Stroke is one of the commonest non-communicable diseases (NCDs) and the commonest cause of death in adult neurology wards     . Stroke prevalence in sub Saharan Africa (SSA) has dramatically increased over the past decades   possibly due to changing life styles, poverty, poor health infrastructures which had led to increased risk factors for stroke. Stroke is also one of the most devastating cardiovascular complications of hypertension and diabetes in Africa occurring at relatively younger ages      with a huge burden on SSA communities   .
The prevalence rates of stroke in SSA vary widely   . In Nigeria, earlier studies by Osuntokun et al.   documented low prevalence rates while recent studies have revealed increased prevalence rates      . An incidence of 1.14/1000 was reported by Danesi et al.  . Hospital-based studies in Nigeria show that stroke accounts for 64.9% - 77.6% of neurological admissions      . This rising prevalence of stroke in Nigeria also reflects the high prevalence of hypertension, diabetes, HIV/AIDS and other risk factors for stroke in the community     . The relationship between stroke, (major risk factors for stroke) and socioeconomic status has been documented   . Most slum dwellers are likely to fall into this group  . Poor nutrition and lack of access to standard medical care predispose these individuals to high rates of stroke morbidity and mortality hence possible low prevalence. Little is known about the prevalence of stroke in people with low socio-economic status in Nigeria.
The study aims at finding the prevalence of stroke in two urban slums in south east Nigeria.
This study was carried out in Agu-Abor and Ugbodogwu, two slums in Enugu, the capital of Enugu State, South East Nigeria. Both settlements occupy the foot of Udi hills and are about 2.5 km from the city center. They have an estimated population of 7000 - 9000. (This based on church and local records). The study design of this study has been published elsewhere   . A three-phase cross-sectional descriptive study was carried out to survey at least 10% of the adult population (i.e. 700 - 800 adults based on the estimated adult population) who have lived in the area for at least 1 year. The study was divided into three phases. The first phase was sensitization of the population through churches, community awareness announcements on the streets and meeting(s) on the selected day(s). The second phase participants were visited at home by teams of research assistants. In this phase, the WHO STEPS instrument  was used to collect data on selected sociodemographic characteristics and lifestyle behaviors including physical activity. The World Health Organization (WHO) Protocol for Epidemiological studies in developing countries was used to screen for neurological disease  . The third phase of the study was done in a field clinic in Aguabor. Participants who screened positive for neurologic disease were further assess using a stroke specific questionnaire  and then examined by two independent neurologists for evidence of focal neurological deficits.
Stroke was defined as a clinical syndrome of rapidly progressive symptoms and signs of focal or global neurological deficit lasting more than twenty-four hours of which there is no apparent cause other than vascular origin, and/or past medical history stroke diagnosed by qualified personnel (doctors). Other clinical symptoms of patients were defined based on clinical description and or diagnosis by a medical doctor. Hypertension and diabetes were defined based on medical history and use of appropriated medications for treatment. Current tobacco use was defined as the use of any form of tobacco in the past 4 weeks. Alcohol use and quantity was defined as (mean number of days) the consumption of any alcoholic beverage in a week.
Artisans were defined as skilled manual laborers. Level of education was the individual’s highest educational (formal) attainment based on the Nigerian school system. The study was conducted between August 2013 and December 2013.
SPSS version 23 (IBM Corporation, New York, USA) was used for data entry and analysis. For database management and statistical analyses, we used the SPSS version 20 (IBM Corporation, New York, USA). Data were presented in tables. For continuous variables, mean values and standard deviations were calculated. Prevalence of stroke was expressed as percentages. Mean values were compared using the independent t-test. In all, p values of <0.05 were regarded as statistically significant. The confidence level was kept at 95%.
A total of 1440 participants were surveyed in the study, this was made up of 769 females and 671 males (p-value <0.001) with a male to female ratio of 1:0.9. The mean age of the subjects was 44.9 (±15.2) years. There were no significant differences between the mean age of males and females (females 43.6 ± 14.7 versus males 45.3 ± 15.3, p value 0.44). The age distribution of the subjects is shown in Table 1. Most of them were young, less than 40 years (914/1440 (63.5%)), engaged in business and at least secondary/tertiary education.
