Effect of adding RUSF to ageneral food distribution on child nutritional status and morbidity: a cluster randomised controlled trial

Summary of research¹

Child during appetite test at a health facility offering treatment in Monrovia, Liberia

The authors of a recent study hypothesized that including a daily dose of 46 g of Lipid based Nutrient Supplement (LNS) as Ready to Use Supplementary Food (RUSF), for consumption by children between 6 and 36 months of age as part of a household food distribution programme would reduce cumulative wasting incidence during the seasonal hunger gap (June to October).

The study was conducted in the city of Abeche, the capital city of the Ouaddai¨ region in eastern Chad. Since 2006, this part of the country has been characterised by chronic political instability, which has led to the decline in nutritional status of children under 5 years of age. Recently, the non-governmental organisation Action Contre la Faim - France (ACF-France) conducted two cross-sectional nutritional surveys of children under 5 years in Abeche. A first survey was conducted at the beginning of the rainy season (June 2009) and revealed a prevalence of wasting of 20.6%, with 3.2% severe wasting, using the National Centre for Health Statistics (NCHS) growth reference. A second survey was carried out during the post-harvest period (January 2010) and reported a wasting prevalence of 16.8%, with 2% severe wasting

The study was conducted in seven vulnerable sectors of the city of Abeche that were preselected from a total of 45 administrative sectors. These seven sectors were identified based on data from a community network organised by ACF-France involving a set of socio-economic, sanitary and nutritional (proportion of children admitted to ACF-France nutrition rehabilitation programmes) criteria. The selected sectors were subdivided into 14 geographical clusters using main roads and rivers as cluster boundaries. The cluster was the unit of randomisation andrandom assignment was conducted through an official ceremonial gathering with officials and community members. Seven clusters were assigned to the intervention group and seven to the control group.

The researchers designed the study as a two-arm cluster-randomised controlled pragmatic trial, targeting children from 6 to 36 months of age from vulnerable households. A household was considered to be ‘‘vulnerable’’ when it met one of the following criteria: (1) household head being disabled, pregnant or lactating, or (2) an economic dependency ratio of 4:1 or more (number of economically inactive versus active household members). The inclusion criteria for the study were being non-wasted (weight-for-height >80% of the NCHS reference median, and lack of bilateral pitting oedema) and being from a ‘‘vulnerable’’ household.

The study used the NCHS growth reference for enrolment in the study, to conform with the Chad national protocol for the management of malnutrition. However, the researchers opted to analyze the data using the WHO international growth standards to make the results more comparable to recent studies. None of the study conclusions were altered when analysing the outcome data using the NCHS growth reference.

The primary study outcome was the cumulative incidence of acute malnutrition or wasting defined as weight-for-height Z-score (WHZ), or presence of bilateral pitting oedema. In order to detect a 50% reduction in the cumulative incidence of wasting over a period of 4 months, with a statistical power of 80%, a sample size of 1,220 children was calculated to be needed. Taking into account a study dropout of 15%, a total sample size of 1,435 children was projected. Secondary outcomes included mean WHZ change over time, prevalence of stunting at end point defined as height-for-age Z score (HAZ), mean HAZ change over time, mid upper arm circumference (MUAC) change over time, mean haemoglobin concentration at end point, prevalence of anaemia at end point (haemoglobin <110 g/l).

Study interventions

Households of both the intervention and control groups received a monthly food package representing a daily ration of 425g of sorghum, 25 g of legumes, 25 g of bleached palm oil, 20 g of sugar, and 5 g of iodized salt. This ration was estimated to cover approximately 86% (<1,800 kcal) of the daily energy requirements for a population at risk of an emergency. The number of food rations distributed per household was proportional to its size. Children from the intervention group received a monthly quantity of RUSF (Plumpy’Doz, Nutriset) representing a daily ration of 46g (<247 kcal/d). Recommendations on dosage and frequency of consumption by targeted children were made to caretakers and repeated at each follow-up visit. The intervention lasted 4 months (June 2010 to September 2010). Prior to this intervention, an acceptability test was conducted in a convenience sample of 30 nonwasted children.

The study team encouraged the mothers to bring their children with them to the monthly food distributions, regardless of their intervention status. Children were enrolled from early June to mid-July 2011 and scheduled to come for four follow-up visits. At each visit, child anthropometric measurements and morbidity were recorded. Children who were classified as moderately wasted (weight-for-height =70- <80% of NCHS reference median) or severely wasted (weight-for-height <70% of NCHS reference median) were discharged from the study and referred to a community-based management of acute malnutrition programme located within the city’s nutrition rehabilitation centres. All participating mothers were given a family food ration as described above.

