Procedures
SECONDARY
The baseline and endline surveys included independently selected study samples. Adolescent girls were selected using a school-based sampling strategy. Lists of eligible girls were taken from primary school enrolment registries. Enrolment records (available at the time of the surveys) were used to verify the birth date or age of eligible students, which were recorded from birth certificates or parent reported. Then, adolescent girls were randomly selected by simple random sampling until the required sample size was reached, and they were visited at home to be recruited and interviewed, along with their parents. Data were collected using structured questionnaires, administered through computer-assisted personal interviewing (CAPI) by trained enumerators; CAPI forms were programmed and data were collected via SurveyCTO. At baseline and endline, school food environments were assessed via direct observation (In February, 2020, following the baseline survey, Alive & Thrive conducted training for principals, teachers, and health extension workers participating in the intervention. Intervention materials (instruction manuals; adolescent nutrition passports; BMI measurement guides; and posters on eating breakfast, healthy snacks, and dietary diversity) were also distributed. However, in March, 2020, the first COVID-19 case was reported in Ethiopia, and the country declared a state of emergency and closed all schools for the remainder of the 2019–20 academic year. All programme activities were halted, and interventions were not delivered to students and parents. Schools reopened for the 2020–21 academic year, and classes resumed in the study schools by October. In November, 2021, Alive & Thrive reinitiated the programme with refresher training for all principals, teachers, and health extension workers in the intervention group. The duration of the school-based interventions was one school semester (about 4 months).Alive & Thrive's core package of school-based interventions included six components: weekly flag ceremonies, weekly classroom lessons, weekly school club meetings, weekly peer group mentoring, BMI measurement and counselling (once per semester), and monthly parent–teacher meetings (In addition to the school-based interventions, health extension workers (working in the same area as an intervention school) were instructed to provide the key intervention messages about adolescent nutrition during routine home visits for other health services at households in which adolescent girls lived. Health extension workers and influential community actors such as community and religious leaders also provided adolescent nutrition messages during community gatherings. These secondary interventions were not considered core interventions of the programme, were conducted irregularly, and reached minimal exposure, and were, therefore, excluded from the results in this paper.Participants in the control group received standard academic curriculum on health and nutrition, provided as part of the government education system. School principals and teachers were not instructed, supervised, or followed up about adolescent nutrition activities. No additional guidance or support was provided to the control schools.