Inflammatory bowel disease (IBD) encompasses a group of chronic intestinal disorders of unknown cause, characterized by non-specific inflammation, including conditions such as ulcerative colitis (UC) and Crohn’s disease (CD) [1]. The global surge in incidence rates has elevated childhood-onset IBD to a top concern among pediatric gastroenterologists, around 25% of IBD patients first exhibit symptoms before the age of 20 [2]. Among various factors such as genetics, environment, diet and lifestyle, infections, and immunological factors that associated with IBD onset, genetics may play a more significant role in the development of IBD in children and adolescents compared to adults [3–6]. Furthermore, factors such as cesarean delivery, limited exposure to breast milk, high dietary fat intake, and early antibiotic exposure have been identified as potential risk factors for the development of IBD in children and adolescents [7–10]. Studies have shown familial involvement in 20% of children with IBD, and heritability is greater with earlier onset in IBD [6, 11, 12].

Despite the current lack of comprehensive epidemiological studies on pediatric and adolescent IBD, it is undeniable that the burden of IBD among children and adolescents worldwide are on the rise [7, 13]. Some research indicates that in the United States and Canada, the incidence rate of IBD among children is approximately 10 cases per 100,000 children, with a continuing upward trend. Specifically, between 1996 and 2006, the annual incidence rate per 100,000 individuals for CD escalated from 2.2 to 4.3, while for UC, it rose from 1.8 to 4.9 [14, 15]. Compared to IBD in adults, the disease burden of IBD in children and adolescents is more severe, especially early-onset IBD [16]. Owing to the chronic disease progression with currently no cure, IBD not only causes physical, but also mental health, and educational problems for children and adolescents [12]. Due to the unique considerations for children with IBD, the treatment goals for pediatric IBD should focus on controlling symptoms, restoring growth, and preventing delays in puberty [12, 17–19]. This necessitates a different therapeutic approach for pediatric IBD compared to adult IBD. Current research suggests that IBD onset during childhood may represent a more severe symptom than those diagnosed in adults, requiring a higher level of treatment and care [20, 21].

Grasping the overall incidence and trends of IBD among children and adolescents across various global regions is pivotal for etiological studies of IBD and for the strategic distribution of healthcare resources. Our analysis utilized data from the Global Burden of Disease (GBD) study spanning from 1990 to 2019, aiming to delineate the burden of IBD in individuals under 20 years of age on a global scale, across different regions, socio-demographic index (SDI) categories, and countries.

We conducted a comprehensive and detailed analysis of the incidence, prevalence, death, and DALY of IBD among children and adolescents aged 0–19 globally. Our study reveals the burden of IBD among children and adolescents on a global scale, highlighting significant variations in these indicators across different regions and populations. Our results indicate a downward trend in the global burden of disease when countries are classified by SDI. Over the past 30 years, significant progress has been made in treating IBD in children and adolescents worldwide. However, the decline in the burden of disease has been slowest in high SDI regions, suggesting that the measures implemented in these regions may be insufficient, further measures are needed to reduce the burden of IBD in children and adolescents.

A large number of studies have indicated a continuous increase in the incidence and prevalence of adult IBD across various regions [23, 24]. However, epidemiological research on pediatric IBD worldwide has been limited [12]. Although the increase in the incidence and prevalence of IBD among children and adolescents was slight during the study period, the increase in the incidence cases and prevalence cases of IBD in children and adolescents was more than 20% due to the global population growth. In countries and regions level, were found that Canada has the highest incidence rate of pediatric IBD, following closely, Denmark stands as the country with the second-highest incidence rate. In contrast, the incidence rate in Asia, Southern Latin America and Africa were significantly lower. A systematic review reported a similar finding that the highest incidence rate of pediatric IBD were observed in Canada, Northern Europe, and New Zealand, while the lowest were in Southern Europe, Africa, Asia, and South America [25]. Furthermore, our study reveals a positive correlation between the incidence of IBD among children and adolescents and the SDI. Specifically, regions with a high SDI exhibit an incidence rate of 19.39, indicating that higher socio-demographic development is associated with an increased incidence of IBD in this population group [26–28].

