Objectives: Seasonal and geographic variations of inflammatory bowel disease (IBD) exacerbations have been described in adults, with inconsistent findings. We sought to determine whether disease activity in pediatric-onset IBD is associated with a seasonal pattern.
Methods: We examined children with Crohn disease (CD) and ulcerative colitis (UC) using data from the ImproveCareNow Collaborative between December 2008 and November 2010. We compared the proportion of patients in continuous remission for all recorded visits in each season. We also compared the distribution of all recorded visits with a physician global assessment (PGA) of remission or active disease across seasons.
Results: A total of 1325 patients with CD (6102 visits) and 587 patients with UC (2394 visits) were included. The proportion of patients with UC in continuous remission during each season was highest in the summer (67%) and lowest in the winter (55%) (P = 0.01). A similar pattern was found for CD but was not significant. Similarly, the proportion of visits in remission was highest in the summer and lowest in the winter for both UC (29%, 21%; P < 0.001) and CD (28%, 23%; P < 0.001); however, the distribution of visits with active disease was not significantly different across seasons.
Conclusions: The higher proportion of patients with UC in continuous remission in the summer may be related to the higher proportion of remission visits in the summer, because the proportion of visits with active disease was similar across seasons. These findings do not support any strong associations between season of the year and disease activity in pediatric IBD.