BACKGROUND Left ventricular hypertrophy (LVH) is an independent risk factor for adverse cardiac outcomes in hypertensive patients. OBJECTIVE This study is designed to assess the cardiovascular responses to treadmill exercise among Nigerian hypertensives with echocardiographically proven LVH. MATERIALS AND METHODS Fifty hypertensive patients with LVH (27 males and 23 females) between 30 and 65 years of age were studied in Nigeria. 50 hypertensive patients without LVH and 50 normal subjects who were age and sex matched served as controls. All patients and control subjects underwent M-mode, 2-D and Doppler ECHO-studies and the Bruce protocol treadmill exercise test. RESULTS The study showed that the estimated maximal oxygen consumption (MVO2) in MET reduced progressively from 8.39 ± 1.26 (normotensive control) to 7.62 ± 1.33 (hypertensive without LVH), 6.27 ± 0.99 (hypertensive with LVH) (P<0.0001ANOVA). The duration of exercise (s) was also reduced in that order from 455.4 ± 79.1 to 411.6 ±8 2.3, 315.8 ± 75.6 respectively (P<0.0001). The systolic blood pressure (SBP) and pressure rate product (PRP) during maximal exercise were also increased in hypertensives with LVH and hypertensive without LVH when compared to normotensive controls. The hypertensives with LVH and hypertensives without LVH also showed significant limitation to heart rate increase with exercise compared to normotensive controls (P<0.003). CONCLUSION This study demonstrated significant impairment of exercise capacity in hypertensives with or without LVH compared to normotensive subjects. Both earlier recognition and improved understanding of LVH may lead to more effective therapeutic strategies for this cardiovascular risk factor.

Ambulatory blood pressure profile and left ventricular geometry in Nigerian hypertensives.

Background: Left ventricular hypertrophy (LVH) is an independent cardiac risk factor in hypertensives and the structural classification of left ventricular (LV) geometry provides additional prognostic information. Ambulatory blood pressure (ABP) monitoring has been shown to be superior to office blood pressure (BP) in relation to hypertension LVH. We investigated ambulatory BP variables in relation to LV geometric patterns in Nigerian hypertensives. Materials and Methods: A total of 130 patients (males = 96, females = 34) with hypertension had their 24-hours ambulatory BP and trans-thoracic 2D/M- mode echocardiography. Data were analyzed with SPSS 13.0. P < 0.05 was considered statistically significant. Results: The mean age of the patients was 54.08±11.88 years. The prevalence rate of abnormal LV geometry was 48.4%. Mean ambulatory Systolic BP (day time, night time and 24-hour-average) was significantly higher in patients with LVH compared with those without LVH. Day-night systolic and diastolic BP decay (i.e. percentage nocturnal decline in BP) was also significantly lower in LVH group than in the group without LVH. Patients with eccentric LVH had abnormal day time mean ambulatory systolic BP, night time mean ambulatory systolic BP, elevated day time and night time systolic BP loads, as well as non-dipping diastolic BP pattern. Significant correlates of LV mass index in this study population were mean ambulatory systolic BP (day time: r = 0.355, P = 0.004; night time: r = 0.343, P = 0.005; 24- hour average: r = 0.358, P = 0.004) and day-night decay (systolic: r = -0.388, P = 0.007; diastolic: r = -0.290, P = 0.022) as well as 24-hour systolic BP variability. Conclusion: The presence of LVH in hypertension was associated with higher mean ambulatory systolic BP and lower percentage nocturnal decline in systolic and diastolic BP than its absence which appeared to be worse in patients with eccentric LV geometry when compared with other geometric patterns.

An assessment of cardiovascular risk among the people of a Nigerian university community

Background The purpose of this study was to assess the level of cardiovascular disorder risk among the staff and students of Obafemi Awolowo University, Ile-Ife, Nigeria. Methods Six hundred apparently healthy subjects voluntarily participated in this study. They consisted of 200 students, 200 junior workers and 200 senior staff. Subjects’ weight, height and blood pressures were taken. Subsequently, the questionnaire used for the Framingham Heart Study was given for completion. The questionnaire sought information on cardiovascular risk factors including smoking habits, sedentary lifestyle, diet, personality trait, age and sex. Results Students had a mean risk score of 10.24, junior staff 11.38, and senior staff 12.42. Significant differences were found between the level of risk for the students and that of the senior staff. However, no significant difference existed between the junior and senior staff and no significant difference existed between the level of risk for the students and the junior staff. Further, there was no significant difference in the level of risk for males compared to females. Conclusion We concluded that the level of cardiovascular risk was low among the subjects selected for this study.

