Chitunhu Simangaliso, Musenge Eustasius
Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 27 St Andrews' Road, Parktown, Johannesburg 2193, South Africa.
Spat Spatiotemporal Epidemiol. 2016 Feb;16:21-33. doi: 10.1016/j.sste.2015.11.001. Epub 2015 Nov 17.
Malaria is a major health challenge in sub-Saharan Africa with children under 5 being most vulnerable. Identifying regions of greater malarial burden is vital in targeting interventions.
This study analysed malaria morbidity using data from the Malawi 2012 Malaria Indicator Survey that were obtained from Demographic and Health Survey (DHS) program website. These data captured malaria related information on children under 5. Poisson regression was done to determine associations between outcome (number of children under 5 with malaria in household) and explanatory variables. A Bayesian smoothing approach was employed to adjust for spatial random effects on child related variables.
There were 1878 households in 140 clusters. The number of children under five was 1900. Spatially structured effects accounted for more than 90% of random effects as these had a mean of 1.32 (95% Credible Interval (CI)=0.37, 2.50) whilst spatially unstructured had a mean of 0.10 (CI=9.0 × 10(-4), 0.38). Spatially adjusted significant variables were; type of place of residence (urban or rural) [posterior odds ratio (POR)=2.06; CI= 1.27, 3.34], not owning land [POR=1.77; CI=1.19, 2.64], not staying in a slum [POR=0.52; CI=0.33, 0.83] and enhanced vegetation index [POR=0.02; CI=0.00, 1.08]. A trend was observed on usage of insecticide treated mosquito nets [POR=0.80; CI=0.63, 1.03].
This study showed that malaria is a disease of poverty. Enhanced vegetation index was an important factor in malaria morbidity. The central region was identified as the area with greatest disease burden.
疟疾是撒哈拉以南非洲地区一项重大的健康挑战，5岁以下儿童最为脆弱。确定疟疾负担较重的地区对于有针对性地采取干预措施至关重要。
本研究利用从人口与健康调查（DHS）项目网站获取的2012年马拉维疟疾指标调查数据，分析疟疾发病率。这些数据记录了5岁以下儿童与疟疾相关的信息。采用泊松回归确定结果（家庭中患疟疾的5岁以下儿童数量）与解释变量之间的关联。采用贝叶斯平滑方法对儿童相关变量的空间随机效应进行调整。
140个群组中有1878户家庭。5岁以下儿童数量为1900名。空间结构效应占随机效应的90%以上，因为其均值为1.32（95%可信区间（CI）=0.37，2.50），而空间非结构效应的均值为0.10（CI=9.0×10⁻⁴，0.38）。经空间调整的显著变量有：居住地点类型（城市或农村）[后验比值比（POR）=2.06；CI=1.27，3.34]、无土地所有权[POR=1.77；CI=1.19，2.64]、不住在贫民窟[POR=0.52；CI=0.33，0.83]以及增强植被指数[POR=0.02；CI=0.00，1.08]。观察到使用经杀虫剂处理的蚊帐存在一种趋势[POR=0.80；CI=0.63，1.03]。
本研究表明疟疾是一种贫困疾病。增强植被指数是疟疾发病率的一个重要因素。中部地区被确定为疾病负担最重的地区。
