Epilepsia, 33(6): 1051-1056, 1992 Raven Press, Ltd., New York 0 International League Against Epilepsy

Prevalence and Incidence of Epilepsy in Ulanga, a Rural Tanzanian District: A Community-Based Study H. T. Rwiza, *G. P. Kilonzo, "9. Haule, W. B. P. Matuja, I. Mteza, $P. Mbena, P. M. Kilima, TG. Mwaluko, §R. Mwang'ombola, F. Mwaijande, G. Rweyemamu, *A. Matowo, and "L. M. Jilek-Aall Neurology Unit, Departments of Medicine, *Psychiatry, and fPharmacology, Faculty of Medicine, University of Dar es Salaam, Dar es Salaam, Tanzania; #Mahenge District Hospital; §Morogoro Regional Hospital, Morogoro Tanzania; and "Department of Psychiatry, University of British Columbia, Vancouver, B . C . , Canada

Summary: A random cluster sample survey of approximately 18,000 people in 11 villages was performed in Ulanga, a Tanzanian district with a population of approximately 139,000 people. Well-instructed fourth-year medical students and neurologic and psychiatry nurses identified persons with epilepsy using a screening questionnaire and sent them to a neurologist for detailed evaluation. Identified were 207 subjects (88 male, 119 female) with epilepsy; of these, 185 (89.4%) (80 male, 105 female) had active epilepsy. The prevalence of active epilepsy was 10.2 in 1,000. Prevalence among villages varied, ranging from 5.1 to 37.1 in 1,000 (age-adjusted 5.837.0). In a 10-year period (1979-1988) 122 subjects living in the 11 villages developed epilepsy, with an annual in-

cidence of 73.3 in 100,000. Generalized tonic-clonic seizures (GTCS) accounted for 58% and partial seizures accounted for 31.9%, whereas in 10.1% seizures were unclassifiable. Of the partial seizures, secondarily generalized seizures were the most common. Possible etiologic or associated factors were identifiable in only 25.3% of cases. Febrile convulsions were associated in 13.4 of cases. Other associated factors included unspecified encephalitis (4.7%), cerebral malaria (1.9%), birth injury (1.4%), and other (3%). In 38% of the cases, there was a positive family history of epilepsy. Key Words: Epileps y-Epidemiology-Prevalence-Incidence-Tanzania-Delivery of health care.

Wide variations occur in worldwide epilepsy prevalence rates, which in developing countries range from 4 to 49 in 11,000 (Levy et al., 1964; Jilek and Aall-Jilek, 1970; Gomez et al., 1978; Osuntokun et al., 1982, 1987; Gerrits, 1983; Goudsmit et al., 1983; Cruz et al., 1985; Li et al., 1985; Marino et al., 1987). The rates, although based on relatively fewer studies, are generally higher than those reported from developed countries. Recent studies in Nigeria and rural Ethiopia, Africa, however, showed a prevalence rate of active epilepsy of 5.3 and 5.2 in 1,000 respectively, rates similar to those of developed countries (Osuntokun et al., 1987; TekleHaimanot et al., 1990). The only epilepsy prevalence report from Tanzania was that of Jilek and Jilek-Aall(1970), who noted a prevalence rate of 20

in 1,000 among the Pogoro tribe. This figure, however, was calculated from the number of patients receiving treatment from an estimated catchment population and assumed that all patients received treatment and that all came from that area only. With financial support from the Netherlands Epilepsy Fund, Holland, we performed a community survey in Ulanga district involving a more extensive area to confirm the high prevalence previously estimated by Jilek and Jilek-Aall (1970). In addition, the incidence was estimated from retrospective interviews. Furthermore, a knowledge, attitude, and practice (KAP) survey toward epilepsy was performed with adults. A treatment program was also incorporated so that all patients detected were prescribed medication which was to be administered by primary health care personnel, after appropriate education and instruction. We report results on the prevalence and incidence of epilepsy. The KAP survey will be published separately.

