Department of Nutrition & Public Health Intervention Research, London School of Hygiene & Tropical Medicine, London, UK.
Br J Ophthalmol. 2011 Oct;95(10):1361-4. doi: 10.1136/bjo.2010.197608. Epub 2011 Jul 6.
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.
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.
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.
This study presents the first direct evidence of low folate status and indoor pollution in the aetiology of endemic bilateral optic neuropathy in Tanzania.
坦桑尼亚达累斯萨拉姆的双侧视神经病变于 1988 年首次报道为流行。如今，这种疾病在 2010 年被认为是地方性疾病，但病因仍不清楚。作者研究了低叶酸和维生素 B₁₂ 状态与视神经病变相关的假设，并试图调查汞、常用药物、饮食因素和室内污染是否也可能是危险因素。
从达累斯萨拉姆的两个三级转诊中心招募了 57 例病例和 102 例对照。收集了人口统计学特征、饮食、用药史和 HIV 状况的数据。在储存的血清样本中测量叶酸和维生素 B₁₂（全反钴胺素）。从随机尿液样本中的浓度评估汞暴露情况。
每周在室内做饭超过两次（OR 54.48（95%CI 9.30 至 319.10））和在室内使用木炭或木柴（OR 21.20（95%CI 2.51 至 179.36））会增加视神经病变的风险。叶酸状态较高（最高与最低四分位数 OR=0.11（95%CI 0.02 至 0.51））和蛋白质摄入量较高（OR=0.84（95%CI 0.72 至 0.96））的人风险降低。与汞暴露或任何常见药物或食品商品均无关联。
本研究首次提供了直接证据，表明低叶酸状态和室内污染是坦桑尼亚地方性双侧视神经病变的病因。
