Early life and socio-economic determinants of dietary trajectories in infancy and early childhood - results from the HSHK birth cohort study

Background Early childhood is a period when dietary behaviours are established. This study aimed to examine the longitudinal intake of core and discretionary foods and identify early life and socio-economic factors influencing those intakes. Methods Mother-infant dyads (n = 934) from the Healthy Smiles Healthy Kids study, an ongoing birth cohort study, were interviewed. The information on 'weekly frequency of core and discretionary foods intake' using a food frequency questionnaire was collected at 4 months, 8 months, 1 year, 2 years and 3 years age points. Group-based trajectory modelling analyses were performed to identify diet trajectories for 'core' and 'discretionary' foods respectively. A multinomial logistic regression was performed to identify the maternal and child-related predictors of resulting trajectories. Results The intake of core and discretionary foods each showed distinct quadratic (n = 3) trajectories with age. Overall, core foods intake increased rapidly in the first year of life, followed by a decline after age two, whereas discretionary foods intake increased steadily across the five age points. Multiparity (Relative Risk (RR): 0.46, 95%CI: 0.27-0.77), non-English speaking ethnicity of mother (RR: 0.66, 95%CI: 0.47-0.91) and having a single mother (RR: 0.40, 95%CI: 0.18-0.85) were associated with low trajectories of core foods intake whereas older maternal age (RR: 1.05, 95%CI: 1.01-1.08) and longer breastfeeding duration (RR: 1.02, 95%CI: 1.00-1.03) were associated with higher trajectories of core foods intake. Also, multiparity (RR 2.63, 95%CI: 1.47-4.70), low maternal education (RR 3.01, 95%CI: 1.61-5.65), and socio-economic disadvantage (RR 2.69, 95%CI: 1.31-5.55) were associated with high trajectories of discretionary foods intake. Conversely, longer duration of breastfeeding (RR 0.99, 95%CI: 0.97-0.99), and timely introduction of complementary foods (RR 0.30, 95%CI: 0.15-0.61) had a protective effect against high discretionary foods consumption in infancy and early childhood. Conclusion Children's frequency of discretionary foods intake increases markedly as they transition from infancy to preschool age, and the trajectories of intake established during early childhood are strongly influenced by socio-demographic factors and infant feeding choices. Hence, there is a need for targeted strategies to improve nutrition in early childhood and ultimately prevent the incidence of chronic diseases in children.