# Intervention to optimise body mass index in adolescents and address the triple burden of malnutrition—the Ntshembo (Hope) trial in rural and urban South Africa study: a study protocol for a randomised controlled trial

## TL;DR

This study aims to improve nutrition and BMI in South African adolescent girls to reduce long-term health risks through a community-based intervention.

## Contribution

A novel community-based intervention targeting the triple burden of malnutrition in adolescent girls in South Africa.

## Key findings

- The trial will assess BMI changes in underweight and overweight adolescent girls.
- Intervention includes household support, micronutrient supplements, and health education.

## Abstract

South Africa faces a complex health burden with burgeoning non-communicable diseases against a background of prevalent infection. The triple burden of malnutrition, comprising undernutrition alongside overweight/obesity and micronutrient deficiencies, is widespread and imposes risks for non-communicable diseases along the life course, especially among adolescent girls. We hypothesise that, by optimising nutrition and body mass index (BMI) of at-risk adolescent girls, we can realise a triple return on investment: improved nutritional status, reduced metabolic risk, and moderated pre-conception exposures to offset transgenerational risk for cardiometabolic disease.

We will enrol 1248 girls 14–19 years with either underweight or overweight defined using age-sex-appropriate BMI cut-offs living either in rural or urban South Africa. After baseline assessments and randomisation, participants will be reassessed at 18–24 months follow-up. If a participant becomes pregnant, further assessments will be conducted during pregnancy (< 28 weeks) and postnatally. We will include both process and economic evaluations. The primary outcome is change in BMI standard deviation score from baseline to follow-up aligned to the target direction, i.e. increase in BMI for underweight, decrease in BMI for overweight. Community health workers will deliver the intervention with both household and individual components. A conditional cash transfer will be provided to the household with guidance to improve dietary diversity. Health literacy material, a multi-micronutrient supplement, health screening and support management (for example anaemia; blood pressure; HIV; depression), and facilitating behaviour change to optimise nutrition, physical and mental health will be provided to the adolescent girl.

The trial has been registered with the Pan African Clinical Trials Registry; identifier: PACTR202201638897606. Registered on 1st August 2022. https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=14656.

The online version contains supplementary material available at 10.1186/s13063-026-09535-4.