Evaluation of Body Mass Index, Neck Circumference, and Abdominal Circumference as Indicators of Adiposity among Adolescents and Young Adults in Rivers State, Nigeria

Abstract

Background: Several studies have demonstrated that specific anthropometric indices are highly sensitive, non-invasive indicators for evaluating obesity and associated metabolic conditions. The aim of this study was to evaluate Body Mass Index (BMI), Neck Circumference (NC), and Abdominal Circumference (AC) as screening indicators for adiposity among adolescents and young adults in Rivers State, Nigeria. Methods: This cross-sectional observational study included 268 subjects aged 10–29 years drawn using purposive sampling from selected institutions within Rivers State (St. Aquinas Secondary School, Our Savior Secondary School, University Demonstration Secondary School, and the University of Port Harcourt). Four core anthropometric variables were measured: weight, height, AC, and NC, from which BMI values were derived. Data were analysed using SPSS version 16.0. Variations across genders and age groups were evaluated using descriptive statistics and the independent-samples t-test, while intervariable relationships were determined using Pearson’s correlation analysis. A p-value  0.05 was considered statistically significant. Results: The mean values reflected significant variations across progressive age cohorts and genders. Subjects had a mean BMI that increased progressively across age groups, from the 10–13 age group (mean BMI: 20.20  3.48 kg/m²) to the 26–29-year age group, which had a mean BMI of 23.31  2.97 kg/m². Females exhibited a significantly larger mean neck circumference (33.91  4.30 cm) than their male counterparts (32.60  3.63 cm). A strong positive correlation existed between age and BMI in males (r = 0.542, p < 0.05), whereas a weaker positive correlation was observed in females (r = 0.264, p < 0.05). Concurrently, AC and NC demonstrated a strong positive correlation, tracking progressively upward with age across both sexes except for temporary plateaus observed in the 10–13 and 26–29 year cohorts. Conclusion: This study establishes clear sexual dimorphism and age-related variations in upper body subcutaneous and central adiposity markers among young Nigerians. The strong positive correlation between NC and AC validates their synchronous utility in clinical screening. These findings provide population-specific reference metrics for early identification of regional adiposity and cardiovascular health tracking.