|Year : 2015 | Volume
| Issue : 2 | Page : 124-128
Hypertension and other cardiovascular risk factors in a semi-nomadic Fulani population in Kano, Nigeria
Kamilu Musa Karaye1, Muzammil M Yakasai1, Umar Abdullahi1, Muhammad Hamza1, Mahmood M Dalhat1, Baffa A Gwaram1, Zaiyad G Habib1, Musa M Bello2, Ahmad M Yakasai3, Aisha H Sadauki4, Faruk Sarkin-Fada5, Usman B Abubakar6, Abdulrazaq G Habib1
1 Department of Medicine, Aminu Kano Teaching Hospital/Bayero University, Kano, Nigeria
2 Department of Community Medicine, Bayero University, Kano, Nigeria
3 Public Health and Diagnostic Institute, College of Medical Sciences, Northwest University, Kano, Nigeria
4 Department of Paediatrics, Aminu Kano Teaching Hospital, Kano, Nigeria
5 Department of Microbiology and Parasitology, Bayero University, Kano, Nigeria
6 Department of Veterinary Medicine, Faculty Veterinary Medicine, Ahmadu Bello University, Zaria, Nigeria
|Date of Web Publication||30-Jul-2015|
Kamilu Musa Karaye
Department of Medicine, Aminu Kano Teaching Hospital/Bayero University, P O Box 4445, Kano
Source of Support: None, Conflict of Interest: None
Introduction: Kano has been described to have the highest burden of hypertension and dyslipidemia in Nigeria. It is not known whether the epidemiologic transition in Kano cuts across all socio-demographic strata. The present study aimed to assess the prevalence and determinants of hypertension and other cardiovascular disease (CVD) risk factors among a semi-nomadic Fulani population in Kano, Nigeria.
Materials and Methods: The study was cross-sectional and carried out in Tofa village, Rano Local Government of Kano State, Nigeria. All semi-nomadic Fulani adults in Tofa and the surrounding hamlets were invited to participate in the study.
Results: A total of 214 consecutive subjects were studied; 57.0% were males and 43.0% were females. The main occupations of the subjects were cattle rearing, subsistence farming and petty trading. The most prevalent CVD risk factor was hypertension found in 28.5% of the subjects. Only 39.3% of the hypertensives were aware of it, and only 25% of the known-hypertensives were taking anti-hypertensive treatment. Age was the only independent predictor of hypertension after controlling for confounding factors, and for every increase in age by 1 year, the risk of developing hypertension was increased by 6.6% (confidence interval, CI = 3.3-9.0; P < 0.001). Body mass index, plasma glucose, and hematocrit were higher among hypertensives than non-hypertensives (P < 0.05). Other CVD risk factors were uncommon.
Conclusion: In the study, hypertension was common; its levels of awareness and treatment were low and mainly determined by increased age. "Western" lifestyle seems to be related to its development as age increased.
Keywords: Cardiovascular risk factors, fulani, hypertension, Nigeria
|How to cite this article:|
Karaye KM, Yakasai MM, Abdullahi U, Hamza M, Dalhat MM, Gwaram BA, Habib ZG, Bello MM, Yakasai AM, Sadauki AH, Sarkin-Fada F, Abubakar UB, Habib AG. Hypertension and other cardiovascular risk factors in a semi-nomadic Fulani population in Kano, Nigeria. Nig J Cardiol 2015;12:124-8
|How to cite this URL:|
Karaye KM, Yakasai MM, Abdullahi U, Hamza M, Dalhat MM, Gwaram BA, Habib ZG, Bello MM, Yakasai AM, Sadauki AH, Sarkin-Fada F, Abubakar UB, Habib AG. Hypertension and other cardiovascular risk factors in a semi-nomadic Fulani population in Kano, Nigeria. Nig J Cardiol [serial online] 2015 [cited 2021 Jan 26];12:124-8. Available from: https://www.nigjcardiol.org/text.asp?2015/12/2/124/152018
| Introduction|| |
Fulanis belong to an ancient ethnic group that speaks dialects of a Niger-Congo language, the Fulfulde, and who originally came to West Africa probably from Nubia.  The Fulanis are considered among the most "widely dispersed and culturally diverse peoples in all of Africa."  There are generally three different types of Fulanis based on settlement patterns, viz., the nomadic/pastoral or Mbororo, the semi-nomadic, and the settled or "Town Fulani".  The pastoral Fulani move around with their cattle throughout the year. Typically, they do not stay around for long stretches (not more than 2-4 months at a time). The semi-nomadic Fulani can either be Fulɓe families who happen to settle down temporarily at particular times of the year, or Fulɓe families who do not "browse" around past their immediate surroundings. Even though they possess livestock, they do not wander away from a fixed or settled homestead too far away. Settled Fulani live in villages, towns, and cities permanently and have given up nomadic life completely, in favor of an urban one. 
