Identification of distinct body mass index trajectories in Australian children.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Recent studies have identified distinct trajectories of obesity development in children, but more research is required to further explore these trajectories. Several socio-demographic variables such as parental education and obesity are associated with these trajectories. WHAT THIS STUDY ADDS: This study further demonstrates that there are distinct trajectories of body mass index in children. The use of raw body mass index values is more sensitive to changes in body composition compared with body mass index categories (e.g. lean vs. overweight). Hence the present results provide a more detailed insight into development patterns of obesity. The socio-demographic predictors of the trajectories offer potential avenues for future obesity interventions.
BACKGROUND: A limited number of studies have demonstrated that there may be distinct developmental trajectories of obesity during childhood.
OBJECTIVE: To identify distinct trajectories of body mass index (BMI) in a large sample of Australian children.
METHODS: Participants included 4601 children aged 4-5 years at baseline, who were followed up at ages 6-7 years, 8-9 years and 10-11 years. Height and weight were measured at each of these time points, and used to calculate BMI. Growth Mixture Modelling was used to identify the presence of distinct BMI trajectories.
RESULTS: Four distinct trajectories were identified (i) High Risk Overweight; (ii) Early Onset Overweight; (iii) Later Onset Overweight and (iv) Healthy Weight. Further analyses indicated that factors such as parental overweight, parent education, parent smoking and child birth weight were significant predictors of these trajectories.
CONCLUSION: These findings indicate that different patterns of BMI development exist in children, which may require tailored interventions.