Worldwide Incidence of IBD May Be Rising

The incidence of inflammatory bowel disease is on the rise worldwide, particularly in developed regions, Natalie A. Molodecky and colleagues reported in the journal Gastroenterology.

"Because mortality in IBD is low and the disease is most often diagnosed in the young, these findings suggest that the global prevalence of IBD will continue to increase substantially," the authors noted.

The pathogenesis of IBD is not fully understood, but these diseases are thought to occur in genetically susceptible individuals exposed to environmental risk factors. Environmental exposures are markedly different in developed versus underdeveloped regions, the authors noted (Gastroenterology 2011 [doi:10.1053/j.gastro.2011.10.001]).

Ms. Molodecky, then a graduate student at the University of Calgary (Alta.), and associates conducted a systematic literature review that identified 260 studies on the incidence and prevalence of Crohn’s disease (CD) and ulcerative colitis (UC). The studies were culled from searches of two databases: MEDLINE (1950 to December 2010) and EMBASE (1980 to December 2010).

Among the 260 included publications, 238 addressed incidence. Of those, 185 investigated the incidence of CD and 161 studied UC incidence.

Of the 122 prevalence studies, 96 investigated the prevalence of CD and 79 studied UC prevalence.

For both diseases, the majority of the studies were from European regions, followed by Asia and the Middle East, then North America. African and South American regions and nations accounted for a small percentage (5% or less) of both incidence and prevalence studies.

"These findings suggest that the global prevalence of IBD will continue to increase substantially."

The researchers found that in Europe, the annual incidence of UC ranged widely, from 0.6 to 24.3 per 100,000 person-years. In Asia and the Middle East, in contrast, the annual incidence rate for UC varied from 0.11 to 6.3 cases per 100,000 person-years. In North America, which was similar to Europe, incidence ranged from 0 to 19.2 per 100,000 person-years.

Looking at CD, incidence ranged from 0.3 to 12.7 per 100,000 person-years in Europe, 0.04 to 5.0 in Asia and the Middle East, and 0 to 20.2 in North America, wrote the authors.

Prevalence studies also showed great heterogeneity. "UC estimates ranged from 4.9 to 505 per 100,000 in Europe; 4.9 to 168.3 per 100,000 in Asia and the Middle East; and 37.5 to 248.6 per 100,000 in North America," wrote the authors.

Similarly, CD prevalence estimates ranged from 0.6 to 322 per 100,000 at-risk persons in Europe, 0.88 to 67.9 per 100,000 in Asia and the Middle East, and 16.7 to 318.5 per 100,000 in North America.

The researchers also uncovered increasing incidence rates over time. Among those studies that examined incidence rates over time, 75% of the CD studies and 60% of the UC studies showed statistically significant (P less than .05) increases, with average annual percentage changes ranging from 1.2% to 23.3% in CD and 2.4% to 18.1% in UC. In contrast, three UC studies (6%) and no CD studies found statistically significant decreases in incidence over time, they added.

In conclusion, wrote the authors, "Emergence of IBD in traditionally low prevalent regions (e.g., Asia), suggests that the development of IBD may be influenced by environmental risk factors.

"However, this increase could be due to increased awareness of IBD by physicians and the public, as well as advancements in diagnostic methods for IBD," they wrote, adding that future studies should "adjust incidence rates by diagnostic procedure (e.g., colonoscopy) utilization."

The authors conceded that unpublished manuscripts and abstracts were not included in this review, and they were not able to conduct a meta-analysis because of variability in the study design of the included studies. However, they described their research as a comprehensive review of CD and UC prevalence and incidence that spans both time and geography.

The review was funded by the Alberta IBD Consortium. No individual conflicts of interest were disclosed.

The incidence of inflammatory bowel disease is on the rise worldwide, particularly in developed regions, Natalie A. Molodecky and colleagues reported in the journal Gastroenterology.

"Because mortality in IBD is low and the disease is most often diagnosed in the young, these findings suggest that the global prevalence of IBD will continue to increase substantially," the authors noted.

The pathogenesis of IBD is not fully understood, but these diseases are thought to occur in genetically susceptible individuals exposed to environmental risk factors. Environmental exposures are markedly different in developed versus underdeveloped regions, the authors noted (Gastroenterology 2011 [doi:10.1053/j.gastro.2011.10.001]).

Ms. Molodecky, then a graduate student at the University of Calgary (Alta.), and associates conducted a systematic literature review that identified 260 studies on the incidence and prevalence of Crohn’s disease (CD) and ulcerative colitis (UC). The studies were culled from searches of two databases: MEDLINE (1950 to December 2010) and EMBASE (1980 to December 2010).

Among the 260 included publications, 238 addressed incidence. Of those, 185 investigated the incidence of CD and 161 studied UC incidence.

Of the 122 prevalence studies, 96 investigated the prevalence of CD and 79 studied UC prevalence.

For both diseases, the majority of the studies were from European regions, followed by Asia and the Middle East, then North America. African and South American regions and nations accounted for a small percentage (5% or less) of both incidence and prevalence studies.

"These findings suggest that the global prevalence of IBD will continue to increase substantially."

The researchers found that in Europe, the annual incidence of UC ranged widely, from 0.6 to 24.3 per 100,000 person-years. In Asia and the Middle East, in contrast, the annual incidence rate for UC varied from 0.11 to 6.3 cases per 100,000 person-years. In North America, which was similar to Europe, incidence ranged from 0 to 19.2 per 100,000 person-years.

