Barreto M L, Santos L M, Assis A M, Araújo M P, Farenzena G G, Santos P A, Fiaccone R L
Department of Preventive Medicine, Federal University of Bahla, Brazil.
Lancet. 1994 Jul 23;344(8917):228-31. doi: 10.1016/s0140-6736(94)92998-x.
A beneficial effect of periodic vitamin A supplementation on childhood mortality has been demonstrated, but the effect on morbidity is less clear. We investigated the effect of vitamin A supplementation on diarrhoea and acute lower-respiratory-tract infections (ALRI) in children from northeastern Brazil in a randomised, double-blind, placebo-controlled community trial. 1240 children aged 6-48 months were assigned vitamin A or placebo every 4 months for 1 year. They were followed up at home three times a week, and data about the occurrence and severity of diarrhoea and ALRI were collected. Any child with cough and respiratory rate above 40 breaths per min was visited by a paediatrician. The overall incidence of diarrhoea episodes was significantly lower in the vitamin-A-supplemented group than in the placebo group (18.42 vs 19.58 x 10(-3) child-days; rate ratio 0.94 [95% Cl 0.90-0.98]). The benefit of supplementation was greater as regards severe episodes of diarrhoea; the incidence was 20% lower in the vitamin A group than in the placebo group (rate ratio 0.80 [0.65-0.98]). With the standard definition of diarrhoea (> or = 3 liquid or semi-liquid stools in 24 h) the effect of vitamin A on mean daily prevalence did not reach significance, but as the definition of diarrhoea was made more stringent (increasing number of stools per day), a significant benefit became apparent, reaching for diarrhoea with 6 or more liquid or semi-liquid stools in 24 h a 23% lower prevalence. We found no effect of vitamin A supplementation on the incidence of ALRI. The reduction in severity of diarrhoea may be the most important factor in the lowering of mortality by vitamin A supplementation.
定期补充维生素A对儿童死亡率有有益影响已得到证实，但对发病率的影响尚不清楚。我们在巴西东北部进行了一项随机、双盲、安慰剂对照的社区试验，调查补充维生素A对儿童腹泻和急性下呼吸道感染（ALRI）的影响。1240名6至48个月大的儿童每4个月被分配服用维生素A或安慰剂，为期1年。每周三次对他们进行家庭随访，并收集有关腹泻和ALRI发生情况及严重程度的数据。任何咳嗽且呼吸频率超过每分钟40次的儿童都由儿科医生进行诊治。补充维生素A组的腹泻发作总发生率显著低于安慰剂组（18.42对19.58×10⁻³儿童日；率比0.94 [95%可信区间0.90 - 0.98]）。补充维生素A对严重腹泻发作的益处更大；维生素A组的发病率比安慰剂组低20%（率比0.80 [0.65 - 0.98]）。按照腹泻的标准定义（24小时内≥3次稀便或半稀便），维生素A对平均每日患病率的影响未达到显著水平，但随着腹泻定义变得更严格（每日排便次数增加），显著益处变得明显，对于24小时内有6次或更多稀便或半稀便的腹泻，患病率降低了23%。我们发现补充维生素A对ALRI的发病率没有影响。腹泻严重程度的降低可能是补充维生素A降低死亡率的最重要因素。
