Walinjom F.T. Muna

The prevalence of hypertension in seven populations of west African origin.

OBJECTIVES This study was undertaken to describe the distribution of blood pressures, hypertension prevalence, and associated risk factors among seven populations of West African origin. METHODS The rates of hypertension in West Africa (Nigeria and Cameroon), the Caribbean (Jamaica, St. Lucia, Barbados), and the United States (metropolitan Chicago, Illinois) were compared on the basis of a highly standardized collaborative protocol. After researchers were given central training in survey methods, population-based samples of 800 to 2500 adults over the age of 25 were examined in seven sites, yielding a total sample of 10014. RESULTS A consistent gradient of hypertension prevalence was observed, rising from 16% in West Africa to 26% in the Caribbean and 33% in the United States. Mean blood pressures were similar among persons aged 25 to 34, while the increase in hypertension prevalence with age was twice as steep in the United States as in Africa. Environmental factors, most notably obesity and the intake of sodium and potassium, varied consistently with disease prevalence across regions. CONCLUSION The findings demonstrate the determining role of social conditions in the evolution of hypertension risk in these populations.

Hypertension treatment and control in sub-Saharan Africa: the epidemiological basis for policy

Although enormous challenges persist in the control of infection in sub-Saharan Africa, non-communicable diseases are also important threats to the health of adult Africans. 1 2 Controversy exists, however, over the priority these conditions deserve in the competition for scarce resources. It has recently been argued that hypertension treatment, for example, should not be attempted in sub-Saharan Africa given the high costs.3 Unfortunately, these discussions take place in an information vacuum, since it is impossible to define the burden of chronic conditions in societies where health statistics are unavailable.4 Cohort studies may serve as a proxy for vital statistics and give approximate answers to questions on the usefulness of treatment for chronic disease.5 Hypertension is particularly suited to this model because it is easily diagnosed, highly prevalent, and information on outcomes is plentiful. Although the relative risk of a cardiovascular event in people with high and normal blood pressure is similar in Africa and the United States, the absolute risk is up to 13 times greater in Africans #### Summary points In sub-Saharan Africa it is difficult to formulate and justify policy on treating chronic conditions such as hypertension as there are no health statistics from which to judge likely costs and benefits Cohort studies on hypertension in Nigeria and Zimbabwe and epidemiological information show that between 10 and 20 million people in sub-Saharan Africa may have hypertension and that treatment could prevent around 250 000 deaths each year Taking account of both relative risk and absolute risk of a cardiovascular event or death, a systolic pressure of 160 mm Hg is recommended as a threshold for treatment in Africa The reduction in population attributable risk associated with treatment could be 2% in Africa compared with 0.15% in the Unites States—some 13 times higher “Number needed to treat” analysis shows …

Standardization of blood pressure measurement in an international comparative study

In the context of a collaborative study on the epidemiology of hypertension in populations of West African origin procedures for standardization of the measurement of blood pressure were evaluated. Comparisons of mean levels of blood pressure, which in large part determine prevalence rates, are highly sensitive to differences in technique. While rotating a single field team may be the ideal approach to multisite studies, it is not practical in international collaborative research. Appropriate techniques to standardize multiple teams over a long period of time have not been well developed, however. In the present study 8981 individuals were examined in eight sites in six countries with the standard mercury sphygmomanometer. An evaluation of the effectiveness of central training, site visits, monitoring of digit preference, and the use of an electronic device for internal standardization is described. In all but one of the sites reliability was high and comparable to the observers at the Coordinating Center. Digit preference for the entire set of measurements was limited (frequency of terminal zero = 23.5% for systolic and 28.9% for diastolic readings) and could be shown to have virtually no effect on prevalence rates or correlation estimates. Mean differences among observers within a given site and between sites were small (+/- 0-5 mmHg). While logistically complex, these methods can provide the basis for standardization in international comparative blood pressure surveys.

Prevalence, awareness, treatment and control of hypertension in a self-selected sub-Saharan African urban population: a cross-sectional study

Objectives Hypertension has been established as a major public health problem in Africa, but its specific contributions to disease burden are still incompletely understood. We report the prevalence and determinants of hypertension, detection, treatment and control rates among adults in major cities in Cameroon. Design Cross-sectional study. Settings Community-based multicentre study in major cities in Cameroon. Participants Participants were self-selected urban dwellers from the Center, Littoral, North-West and West Regions, who attended on 17 May 2011 a screening campaign advertised through mass media. Primary and secondary outcomes measures Hypertension defined as systolic (and/or diastolic) blood pressure (BP)≥ 140 (90) mm Hg, or ongoing BP-lowering medications. Results In all, 2120 participants (1003 women) were included. Among them, 1007 (prevalence rate 47.5%) had hypertension, including 319 (awareness rate 31.7%) who were aware of their status. The prevalence of hypertension increased with age overall and by sex and region. Among aware hypertensive participants, 191 (treatment rate 59.9%) were on regular BP-lowering medication, and among those treated, 47 (controlled rate 24.6%) were at target BP levels (ie, systolic (and diastolic) BP<140 (90) mm Hg). In multivariable logistic regression analysis, male gender, advanced age, parental history of hypertension, diabetes mellitus, elevated waist and elevated body mass index (BMI) were the significant predictors of hypertension. Likewise, male gender, high BMI and physical inactivity were associated with poor control. Conclusions High prevalence of hypertension with low awareness, treatment and control were found in this urban population; these findings are significant and alarming with consideration to the various improvements in the access to healthcare and the continuing efforts to educate communities over the last few decades.

