Associations between Body Mass Index Trajectories in the first two years of life and Allergic Rhinitis, Eczema and Food Allergy outcomes up to early adulthood

Background Early life body mass index (BMI) trajectories influence the risk of asthma at 18 years of age. However, it is unclear if these are also associated with other allergic diseases. Objectives We investigated the associations between BMI trajectories and subsequent allergic rhinitis, eczema and food sensitisation/allergies. Methods Parent-reported anthropometric data were collected 18 times in the first two years of life from a cohort of 620 participants in a high-risk cohort. Group-based trajectory modelling was applied to develop BMI trajectories. Associations between trajectories and allergic rhinitis, eczema and food sensitisation at 6, 12 and 18 years of age were assessed using logistic regression models. Potential effect modifications by parental allergic disease, sex and allocated infant formula were assessed. Results We identified five BMI trajectories: average, below average, persistently low, early low and catch up, and persistently high. None showed an association with allergic rhinitis. In participants with maternal allergic rhinitis, 'early-low and catch-up' (OR = 2.83;95%CI 1.34-5.96, P-int = 0.05) and 'below average' trajectories (OR = 2.39; 1.18-7.23, P-int = 0.02) were associated with allergic rhinitis at 18 years of age compared with the average trajectory. No associations were observed with eczema or food sensitisation. Conclusion Infants with early-low and catch-up, or below average BMI growth, were at increased risk of allergic rhinitis at 18 years if they had a mother with allergic rhinitis. These results require replication, but suggest that interactions between poor intrauterine growth, failure to thrive and maternal allergies may influence the risk of allergic rhinitis.