Background
Annually 500,000 children become blind worldwide; 75% of them live in low-income countries. The major causes of blindness in children vary widely from region to region and are related to the standard of living of the community. Scarring of the eyes from measles, vitamin A deficiency, use of harmful traditional eye remedies and eye infection of the newborn, are the major causes of blindness in low-income countries. Vitamin A is an important nutrient in the body and is required for the normal functioning of the eye. Its deficiency results in poor vision.
Measles infection in children has been associated with vitamin A deficiency and blindness. The control of blindness in children is considered a high priority within the World Health Organization's VISION 2020 The Right to Sight Program. Studies have reported the beneficial effect of vitamin A in reducing disease burden and rate of death in children with measles. This review examined vitamin A use in preventing blindness in children infected with measles without features of vitamin A deficiency.
Study characteristics
We included two randomised controlled trials of moderate quality, including 260 children with measles, comparing children given vitamin A with children not given vitamin A.
Key results
The evidence is current to December 2015. Two doses of vitamin A given on two consecutive days to hospitalised children with measles led to an increase in the blood concentration of vitamin A after one week. However, there is a limitation in that neither of the two included studies reported blindness or other eye problems in children infected with measles. Also, no side effects of the treatment were reported in the included studies. We do not have sufficient evidence to demonstrate the benefit or otherwise of vitamin A in the prevention of blindness in children infected with measles.
Quality of evidence
The quality of the evidence and methodology of both studies was moderate. The sample size of the included studies was relatively small, which could affect the accuracy of the results.
阅读完整摘要
Reduced vitamin A concentration increases the risk of blindness in children infected with the measles virus. Promoting vitamin A supplementation in children with measles contributes to the control of blindness in children, which is a high priority within the World Health Organization (WHO) VISION 2020 The Right to Sight Program.
研究目的
To assess the efficacy of vitamin A in preventing blindness in children with measles without prior clinical features of vitamin A deficiency.
检索策略
We searched CENTRAL 2015, Issue 11, MEDLINE (1950 to December week 3, 2015), Embase (1974 to December 2015) and LILACS (1985 to December 2015).
纳入排除标准
Randomised controlled trials (RCTs) assessing the efficacy of vitamin A in preventing blindness in well-nourished children diagnosed with measles but with no prior clinical features of vitamin A deficiency.
资料收集与分析
For the original review, two review authors independently assessed studies for eligibility and extracted data on reported outcomes. We contacted trial authors of the included studies for additional information on unpublished data. We included two RCTs which were clinically heterogenous. We presented the continuous outcomes reported as the mean difference (MD) with 95% confidence interval (CI) and dichotomous outcomes as risk ratio (RR) with 95% CI. Due to marked clinical heterogeneity we considered it inappropriate to perform a meta-analysis.
主要结果
For the first publication of this review, two RCTs involving 260 children with measles which compared vitamin A with placebo met the inclusion criteria. Neither study reported blindness or other ocular morbidities as end points. One trial of moderate quality suggested evidence of a significant increase in serum retinol levels in the vitamin A group one week after two doses of vitamin A (MD 9.45 µg/dL, 95% CI 2.19 to 16.71; 17 participants, moderate-quality evidence), but not six weeks after three doses of vitamin A (MD 2.56 µg/dL, 95% CI -5.28 to 10.40; 39 participants, moderate-quality evidence). There was no significant difference in weight gain six weeks (MD 0.39 kg, -0.04 to 0.82; 48 participants, moderate-quality evidence) and six months (MD 0.52 kg, 95% CI -0.08 to 1.12; 36 participants, moderate-quality evidence) after three doses of vitamin A.
The second trial found no significant difference in serum retinol levels two weeks after a single dose of vitamin A (MD 2.67 µg/dL, 95% CI -0.29 to 5.63; 155 participants, moderate-quality evidence). Percentage of undernutrition between the two groups did not differ significantly at one week (RR 0.93, 95% CI 0.56 to 1.54, 145 participants) and two weeks (RR 0.82, 95% CI 0.52 to 1.29, 147 participants) after a single dose of vitamin A. No adverse event was reported in either study. We did not find any new RCTS for this second update.
作者结论
We did not find any trials assessing whether or not vitamin A supplementation in children with measles prevents blindness, as neither study reported blindness or other ocular morbidities as end points.