Predictive value of abdominal obesity cut-off points for hypertension in Blacks from West African and Caribbean island nations

BACKGROUND: Waist circumferences (WC) ≥94 cm for men and ≥80 cm for women (action level I) and ≥102 cm for men and ≥88  cm for women (action level II) have been suggested as limits for health promotion purposes to alert the general public to the need for weight loss. In this analysis we examined the ability of the above cut-off points to correctly identify subjects with or without hypertension in Nigeria, Cameroon, Jamaica, St Lucia and Barbados. We also determined population- and gender-specific abdominal adiposity cut-off points for epidemiological identification of risk of hypertension.METHODS: Waist measurement was made at the narrowest part of the torso as seen from the front or at midpoint between the bottom of the rib cage and 2 cm above the top of the iliac crest. Sensitivity and specificity of the established WC cut-off points for hypertension were compared across sites. With receiver operating characteristics (ROC), population- and gender-specific cut-off points associated with risk of hypertension were determined over the entire range of WC values.RESULTS: Predictive abilities of the established WC cut-off points for hypertension were poor compared to the specific cut-off points estimated for each population. Different values of WC were associated with increased risk of hypertension in these populations. In men, WC cut-off points of 76, 81, 80, 83 and 87 cm provided the highest sensitivity for identifying hypertensives in Nigeria, Cameroon, Jamaica, St Lucia and Barbados, respectively. The analogous cut-off points in women were 72, 82, 85, 86 and 88 cm.CONCLUSIONS: The waist cut-off points from this study represent values for epidemiological identification of risk of hypertension. For the purpose of health promotion, the decision on what cut–off points to use must be made by considering other additional factors including overall impact on health due to intervention (e.g. weight reduction) and potential burden on health services if a low cut-off point is employed. There is a need to develop abdominal adiposity cut-off points associated with increased risks for cardiovascular diseases in different societies, especially for those populations where the distribution of obesity and associated risk factors tends to be very different from those of the technologically advanced nations.

General public knowledge, attitudes, and practices with respect to epilepsy in the Batibo Health District, Cameroon

Our aim was to obtain baseline data for an epilepsy education program adapted to communities in Cameroon. We conducted 302 face-to-face interviews with patients without epilepsy, caregivers, and visitors in the Batibo District Hospital. Most respondents (99.3%) had heard or read about epilepsy, 89.7% knew someone with epilepsy, and 87.7% had witnessed a seizure. About 43% would object to associating with people with epilepsy (PWE) and 75.8% would object to their children marrying PWE, whereas 35.1% would offer PWE equal employment. Predictors of negative attitudes were: advanced age, lack of formal education, and the belief that epilepsy is hereditary, contagious, or a form of insanity. In conclusion, the high level of public awareness of epilepsy in the Batibo Health District may reflect the magnitude of the condition, contrasting with the prevalent negative attitudes. A successful epilepsy education program must take into account the beliefs and value systems of the community.

A community survey of knowledge, perceptions, and practice with respect to epilepsy among traditional healers in the Batibo Health District, Cameroon

OBJECTIVE The purpose of this study was to gain an understanding of the approach of traditional healers to epilepsy care, in order to develop a community-based epilepsy care program in Batibo Health District. METHODS With an 18-item questionnaire, interviews were carried out with 102 traditional healers randomly selected from two associations of traditional healers in the Batibo Health District. RESULTS Most traditional healers had heard about epilepsy (98.0%), knew someone with epilepsy (97.8%), or had witnessed a seizure (92.2%). About 40% would object to their children associating with people with epilepsy (PWE), 46.1% would object to their children marrying PWE, and 51% linked the disease to insanity. Though 61.8% of the traditional healers could not offer any treatment for epilepsy, most of them thought it was treatable (74.5%) and would readily refer a patient to the hospital (95.1%). The independent predictors of attitudes were: middle age (30-49 years), P=0.00003; female gender, P=0.007; correct knowledge of the cause(s) of epilepsy, P=0.001; and the misconceptions that epilepsy is contagious and that epilepsy is a form of insanity, P=0.003 and 0.019, respectively. CONCLUSION Traditional healers constituted the focus group studied so far in Cameroon that is most familiar with epilepsy. Although they still have some negative practices, the attitudes of traditional healers toward PWE in Batibo Health District are satisfactory, compared with those of the general public and students in the same community. These findings provide evidence for the first time in Cameroon suggesting that collaboration between the modern and traditional health systems with the view of bridging the epilepsy treatment gap is possible. There is a need to train traditional healers in epilepsy care in our context.

