Routine vitamin A supplementation for the prevention of blindness due to measles infection in children

 

Abstract

Background

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.

Objectives

To assess the efficacy of vitamin A in preventing blindness in children with measles without prior clinical features of vitamin A deficiency.

Search methods

We searched CENTRAL (2011, issue 1), which includes the Cochrane Acute Respiratory Infections Group Specialised Register, MEDLINE (1950 to January 2011), EMBASE.com (1974 to January 2011) and LILACS (1985 to January 2011).

Selection criteria

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.

Data collection and analysis

Two review authors independently searched the results for eligible studies 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 We contacted trial authors of the included studies for additional information on unpublished data.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). Due to marked clinical heterogeneity we considered it inappropriate to perform a meta-analysis.

Main results

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) but not six weeks after three doses of vitamin A (MD 2.56 µg/dL; 95% CI -5.28 to 10.40; 39 participants). There was no significant difference in weight gain six weeks (MD 0.39 kg; -0.04 to 0.82; 48 participants) and six months (MD 0.52 kg; 95% CI -0.08 to 1.12; 36 participants) 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).

Authors' conclusions

We did not find any trials assessing whether or not vitamin A supplementation in children with measles prevents blindness. However, vitamin A use in children should be encouraged for its proven clinical benefits.

 

Plain language summary

Vitamin A for preventing blindness in children with measles

Annually 500,000 children become blind worldwide, 75% of them living 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. Corneal scarring from measles, vitamin A deficiency, use of harmful traditional eye remedies and ophthalmia neonatorium are the major causes 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 morbidity and mortality in children with measles. This review examined vitamin A use in preventing blindness in children infected with measles without features of vitamin A deficiency. We included two randomised controlled trials of 260 children with measles comparing vitamin A with placebo. Two doses of vitamin A given on two consecutive days to hospitalised children with measles significantly increased the blood concentration of vitamin A after one week.

However, there is a limitation in that we did not find any study that examined the efficacy of vitamin A in preventing blindness (which is the primary outcome of interest in this review) in children infected with measles. The sample size of the included studies was also relatively small which could affect the precision of the estimates given. Also no adverse event was 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.

 

Resumen

Antecedentes

Administración sistemática de suplementos con vitamina A para la prevención de la ceguera debida a infección por sarampión en niños

La reducción de la concentración de vitamina A aumenta el riesgo de ceguera en niños infectados por el virus del sarampión. La promoción de la administración de suplementos con vitamina A en niños con sarampión contribuye al control de la ceguera en los mismos, y constituye una prioridad alta dentro de la Organización Mundial de la Salud (OMS) VISION 2020 The Right to Sight Program.

Objetivos

Evaluar la eficacia de la vitamina A para prevenir la ceguera en niños con sarampión sin características clínicas previas de deficiencia de vitamina A.

Estrategia de búsqueda

Se hicieron búsquedas en CENTRAL (2011, número 1), que contiene el Registro Especializado de Ensayos Controlados del Grupo Cochrane de Infecciones Respiratorias Agudas (Cochrane Acute Respiratory Infections Group), MEDLINE (1950 hasta enero 2011), EMBASE.com (1974 hasta enero 2011) y en LILACS (1985 hasta enero 2011).

Criterios de selección

Ensayos controlados con asignación aleatoria (ECAs) que evaluaran la eficacia de la vitamina A para prevenir la ceguera en niños bien alimentados con diagnóstico de sarampión, pero sin características clínicas previas de deficiencia de vitamina A.

Obtención y análisis de los datos

Dos revisores de forma independiente buscaron los resultados de los estudios elegibles y extrajeron los datos sobre las medidas de resultado informadas. Se estableció contacto con los autores de los ensayos incluidos para obtener información adicional sobre datos no publicados. Se incluyeron dos ECAs que fueron clínicamente heterogéneos. Los resultados continuos informados se presentaron como diferencia de medias (DM) con el intervalo de confianza (IC) del 95%. No se consideró apropiado realizar un metanálisis debido a la heterogeneidad clínica considerable.

Resultados principales

Dos ECAs que incluyeron 260 niños con sarampión y que compararon vitamina A con placebo cumplieron los criterios de inclusión. Ningún estudio informó ceguera ni otras morbilidades oculares como variables principales de evaluación. Un ensayo de calidad moderada informó pruebas de un aumento significativo de los niveles de retinol sérico en el grupo de vitamina A una semana después de dos dosis de vitamina A (DM 9,45 µg/dl, IC del 95%: 2,19 a 16,71; 17 participantes), pero no seis semanas después de tres dosis de vitamina A (DM 2,56 µg/dl, IC del 95%: −5,28 a 10,40; 39 participantes). No hubo diferencias significativas en el aumento de peso a las seis semanas (DM 0,39 kg, −0,04 a 0,82; 48 participantes) ni a los seis meses (DM 0,52 kg, IC del 95%: −0,08 a 1,12; 36 participantes) después de tres dosis de vitamina A. El segundo ensayo no encontró diferencias significativas en los niveles de retinol sérico dos semanas después de una dosis única de vitamina A (DM 2,67 µg/dl, IC del 95%: −0,29 a 5,63; 155 participantes).

Conclusiones de los autores

No se encontraron ensayos que evaluaran si la administración de suplementos con vitamina A en niños con sarampión previene la ceguera. Sin embargo, debe promoverse el uso de vitamina A en niños por sus beneficios clínicos comprobados.

Traducción

Traducción realizada por el Centro Cochrane Iberoamericano