A cash-based intervention and the risk of acute malnutrition in children aged 6–59 months living in internally displaced persons camps in Mogadishu, Somalia: A non-randomised cluster trial

Background
Somalia has been affected by conflict since 1991, with children aged <5 years presenting a high acute malnutrition prevalence. Cash-based interventions (CBIs) have been used in this context since 2011, despite sparse evidence of their nutritional impact. We aimed to understand whether a CBI would reduce acute malnutrition and its risk factors.
Methods and findings
We implemented a non-randomised cluster trial in internally displaced person (IDP) camps, located in peri-urban Mogadishu, Somalia. Within 10 IDP camps (henceforth clusters) selected using a humanitarian vulnerability assessment, all households were targeted for the CBI. Ten additional clusters located adjacent to the intervention clusters were selected as controls. The CBI comprised a monthly unconditional cash transfer of US$84.00 for 5 months, a once-only distribution of a non-food-items kit, and the provision of piped water free of charge. The cash transfers started in May 2016. Cash recipients were female household representatives. In March and September 2016, from a cohort of randomly selected households in the intervention (n = 111) and control (n = 117) arms (household cohort), we collected household and individual level data from children aged 6–59 months (155 in the intervention and 177 in the control arms) and their mothers/primary carers, to measure known malnutrition risk factors. In addition, between June and November 2016, data to assess acute malnutrition incidence were collected monthly from a cohort of children aged 6–59 months, exhaustively sampled from the intervention (n = 759) and control (n = 1,379) arms (child cohort). Primary outcomes were the mean Child Dietary Diversity Score in the household cohort and the incidence of first episode of acute malnutrition in the child cohort, defined by a mid-upper arm circumference < 12.5 cm and/or oedema. Analyses were by intention-to-treat. For the household cohort we assessed differences-in-differences, for the child cohort we used Cox proportional hazards ratios. In the household cohort, the CBI appeared to increase the Child Dietary Diversity Score by 0.53 (95% CI 0.01; 1.05). In the child cohort, the acute malnutrition incidence rate (cases/100 child-months) was 0.77 (95% CI 0.70; 1.21) and 0.92 (95% CI 0.53; 1.14) in intervention and control arms, respectively. The CBI did not appear to reduce the risk of acute malnutrition: unadjusted hazard ratio 0.83 (95% CI 0.48; 1.42) and hazard ratio adjusted for age and sex 0.94 (95% CI 0.51; 1.74). The CBI appeared to increase the monthly household expenditure by US$29.60 (95% CI 3.51; 55.68), increase the household Food Consumption Score by 14.8 (95% CI 4.83; 24.8), and decrease the Reduced Coping Strategies Index by 11.6 (95% CI 17.5; 5.96). The study limitations were as follows: the study was not randomised, insecurity in the field limited the household cohort sample size and collection of other anthropometric measurements in the child cohort, the humanitarian vulnerability assessment data used to allocate the intervention were not available for analysis, food market data were not available to aid results interpretation, and the malnutrition incidence observed was lower than expected.
Conclusions
The CBI appeared to improve beneficiaries’ wealth and food security but did not appear to reduce acute malnutrition risk in IDP camp children. Further studies are needed to assess whether changing this intervention, e.g., including specific nutritious foods or social and behaviour change communication, would improve its nutritional impact.
Trial registration
ISRCTN Registy ISRCTN29521514.

背景
索马里自1991年起持续受冲突影响，5岁以下儿童急性营养不良患病率居高不下。尽管现金救助干预（Cash-Based Interventions, CBIs）的营养影响证据尚且匮乏，但该类干预自2011年起已在当地应用。本研究旨在探究现金救助干预能否降低急性营养不良及其风险因素的发生水平。

方法与结果
本研究在索马里摩加迪沙城郊的国内流离失所者（Internally Displaced Person, IDP）营地开展非随机整群试验。通过人道主义脆弱性评估选取10个IDP营地（以下简称整群），将其中所有家庭作为现金救助干预的研究对象；另选取干预营地周边的10个整群作为对照。本次干预方案包括：连续5个月每月发放84.00美元的无条件现金转移支付，一次性发放非食品物资包，以及免费提供管道供水。现金转移支付于2016年5月启动，领取人为女性家庭代表。
2016年3月与9月，研究人员从干预组（n=111）与对照组（n=117）的随机抽取家庭队列（household cohort）中，收集6~59月龄儿童（干预组155名、对照组177名）及其母亲/主要照料者的家庭与个体层面数据，用于评估已知的营养不良风险因素。此外，2016年6月至11月期间，研究人员每月从干预组（n=759）与对照组（n=1379）的6~59月龄儿童队列（child cohort）中全面抽样，收集用于评估急性营养不良发病率的数据。
本研究的主要结局指标为：家庭队列的儿童饮食多样性得分（Child Dietary Diversity Score）均值，以及儿童队列的首次急性营养不良发作发病率，急性营养不良判定标准为上臂围（mid-upper arm circumference）<12.5cm和/或水肿（oedema）。分析采用意向性分析（intention-to-treat）方法：针对家庭队列采用双重差分法，针对儿童队列采用Cox比例风险模型。
家庭队列结果显示，现金救助干预可使儿童饮食多样性得分提升0.53（95%置信区间：0.01~1.05）。儿童队列结果显示，干预组与对照组的急性营养不良发病率（病例数/100儿童月）分别为0.77（95%CI：0.70~1.21）与0.92（95%CI：0.53~1.14）。现金救助干预未显著降低急性营养不良风险：未校正风险比为0.83（95%CI：0.48~1.42），校正年龄与性别后的风险比为0.94（95%CI：0.51~1.74）。此外，干预可使家庭月度支出增加29.60美元（95%CI：3.51~55.68），家庭食物消费得分（Food Consumption Score）提升14.8（95%CI：4.83~24.8），并使简化应对策略指数（Reduced Coping Strategies Index）降低11.6（95%CI：5.96~17.5）。
本研究存在以下局限性：本研究未采用随机分组；实地安全局势限制了家庭队列的样本量，以及儿童队列其他人体测量学指标的采集；用于分配干预措施的人道主义脆弱性评估数据无法用于分析；缺乏食品市场数据以辅助结果解读；观测到的营养不良发病率低于预期水平。

结论
现金救助干预可改善受助者的经济状况与食物安全水平，但未降低国内流离失所者营地儿童的急性营养不良风险。未来需开展进一步研究，以评估调整干预方案（例如添加特定营养食品或加入社会与行为改变沟通内容）是否可提升其营养干预效果。

试验注册
ISRCTN注册库：ISRCTN29521514。