Inflammatory bowel disease: an expanding global health problem

Abstract

This review provides a summary of the global epidemiology of inflammatory bowel diseases (IBD). It is now clear that IBD is increasing worldwide and has become a global emergence disease. IBD, which includes Crohn's disease (CD) and ulcerative colitis (UC), has been considered a problem in industrial-urbanized societies and attributed largely to a Westernized lifestyle and other associated environmental factors. Its incidence and prevalence in developing countries is steadily rising and has been attributed to the rapid modernization and Westernization of the population. There is a need to reconcile the most appropriate treatment for these patient populations from the perspectives of both disease presentation and cost. In the West, biological agents are the fastest-growing segment of the prescription drug market. These agents cost thousands of dollars per patient per year. The healthcare systems, and certainly the patients, in developing countries will struggle to afford such expensive treatments. The need for biological therapy will inevitably increase dramatically, and the pharmaceutical industry, healthcare providers, patient advocate groups, governments and non-governmental organizations should come to a consensus on how to handle this problem. The evidence that IBD is now affecting a much younger population presents an additional concern. Meta-analyses conducted in patients acquiring IBD at a young age also reveals a trend for their increased risk of developing colorectal cancer (CRC), since the cumulative incidence rates of CRC in IBD-patients diagnosed in childhood are higher than those observed in adults. In addition, IBD-associated CRC has a worse prognosis than sporadic CRC, even when the stage at diagnosis is taken into account. This is consistent with additional evidence that IBD negatively impacts CRC survival. A continuing increase in IBD incidence worldwide associated with childhood-onset of IBD coupled with the diseases' longevity and an increase in oncologic transformation suggest a rising disease burden, morbidity, and healthcare costs. IBD and its associated neoplastic transformation appear inevitable, which may significantly impact pediatric gastroenterology and adult CRC care. Due to an infrastructure gap in terms of access to care between developed vs. developing nations and the uneven representation of IBD across socioeconomic strata, a plan is needed in the developing world regarding how to address this emerging problem.

Keywords: Inflammatory bowel disease; colorectal cancer; industrial-urbanized-societies.

Figure 1

Incidence of reported CD and UC worldwide. Reproduced with permission from the publisher: Rogler et al. Gut. 2012;61:706–712.

Figure 2

Worldwide CD incidence rates and/or prevalence for countries reporting data: (A) before 1960, (B) from 1960 to 1979, and (C) after 1980. Incidence and prevalence values were ranked into quintiles representing low (dark and light blue) to intermediate (green) to high (yellow and red) occurrence of disease. Reproduced with permission from the publisher: Molodecky et al. Gastroenterology. 2012;142:46–54, e42.

Figure 3

Worldwide UC incidence rates and/or prevalence for countries reporting data: (A) before 1960, (B) from 1960 to 1979, and (C) after 1980. Incidence and prevalence values were ranked into quintiles representing low (dark and light blue) to intermediate (green) to high (yellow and red) occurrence of disease. Reproduced with permission from the publisher: Molodecky et al. Gastroenterology. 2012;142:46–54, e42.

Figure 4

Incidence rate of CD by gender and age in Northern France from 1988 to 2007. Reproduced with permission from the publisher: Chouraki et al, Aliment Pharmacol Ther. 2011;33:1133–1142. Study shows a higher newly diagnosed young population between the ages of 4–20 years (shown by arrow on abscissa). Young female is higher than male. The increase in CD in this school-age population can be speculated to be based on the lack of predisposition to environmental factors that can establish a defensive immunity.

Figure 5

Incidence rate of UC by gender and age in Northern France from 1988–2007. Reproduced with permission from the publisher: Chouraki et al, Aliment Pharmacol Ther. 2011;33:1133–1142. This figure represents several observations from current epidemiological studies. Young females are at higher rate than males. The age with highest incidence is 4–20 years of age (shown by arrow on abscissa). The increase in UC in this school-age population can be speculated to be based on the lack of predisposition to environmental factors.