The lipid profile and glycemic status of the Fulani have been previously studied in Jos and Sokoto in Nigeria, respectively, and the results showed that dyslipidemia and dysglycemia were uncommon among them. , The cities of Jos and Sokoto are approximately 300 km and 500 km away from Kano, respectively. However, Kano has been described in a national survey to have the highest burden of hypertension and dyslipidemia in the country.  Therefore the epidemiologic transition in Kano is different from those of its neighbors across socio-demographic strata. In addition, previous studies on the Fulani in Nigeria have not comprehensively assessed their traditional cardiovascular disease (CVD) risk factors. This information could provide a good opportunity for a holistic preventive intervention at a relatively early stage of epidemiologic transition.
The present study thus aimed to assess the prevalence and determinants of hypertension and other traditional CVD risk factors among a semi-nomadic Fulani population in Kano, Nigeria.
| Materials and methods|| |
The study was carried out in Tofa village, Rano Local Government Area of Kano State, Nigeria. All the inhabitants of Tofa and the surrounding hamlets were invited to participate in the study, but here we present only the data on adults. The settlements are remote, without basic social amenities and predominantly inhabited by the semi-nomadic Fulanis. It was a large cross-sectional study carried out on 3 rd November 2013. Subjects found to have illnesses during the study were offered free treatment onsite and/or referred to appropriate health facilities for further treatment.
Before the commencement of the study, ethics approval was obtained from the Research Ethics Committee of Kano State Hospitals Services Management Board, and permission obtained from Kano State Primary Health Care Management Board and Rano Local Government Authority, Kano. A courtesy call was paid to the Village Head of Tofa in the presence of other traditional leaders, and their consent to carry out the study was obtained. In addition, an informed consent was obtained from all the participants in the study. The study conformed to the principles outlined in the Declaration of Helsinki, on the ethical principles for medical research involving human subjects. 
Evaluation of subjects
Criteria for inclusion into the study were: Age ≥18 years and giving informed consent. Detailed history and information on weight, height, pulse rate, and blood pressure (BP) were obtained from all the participants who had consented, consecutively. Non-fasting blood sample was taken for random blood sugar (RBS), packed cell volume (PCV), serum total cholesterol (TC), high-density lipoprotein cholesterol (HDLc), low-density lipoprotein cholesterol (LDLc), and triglycerides (TG). The laboratory tests were measured in the laboratories of a tertiary-level hospital in Kano based on a standard protocol.
Definitions of terms
For the purpose of this study, increased age was defined as ≥55 years. Body mass index (BMI) was calculated from the weight and height using the formula: Weight in kilograms/(height in meters).  Patients were measured in light clothes and without shoes or head coverings. BP was measured in each arm using a mercury sphygmomanometer, after the patient had rested for at least 10 minutes. BP measurement was repeated after resting for at least 1 hour using the arm with the higher BP, and the average of the 2 BP readings was recorded for each participant.
Overweight and obesity were defined as BMI of 25.0-29.9 kg/m 2 and ≥30.0 kg/m 2 , respectively. Hypertension was defined as presence of systolic BP (SBP) and/or diastolic BP (DBP) of ≥140 and/or 90 mmHg, respectively. Dyslipidemia was defined as the presence of any of high TC (>5.2 mmol/l), high LDLc (>3.3 mmol/l), high TG (>1.7 mmol/l), or low HDLc (<1.0 mmol/l). These cut-off values are based on the Adult Treatment Panel III (ATP III) recommendations. 
