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Br J Ophthalmol. 2011 Oct;95(10):1361-4. doi: 10.1136/bjo.2010.197608. Epub 2011 Jul 6.

Low folate status and indoor pollution are risk factors for endemic optic neuropathy in Tanzania.

Author information

1
Department of Nutrition & Public Health Intervention Research, London School of Hygiene & Tropical Medicine, London, UK.

Abstract

AIMS:

Bilateral optic neuropathy in Dar-es-Salaam, Tanzania was first reported as an epidemic in 1988. Now argued to be endemic in 2010, the aetiology remains unclear. The authors investigated the hypothesis that low folate and vitamin B₁₂ status are associated with optic neuropathy, and also sought to investigate whether mercury, commonly used drugs, dietary factors and indoor pollution may also be risk factors.

METHODS:

57 cases and 102 controls were recruited from two tertiary referral centres in Dar-es-Salaam. Data were collected on demographic characteristics, diet, medication history and HIV status. Folate and vitamin B₁₂ (holo-transcobalamin) were measured in stored serum samples. Exposure to mercury was assessed from concentrations in random urine samples.

RESULTS:

Cooking indoors more than twice per week (OR 54.48 (95% CI 9.30 to 319.10)) and indoor use of charcoal or firewood (OR 21.20 (95% CI 2.51 to 179.36)) increased the risk of optic neuropathy. Risk was reduced in those with a higher folate status (highest versus lowest quartile OR=0.11 (95% CI 0.02 to 0.51)) and higher protein intakes (OR=0.84 (95% CI 0.72 to 0.96). No association was found with mercury exposure or any common drug or food commodity.

CONCLUSION:

This study presents the first direct evidence of low folate status and indoor pollution in the aetiology of endemic bilateral optic neuropathy in Tanzania.

PMID:
21733919
DOI:
10.1136/bjo.2010.197608
[Indexed for MEDLINE]

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