Evidence for Over-Dispersion in the Distribution of Clinical Malaria Episodes in Children
Evidence for Over-Dispersion in the Distribution of Clinical Malaria Episodes in Children
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DOI：
10.1371/journal.pone.0002196
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发表时间：
2008-05-21
期刊：
影响因子：
3.7
通讯作者：
Marsh, Kevin
中科院分区：
文献类型：
--
作者：
Mwangi, Tabitha Wanja;Fegan, Gregory;Marsh, Kevin
工作背景：可以假定，在相同暴露水平下，年龄相似的儿童的临床疟疾模式将遵循泊松分布，没有过度分散。多年来进行的纵向研究表明，一些儿童可能会经历比预期更多的临床疟疾发作。本研究的目的是确定这组儿童，并调查可能的原因，这种增加的susceptibility.Methodology和主要调查结果：使用泊松回归，我们选择了一组儿童，我们指定为“更容易”疟疾从373名儿童10岁以下，随访3至5年，从1998年至2003年。大约21%的儿童被归类为“更易感”，尽管他们只占随访人次的23%，但他们经历了总临床疟疾发作的55%。在所有横断面调查中均为寄生虫阴性的儿童不太可能属于这一组[AOR = 0.09，（95%CI：0.14-0.61），p = 0.001]。使用在一定时间段内没有临床疟疾发作作为干预或免疫学研究的终点可能无法充分区分免疫力较强或较弱的群体。在此类研究中，除了通常的至首次发作时间终点外，纳入考虑到每个儿童经历的临床发作总数的终点可能是有用的。
Background: It may be assumed that patterns of clinical malaria in children of similar age under the same level of exposure would follow a Poisson distribution with no over-dispersion. Longitudinal studies that have been conducted over many years suggest that some children may experience more episodes of clinical malaria than would be expected. The aim of this study was to identify this group of children and investigate possible causes for this increased susceptibility.Methodology and Principal Findings: Using Poisson regression, we chose a group of children whom we designated as 'more susceptible' to malaria from 373 children under 10 years of age who were followed up for between 3 to 5 years from 1998-2003. About 21% of the children were categorized as 'more susceptible' and although they contributed only 23% of the person-time of follow-up, they experienced 55% of total clinical malaria episodes. Children that were parasite negative at all cross-sectional survey were less likely to belong to this group [AOR = 0.09, (95% CI: 0.14-0.61), p = 0.001].Conclusions and Significance: The pattern of clinical malaria episodes follows a negative binomial distribution. Use of lack of a clinical malaria episode in a certain time period as endpoints for intervention or immunological studies may not adequately distinguish groups who are more or less immune. It may be useful in such studies, in addition to the usual endpoint of the time to first episode, to include end points which take into account the total number of clinical episodes experienced per child.