Sommer A
School of Hygiene and Public Health, Johns Hopkins University, Baltimore, Maryland 21205-2179.
J Infect Dis. 1993 May;167(5):1003-7. doi: 10.1093/infdis/167.5.1003.
Vitamin A was first discovered in 1913. Its deficiency was soon associated in animal models and case reports with stunting, infection, and ocular changes (xerophthalmia) resulting in blindness. The ocular consequences dominated clinical interest through the early 1980s. A longitudinal prospective study of risk factors contributing to vitamin A deficiency and xerophthalmia revealed a close, dose-response relationship between the severity of mild preexisting vitamin A deficiency and the subsequent incidence of respiratory and diarrheal infection (relative risk [RR], 2.0-3.0) and, most dramatically, death (RR, 3.0-10.0). Subsequent community-based prophylaxis trials of varying design confirmed that vitamin A supplementation of deficient populations could reduce childhood (1-5 years old) mortality by an average of 35%. Concurrent hospital-based treatment trials with vitamin A in children with measles revealed a consistent reduction in measles-associated mortality in Africa of at least 50%. It is now estimated that improving the vitamin A status of all deficient children worldwide would prevent 1-3 million childhood deaths annually.
维生素A于1913年首次被发现。在动物模型和病例报告中，其缺乏症很快与发育迟缓、感染以及导致失明的眼部变化（干眼病）联系在一起。直到20世纪80年代初，眼部后果一直主导着临床关注。一项关于导致维生素A缺乏和干眼病的危险因素的纵向前瞻性研究表明，轻度的既往维生素A缺乏严重程度与随后呼吸道和腹泻感染的发生率（相对风险[RR]，2.0 - 3.0）之间存在密切的剂量反应关系，最显著的是与死亡（RR，3.0 - 10.0）之间的关系。随后，不同设计的社区预防试验证实，对缺乏维生素A的人群补充维生素A可使儿童（1至5岁）死亡率平均降低35%。同时，在麻疹患儿中进行的以医院为基础的维生素A治疗试验表明，在非洲，与麻疹相关的死亡率持续降低至少50%。据估计，改善全球所有缺乏维生素A儿童的维生素A状况每年可预防100万至300万例儿童死亡。