Echocardiographic Assessment of Left Ventricular Geometric Patterns in Hypertensive Patients in Nigeria

Left ventricular (LV) hypertrophy is an important predictor of morbidity and mortality in hypertensive patients, and its geometric pattern is a useful determinant of severity and prognosis of heart disease. Studies on LV geometric pattern involving large number of Nigerian hypertensive patients are limited. We examined the LV geometric pattern in hypertensive patients seen in our echocardiographic laboratory. A two-dimensional, pulsed, continuous and color flow Doppler echocardiographic evaluation of 1020 consecutive hypertensive patients aged between 18 and 91 years was conducted over an 8-year period. LV geometric patterns were determined using the relationship between the relative wall thickness and LV mass index. Four patterns of LV geometry were found: 237 (23.2%) patients had concentric hypertrophy, 109 (10.7%) had eccentric hypertrophy, 488 (47.8%) had concentric remodeling, and 186 (18.2%) had normal geometry. Patients with concentric hypertrophy were significantly older in age, and had significantly higher systolic blood pressure (BP), diastolic BP, and pulse pressure than those with normal geometry. Systolic function index in patients with eccentric hypertrophy was significantly lower than in other geometric patterns. Doppler echocardiographic parameters showed some diastolic dysfunction in hypertensive patients with abnormal LV geometry. Concentric remodeling was the most common LV geometric pattern observed in our hypertensive patients, followed by concentric hypertrophy and eccentric hypertrophy. Patients with concentric hypertrophy were older than those with other geometric patterns. LV systolic function was significantly lower in patients with eccentric hypertrophy and some degree of diastolic dysfunction were present in patients with abnormal LV geometry.

Prognostic indices among hypertensive heart failure patients in Nigeria: the roles of 24-hour Holter electrocardiography and 6-minute walk test

Background Hypertensive heart failure (HHF) is associated with a poor prognosis. There is paucity of data in Nigeria on prognosis among HHF patients elucidating the role of 24-hour Holter electrocardiogram (ECG) in concert with other risk factors. Objective The aim of this study was to determine the prognostic utility of 24-hour Holter ECG, the 6-minute walk test (6-MWT), echocardiography, clinical and laboratory parameters among HHF patients. Methods A total of 113 HHF patients were recruited and followed up for 6 months. Thirteen of these patients were lost to follow-up, and as a result only 100 HHF patients were analyzed. All the patients underwent baseline laboratory tests, echocardiography, 24-hour Holter ECG and the 6-MWT. HHF patients were analyzed as “mortality vs alive” and as “events vs no-events” based on the outcome at the end of 6 months. Events was defined as HHF patients who were rehospitalized for heart failure (HF), had prolonged hospital stay or died. No-events group was defined as HHF patients who did not meet the criteria for the events group. Results HHF patients in the mortality group (n = 7) had significantly higher serum urea (5.71 ± 2.07 mmol/L vs 3.93 ± 1.45 mmol/L, p = 0.003) than that in those alive. After logistic regression, high serum urea conferred increased mortality risk (p = 0.035). Significant premature ventricular complexes (PVCs) on 24-hour Holter ECG following logistic regression were also significantly higher (p = 0.015) in the mortality group than in the “alive” group (n = 93) at the end of the 6-month follow-up period. The 6-minute walk distance (6-MWD) was least among the HHF patients who died (167.26 m ± 85.24 m). However, following logistic regression, the 6-MWT was not significant (p = 0.777) for predicting adverse outcomes among HHF patients. Patients in the events group (n = 41) had significantly higher New York Heart Association (NYHA) class (p = 0.001), Holter-detected ventricular tachycardia (VT; p = 0.009), Holter-detected atrial fibrillation (AF; p = 0.028) and PVCs (p = 0.017) following logistic regression than those in the no-events group (n = 59). Conclusion High NYHA class, elevated serum urea, Holter ECG-detected AF and ventricular arrhythmias are predictive of a poor outcome among HHF patients. The 6-MWT was not a useful prognostic index in this study.