Table 1. Characteristics of participants.
3.1. Lifestyle and Medical History
About 12.6% and 5.9% of the subjects used snuff and smoked cigarettes. The proportion of tobacco users was significantly higher among males (p > 0.001). A small number of the subjects used marijuana. About 5.8% of the subjects drank alcohol at least daily but the majority 599 (41.6) drank less than 3 days in a week. Medical history revealed that 10.9% reported a history of hypertension, 3.5% diabetes and 26 (1.8%) reported a history of stroke. Seven (0.5%) had a medical history of sickle cell disease (see Table 1).
3.2. Demography of Those Who Had Stroke
Three hundred and twenty-one participants (22.3%) screened positive for various neurological disease in the stage 2 of the study based on the study protocol (Figure 1). Out of this 17 (5.3%; 9 males and 8 females) had evidence for stroke giving an overall prevalence of 1.2% (12 per 1000). The mean age of stroke survivors was 60.1 years, similar in males and females (p = 0.6). The distribution of stroke survivors is shown in Table 2. The highest prevalence was recorded from 70 years and above (10%), in those with hypertension (3.8%), diabetes (7.8%) and leg swelling (8.5%) (Table 2).
3.3. Factors Associated with Stroke
The prevalence of stroke and odds ratio for stroke is shown in Table 3. The odds ratio for stroke from 40 years and above showed progress increment. It doubled between 60 and 70 years and tripled between 40 and 70 years. Sickle cell disease had the highest odds ratio recorded in the study. Age, lower level of education, positive history of hypertension, sickle cell disease, leg swelling and use of snuff positively correlated with clinical diagnosis of stroke (Table 4).
This study has revealed a modest (12/1000) prevalence of stroke in an urban slum in Enugu Metropolis which did not vary between males and females. Though stroke prevalence in this study was highest after 70 years (100/1000) the prevalence of stroke was also relatively high between the ages of 40 - 49 (23/1000). Stroke rates above 12/1000 were recorded in individuals with lower educational status (41/1000), hypertension (38/1000), diabetes (78/1000), snuff users (33/1000)
Figure 1. Frequency of severe neurologic disorders in the community.
Table 2. Prevalence of stroke.
*p-values are for the sex differences.
Table 3. Odds ratio for stroke in the community.
Table 4. Correlation statistics for stroke in the communities.
and leg swelling (85/1000). These variables also demonstrated a positive correlation with stroke. Other interesting findings are the steep rise in the odds of having stroke after 50 years which dropped after 60 years.
Studies reveal an increasing prevalence rate of stroke in SSA. Early studies by Osuntokun et al.   found a community prevalence of 58 - 400/100,000, a crude annual mortality rate of about 700/100,000 per year and age specific mortality in the elderly of about 100/100,000 per year while more recent studies have reported higher rates   . The increasing prevalence of stroke is clearly related to increasing rates of cardiovascular and metabolic disorders which were rare in the early and middle decades of the last century      . Related to this is are high rates of HIV/AIDS, smoking and alcohol abuse as well as poor healthcare infrastructure and public health educational strategies      . Related to these are high rates of alcohol and tobacco use as well as increasing use of amphetamines and cocaine  . Surveys from other African countries have also reported increasing prevalence of stroke     .
The prevalence of stroke in the index study is within the reported global prevalence and continental of 4 and 20 per 1000 population       with higher rates among people with socioeconomic status      . Poor health facilities, lack of access to care, high cost as well as inherent risky cultural practices/beliefs among the urban poor may coalesce in high rates of mortality leading to low prevalence. Other factors include low health insurance coverage in the country, poor health infrastructure (with few if any functional emergency stroke services) as well as lack of neurologists/stroke specialists. The stroke burden in south-east Nigeria and especially in urban slums may be therefore affected by these multifaceted factors. Basic stroke evaluation tools such as radio-imaging, echo studies as well blood investigations are available but remain out of reach of most patients. Furthermore, the non-existent stroke educational programs which should form the basis for any meaningful community based preventive programs is also contributory. Studies have shown that low cost strategies such as public educational programs produce attitudinal change  . Results from the index may be explained not only by population specific characteristics (age distribution in favor of the young, the area surveyed (urban slum)) but also on methodological issues. Most studies from the continent used WHO criteria similar to the index study.