Looking at CD, incidence ranged from 0.3 to 12.7 per 100,000 person-years in Europe, 0.04 to 5.0 in Asia and the Middle East, and 0 to 20.2 in North America, wrote the authors.

Prevalence studies also showed great heterogeneity. "UC estimates ranged from 4.9 to 505 per 100,000 in Europe; 4.9 to 168.3 per 100,000 in Asia and the Middle East; and 37.5 to 248.6 per 100,000 in North America," wrote the authors.

Similarly, CD prevalence estimates ranged from 0.6 to 322 per 100,000 at-risk persons in Europe, 0.88 to 67.9 per 100,000 in Asia and the Middle East, and 16.7 to 318.5 per 100,000 in North America.

The researchers also uncovered increasing incidence rates over time. Among those studies that examined incidence rates over time, 75% of the CD studies and 60% of the UC studies showed statistically significant (P less than .05) increases, with average annual percentage changes ranging from 1.2% to 23.3% in CD and 2.4% to 18.1% in UC. In contrast, three UC studies (6%) and no CD studies found statistically significant decreases in incidence over time, they added.

In conclusion, wrote the authors, "Emergence of IBD in traditionally low prevalent regions (e.g., Asia), suggests that the development of IBD may be influenced by environmental risk factors.

"However, this increase could be due to increased awareness of IBD by physicians and the public, as well as advancements in diagnostic methods for IBD," they wrote, adding that future studies should "adjust incidence rates by diagnostic procedure (e.g., colonoscopy) utilization."

The authors conceded that unpublished manuscripts and abstracts were not included in this review, and they were not able to conduct a meta-analysis because of variability in the study design of the included studies. However, they described their research as a comprehensive review of CD and UC prevalence and incidence that spans both time and geography.

The review was funded by the Alberta IBD Consortium. No individual conflicts of interest were disclosed.

The incidence of inflammatory bowel disease is on the rise worldwide, particularly in developed regions, Natalie A. Molodecky and colleagues reported in the journal Gastroenterology.

"Because mortality in IBD is low and the disease is most often diagnosed in the young, these findings suggest that the global prevalence of IBD will continue to increase substantially," the authors noted.

The pathogenesis of IBD is not fully understood, but these diseases are thought to occur in genetically susceptible individuals exposed to environmental risk factors. Environmental exposures are markedly different in developed versus underdeveloped regions, the authors noted (Gastroenterology 2011 [doi:10.1053/j.gastro.2011.10.001]).

Ms. Molodecky, then a graduate student at the University of Calgary (Alta.), and associates conducted a systematic literature review that identified 260 studies on the incidence and prevalence of Crohn’s disease (CD) and ulcerative colitis (UC). The studies were culled from searches of two databases: MEDLINE (1950 to December 2010) and EMBASE (1980 to December 2010).

Among the 260 included publications, 238 addressed incidence. Of those, 185 investigated the incidence of CD and 161 studied UC incidence.

Of the 122 prevalence studies, 96 investigated the prevalence of CD and 79 studied UC prevalence.

For both diseases, the majority of the studies were from European regions, followed by Asia and the Middle East, then North America. African and South American regions and nations accounted for a small percentage (5% or less) of both incidence and prevalence studies.

"These findings suggest that the global prevalence of IBD will continue to increase substantially."

The researchers found that in Europe, the annual incidence of UC ranged widely, from 0.6 to 24.3 per 100,000 person-years. In Asia and the Middle East, in contrast, the annual incidence rate for UC varied from 0.11 to 6.3 cases per 100,000 person-years. In North America, which was similar to Europe, incidence ranged from 0 to 19.2 per 100,000 person-years.

Looking at CD, incidence ranged from 0.3 to 12.7 per 100,000 person-years in Europe, 0.04 to 5.0 in Asia and the Middle East, and 0 to 20.2 in North America, wrote the authors.

Prevalence studies also showed great heterogeneity. "UC estimates ranged from 4.9 to 505 per 100,000 in Europe; 4.9 to 168.3 per 100,000 in Asia and the Middle East; and 37.5 to 248.6 per 100,000 in North America," wrote the authors.

Similarly, CD prevalence estimates ranged from 0.6 to 322 per 100,000 at-risk persons in Europe, 0.88 to 67.9 per 100,000 in Asia and the Middle East, and 16.7 to 318.5 per 100,000 in North America.

The researchers also uncovered increasing incidence rates over time. Among those studies that examined incidence rates over time, 75% of the CD studies and 60% of the UC studies showed statistically significant (P less than .05) increases, with average annual percentage changes ranging from 1.2% to 23.3% in CD and 2.4% to 18.1% in UC. In contrast, three UC studies (6%) and no CD studies found statistically significant decreases in incidence over time, they added.

In conclusion, wrote the authors, "Emergence of IBD in traditionally low prevalent regions (e.g., Asia), suggests that the development of IBD may be influenced by environmental risk factors.

"However, this increase could be due to increased awareness of IBD by physicians and the public, as well as advancements in diagnostic methods for IBD," they wrote, adding that future studies should "adjust incidence rates by diagnostic procedure (e.g., colonoscopy) utilization."

The authors conceded that unpublished manuscripts and abstracts were not included in this review, and they were not able to conduct a meta-analysis because of variability in the study design of the included studies. However, they described their research as a comprehensive review of CD and UC prevalence and incidence that spans both time and geography.

The review was funded by the Alberta IBD Consortium. No individual conflicts of interest were disclosed.