Risk factors for HIV-associated neurocognitive disorders (HAND) in sub-Saharan Africa: The case of Yaoundé-Cameroon

BACKGROUND The prevalence of HIV-associated neurocognitive disorders (HAND), especially HIV-associated dementia (HAD) is influenced by several risk factors. The prevalence as well as risk factors for HAD are not well known in sub-Saharan Africa (SSA). We have shown that the International HIV Dementia Scale (IHDS) is a useful screening tool for HAND in Yaoundé [Njamnshi AK, Djientcheu VdP, Fonsah JY, Yepnjio FN, Njamnshi DM, Muna WFT. The IHDS is a useful screening tool for HAD/Cognitive Impairment in HIV-infected adults in Yaoundé-Cameroon. Journal of Acquired Immune Deficiency Syndromes 2008;49(4):393-397], but no study in Cameroon has yet investigated the risk factors for HAND or HAD. PATIENTS AND METHODS A cross-sectional study was conducted in Yaoundé, the capital of Cameroon from September to December 2006. One hundred and eighty-five HIV-positive subjects were included. Diagnosis of HAND was done using the IHDS with a score < or = 10 considered as abnormal. Age, sex, level of education, IV drug use, body mass index (BMI), CDC clinical stage, CD4 counts, hemoglobin levels, administration of highly active antiretroviral therapy (HAART) and type of regimen used, were considered in univariate analysis, with level of significance set at P < or = 0.05. A binary logistic regression was used to determine independent risk factors. RESULTS The following factors were independent predictors of HAND: advanced clinical stage (OR=7.43, P=0.001), low CD4 count especially CD4 < or = 200 cells/microL (OR=4.88, P=0.045) and low hemoglobin concentration (OR=1.16, P=0.048). CONCLUSION This first study of the risk factors for HAND in Yaoundé-Cameroon shows findings similar to those described in other studies. These results call for rapid action by policy makers to include HAND prevention strategies such as providing early universal access to HAART based on these risk factors, in the management of HIV patients at risk of HAND in resource-limited settings of SSA like ours.

Secondary school students' knowledge, attitudes, and practice toward epilepsy in the Batibo Health District--Cameroon.

Using a 12‐item questionnaire, we assessed knowledge, attitudes, and practice (KAP) toward epilepsy and identified determinants of inappropriate attitudes toward people with epilepsy (PWE) among 910 randomly selected secondary school students in Batibo (Cameroon). Ninety‐five percent of the students had heard or read about epilepsy, 73.3% knew an epileptic, and 76.4% had witnessed a seizure. Those who would offer equal employment opportunities to PWE, refuse to associate with, or refuse to marry PWE represented 58.6%, 25.4%, and 64.2%, respectively. Negative attitudes appeared to be reinforced by beliefs that epilepsy is hereditary (25.7%), contagious (49.9%), or a kind of insanity (38%). Acquaintance with PWE tended to improve the misconception that epilepsy is contagious (p < 0.001), and to reinforce the view that it is a form of insanity (p < 0.01). A successful epilepsy education program must account for local beliefs, and secondary school students may constitute a good channel for community education.

General public awareness, perceptions, and attitudes with respect to epilepsy in the Akwaya Health District, South-West Region, Cameroon

BACKGROUND This study was part of a series mandated by the Ministry of Public Healths National Epilepsy Control Program to obtain baseline data for a community-adapted epilepsy education program. METHODS We conducted 387 face-to-face interviews with subjects without epilepsy aged 15 years and above in 12 villages of the Akwaya Health District, Cameroon. RESULTS Most respondents (97.9%) had heard or read about epilepsy, 90.2% knew someone with epilepsy, and 90.4% had witnessed a seizure. About 51.4% would object to association with people with epilepsy (PWE), 68.7% would object to marriage to PWE, while 41.6% would offer them equal employment. For treatment, 30.2% would suggest going to a traditional healer or witch doctor, while 3.9% would not recommend any treatment at all. Predictors of attitudes were male gender, low or no level of education, having children, knowledge of the cause of epilepsy, and beliefs that epilepsy is contagious or is a form of insanity. CONCLUSION The high level of public awareness on epilepsy in the Akwaya Health District may suggest a high prevalence. This contrasts with prevailing negative attitudes. Our data provide new evidence for our hypothesis of regional variation in the determinants of epilepsy stigma in Cameroon.