Ethnic Differences in the Timing and Incidence of Childhood Health Conditions: Evidence from the Born in Bradford Cohort

Objective To examine ethnic differences in the incidence and age-related trajectories of childhood health conditions from birth to adolescence within a UK birth cohort. Design Longitudinal population-based birth cohort with linkage to primary care electronic health records. Setting Born in Bradford (BiB), a multi-ethnic birth cohort in Bradford, UK. Participants 13,282 children (36% White British, 44% Pakistani British, 20% other ethnicity) born 2007 to 2011 with linked primary care records and over 1 year follow-up. Main outcome measures Incident diagnoses of atopic conditions (asthma, eczema, allergic rhinoconjunctivitis), overweight/obesity, common mental health disorders (anxiety, depression), and neurodevelopmental disorders (including ADHD and autism). Incidence rates, Kaplan-Meier cumulative incidence, and Cox regression hazards ratios (HRs) were estimated. Results Atopic conditions emerged early (median onset 5 to 6 years) and were more common among Pakistani British children, with higher hazards of eczema (HR 2.29, 95% CI 2.01 to 2.61), allergic rhinoconjunctivitis (HR 2.27, 2.00 to 2.58), and asthma (HR 1.35, 1.22 to 1.50). Overweight/ obesity developed later (median 9 to 10 years) and were also more frequent in Pakistani British children (HR 1.25, 1.16 to 1.35). In contrast, common mental health disorders emerged predominantly in early adolescence (median around 13 years), and both mental health and neurodevelopmental diagnoses were more frequently recorded among White British children; Pakistani British children had lower hazards of neurodevelopmental diagnoses (HR 0.28, 0.23 to 0.35) and mental health disorders (HR 0.53, 0.41 to 0.70). Conclusions Ethnic differences in childhood health are condition-specific and vary by age of onset, emerging at distinct stages. These findings inform the timing of prevention, service planning, and research into underlying mechanism.