Our study found a significant decline in the mortality and DALY associated with IBD among children and adolescents in all SDI regions expect for high SDI region from 1990 to 2019. This decline could likely be attributed to the relatively stable incidence and the use of emerging medications such as immunosuppressants and biologics [23, 27]. Despite high SDI regions having advanced medical technology, the increase in incidence and the rising number of cases have prevented a significant decline in overall DALYs. Compared to IBD in adulthood, the onset of the disease in childhood may present with higher disease activity and a more complex course [12]. When treating children and adolescents with IBD, it is essential to consider the impact of the disease on growth, skeletal health, and psychosocial functioning [29–31]. Although low SDI areas show a clear downward trend in DALYs, they still have the highest overall DALY burden. Our research indicates that in regions with a low SDI, such as sub-Saharan Africa, despite having the lowest incidence rate, they exhibit the highest global DALY, suggesting a significant underemphasis on IBD in children and adolescents in less developed countries, leading to a considerable disease burden. There is currently a lack of clinical evidence related to IBD in children and adolescents, making the treatment and management of these patients more challenging, especially in the low SDI region [12, 29]. Compared to low SDI areas, although the absolute number of DALYs in high SDI areas was lower, the trend in DALYs remained relatively flat during the study period, indicating no significant improvement in disease burden. Countries with high SDI are in the third of four epidemiological phases in the global evolution of IBD, the disease worsening phase. Since IBD is a chronic disease with no cure, as long as the incidence exceeds the mortality rate, the prevalence will steadily increase. Despite the higher level of medical care in high SDI areas, the disease burden remains high due to the increasing number of patients [32]. The imperative to intensify research and clinical attention towards IBD in pediatric and adolescent populations is underscored by the considerable disease burden this group endures. Enhancing the focus on these younger cohorts is essential for both mitigating the immediate impacts of the disease and reducing long-term complications, especially in regions with a higher disease burden.

According to the international diagnostic standards such as the Montreal and Paris classifications, IBD diagnosed before the age of 10 is referred to as early-onset IBD [16, 31]. Early-onset IBD is characterized by early onset, severe disease course, difficult-to-control diarrhea, significant impact on growth and development, frequent severe perianal lesions, and often hidden genetic defects, with earlier onset predicting worse prognosis [33]. Studies have indicated that patients with early-onset IBD may differ in etiology and disease manifestation from non-early-onset pediatric IBD patients [31]. Therefore, in our research, we compared the groups aged 0–9 with those aged 10–14 and 15–19 years. Compared to non-early-onset IBDs, early-onset IBD has a lower incidence rate but higher mortality and DALY rate. Furthermore, compared to other SDI regions, early-onset IBD in low SDI regions has higher mortality and DALY rate. Due to the inflammatory mechanisms of early-onset IBD caused by gene mutations and non-gene mutations are different, conventional immunosuppressants and medications like mesalamine have minimal effect on early-onset IBD caused by genetic mutations [17, 34]. Joinpoint analysis results indicate that the reduction in mortality and DALY rate for early-onset IBD far exceeds that of non-early-onset pediatric IBD, with an AAPC reaching −3.6%. Studies have shown that early-onset IBD patients diagnosed at the initial stages of the disease have relatively better treatment outcomes and require significantly less subsequent healthcare and surgical interventions compared to those diagnosed after the age of 10 [12]. There is still a need to enhance the focus on early-onset IBD, to improve the diagnostic capabilities and enhance the quality of life for patients with early-onset IBD.

This study provides a thorough evaluation of the burden of pediatric IBD from 1990 to 2019, including incidence, prevalence, mortality, and DALY, with an in-depth analysis of early-onset IBD. Pediatric IBD represents a distinct group, and based on our findings, there are significant differences compared to adults, necessitating increased attention in epidemiological, basic, and clinical research. Our work has filled the gap in understanding the disease burden of IBD. Nevertheless, our research has several limitations. First, GBD data do not distinguish between CD and UC, requiring further epidemiological analysis of each subtype [23, 27]. Second, our study is constrained by the inherent limitations related to the GBD study, including the quality and accessibility of the original data. Due to the limited research on pediatric and adolescent IBD, GBD data may exhibit certain biases [22]. Due to the feasibility of data collection, GBD data reflects not only the burden of disease but also the level of local medical care and development. In some underdeveloped areas, data collection can be challenging, particularly for rare diseases such as IBD, which require a high level of medical expertise for diagnosis. In data-scarce locations, GBD had to rely on predictive covariates and spatiotemporal trends. For non-fatal models, where data were especially scarce, estimates for some regions were determined entirely by global trends and associations with income and healthcare access, along with data from a single country. This is reflected in wider UIs in these locations, suggesting that extra caution should be applied when interpreting estimates for these areas. Additionally, with each iteration, the GBD database becomes increasingly refined, enhancing its alignment with real-world conditions. This iterative process continuously improves data quality, making the estimates more reliable over time [27]. Finally, current research categorizes pediatric IBD into neonatal IBD, infantile IBD, very early-onset IBD, and early-onset IBD. However, due to the constraints of GBD data, our focus was solely on early-onset IBD.