Effect of a health belief model-based nutrition education intervention on dietary diversity among adults on antiretroviral treatment in Ilu Abbabor Zone, Southwestern Ethiopia.

Poor nutrition and HIV disease progression form a vicious cycle. Nutrition education interventions based on behavioural theories may improve dietary practices among people living with HIV/AIDS (PLWHA). This study examined the effects of a Health Belief Model (HBM)-based nutrition education intervention on dietary diversity practices among adults on antiretroviral treatment (ART) in the Ilu Abbabor Zone, southwestern Ethiopia. A facility-based quasi-experimental study with a control group was conducted from September 2019 to May 2020. A total of 384 adult PLWHA (192 intervention, 192 control) were recruited from six health facilities selected by simple random sampling. The intervention group received HBM-based nutrition education every 15 days for 4 months (8 sessions total), while the control group received standard education at baseline only. Dietary diversity was assessed using the FAO/FANTA Individual Dietary Diversity Score (IDDS). Difference-in-differences (DID) regression estimated the intervention effect while controlling for baseline demographic differences. At baseline, good dietary diversity was similar between groups (37·5 % v. 39 %, P = 0·375). After the intervention, good dietary diversity increased to 66 % in the intervention group v. 53 % in the control group (P = 0·004). The DID estimate was 9 % (95 % CI: 0·05 to 0·13; β = 0·09; P < 0·001), indicating a significant intervention effect. All HBM constructs except perceived self-efficacy showed significant correlations with dietary diversity practices, with perceived barriers negatively correlated. HBM-based nutrition education significantly improved dietary diversity among adults on ART. Incorporating behavioural models such as HBM into routine nutritional counselling may strengthen HIV care and support nutritional science-informed practice in resource-limited settings.