Received March 1991; revision accepted July 1992. Address correspondence and reprint requests to Dr. H. T. Rwiza at Muhimbili Medical Centre, P.O. Box 65471, Dar es Salaam, Tanzania.

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MATERIALS AND METHODS The study was performed in Ulanga, a Tanzanian district with a population of 138,837 persons (Tanzania has a population of 22,533,758 persons; 1988 population census). Ulanga is situated -500 km from the Indian Ocean coast and is inhabited mostly by subsistence peasants. Geographically, it is constituted of lowlands and a mountainous area occupying the Eastern portion. Sampling method A random cluster sample survey method was used, with each village constituting one cluster. Ulanga District consists of five geographically and administratively distinct divisions. Of the five divisions, Mahenge is situated in the mountainous portion, and the remaining four divisions (Mwaya, Lupilo, Mtimbira, and Malinyi) are in the lowlands. Villages per division range from 13 to 15. We selected l l villages by randomly choosing two villages from each of the four divisions and three from one division. All individuals living in the selected villages were included in the sample. Survey method Administratively, each village consists of 10 household units administered by a 10-house leader who constitutes the lowest level of administration. Above this level are the village leaders, who are answerable to the division leader. The division leaders are in turn answerable to the district administration. Mobilization began at the district, through the intermediate levels, down to the 10 house leaders. Through the help of the village and 10 house leaders who identified all the households under their administration, a prior population census was performed in all villages in the sample. Each head of the household was registered together with every member of his household. The survey was conducted in a 3-week period by a 24-member team of 2 psychiatrists, a neurologist, 2 general-duty doctors, 5 registered nurses with extra training or experience in psychiatry and neurology, and 14 medical students in clinical apprenticeship. Before the survey, all members of the survey team underwent 1 week of orientation to the survey questionnaires and standardization of the interview technique. During the survey, each head of the household presented every member of his family; this enumeration was counterchecked against the census record. Each individual was then screened for epilepsy by use of the three questions in the World Health Organization (WHO) screening questionnaire for neurologic diseases, (World Health Epilepsia, Vol. 33, NO. 6, 1992

Organization, 1981), to which a fourth question, “Have you ever had any episodes of falling or dropping down without any obvious cause or which you could not recall?” was added. For children, the questions were reframed in the third person. Data on the incidence of epilepsy was obtained by asking the head of the household to give the age of onset and year of onset for any member of the family with epilepsy whether dead or alive. The father or the mother in each family were alternately interviewed with respect to their knowledge, attitude, and practice toward epilepsy. Case ascertainment, definition, and diagnostic criteria All cases identified during the screening interview were immediately referred to the neurologist who was in the field as a member of the team. The diagnosis of epilepsy was confirmed on clinical grounds using only criteria used in other studies in Africa, Asia, and South America for tonic-clonic seizures (Shorvon and Farmer, 1988) and the clinical descriptions of the International League Against Epilepsy (ILAE) Classification for partial seizures (Commission, 1981). No EEGs were performed. Epilepsy was defined as two or more nonfebrile seizures unrelated to any acute metabolic disorder or to withdrawal of alcohol or drugs. All subjects satisfying this definition were further categorized as having active epilepsy if they had had at least one of the seizures the 24 months preceding the survey, were receiving treatment, or both. Patients receiving no treatment and with no history of seizures in the previous 24 months were categorized as having inactive epilepsy. Possible etiologic factors were determined after a thorough history and physical examination while the various factors identified from studies in Africa and elsewhere were specifically sought (Li et al., 1985; Shridharan, et al., 1986; Mani, 1987; Osuntokun et al., 1987). The overall coverage was 92.5%. The families not examined had temporarily shifted to their farms several kilometers from the villages and could not be reached. RESULTS The age and sex distribution of the 18,183 sample subjects (Table 1) is similar to the age and sex patterns observed in other developing countries, with 60.8% of the subjects aged

Prevalence and incidence of epilepsy in Ulanga, a rural Tanzanian district: a community-based study.

A random cluster sample survey of approximately 18,000 people in 11 villages was performed in Ulanga, a Tanzanian district with a population of approx...
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