Statistical analysis
All statistical analyses were performed with IBM SPSS Statistics for Windows, Version 28. Due to multiple testing, p-values of <0.001 (two-sided) instead of p<0.05 were considered statistically significant.
Descriptive statistics were used to evaluate and summarize the demographic and clinical characteristics of the participants and the mean scores for the GI Symptom Tracker, GAD-7, PHQ-9 and CFQ-R.
Independent t-tests were used to examine differences in GI symptoms, anxiety, depression, and HRQoL between adults and adolescents. Regression analyses were used to analyse the univariable associations between GI symptoms, anxiety, depression and HRQoL across the two groups. All regression analyses were adjusted for age, gender, BMI and lung function.