title: Risk factors for optic nerve disease in communities mesoendemic for savannah onchocerciasis, Kaduna State, Nigeria.
abstract: Ophthalmic examinations on 6831 individuals aged 5 years or more, living in 34 guinea savannah communities mesoendemic for onchocerciasis, in Kaduna State, Nigeria, revealed a relatively high prevalence (9%) of optic nerve disease (OND). Further investigations were performed to determine what proportion of this burden of OND might be due to onchocercal infection. Information on history of cerebro-spinal meningitis (CSM), past use of diethylcarbamazine (DEC) and chloroquine, consumption of cassava and locally produced alcohol was collected for all individuals by questioning. In addition, a nested case-control study of 81 cases of OND and 136 age and sex-matched controls was performed to investigate whether syphilis or a variety of other neurological disorders were responsible for a substantial proportion of cases of OND. Our data suggest that in this population, onchocercal infection is the single most important cause of OND and may account for 50% of all cases. Some 13% of cases were associated with signs suggestive of glaucoma. DEC use might be responsible for up to 30% of all OND. We found no evidence to suggest that any of the following are important causes of OND in the communities studied: CSM, syphilis, neurological syndromes such as polyneuropathy or other generalized neurological disease, consumption of raw cassava, consumption of locally prepared alcohol.
authors.affiliation: Department of Epidemiology and Population Sciences, London School of Hygiene and Tropical Medicine, UK.
authors.forename: S N
authors.initials: SN
authors.lastname: Cousens
authors.forename: H
authors.initials: H
authors.lastname: Yahaya
authors.forename: I
authors.initials: I
authors.lastname: Murdoch
authors.forename: E
authors.initials: E
authors.lastname: Samaila
authors.forename: J
authors.initials: J
authors.lastname: Evans
authors.forename: O E
authors.initials: OE
authors.lastname: Babalola
authors.forename: M
authors.initials: M
authors.lastname: Zakari
authors.forename: A
authors.initials: A
authors.lastname: Abiose
authors.forename: B R
authors.initials: BR
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002648:Child; D004049:Diethylcarbamazine / Q000009:adverse effects; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009549:Nigeria; D009748:Nutrition Disorders / Q000150:complications; D015827:Onchocerciasis, Ocular / Q000209:etiology*; D009901:Optic Nerve Diseases / Q000209:etiology*; D012307:Risk Factors
chemical_list: D004049:Diethylcarbamazine