Several traditional risk factors for stroke such as older age, hypertension and diabetes were reported in the present study. Stroke is relatively more common in young Africans and the peak age has been shown to be lower in Africans compared to their Caucasian counterparts   . The age specific rates of stroke and the mean age of stroke survivors are similar to findings from both epidemiological and hospital-based studies from Nigeria and SSA. Slightly different findings from earlier studies  may suggest a paradigm shift in the age of stroke occurrence among Africans as an increasing number of the population are surviving to old age. This will definitely increase the burden of stroke in the country. There is need for strict and effect health policies to reduce the modifiable risk factors for stroke and thereby reduce its overall burden.
Significant independent risk factors for stroke in this study included the use of snuff. In South-East Nigeria the use of snuff is widely accepted in the community more than cigarette smoking hence it is widespread in most communities. Snuff (mostly homemade) likely contains lots of tobacco specific nitrosamines which have been implicated in predisposing to cardiovascular diseases   . Earlier studies did not find an excess risk of stroke with smokeless tobacco  , however, there are some evidence that smokeless tobacco may be associated with an increased risk of fatal ischemic stroke and myocardial infarction   .
Other risk factors for stroke like alcohol use and cigarette smoking are very common in many Nigerian communities   . These substances were not significant risk for stroke in the index study probably because we surveyed the rates of current use rate than lifetime use of these substances. The prevalences of hypertension and diabetes in the index communities have been previously documented   . The overlapping impact of low socio-economic status and these factors may contribute to high rates of stroke severity and mortality. Poor health seeking behavior and lack of health insurance schemes with consequent out of pocket funding of medical expenses may all be contributory. Lower life expectancy and possibly higher stroke fatality rates in poor communities might present with “false” low prevalence rate of stroke.
We found a positive association between stroke and lower level of education in the index study which was also is similar to the report by Amarenco et al.  who observed that low level of education, unemployment status and low quality of living were predictive of major vascular events. People in low level of education are more likely to earn less and affected by factors discussed earlier. Furthermore, factors such as poor nutrition and use substances such as alcohol and tobacco may also be contributory. People with low levels of education are less likely to understand and apply health related behavioral changes that may be disseminated by public health workers. The relationship between leg welling and stroke is not very clear as we did not explore the causes of this symptoms. However, leg swelling is a cardinal symptom of heart failure, immobility and renal failure with are in turn risk factors for stroke.
5. Limitations of the Study
This study has some limitations. First, we did not account for stroke mortality which might lead to low prevalence rates. The age and gender distribution of the population might have skewed our findings to the lower end of the spectrum because of the high proportion of young people in the study. The diagnosis of stroke was limited to history and clinical diagnosis instead of neuro imaging. The study did not find out the exact time of the stroke and hence could not ascertain the time lapse before a possible repeat stroke.
The prevalence of stroke in an urban slum in Enugu metropolis was 12/1000 and is within the range previously reported but higher than the current studies in Nigeria. Hypertension, diabetes, use of snuff, and low levels of education were significant risk factors for stroke. Public health educational measures, promoting prevention and early detection of diabetes should be encouraged. Efforts should be made to educate the populace on the need for early detection and treatment.
We acknowledge the leaders of Agu-Abor and Ugbodogwu communities for their support, and to Miss Loveth Emmanuel, Secretary, Neurology and EEG services, Mount Carmel Hospital Enugu, for her help in the office.
The project described was supported by the Medical Education Partnership Initiative in Nigeria (MEPIN) project funded by Fogarty International Center, the Office of AIDS Research, and the National Human Genome Research Institute of the National Institute of Health, the Health Resources and Services Administration (HRSA) and the Office of the US Global AIDS Coordinator under Award Number R24TW008878. The content is solely the responsibility of the authors and does not necessarily represent the official views of the funding organizations.