The study team used a pretested questionnaire to collect data on socioeconomic and demographic characteristics of enrolled households. Child age at screening was estimated using a locally adapted event calendar if a birth certificate was unavailable. Anthropometric measurements were conducted monthly. Episodes of diarrhoea, respiratory tract infection, and fever were recalled for 1 week before the monthly interview. Respiratory tract infection was diagnosed through reports by the mother/ caregiver of persistent cough or difficulty in breathing during the last week (yes/no). A diarrheal episode was defined as having at least three loose stools within a day. Fever episodes were diagnosed by mother/caretaker during the last week (yes/ no). In case of death, the team carried out a verbal autopsy adapted from WHO standards. Haemoglobin concentration was measured at baseline (June) and at the end of the intervention (November) or when a child was discharged from the study, using a daily calibrated electronic device HemoCue Hb 201+. Standardised forms were used to collect data.

Results

The overall sample size was 1,038 children in 784 households: 598 children in the intervention group and 440 children in the control group.

Table 1 details the effects of preventive RUSF on child anthropometry. Compared to baseline values, mean WHZ for both control and intervention groups were slightly higher at end point, while mean HAZ was slightly lower. There was no difference in the incidence of wasting (incidence rate ratio: 0.86; 95% CI: 0.67, 1.11; p= 0.25) or mean change in WHZ (20.002 WHZ/month; 95% CI: 20.032, 0.028; p =0.89) between the arms. The difference in weight increase between groups was 0.02 kg/month (95% CI: 20.01, 0.04; p=0.10). Children in the intervention group had a significantly higher linear growth velocity of 0.03 HAZscore/ month (95% CI: 0.02, 0.05; p<0.001) compared to the control group . This observed difference was equivalent to a small difference in height gain of 0.09 cm/month (95% CI: 0.04, 0.14; p<0.001).

Identical ponderal (weight)growth in control and intervention groups was confirmed by a lack of difference in MUAC growth. Age at inclusion was not found to modify the intervention effects on child anthropometric measurements. After adjustment for age, sex, socioeconomic status, and morbidity status at inclusion, the study found that children from the RUSF group had lower risk of self-reported diarrhoea by 29.3% (95% CI: 20.5, 37.2; p<0.001) and fever by 22.5% (95% CI: 14.0, 30.2; p<0.001), compared to the control group. RUSF significantly increased mean haemoglobin concentration at end point by 3.8 g/l (95% CI: 0.6, 7.0; p= 0.02), resulting in significantly lower odds of anaemia (OR: 0.52; 95% CI: 0.34, 0.82; p= 0.004) for children in the intervention group.

The absence of an effect on wasting incidence could have multiple explanations. First, the energy contribution of RUSF may have been ‘‘diluted’’ by the general food distribution, which mainly provided a supplement of energy and protein. Second, the energy dose of 46 g (<247 kcal) daily RUSF and the duration of the supplementation could have been insufficient to support ponderal growth, particularly for the older children in the cohort. Furthermore, it is possible that the RUSF may have been shared with other children in the household. However, if this were done to a large extent, the observed intervention effects on secondary outcomes like HAZ and haemoglobin concentration are hard to explain.

The absence of an effect on ponderal growth, but modest effects on morbidity, linear growth, and, most of all, haemoglobin could suggest that a multiple micronutrients (MMN) effect is at play. For example, zinc, one of the micronutrients added to RUSF, is currently recommended as adjunct therapy by the United Nations Children’s Fund and WHO for the treatment of diarrhoea.

These observations could lead to the speculative hypothesis that supplementation with MMN supplements like powders or tablets might result in the same effects as RUSF, if basic food rations were provided.

One important additional benefit that LNS offer is the lipid component. In addition to providing a small amount of essential fatty acids, which hold a potential to support child growth, the lipid component serves as an essential matrix that ensures that fat-soluble vitamins like vitamin A, D, and E are properly absorbed. Particularly when the child’s diet is poor in fat, this would provide leverage to increase the efficacy of supplemented fat-soluble vitamins. Therefore, more mechanistic studies are required to elucidate the additional contribution to the efficacy of the MMNs by the functional fat fraction of the RUSF.

The study had a number of limitations. The projected sample size was not attained, limiting the study’s statistical power. The study participantswere not blinded with respect to the intervention assignment because of the type of supplement (paste) provided to children. Clusters were not always geographically separated from each other. And finally, child morbidity was recorded through caretaker recall, which could have resulted in underestimation.

In conclusion, adding child-targeted RUSF supplementation to a general food distribution resulted in increased haemoglobin status and linear growth, accompanied by a reduction in diarrhoea and fever episodes. However the study did not find clear evidence that adding RUSF to a household food ration distribution of staple foods was more effective in preventing acute malnutrition. Other context-specific alternatives for preventing acute malnutrition should therefore be investigated.

¹Huybregts L et al (2012). The Effect of Adding Ready-to- Use Supplementary Food to a General Food Distribution on Child Nutritional Status and Morbidity: A Cluster- Randomized Controlled Trial. PLOS Medicine. www.plosmedicine.org. September 2012, volume 9, issue, 9, e1001313, pp 1-11