In our novel study in JAMA Network Open, pediatric patients show signs of impaired weight and height up to 3 years before a diagnosis of CD and up to 1 year before a diagnosis of UC, which indicates impaired nutritional status and/or chronic inflammation occurring even before that. Hence, IBD in children may begin long before it is clinically identified. 
 
This large-scale population study was based on unique measurements of height and weight from birth to school age in 916,133 Danish children.