Department of Public Health, School of Public Health, University of Malawi College of Medicine, Mahatma Gandhi Road, Private Bag 360, Blantyre 3, Malawi.
Faculty of Medicine and Life Sciences, Center for Child Health Research, University of Tampere, Tampere, Finland.
Malar J. 2019 Apr 22;18(1):143. doi: 10.1186/s12936-019-2778-y.
In malaria-endemic settings, a small proportion of children suffer repeated malaria infections, contributing to most of the malaria cases, yet underlying factors are not fully understood. This study was aimed to determine whether undernutrition predicts this over-dispersion of malaria infections in children aged 6-18 months in settings of high malaria and undernutrition prevalence.
Prospective cohort study, conducted in Mangochi, Malawi. Six-months-old infants were enrolled and had length-for-age z-scores (LAZ), weight-for-age z-scores (WAZ), and weight-for-length z-scores (WLZ) assessed. Data were collected for 'presumed', clinical, and rapid diagnostic test (RDT)-confirmed malaria until 18 months. Malaria microscopy was done at 6 and 18 months. Negative binomial regression was used for malaria incidence and modified Poisson regression for malaria prevalence.
Of the 2723 children enrolled, 2561 (94%) had anthropometry and malaria data. The mean (standard deviation [SD]) of LAZ, WAZ, and WLZ at 6 months were - 1.4 (1.1), - 0.7 (1.2), and 0.3 (1.1), respectively. The mean (SD) incidences of 'presumed', clinical, and RDT-confirmed malaria from 6 to 18 months were: 1.1 (1.6), 0.4 (0.8), and 1.3 (2.0) episodes/year, respectively. Prevalence of malaria parasitaemia was 4.8% at 6 months and 9.6% at 18 months. Higher WLZ at 6 months was associated with lower prevalence of malaria parasitaemia at 18 months (prevalence ratio [PR] = 0.80, 95% confidence interval [CI] 0.67 to 0.94, p = 0.007), but not with incidences of 'presumed' malaria (incidence rate ratio [IRR] = 0.97, 95% CI 0.92 to 1.02, p = 0.190), clinical malaria (IRR = 1.03, 95% CI 0.94 to 1.12, p = 0.571), RDT-confirmed malaria (IRR = 1.00, 95% CI 0.94 to 1.06, p = 0.950). LAZ and WAZ at 6 months were not associated with malaria outcomes. Household assets, maternal education, and food insecurity were significantly associated with malaria. There were significant variations in hospital-diagnosed malaria by study site.
In children aged 6-18 months living in malaria-endemic settings, LAZ, WAZ, and WLZ do not predict malaria incidence. However, WLZ may be associated with prevalence of malaria. Socio-economic and micro-geographic factors may explain the variations in malaria, but these require further study. Trial registration NCT00945698. Registered July 24, 2009, https://clinicaltrials.gov/ct2/show/NCT00945698 , NCT01239693. Registered Nov 11, 2010, https://clinicaltrials.gov/ct2/show/NCT01239693.
在疟疾流行地区，一小部分儿童会反复感染疟疾，导致大部分疟疾病例，但导致这种过度分散感染的潜在因素尚不完全清楚。本研究旨在确定在高疟疾和营养不良流行地区，6-18 个月大的儿童中，是否存在营养不足导致这种疟疾过度分散感染的情况。
前瞻性队列研究，在马拉维曼戈切进行。6 个月大的婴儿被招募并进行了身长年龄 z 评分（LAZ）、体重年龄 z 评分（WAZ）和体重身长 z 评分（WLZ）评估。在 18 个月时收集了“疑似”、临床和快速诊断测试（RDT）确诊疟疾的数据。6 个月和 18 个月时进行了疟疾显微镜检查。使用负二项回归分析疟疾发病率，使用修正泊松回归分析疟疾患病率。
在 2723 名入组的儿童中，有 2561 名（94%）具有人体测量学和疟疾数据。6 个月时 LAZ、WAZ 和 WLZ 的平均值（标准差[SD]）分别为-1.4（1.1）、-0.7（1.2）和 0.3（1.1）。从 6 个月到 18 个月的“疑似”、临床和 RDT 确诊疟疾的平均发生率分别为：1.1（1.6）、0.4（0.8）和 1.3（2.0）/年。6 个月时疟疾寄生虫血症的患病率为 4.8%，18 个月时为 9.6%。6 个月时较高的 WLZ 与 18 个月时疟疾寄生虫血症的患病率较低相关（患病率比[PR] = 0.80，95%置信区间[CI] 0.67 至 0.94，p = 0.007），但与“疑似”疟疾的发病率无关（发病率比[IRR] = 0.97，95%CI 0.92 至 1.02，p = 0.190），临床疟疾（IRR = 1.03，95%CI 0.94 至 1.12，p = 0.571），RDT 确诊疟疾（IRR = 1.00，95%CI 0.94 至 1.06，p = 0.950）。6 个月时的 LAZ 和 WAZ 与疟疾结局无关。家庭资产、母亲教育和粮食不安全状况与疟疾显著相关。不同研究地点的医院诊断疟疾存在显著差异。
在生活在疟疾流行地区的 6-18 个月大的儿童中，LAZ、WAZ 和 WLZ 与疟疾发病率无关。然而，WLZ 可能与疟疾的患病率有关。社会经济和微观地理因素可能解释了疟疾的变化，但这些因素需要进一步研究。试验注册 NCT00945698。2009 年 7 月 24 日注册，https://clinicaltrials.gov/ct2/show/NCT00945698，NCT01239693。2010 年 11 月 11 日注册，https://clinicaltrials.gov/ct2/show/NCT01239693。
