The association between dietary trajectories across childhood and blood pressure in early adolescence: The Longitudinal Study of Australian Children

Background: Cardio-metabolic risk factors, including hypertension, are increasingly appearing in childhood. This study examined associations between dietary trajectories across childhood and subsequent blood pressure (BP) at age 10/11, and whether these associations were explained by BMI or fat mass. Methods: Data from 4360 participants in the Longitudinal Study of Australian Children were analyzed. Dietary scores (0–14) reflected similarity to the Australian Dietary Guidelines. Group-based trajectory modelling identified distinct trajectories from up to four time points between ages 4 and 11. Linear regression assessed associations between trajectories and BP at age 10/11, adjusting for covariates, and additionally for BMI or fat mass. Results: Four dietary trajectories were identified: never healthy (4.3%), moderately healthy (23.1%), becoming less healthy (14.2%), and always healthy (58.4%). Compared with never healthy, the always healthy trajectory was associated with lower systolic BP (-2.19 mmHg; 95% CI -3.78, -0.59) and diastolic BP (-1.71 mmHg; 95% CI -2.95, -0.47) after covariate adjustment. Associations attenuated after adjustment for BMI or fat mass but remained significant for diastolic BP. Conclusions: A dietary trajectory largely aligned with the Australian Dietary Guidelines across childhood was associated with slightly lower BP at age 10/11, not fully explained by BMI or fat mass, supporting early promotion of healthy dietary habits.