Congdon N G, Dreyfuss M L, Christian P, Navitsky R C, Sanchez A M, Wu L S, Khatry S K, Thapa M D, Humphrey J, Hazelwood D, West K P
Center for Human Nutrition, Department of International Health, The Johns Hopkins School of Hygiene and Public Health, Baltimore, MD, USA.
Am J Clin Nutr. 2000 Oct;72(4):1004-9. doi: 10.1093/ajcn/72.4.1004.
Impaired dark adaptation occurs commonly in vitamin A deficiency.
We sought to examine the responsiveness of dark-adaptation threshold to vitamin A and beta-carotene supplementation in Nepali women.
The dark-adapted pupillary response was tested in 298 pregnant women aged 15-45 y in a placebo-controlled trial of vitamin A and beta-carotene; 131 of these women were also tested at 3 mo postpartum. Results were compared with those for 100 nonpregnant US women of similar age. The amount of light required for pupillary constriction was recorded after bleaching and dark adaptation.
Pregnant women receiving vitamin A had better dark-adaptation thresholds (-1.24 log cd/m(2)) than did those receiving placebo (-1.11 log cd/m(2); P: = 0. 03) or beta-carotene (-1.13 log cd/m(2); P: = 0.05) (t tests with Bonferroni correction). Dark-adaptation threshold was associated with serum retinol concentration in pregnant women receiving placebo (P: = 0.001) and in those receiving beta-carotene (P: = 0.003) but not in those receiving vitamin A. Among women receiving placebo, mean dark-adaptation thresholds were better during the first trimester (-1.23 log cd/m(2)) than during the second and third trimesters (-1.03 log cd/m(2); P: = 0.02, t test). The mean threshold of nonpregnant US women (-1.35 log cd/m(2)) was better than that of all 3 Nepali groups (P: < 0.001, t test, for all 3 groups).
During pregnancy, pupillary dark adaptation was strongly associated with serum retinol concentration and improved significantly in response to vitamin A supplementation. This noninvasive testing technique is a valid indicator of population vitamin A status in women of reproductive age.
暗适应受损在维生素A缺乏症中很常见。
我们试图研究尼泊尔女性暗适应阈值对维生素A和β-胡萝卜素补充剂的反应。
在一项维生素A和β-胡萝卜素的安慰剂对照试验中，对298名年龄在15至45岁的孕妇进行了暗适应瞳孔反应测试；其中131名女性在产后3个月也进行了测试。将结果与100名年龄相仿的非怀孕美国女性的结果进行比较。在漂白和暗适应后，记录瞳孔收缩所需的光量。
接受维生素A的孕妇的暗适应阈值（-1.24 log cd/m²）优于接受安慰剂的孕妇（-1.11 log cd/m²；P = 0.03）或接受β-胡萝卜素的孕妇（-1.13 log cd/m²；P = 0.05）（经Bonferroni校正的t检验）。在接受安慰剂的孕妇（P = 0.001）和接受β-胡萝卜素的孕妇（P = 0.003）中，暗适应阈值与血清视黄醇浓度相关，但在接受维生素A的孕妇中不相关。在接受安慰剂的女性中，孕早期的平均暗适应阈值（-1.23 log cd/m²）优于孕中期和孕晚期（-1.03 log cd/m²；P = 0.02，t检验）。非怀孕美国女性的平均阈值（-1.35 log cd/m²）优于所有3组尼泊尔女性（对所有3组进行t检验，P < 0.001）。
在怀孕期间，瞳孔暗适应与血清视黄醇浓度密切相关，并且补充维生素A后有显著改善。这种非侵入性检测技术是育龄妇女群体维生素A状况的有效指标。