Frequencies, ranges, and means with standard deviations were used to describe patients' characteristics. Chi-squared, Fisher's exact, and Student's T tests were used to compare categorical and continuous variables as appropriate. To assess for the determinants of hypertension in the population, univariate and multivariate logistic regression models were applied. Estimates were computed as Odds Ratios (OR) with 95% confidence interval (CI) limits. A P - value of < 0.05 was considered statistically significant. The statistical analysis was carried out using statistical package of social sciences (SPSS) version 16.0 software.
| Results|| |
A total of 214 consecutive adult subjects who satisfied the inclusion criteria were studied. They had a mean age of 40.1 ± 14.3 years, among whom 122 (57.0%) were males while the remaining 92 (43.0%) were females. Their demographic and clinical characteristics are presented in [Table 1]. All the subjects were semi-nomadic Fulani whose main occupations were cattle rearing, subsistence farming and petty trading.
A total of 61 (28.5%) subjects were found to have hypertension, out of whom 37 (60.7% of all hypertensives) were newly discovered during the study. Among the 24 subjects (39.3% of all hypertensives) who gave a history of hypertension, only six (25% of known-hypertensives) were taking anti-hypertensive medications. Dyslipidemia was found in 13.1% and overweight or obesity in 10.3%, while history of smoking, diabetes mellitus (DM), any form of heart disease and stroke were rare. [Table 2] compares subjects by their gender and hypertension status.
|Table 2: Comparison of clinical characteristics by gender and hypertension status|
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In the logistic regression model assessing for determinants of hypertension, the following variables were identified in the univariate analysis: Age (OR = 1.063; CI = 1.038-1.089; P < 0.001), BMI (OR = 1.140; CI = 1.044-1.245; P = 0.004), RBS (OR = 1.014; CI = 1.020-1.27; P = 0.022), and PCV (OR = 1.067; CI = 1.040-1.133; P = 0.035). However, age was the only variable that maintained its statistical significance as a determinant of hypertension after controlling for confounding factors. The multiple regression analysis showed that for every increase in age by 1 year, the risk of developing hypertension was increased by 6.6% (OR = 1.066; CI = 1.033-1.090; P < 0.001). The relationship between age and hypertension in the population is further illustrated in [Figure 1].
|Figure 1: Relationship between age and hypertension status. Hypertension status: Group 1 = no-hypertension; group 2 = hypertension. Age-groups: 1 = < 25 years; 2 = 25-34 years; 3 = 35-44 years; 4 = 45-55 years; 5 = > 55 years|
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| Discussion|| |
In the present study, 28.5% of subjects were found to have hypertension and nearly two-thirds (60.7%) of them were newly discovered during the study. Sadly, only 25% of the known-hypertensives were taking anti-hypertensive treatment. Increased age was found in 15.9%, dyslipidemia in 13.1%, and overweight in 7.5%, while history of obesity, smoking, DM, heart disease, and stroke were rare. The dyslipidemia comprised principally low HDLc and high TG, while high LDLc and TC were rare. However, the finding of self-reported family history of heart disease in up to 15.4% was surprising, given the low prevalence of personal history of heart disease, and family history of DM and kidney disease.
The most common CVD risk factor in the studied semi-nomadic population was hypertension, and the prevalence is higher than what was estimated (20%) for the general Nigerian population in 1997.  A recent study on urban adults aged over 40 years, recruited during a national survey on blindness in Nigeria, showed a much higher prevalence of hypertension of 44.9% overall, and 54.6% among the "Settled" Fulani ethnic group.  This was an urban and much older population when compared with subjects in the present study (mean age = 55.9 ± 12.4 vs 40.1 ± 14.3 years, respectively).  The prevalence of hypertension (28.5%) and its awareness (39.3%) in the present study are however higher than what were found among non-Fulani adults in rural Kenya (21.4% and 17.4%, respectively).  The prevalence of hypertension in the present study is already approaching what was previously reported among non-hispanic blacks in the US (32.4%).  This tells how advanced its epidemiologic transition is, and calls for an urgent preventive intervention.
