This longitudinal study investigated differences in body mass index z-score (zBMI) among Australian children and adolescents (n=9417) from priority populations, categorized by cultural/ethnic groups and socioeconomic position (SEP). Analyses used multilevel mixed linear regression models stratified by developmental periods (early childhood, middle childhood, adolescence). Children from Middle East & North Africa, Americas, and Oceania showed higher zBMI, while those from Asian groups showed lower zBMI compared to the English-speaking reference group. Higher zBMI was consistently associated with greater socioeconomic disadvantage. These findings highlight key population groups at risk of overweight and obesity, emphasizing the need for targeted prevention efforts.

Thomas Lung, Anagha Killedar, Sarah Taki, Li Ming Wen, Michelle Dickson, Kirsten Howard, Louise Baur, Patrick Kelly, Simone Sherriff, Alison Hayes