Institute for Global Health and Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA.
BMJ. 2012 Jan 10;344:d7962. doi: 10.1136/bmj.d7962.
To determine whether vitamin A supplementation administered in the preschool years can lower the risk of hearing loss in adolescence and adulthood.
Follow-up study of adolescents and young adults who, as preschool aged children in 1989, were enrolled into a cluster randomised, double blinded, placebo controlled trial of vitamin A supplementation.
South central, rural Nepal.
2378 adolescents and young adults aged 14 to 23, representing 51% of those who finished the original trial and 71% of those living in the study area in 2006.
Every four months for 16 months preschool children were visited at home, given an oral 200,000 IU dose of vitamin A (half dose at age 1-11 months, quarter dose at <1 month) or placebo and the parents were queried about any childhood illnesses in the previous week, including purulent discharge from the ears.
Prevalence of mild or worse hearing loss (≥ 30 dB) in the most affected ear and tympanometric measures of middle ear function (peak height, ear canal volume, and gradient).
During the original trial, the prevalence of middle ear infection during the preschool years did not differ between the supplement groups. By adolescence and early adulthood, a non-significant 17% reduction in hearing loss occurred among those who had periodically received vitamin A compared with placebo as preschool aged children (odds ratio 0.83, 95% confidence interval 0.62 to 1.12). Among participants with any ear discharge in early childhood, vitamin A supplementation was associated with a reduced risk of hearing loss, by 42% (0.58, 0.37 to 0.92) compared with controls, after adjusting the confidence interval for the design effect of the original trial. Abnormal tympanometric peak height of the middle ear system was less likely among participants supplemented with vitamin A in childhood.
In undernourished settings, periodic, high dose vitamin A supplementation may reduce the risk of hearing loss associated with purulent ear infections in early childhood.
确定在学龄前补充维生素 A 是否可以降低青少年和成年人听力损失的风险。
对在 1989 年作为学龄前儿童参加维生素 A 补充剂随机分组、双盲、安慰剂对照试验的青少年和年轻人进行随访研究。
尼泊尔中南部农村。
2378 名年龄在 14 至 23 岁的青少年和年轻人，代表完成原始试验的 51%和 2006 年居住在研究地区的 71%。
每隔四个月，对在家中的学龄前儿童进行一次 20 万国际单位的口服维生素 A 剂量（1-11 个月时半剂量，<1 个月时四分之一剂量）或安慰剂，并询问父母在过去一周中是否有任何儿童疾病，包括耳内脓性分泌物。
受影响最严重耳朵的轻度或更严重听力损失（≥30dB）的患病率和中耳功能的鼓室图测量（峰值高度、耳道容积和梯度）。
在原始试验期间，补充组学龄前儿童中耳感染的患病率没有差异。到青少年和成年早期，与作为学龄前儿童接受安慰剂相比，定期接受维生素 A 的儿童听力损失的发生率降低了 17%（比值比 0.83，95%置信区间 0.62 至 1.12）。在早期有耳漏的参与者中，与对照组相比，维生素 A 补充与听力损失风险降低 42%相关（0.58，0.37 至 0.92），在调整原始试验设计效果的置信区间后。在儿童时期补充维生素 A 的参与者中，中耳系统的异常鼓室图峰值高度不太可能。
在营养不足的环境中，定期、高剂量补充维生素 A 可能会降低与早期脓性耳感染相关的听力损失风险。
