Anthropometric indices, nutrition knowledge and perceived dietary behaviours of adolescents attending private and public secondary schools in Odeda, Ogun State, Nigeria, based on the Health Belief Model

Abstract

Background
Adolescence is a critical stage for establishing lifelong dietary habits. In Nigeria, socio-economic differences between public and private school adolescents may influence nutrition knowledge, anthropometric status, and dietary behaviour. The Health Belief Model (HBM) provides a useful framework to understand this behaviour and guide interventions aimed at improving it.
Objective
This study examined the relationship between anthropometric indices, nutrition knowledge, and perception of dietary behaviours among in-school adolescents, and compared outcomes between public and private schools within the HBM framework. The null hypotheses tested were that no significant differences exist in anthropometric indices, nutrition knowledge, or dietary behaviours across school types, and that these factors do not predict anthropometric outcomes.
Methods
A descriptive cross-sectional study was conducted among a probability sample of 402 adolescents aged 13–17 years from 2 public and 2 private schools in the Odega Local Government Area. Data were collected through validated questionnaires assessing socio-demographics, nutrition knowledge, and HBM constructs, alongside anthropometric measurements following WHO and CDC protocols. Data analysis employed Chi-square, Mann-Whitney U, Spearman’s correlation, and multiple regression, with significance set at p < 0.05.
Results
Most of these adolescents had normal BMI-for-age (77.9%) and height-for-age (94.5%). Nutrition knowledge was moderate, at 73.6%. Significant differences by school type were observed in anthropometric indices, nutrition knowledge, and HBM constructs. Regression revealed that nutrition knowledge was associated with BMI-for-age, while perceived benefits, barriers, and self-efficacy were associated with height-for-age. 

Conclusions
Private school students demonstrated better anthropometric status and knowledge, while public school students exhibited stronger self-efficacy and cues to action. These findings highlight the influence of school setting and the importance of behaviour-focused, school-based nutrition education for improving adolescent health.