Crohn`s disease. Increasing trend in Saudi Arabia.

We attempted, through systematic review to explore the epidemiology and risk factors of Crohn's disease (CD) with special attention to the Kingdom of Saudi Arabia (KSA). We selected articles that contained population-based, epidemiological, and clinical character studies of CD. We collected data concerned with the prevalence, demographic features, and the possible etiology of CD that might explain its emergence in KSA. The prevalence of CD in Western countries ranged between 11-43/100,000 with flawless evidence of CD prevalence emerging in previously low incidence areas like Asia. Prevalence in KSA has markedly increased over the last 3 decades. Combined ileal and colonic involvement was the most frequently affected site. Diet, smoking, drugs, and westernization of life are assumed to contribute to the pathogenesis. There is convincing evidence of CD emerging in Asia, including KSA. Westernization of lifestyle and smoking is probably the major contributing factors. Genetic studies are warranted.