Humphrey J H, West K P, See L C, Natadisastra G, Sommer A
Dana Center for Preventive Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD 21287.
J Nutr. 1993 Aug;123(8):1363-9. doi: 10.1093/jn/123.8.1363.
A randomized trial tested whether a priming dose of vitamin A would extend the protection of a subsequent 60,000-micrograms retinol equivalent (RE) oral dose. Seventy-five xerophthalmic and 74 age- and neighborhood-matched non-xerophthalmic preschool children were randomized to one of three oral regimens of vitamin A, receiving peanut oil only (Group A), 7500 micrograms RE (Group B) or 60,000 micrograms RE (Group C), followed in all instances by 60,000 micrograms RE 1 wk later. Serum retinol was measured 2, 4, 6 and 12 mo following the second dose by technicians unaware of the children's treatment status. Among xerophthalmic children, mean values differed across treatment groups at 2 mo (C > A) and tended to be different at 12 mo (C > A and B > A). Among non-xerophthalmic children mean retinol concentrations differed across treatment groups at 6 mo, but not in a consistent way (A > C > B), and at 12 mo (C > A and B > A). Xerophthalmic children reverted to biochemical deficiency faster than non-xerophthalmic children. A small or large priming dose may extend the protection conferred by a 60,000-micrograms RE dose, supporting the use of repeated, spaced doses of vitamin A for treating xerophthalmia. Similar retinol concentrations in Groups B and C at 12 mo suggest the 60,000-micrograms RE prophylactic dose currently recommended by the World Health Organization need not be increased.
一项随机试验检验了维生素A的预充剂量是否会延长随后60,000微克视黄醇当量（RE）口服剂量的保护作用。75名患干眼病的学龄前儿童以及74名年龄和居住社区匹配的未患干眼病的学龄前儿童被随机分为三种维生素A口服方案之一，分别仅接受花生油（A组）、7500微克RE（B组）或60,000微克RE（C组），所有情况下1周后均再给予60,000微克RE。由不了解儿童治疗情况的技术人员在第二次给药后2、4、6和12个月测量血清视黄醇。在患干眼病的儿童中，各治疗组在2个月时的平均值有所不同（C组>A组），在12个月时也有差异趋势（C组>A组且B组>A组）。在未患干眼病的儿童中，各治疗组在6个月时的平均视黄醇浓度有所不同，但并不一致（A组>C组>B组），在12个月时也是如此（C组>A组且B组>A组）。患干眼病的儿童比未患干眼病的儿童更快恢复到生化缺乏状态。小剂量或大剂量的预充剂量可能会延长60,000微克RE剂量所提供的保护作用，这支持使用重复、间隔给药的维生素A来治疗干眼病。B组和C组在12个月时视黄醇浓度相似，这表明世界卫生组织目前推荐的60,000微克RE预防剂量无需增加。