Compared with non-hypertensives, the hypertensive group in the present study were significantly older, and had higher BMI, RBS, and PCV. After controlling for confounding factors, age emerged as the only independent predictor of hypertension. We found that for every increase in age by 1 year, the risk of developing hypertension was increased by 6.6%. The relationship between age and prevalence of hypertension was consistent across all the age groups. A study in Ibadan (Nigeria) among non-Fulani population also demonstrated a highly significant correlation between increased age and the prevalence of hypertension.  A prospective community-based study from the Gambia similarly revealed that increasing age was the major independent risk factor for hypertension in both sexes.  In the Framingham study cohort, an average 20 mmHg systolic and 10 mmHg diastolic increase in BP was noted from age 30 years to age 65 years.  SBP continued to rise into the 80s in women and into the 70s in men, while DBP peaks earlier and then declines precipitously beyond the age of 55 years in men and 60 years in women.  In contrast, a comparative prospective study of the remote Amondava population of the Brazilian Amazon with matched controls from African, Italian, and Polish populations, for the effects of traditional lifestyle on cardiovascular risk profile, it was discovered that among the Amondava, BP was always < 140/90 mmHg and it did not increase with age nor did it correlate with any other variable.  Among Amondava subjects, 46.6% had SBP < 100 mmHg, and the prevalence of other CVD risk factors were the lowest. The logical conclusion reached was therefore that in addition to possible genetic predisposition not analyzed in the study, a traditional lifestyle might have protected the Amondava against hypertension, hypercholesterolemia, and diabetes mellitus.  In conjunction with the findings of the Amandova study, the findings of higher BMI, RBS, and PCV among hypertensives as compared with non-hypertensives in our study strongly suggest that lifestyle also plays an important role in the development of the hypertension.
High TG and low HDLc were significantly more common than high TC or LDLc in the present study. Similar observations were made among the Fulani in Sokoto, Nigeria.  The Fulani adults in northern Nigeria consume a low-calorie diet (approximately 1,750 kcal per day) in which protein and fat account for 20% and 50% of calories respectively.  Milk and other dairy products, e. g., butter oil, yogurt, and cheese, supply about 30% of calories. Meat and milk together provide about 75% of total protein.  Therefore, the diets of the Fulanis can explain the observed pattern of dyslipidemia.
In the present study, males outnumbered females and were older. However, the females had higher mean TC and LDLc in spite of having similar mean BMI. Very similar observations among the semi-nomadic Fulanis were made by Glew et al., in northern Nigerian city of Gombe (about 300Km from Kano).  Glew et al., further confirmed their observations by the results of bioelectrical impedance analysis of their body composition: men had 13.8% fat, and women had 26.5% fat, which could explain the gender differences in serum lipids. 
The study has some limitations. Novel CVD risk factors such as serum fibrinogen and some baseline investigations such as the electrocardiogram could not be carried out due to lack of availability of facilities and/or funding. Secondly, the cross-sectional design of the study did not allow for assessment of prognosis in the population.
| Conclusion|| |
In the present study among the semi-nomadic Fulanis in Kano, the most prevalent CVD risk factor was hypertension found in 28.5% of subjects. Nearly two-thirds (60.7%) of all the hypertensives were not aware of it, putting the prevalence of awareness of hypertension at 39.3%. Sadly, only one-in-four of the known-hypertensives were taking anti-hypertensive treatment. The findings of higher BMI, RBS, and PCV among hypertensives as compared with non-hypertensives strongly suggest that lifestyle plays an important role in the development of the hypertension. Other CVD risk factors were uncommon.
In the present study, males outnumbered females and were older. However, the females had higher mean TC and LDLc in spite of having similar mean BMI.
The study has shown that hypertension was common and its level of awareness and treatment were low. Therefore, measures of intervention and prevention should be extended to even remote populations such as the one studied, in order to halt the rapid rate of epidemiologic transition being observed across populations in developing and under-developed countries.
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[Table 1], [Table 2]