This work is designed to find out how many people at Agu-Abor and Ugboodogwu have disorders that affect the nervous system. Your identity will not be disclosed to anyone or released for any other purpose except for the goal of this study without your permission.
Thank you for cooperating with us.
House number -------------------- Phone/phone of next of kin ------------------
Place of origin. State……… Tribe ---------- LGA………. Town Village……….
Past medical history
Previous hospitalizations Yes No Reasons................................
History of head injury Yes No
With loss of consciousness… Yes No without loss of consciousness Yes No
Have you been told that you have/ had
· Sickle cell disease
Which other “sickness” are you suffering from? ----------------------------------
Please if you have of had convulsions or up rolling of the eyes associated with fever
Please if you have of had up rolling of the eyes not associated with fever
History of convulsion/episodic up rolling of the eyes in the family
History of (suspected) mental illness
Have you had brain surgery in the past
Obstetric history (for children less than 11 years).
Number in the family (including all pregnancies)……………
Mother’s illness during pregnancy………………
Duration of pregnancy………months
Type of delivery. SVD……
Eclampsia (convulsion and high blood pressure during pregnancy) Yes No
Labour for (this present child)
Normal Prolonged Yes No
place of delivery
home maternity hospital
church other places --------------------------
Labour (delivery) Assisted delivery
Illness……… Type (convulsions) (fever) (diarrhea) (pneumonia) (Jaundice) Others describe…………………………………
Normal… Yes No
Delayed… Yes No
Immunization history………… completed……… Yes No
Total number of immunizations……
Family and social history.
Illnesses in the family.
Hypertension Yes No
Stroke Yes No
Leg swelling Yes No
Chronic cough Yes No
Type. asthma tuberculosis
USE OF TOBACCO
Do smoke or use snuff (in any form)
Cigarette Yes No
Snuff Yes No
Marijuana Yes No
Others (describe)-glue-cocaine-(etc.) ASK!
Do smoke or use snuff (in any form)
Cigarette Yes No
Snuff Yes No
Marijuana Yes No
Others (describe)-glue-cocaine (etc.)
Do you drink alcohol Yes No
What type of alcohol
What quantity do you think you consume in a week -----------------------------
Do you know the names of the drugs you are taking now at home
------------------------------------------------------ Where do you normally get your drugs from
Market Yes No
Pharmacy Yes No
Chemist Yes No
Hospital Yes No
Maternity Yes No
Q1 Have you ever lost consciousness?
Q2 Have you ever had episodes where you lost contact with your surroundings?
Q3 Have you ever had episodes of shaking of your arms or legs which you could not control?
Q4 Is your speech normal?
Q5 Have you had episodes of pain in the face?
Q6 Has your face or part of your face ever been paralyzed even for few minutes?
Q7 Have you ever had weakness in your arms or legs paralyzed even for few minutes?
Q8 Have you been unable to walk properly?
Q9 Have you ever had loss of sensation or abnormal sensation affecting your arms and legs paralyzed even for few minutes?
Q10 Have you ever suffered from headache?
Q11 Do you suffer from severe headaches, chiefly on one side of the head, which come on from time to time?
Q12 In association with these headaches, do you suffer from visual disturbances: e.g. black spots or zigzag lines in front of your eyes?
Q13 In association with these headaches, do you suffer from nausea or vomiting?
Q14 In association with these headaches, do you suffer from weakness or numbness in the limbs that lasts less than a few days?
Q15 Do these headaches occur only when you have a febrile illness?
Q16 Do you have problems with remembering recent events?
E1 Hold both arms above head for 30 s.
E2 Pick up matchstick from ground.
E3 Close your eyes. Feel cloth sample. Is it smooth or rough?
E4 Put your hands out in front of you. Close your eyes. Touch your nose with the right index. Repeat it using your left.
E5 Walk heel to toe along the white line (distance of one meter).
E6 Stand with both feet together.
E7 Close your eyes and stand still for 15 s (only if able to perform).