Kennedy K A, Stoll B J, Ehrenkranz R A, Oh W, Wright L L, Stevenson D K, Lemons J A, Sowell A, Mele L, Tyson J E, Verter J
Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas 75235-9063, USA.
Early Hum Dev. 1997 Jul 24;49(1):19-31. doi: 10.1016/s0378-3782(97)01869-0.
Inconsistent effects of vitamin A supplementation on prevention of bronchopulmonary dysplasia have been reported. Meta-analysis of these reports resulted in a relative risk of 0.69-1.02 for death or bronchopulmonary dysplasia associated with vitamin A supplementation. Effective dosage regimens or serum retinol concentrations have not been determined in previous reports. The purpose of this pilot study was to define a vitamin A regimen that produces serum retinol concentrations of 25-55 micrograms/dl.
In this three-phase study, 91 infants (mean birth weight 799-864 g) were enrolled. Vitamin A was administered three times/week for 4 weeks at an average daily dose of 986-2143 IU/day. Physical examinations were performed and serum retinol specimens were collected weekly to assess clinical signs of toxicity.
The majority of serum retinol concentrations remained < 25 micrograms/dl until an intramuscular vitamin A dose of 5000 IU/dose three times/week was used. No clinical signs of toxicity were associated with the higher dosage and higher serum concentrations of vitamin A.
A large clinical trial of vitamin A supplementation with 5000 IU/dose three times/week (25-114% more than the dose used in the three published clinical trials) is needed to assess whether vitamin A supplementation safely reduces the risk of bronchopulmonary dysplasia in very-low-birth-weight infants.
已有报道称维生素A补充剂对预防支气管肺发育不良的效果不一致。对这些报道进行的荟萃分析得出，与维生素A补充剂相关的死亡或支气管肺发育不良的相对风险为0.69 - 1.02。先前的报道尚未确定有效的剂量方案或血清视黄醇浓度。这项初步研究的目的是确定一种能使血清视黄醇浓度达到25 - 55微克/分升的维生素A方案。
在这项分三个阶段的研究中，纳入了91名婴儿（平均出生体重799 - 864克）。维生素A每周给药3次，共4周，平均每日剂量为986 - 2143国际单位/天。每周进行体格检查并采集血清视黄醇样本，以评估毒性的临床体征。
在每周三次使用5000国际单位/剂量的肌肉注射维生素A之前，大多数血清视黄醇浓度仍低于25微克/分升。较高剂量和较高血清浓度的维生素A未出现毒性的临床体征。
需要进行一项大型临床试验，每周三次补充5000国际单位/剂量的维生素A（比三项已发表的临床试验中使用的剂量高25% - 114%），以评估补充维生素A是否能安全降低极低出生体重儿患支气管肺发育不良的风险。
