Independent and combined effects of nutrition and sanitation interventions on child growth in rural Cambodia: a factorial cluster-randomized controlled trial

Abstract

Background Childhood exposure to fecal pathogens contributes to growth faltering, which is linked with adverse side effects later in life. The prevalence of stunting remains high in rural Cambodia, despite rapid economic development over the last two decades. This study aimed to assess the independent and combined effects of nutrition and sanitation programming on child growth outcomes in rural Cambodia. Methods We conducted a factorial cluster-randomized controlled trial of 4,015 households with 4,124 children (1-28 months of age) across rural Cambodia. Fifty-five communes (clusters) were randomly assigned to a control arm or one of three treatments: a nutrition-only arm, a sanitation-only arm, and a combined nutrition and sanitation arm receiving both treatments. The primary outcome was length-for-age Z-score (LAZ). Secondary outcomes were weight-for-age Z-score (WAZ), weight-for-height Z-score (WHZ), stunting, wasting, underweight, and caregiver-reported diarrhea. Analysis was by intention-to-treat. The trial was pre-registered with ISRCTN Registry (ISRCTN77820875). Findings Compliance in the arms receiving the nutrition intervention was high, but compliance in the arms receiving the sanitation intervention was low. Compared with a mean LAZ of -1.04 (SD 1.2) in the control arm, children in the nutrition-only arm (LAZ +0.08, 95% CI: -0.01-0.18) and combined nutrition and sanitation arm (LAZ +0.10, 95% CI: 0.01-0.20) experienced greater linear growth; there were no measurable differences in LAZ in the sanitation-only arm. Similarly, compared with a mean WAZ of -1.05 (SD 1.1) in the control arm, children in the nutrition-only arm (WAZ +0.10, 95% CI 0.00-0.19) and combined-intervention arm (WAZ +0.11, 95% CI 0.03-0.20) were heavier for their age; there was no measurable difference in WAZ in the sanitation-only arm. There were no differences between arms in prevalence of stunting, wasting, underweight status, or one week period prevalence of diarrhea. Interpretation Improvements in child growth in nutrition and combined nutrition and sanitation arms are consistent with other recent trials but we found no evidence that this sanitation intervention improved child growth. The sanitation intervention achieved only modest changes in sanitation access and use suggesting that more effective approaches are needed to reduce open defecation in this setting.